]>
Commit | Line | Data |
---|---|---|
8d8da227 | 1 | @c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1996, 1998, 1999, 2000, 2001, |
770da00a | 2 | @c 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 |
66647d44 | 3 | @c Free Software Foundation, Inc. |
9a8ce21f | 4 | |
c1f7febf RK |
5 | @c This is part of the GCC manual. |
6 | @c For copying conditions, see the file gcc.texi. | |
7 | ||
8 | @node C Extensions | |
9 | @chapter Extensions to the C Language Family | |
10 | @cindex extensions, C language | |
11 | @cindex C language extensions | |
12 | ||
84330467 | 13 | @opindex pedantic |
161d7b59 | 14 | GNU C provides several language features not found in ISO standard C@. |
f0523f02 | 15 | (The @option{-pedantic} option directs GCC to print a warning message if |
c1f7febf RK |
16 | any of these features is used.) To test for the availability of these |
17 | features in conditional compilation, check for a predefined macro | |
161d7b59 | 18 | @code{__GNUC__}, which is always defined under GCC@. |
c1f7febf | 19 | |
161d7b59 | 20 | These extensions are available in C and Objective-C@. Most of them are |
c1f7febf RK |
21 | also available in C++. @xref{C++ Extensions,,Extensions to the |
22 | C++ Language}, for extensions that apply @emph{only} to C++. | |
23 | ||
7e1542b9 MLI |
24 | Some features that are in ISO C99 but not C90 or C++ are also, as |
25 | extensions, accepted by GCC in C90 mode and in C++. | |
5490d604 | 26 | |
c1f7febf RK |
27 | @menu |
28 | * Statement Exprs:: Putting statements and declarations inside expressions. | |
14e33ee8 | 29 | * Local Labels:: Labels local to a block. |
c1f7febf RK |
30 | * Labels as Values:: Getting pointers to labels, and computed gotos. |
31 | * Nested Functions:: As in Algol and Pascal, lexical scoping of functions. | |
6ccde948 | 32 | * Constructing Calls:: Dispatching a call to another function. |
c1f7febf | 33 | * Typeof:: @code{typeof}: referring to the type of an expression. |
c1f7febf | 34 | * Conditionals:: Omitting the middle operand of a @samp{?:} expression. |
6ccde948 | 35 | * Long Long:: Double-word integers---@code{long long int}. |
a6766312 | 36 | * __int128:: 128-bit integers---@code{__int128}. |
c1f7febf | 37 | * Complex:: Data types for complex numbers. |
c77cd3d1 | 38 | * Floating Types:: Additional Floating Types. |
0fd8c3ad | 39 | * Half-Precision:: Half-Precision Floating Point. |
ff2ce160 | 40 | * Decimal Float:: Decimal Floating Types. |
6f4d7222 | 41 | * Hex Floats:: Hexadecimal floating-point constants. |
0f996086 | 42 | * Fixed-Point:: Fixed-Point Types. |
09e881c9 | 43 | * Named Address Spaces::Named address spaces. |
c1f7febf RK |
44 | * Zero Length:: Zero-length arrays. |
45 | * Variable Length:: Arrays whose length is computed at run time. | |
ba05abd3 | 46 | * Empty Structures:: Structures with no members. |
6ccde948 | 47 | * Variadic Macros:: Macros with a variable number of arguments. |
ccd96f0a | 48 | * Escaped Newlines:: Slightly looser rules for escaped newlines. |
c1f7febf RK |
49 | * Subscripting:: Any array can be subscripted, even if not an lvalue. |
50 | * Pointer Arith:: Arithmetic on @code{void}-pointers and function pointers. | |
51 | * Initializers:: Non-constant initializers. | |
4b404517 | 52 | * Compound Literals:: Compound literals give structures, unions |
6ccde948 RW |
53 | or arrays as values. |
54 | * Designated Inits:: Labeling elements of initializers. | |
c1f7febf | 55 | * Cast to Union:: Casting to union type from any member of the union. |
6ccde948 RW |
56 | * Case Ranges:: `case 1 ... 9' and such. |
57 | * Mixed Declarations:: Mixing declarations and code. | |
c1f7febf | 58 | * Function Attributes:: Declaring that functions have no side effects, |
6ccde948 | 59 | or that they can never return. |
2c5e91d2 | 60 | * Attribute Syntax:: Formal syntax for attributes. |
c1f7febf RK |
61 | * Function Prototypes:: Prototype declarations and old-style definitions. |
62 | * C++ Comments:: C++ comments are recognized. | |
63 | * Dollar Signs:: Dollar sign is allowed in identifiers. | |
64 | * Character Escapes:: @samp{\e} stands for the character @key{ESC}. | |
6ccde948 RW |
65 | * Variable Attributes:: Specifying attributes of variables. |
66 | * Type Attributes:: Specifying attributes of types. | |
c1f7febf RK |
67 | * Alignment:: Inquiring about the alignment of a type or variable. |
68 | * Inline:: Defining inline functions (as fast as macros). | |
8f0fe813 | 69 | * Volatiles:: What constitutes an access to a volatile object. |
c1f7febf | 70 | * Extended Asm:: Assembler instructions with C expressions as operands. |
6ccde948 | 71 | (With them you can define ``built-in'' functions.) |
c1f7febf RK |
72 | * Constraints:: Constraints for asm operands |
73 | * Asm Labels:: Specifying the assembler name to use for a C symbol. | |
74 | * Explicit Reg Vars:: Defining variables residing in specified registers. | |
75 | * Alternate Keywords:: @code{__const__}, @code{__asm__}, etc., for header files. | |
76 | * Incomplete Enums:: @code{enum foo;}, with details to follow. | |
6ccde948 RW |
77 | * Function Names:: Printable strings which are the name of the current |
78 | function. | |
c1f7febf | 79 | * Return Address:: Getting the return or frame address of a function. |
1255c85c | 80 | * Vector Extensions:: Using vector instructions through built-in functions. |
7a3ea201 | 81 | * Offsetof:: Special syntax for implementing @code{offsetof}. |
86951993 AM |
82 | * __sync Builtins:: Legacy built-in functions for atomic memory access. |
83 | * __atomic Builtins:: Atomic built-in functions with memory model. | |
10a0d495 JJ |
84 | * Object Size Checking:: Built-in functions for limited buffer overflow |
85 | checking. | |
c5c76735 | 86 | * Other Builtins:: Other built-in functions. |
0975678f | 87 | * Target Builtins:: Built-in functions specific to particular targets. |
a2bec818 | 88 | * Target Format Checks:: Format checks specific to particular targets. |
0168a849 | 89 | * Pragmas:: Pragmas accepted by GCC. |
b11cc610 | 90 | * Unnamed Fields:: Unnamed struct/union fields within structs/unions. |
3d78f2e9 | 91 | * Thread-Local:: Per-thread variables. |
f7fd775f | 92 | * Binary constants:: Binary constants using the @samp{0b} prefix. |
c1f7febf | 93 | @end menu |
c1f7febf RK |
94 | |
95 | @node Statement Exprs | |
96 | @section Statements and Declarations in Expressions | |
97 | @cindex statements inside expressions | |
98 | @cindex declarations inside expressions | |
99 | @cindex expressions containing statements | |
100 | @cindex macros, statements in expressions | |
101 | ||
102 | @c the above section title wrapped and causes an underfull hbox.. i | |
103 | @c changed it from "within" to "in". --mew 4feb93 | |
c1f7febf | 104 | A compound statement enclosed in parentheses may appear as an expression |
161d7b59 | 105 | in GNU C@. This allows you to use loops, switches, and local variables |
c1f7febf RK |
106 | within an expression. |
107 | ||
108 | Recall that a compound statement is a sequence of statements surrounded | |
109 | by braces; in this construct, parentheses go around the braces. For | |
110 | example: | |
111 | ||
3ab51846 | 112 | @smallexample |
c1f7febf RK |
113 | (@{ int y = foo (); int z; |
114 | if (y > 0) z = y; | |
115 | else z = - y; | |
116 | z; @}) | |
3ab51846 | 117 | @end smallexample |
c1f7febf RK |
118 | |
119 | @noindent | |
120 | is a valid (though slightly more complex than necessary) expression | |
121 | for the absolute value of @code{foo ()}. | |
122 | ||
123 | The last thing in the compound statement should be an expression | |
124 | followed by a semicolon; the value of this subexpression serves as the | |
125 | value of the entire construct. (If you use some other kind of statement | |
126 | last within the braces, the construct has type @code{void}, and thus | |
127 | effectively no value.) | |
128 | ||
129 | This feature is especially useful in making macro definitions ``safe'' (so | |
130 | that they evaluate each operand exactly once). For example, the | |
131 | ``maximum'' function is commonly defined as a macro in standard C as | |
132 | follows: | |
133 | ||
3ab51846 | 134 | @smallexample |
c1f7febf | 135 | #define max(a,b) ((a) > (b) ? (a) : (b)) |
3ab51846 | 136 | @end smallexample |
c1f7febf RK |
137 | |
138 | @noindent | |
139 | @cindex side effects, macro argument | |
140 | But this definition computes either @var{a} or @var{b} twice, with bad | |
141 | results if the operand has side effects. In GNU C, if you know the | |
962e6e00 | 142 | type of the operands (here taken as @code{int}), you can define |
c1f7febf RK |
143 | the macro safely as follows: |
144 | ||
3ab51846 | 145 | @smallexample |
c1f7febf RK |
146 | #define maxint(a,b) \ |
147 | (@{int _a = (a), _b = (b); _a > _b ? _a : _b; @}) | |
3ab51846 | 148 | @end smallexample |
c1f7febf RK |
149 | |
150 | Embedded statements are not allowed in constant expressions, such as | |
c771326b | 151 | the value of an enumeration constant, the width of a bit-field, or |
c1f7febf RK |
152 | the initial value of a static variable. |
153 | ||
154 | If you don't know the type of the operand, you can still do this, but you | |
95f79357 | 155 | must use @code{typeof} (@pxref{Typeof}). |
c1f7febf | 156 | |
a5bcc582 NS |
157 | In G++, the result value of a statement expression undergoes array and |
158 | function pointer decay, and is returned by value to the enclosing | |
8a36672b | 159 | expression. For instance, if @code{A} is a class, then |
b98e139b | 160 | |
a5bcc582 NS |
161 | @smallexample |
162 | A a; | |
b98e139b | 163 | |
a5bcc582 NS |
164 | (@{a;@}).Foo () |
165 | @end smallexample | |
b98e139b MM |
166 | |
167 | @noindent | |
a5bcc582 NS |
168 | will construct a temporary @code{A} object to hold the result of the |
169 | statement expression, and that will be used to invoke @code{Foo}. | |
170 | Therefore the @code{this} pointer observed by @code{Foo} will not be the | |
171 | address of @code{a}. | |
172 | ||
173 | Any temporaries created within a statement within a statement expression | |
174 | will be destroyed at the statement's end. This makes statement | |
175 | expressions inside macros slightly different from function calls. In | |
176 | the latter case temporaries introduced during argument evaluation will | |
177 | be destroyed at the end of the statement that includes the function | |
178 | call. In the statement expression case they will be destroyed during | |
179 | the statement expression. For instance, | |
b98e139b | 180 | |
a5bcc582 NS |
181 | @smallexample |
182 | #define macro(a) (@{__typeof__(a) b = (a); b + 3; @}) | |
183 | template<typename T> T function(T a) @{ T b = a; return b + 3; @} | |
184 | ||
185 | void foo () | |
186 | @{ | |
187 | macro (X ()); | |
188 | function (X ()); | |
189 | @} | |
190 | @end smallexample | |
b98e139b MM |
191 | |
192 | @noindent | |
a5bcc582 NS |
193 | will have different places where temporaries are destroyed. For the |
194 | @code{macro} case, the temporary @code{X} will be destroyed just after | |
195 | the initialization of @code{b}. In the @code{function} case that | |
196 | temporary will be destroyed when the function returns. | |
b98e139b MM |
197 | |
198 | These considerations mean that it is probably a bad idea to use | |
199 | statement-expressions of this form in header files that are designed to | |
54e1d3a6 MM |
200 | work with C++. (Note that some versions of the GNU C Library contained |
201 | header files using statement-expression that lead to precisely this | |
202 | bug.) | |
b98e139b | 203 | |
16ef3acc JM |
204 | Jumping into a statement expression with @code{goto} or using a |
205 | @code{switch} statement outside the statement expression with a | |
206 | @code{case} or @code{default} label inside the statement expression is | |
207 | not permitted. Jumping into a statement expression with a computed | |
208 | @code{goto} (@pxref{Labels as Values}) yields undefined behavior. | |
209 | Jumping out of a statement expression is permitted, but if the | |
210 | statement expression is part of a larger expression then it is | |
211 | unspecified which other subexpressions of that expression have been | |
212 | evaluated except where the language definition requires certain | |
213 | subexpressions to be evaluated before or after the statement | |
214 | expression. In any case, as with a function call the evaluation of a | |
215 | statement expression is not interleaved with the evaluation of other | |
216 | parts of the containing expression. For example, | |
217 | ||
218 | @smallexample | |
219 | foo (), ((@{ bar1 (); goto a; 0; @}) + bar2 ()), baz(); | |
220 | @end smallexample | |
221 | ||
222 | @noindent | |
223 | will call @code{foo} and @code{bar1} and will not call @code{baz} but | |
224 | may or may not call @code{bar2}. If @code{bar2} is called, it will be | |
225 | called after @code{foo} and before @code{bar1} | |
226 | ||
c1f7febf RK |
227 | @node Local Labels |
228 | @section Locally Declared Labels | |
229 | @cindex local labels | |
230 | @cindex macros, local labels | |
231 | ||
14e33ee8 | 232 | GCC allows you to declare @dfn{local labels} in any nested block |
8a36672b | 233 | scope. A local label is just like an ordinary label, but you can |
14e33ee8 | 234 | only reference it (with a @code{goto} statement, or by taking its |
daf2f129 | 235 | address) within the block in which it was declared. |
c1f7febf RK |
236 | |
237 | A local label declaration looks like this: | |
238 | ||
3ab51846 | 239 | @smallexample |
c1f7febf | 240 | __label__ @var{label}; |
3ab51846 | 241 | @end smallexample |
c1f7febf RK |
242 | |
243 | @noindent | |
244 | or | |
245 | ||
3ab51846 | 246 | @smallexample |
0d893a63 | 247 | __label__ @var{label1}, @var{label2}, /* @r{@dots{}} */; |
3ab51846 | 248 | @end smallexample |
c1f7febf | 249 | |
14e33ee8 ZW |
250 | Local label declarations must come at the beginning of the block, |
251 | before any ordinary declarations or statements. | |
c1f7febf RK |
252 | |
253 | The label declaration defines the label @emph{name}, but does not define | |
254 | the label itself. You must do this in the usual way, with | |
255 | @code{@var{label}:}, within the statements of the statement expression. | |
256 | ||
14e33ee8 ZW |
257 | The local label feature is useful for complex macros. If a macro |
258 | contains nested loops, a @code{goto} can be useful for breaking out of | |
259 | them. However, an ordinary label whose scope is the whole function | |
260 | cannot be used: if the macro can be expanded several times in one | |
261 | function, the label will be multiply defined in that function. A | |
262 | local label avoids this problem. For example: | |
263 | ||
3ab51846 | 264 | @smallexample |
14e33ee8 ZW |
265 | #define SEARCH(value, array, target) \ |
266 | do @{ \ | |
267 | __label__ found; \ | |
268 | typeof (target) _SEARCH_target = (target); \ | |
269 | typeof (*(array)) *_SEARCH_array = (array); \ | |
270 | int i, j; \ | |
271 | int value; \ | |
272 | for (i = 0; i < max; i++) \ | |
273 | for (j = 0; j < max; j++) \ | |
274 | if (_SEARCH_array[i][j] == _SEARCH_target) \ | |
275 | @{ (value) = i; goto found; @} \ | |
276 | (value) = -1; \ | |
277 | found:; \ | |
278 | @} while (0) | |
3ab51846 | 279 | @end smallexample |
14e33ee8 ZW |
280 | |
281 | This could also be written using a statement-expression: | |
c1f7febf | 282 | |
3ab51846 | 283 | @smallexample |
c1f7febf | 284 | #define SEARCH(array, target) \ |
310668e8 | 285 | (@{ \ |
c1f7febf RK |
286 | __label__ found; \ |
287 | typeof (target) _SEARCH_target = (target); \ | |
288 | typeof (*(array)) *_SEARCH_array = (array); \ | |
289 | int i, j; \ | |
290 | int value; \ | |
291 | for (i = 0; i < max; i++) \ | |
292 | for (j = 0; j < max; j++) \ | |
293 | if (_SEARCH_array[i][j] == _SEARCH_target) \ | |
310668e8 | 294 | @{ value = i; goto found; @} \ |
c1f7febf RK |
295 | value = -1; \ |
296 | found: \ | |
297 | value; \ | |
298 | @}) | |
3ab51846 | 299 | @end smallexample |
c1f7febf | 300 | |
14e33ee8 ZW |
301 | Local label declarations also make the labels they declare visible to |
302 | nested functions, if there are any. @xref{Nested Functions}, for details. | |
303 | ||
c1f7febf RK |
304 | @node Labels as Values |
305 | @section Labels as Values | |
306 | @cindex labels as values | |
307 | @cindex computed gotos | |
308 | @cindex goto with computed label | |
309 | @cindex address of a label | |
310 | ||
311 | You can get the address of a label defined in the current function | |
312 | (or a containing function) with the unary operator @samp{&&}. The | |
313 | value has type @code{void *}. This value is a constant and can be used | |
314 | wherever a constant of that type is valid. For example: | |
315 | ||
3ab51846 | 316 | @smallexample |
c1f7febf | 317 | void *ptr; |
0d893a63 | 318 | /* @r{@dots{}} */ |
c1f7febf | 319 | ptr = &&foo; |
3ab51846 | 320 | @end smallexample |
c1f7febf RK |
321 | |
322 | To use these values, you need to be able to jump to one. This is done | |
323 | with the computed goto statement@footnote{The analogous feature in | |
324 | Fortran is called an assigned goto, but that name seems inappropriate in | |
325 | C, where one can do more than simply store label addresses in label | |
326 | variables.}, @code{goto *@var{exp};}. For example, | |
327 | ||
3ab51846 | 328 | @smallexample |
c1f7febf | 329 | goto *ptr; |
3ab51846 | 330 | @end smallexample |
c1f7febf RK |
331 | |
332 | @noindent | |
333 | Any expression of type @code{void *} is allowed. | |
334 | ||
335 | One way of using these constants is in initializing a static array that | |
336 | will serve as a jump table: | |
337 | ||
3ab51846 | 338 | @smallexample |
c1f7febf | 339 | static void *array[] = @{ &&foo, &&bar, &&hack @}; |
3ab51846 | 340 | @end smallexample |
c1f7febf RK |
341 | |
342 | Then you can select a label with indexing, like this: | |
343 | ||
3ab51846 | 344 | @smallexample |
c1f7febf | 345 | goto *array[i]; |
3ab51846 | 346 | @end smallexample |
c1f7febf RK |
347 | |
348 | @noindent | |
349 | Note that this does not check whether the subscript is in bounds---array | |
350 | indexing in C never does that. | |
351 | ||
352 | Such an array of label values serves a purpose much like that of the | |
353 | @code{switch} statement. The @code{switch} statement is cleaner, so | |
354 | use that rather than an array unless the problem does not fit a | |
355 | @code{switch} statement very well. | |
356 | ||
357 | Another use of label values is in an interpreter for threaded code. | |
358 | The labels within the interpreter function can be stored in the | |
359 | threaded code for super-fast dispatching. | |
360 | ||
02f52e19 | 361 | You may not use this mechanism to jump to code in a different function. |
47620e09 | 362 | If you do that, totally unpredictable things will happen. The best way to |
c1f7febf RK |
363 | avoid this is to store the label address only in automatic variables and |
364 | never pass it as an argument. | |
365 | ||
47620e09 RH |
366 | An alternate way to write the above example is |
367 | ||
3ab51846 | 368 | @smallexample |
310668e8 JM |
369 | static const int array[] = @{ &&foo - &&foo, &&bar - &&foo, |
370 | &&hack - &&foo @}; | |
47620e09 | 371 | goto *(&&foo + array[i]); |
3ab51846 | 372 | @end smallexample |
47620e09 RH |
373 | |
374 | @noindent | |
375 | This is more friendly to code living in shared libraries, as it reduces | |
376 | the number of dynamic relocations that are needed, and by consequence, | |
377 | allows the data to be read-only. | |
378 | ||
86631ea3 MJ |
379 | The @code{&&foo} expressions for the same label might have different |
380 | values if the containing function is inlined or cloned. If a program | |
381 | relies on them being always the same, | |
382 | @code{__attribute__((__noinline__,__noclone__))} should be used to | |
383 | prevent inlining and cloning. If @code{&&foo} is used in a static | |
384 | variable initializer, inlining and cloning is forbidden. | |
2092ee7d | 385 | |
c1f7febf RK |
386 | @node Nested Functions |
387 | @section Nested Functions | |
388 | @cindex nested functions | |
389 | @cindex downward funargs | |
390 | @cindex thunks | |
391 | ||
392 | A @dfn{nested function} is a function defined inside another function. | |
393 | (Nested functions are not supported for GNU C++.) The nested function's | |
394 | name is local to the block where it is defined. For example, here we | |
395 | define a nested function named @code{square}, and call it twice: | |
396 | ||
3ab51846 | 397 | @smallexample |
c1f7febf RK |
398 | @group |
399 | foo (double a, double b) | |
400 | @{ | |
401 | double square (double z) @{ return z * z; @} | |
402 | ||
403 | return square (a) + square (b); | |
404 | @} | |
405 | @end group | |
3ab51846 | 406 | @end smallexample |
c1f7febf RK |
407 | |
408 | The nested function can access all the variables of the containing | |
409 | function that are visible at the point of its definition. This is | |
410 | called @dfn{lexical scoping}. For example, here we show a nested | |
411 | function which uses an inherited variable named @code{offset}: | |
412 | ||
3ab51846 | 413 | @smallexample |
aee96fe9 | 414 | @group |
c1f7febf RK |
415 | bar (int *array, int offset, int size) |
416 | @{ | |
417 | int access (int *array, int index) | |
418 | @{ return array[index + offset]; @} | |
419 | int i; | |
0d893a63 | 420 | /* @r{@dots{}} */ |
c1f7febf | 421 | for (i = 0; i < size; i++) |
0d893a63 | 422 | /* @r{@dots{}} */ access (array, i) /* @r{@dots{}} */ |
c1f7febf | 423 | @} |
aee96fe9 | 424 | @end group |
3ab51846 | 425 | @end smallexample |
c1f7febf RK |
426 | |
427 | Nested function definitions are permitted within functions in the places | |
475b6e22 JM |
428 | where variable definitions are allowed; that is, in any block, mixed |
429 | with the other declarations and statements in the block. | |
c1f7febf RK |
430 | |
431 | It is possible to call the nested function from outside the scope of its | |
432 | name by storing its address or passing the address to another function: | |
433 | ||
3ab51846 | 434 | @smallexample |
c1f7febf RK |
435 | hack (int *array, int size) |
436 | @{ | |
437 | void store (int index, int value) | |
438 | @{ array[index] = value; @} | |
439 | ||
440 | intermediate (store, size); | |
441 | @} | |
3ab51846 | 442 | @end smallexample |
c1f7febf RK |
443 | |
444 | Here, the function @code{intermediate} receives the address of | |
445 | @code{store} as an argument. If @code{intermediate} calls @code{store}, | |
446 | the arguments given to @code{store} are used to store into @code{array}. | |
447 | But this technique works only so long as the containing function | |
448 | (@code{hack}, in this example) does not exit. | |
449 | ||
450 | If you try to call the nested function through its address after the | |
451 | containing function has exited, all hell will break loose. If you try | |
452 | to call it after a containing scope level has exited, and if it refers | |
453 | to some of the variables that are no longer in scope, you may be lucky, | |
454 | but it's not wise to take the risk. If, however, the nested function | |
455 | does not refer to anything that has gone out of scope, you should be | |
456 | safe. | |
457 | ||
9c34dbbf | 458 | GCC implements taking the address of a nested function using a technique |
ff2ce160 | 459 | called @dfn{trampolines}. This technique was described in |
63a26b78 SL |
460 | @cite{Lexical Closures for C++} (Thomas M. Breuel, USENIX |
461 | C++ Conference Proceedings, October 17-21, 1988). | |
c1f7febf RK |
462 | |
463 | A nested function can jump to a label inherited from a containing | |
464 | function, provided the label was explicitly declared in the containing | |
465 | function (@pxref{Local Labels}). Such a jump returns instantly to the | |
466 | containing function, exiting the nested function which did the | |
467 | @code{goto} and any intermediate functions as well. Here is an example: | |
468 | ||
3ab51846 | 469 | @smallexample |
c1f7febf RK |
470 | @group |
471 | bar (int *array, int offset, int size) | |
472 | @{ | |
473 | __label__ failure; | |
474 | int access (int *array, int index) | |
475 | @{ | |
476 | if (index > size) | |
477 | goto failure; | |
478 | return array[index + offset]; | |
479 | @} | |
480 | int i; | |
0d893a63 | 481 | /* @r{@dots{}} */ |
c1f7febf | 482 | for (i = 0; i < size; i++) |
0d893a63 MK |
483 | /* @r{@dots{}} */ access (array, i) /* @r{@dots{}} */ |
484 | /* @r{@dots{}} */ | |
c1f7febf RK |
485 | return 0; |
486 | ||
487 | /* @r{Control comes here from @code{access} | |
488 | if it detects an error.} */ | |
489 | failure: | |
490 | return -1; | |
491 | @} | |
492 | @end group | |
3ab51846 | 493 | @end smallexample |
c1f7febf | 494 | |
28697267 DJ |
495 | A nested function always has no linkage. Declaring one with |
496 | @code{extern} or @code{static} is erroneous. If you need to declare the nested function | |
c1f7febf RK |
497 | before its definition, use @code{auto} (which is otherwise meaningless |
498 | for function declarations). | |
499 | ||
3ab51846 | 500 | @smallexample |
c1f7febf RK |
501 | bar (int *array, int offset, int size) |
502 | @{ | |
503 | __label__ failure; | |
504 | auto int access (int *, int); | |
0d893a63 | 505 | /* @r{@dots{}} */ |
c1f7febf RK |
506 | int access (int *array, int index) |
507 | @{ | |
508 | if (index > size) | |
509 | goto failure; | |
510 | return array[index + offset]; | |
511 | @} | |
0d893a63 | 512 | /* @r{@dots{}} */ |
c1f7febf | 513 | @} |
3ab51846 | 514 | @end smallexample |
c1f7febf RK |
515 | |
516 | @node Constructing Calls | |
517 | @section Constructing Function Calls | |
518 | @cindex constructing calls | |
519 | @cindex forwarding calls | |
520 | ||
521 | Using the built-in functions described below, you can record | |
522 | the arguments a function received, and call another function | |
523 | with the same arguments, without knowing the number or types | |
524 | of the arguments. | |
525 | ||
526 | You can also record the return value of that function call, | |
527 | and later return that value, without knowing what data type | |
528 | the function tried to return (as long as your caller expects | |
529 | that data type). | |
530 | ||
6429bc7c EB |
531 | However, these built-in functions may interact badly with some |
532 | sophisticated features or other extensions of the language. It | |
533 | is, therefore, not recommended to use them outside very simple | |
534 | functions acting as mere forwarders for their arguments. | |
535 | ||
84330467 JM |
536 | @deftypefn {Built-in Function} {void *} __builtin_apply_args () |
537 | This built-in function returns a pointer to data | |
c1f7febf RK |
538 | describing how to perform a call with the same arguments as were passed |
539 | to the current function. | |
540 | ||
541 | The function saves the arg pointer register, structure value address, | |
542 | and all registers that might be used to pass arguments to a function | |
543 | into a block of memory allocated on the stack. Then it returns the | |
544 | address of that block. | |
84330467 | 545 | @end deftypefn |
c1f7febf | 546 | |
84330467 JM |
547 | @deftypefn {Built-in Function} {void *} __builtin_apply (void (*@var{function})(), void *@var{arguments}, size_t @var{size}) |
548 | This built-in function invokes @var{function} | |
549 | with a copy of the parameters described by @var{arguments} | |
550 | and @var{size}. | |
c1f7febf RK |
551 | |
552 | The value of @var{arguments} should be the value returned by | |
553 | @code{__builtin_apply_args}. The argument @var{size} specifies the size | |
554 | of the stack argument data, in bytes. | |
555 | ||
84330467 | 556 | This function returns a pointer to data describing |
c1f7febf RK |
557 | how to return whatever value was returned by @var{function}. The data |
558 | is saved in a block of memory allocated on the stack. | |
559 | ||
560 | It is not always simple to compute the proper value for @var{size}. The | |
561 | value is used by @code{__builtin_apply} to compute the amount of data | |
562 | that should be pushed on the stack and copied from the incoming argument | |
563 | area. | |
84330467 | 564 | @end deftypefn |
c1f7febf | 565 | |
84330467 | 566 | @deftypefn {Built-in Function} {void} __builtin_return (void *@var{result}) |
c1f7febf RK |
567 | This built-in function returns the value described by @var{result} from |
568 | the containing function. You should specify, for @var{result}, a value | |
569 | returned by @code{__builtin_apply}. | |
84330467 | 570 | @end deftypefn |
c1f7febf | 571 | |
ab940b73 | 572 | @deftypefn {Built-in Function} {} __builtin_va_arg_pack () |
6ef5231b JJ |
573 | This built-in function represents all anonymous arguments of an inline |
574 | function. It can be used only in inline functions which will be always | |
575 | inlined, never compiled as a separate function, such as those using | |
576 | @code{__attribute__ ((__always_inline__))} or | |
577 | @code{__attribute__ ((__gnu_inline__))} extern inline functions. | |
578 | It must be only passed as last argument to some other function | |
579 | with variable arguments. This is useful for writing small wrapper | |
580 | inlines for variable argument functions, when using preprocessor | |
581 | macros is undesirable. For example: | |
582 | @smallexample | |
583 | extern int myprintf (FILE *f, const char *format, ...); | |
584 | extern inline __attribute__ ((__gnu_inline__)) int | |
585 | myprintf (FILE *f, const char *format, ...) | |
586 | @{ | |
587 | int r = fprintf (f, "myprintf: "); | |
588 | if (r < 0) | |
589 | return r; | |
590 | int s = fprintf (f, format, __builtin_va_arg_pack ()); | |
591 | if (s < 0) | |
592 | return s; | |
593 | return r + s; | |
594 | @} | |
595 | @end smallexample | |
596 | @end deftypefn | |
597 | ||
ab940b73 | 598 | @deftypefn {Built-in Function} {size_t} __builtin_va_arg_pack_len () |
ab0e176c JJ |
599 | This built-in function returns the number of anonymous arguments of |
600 | an inline function. It can be used only in inline functions which | |
601 | will be always inlined, never compiled as a separate function, such | |
602 | as those using @code{__attribute__ ((__always_inline__))} or | |
603 | @code{__attribute__ ((__gnu_inline__))} extern inline functions. | |
604 | For example following will do link or runtime checking of open | |
605 | arguments for optimized code: | |
606 | @smallexample | |
607 | #ifdef __OPTIMIZE__ | |
608 | extern inline __attribute__((__gnu_inline__)) int | |
609 | myopen (const char *path, int oflag, ...) | |
610 | @{ | |
611 | if (__builtin_va_arg_pack_len () > 1) | |
612 | warn_open_too_many_arguments (); | |
613 | ||
614 | if (__builtin_constant_p (oflag)) | |
615 | @{ | |
616 | if ((oflag & O_CREAT) != 0 && __builtin_va_arg_pack_len () < 1) | |
617 | @{ | |
618 | warn_open_missing_mode (); | |
619 | return __open_2 (path, oflag); | |
620 | @} | |
621 | return open (path, oflag, __builtin_va_arg_pack ()); | |
622 | @} | |
ff2ce160 | 623 | |
ab0e176c JJ |
624 | if (__builtin_va_arg_pack_len () < 1) |
625 | return __open_2 (path, oflag); | |
626 | ||
627 | return open (path, oflag, __builtin_va_arg_pack ()); | |
628 | @} | |
629 | #endif | |
630 | @end smallexample | |
631 | @end deftypefn | |
632 | ||
c1f7febf RK |
633 | @node Typeof |
634 | @section Referring to a Type with @code{typeof} | |
635 | @findex typeof | |
636 | @findex sizeof | |
637 | @cindex macros, types of arguments | |
638 | ||
639 | Another way to refer to the type of an expression is with @code{typeof}. | |
640 | The syntax of using of this keyword looks like @code{sizeof}, but the | |
641 | construct acts semantically like a type name defined with @code{typedef}. | |
642 | ||
643 | There are two ways of writing the argument to @code{typeof}: with an | |
644 | expression or with a type. Here is an example with an expression: | |
645 | ||
3ab51846 | 646 | @smallexample |
c1f7febf | 647 | typeof (x[0](1)) |
3ab51846 | 648 | @end smallexample |
c1f7febf RK |
649 | |
650 | @noindent | |
89aed483 JM |
651 | This assumes that @code{x} is an array of pointers to functions; |
652 | the type described is that of the values of the functions. | |
c1f7febf RK |
653 | |
654 | Here is an example with a typename as the argument: | |
655 | ||
3ab51846 | 656 | @smallexample |
c1f7febf | 657 | typeof (int *) |
3ab51846 | 658 | @end smallexample |
c1f7febf RK |
659 | |
660 | @noindent | |
661 | Here the type described is that of pointers to @code{int}. | |
662 | ||
5490d604 | 663 | If you are writing a header file that must work when included in ISO C |
c1f7febf RK |
664 | programs, write @code{__typeof__} instead of @code{typeof}. |
665 | @xref{Alternate Keywords}. | |
666 | ||
667 | A @code{typeof}-construct can be used anywhere a typedef name could be | |
668 | used. For example, you can use it in a declaration, in a cast, or inside | |
669 | of @code{sizeof} or @code{typeof}. | |
670 | ||
928c19bb JM |
671 | The operand of @code{typeof} is evaluated for its side effects if and |
672 | only if it is an expression of variably modified type or the name of | |
673 | such a type. | |
674 | ||
95f79357 ZW |
675 | @code{typeof} is often useful in conjunction with the |
676 | statements-within-expressions feature. Here is how the two together can | |
677 | be used to define a safe ``maximum'' macro that operates on any | |
678 | arithmetic type and evaluates each of its arguments exactly once: | |
679 | ||
3ab51846 | 680 | @smallexample |
95f79357 ZW |
681 | #define max(a,b) \ |
682 | (@{ typeof (a) _a = (a); \ | |
683 | typeof (b) _b = (b); \ | |
684 | _a > _b ? _a : _b; @}) | |
3ab51846 | 685 | @end smallexample |
95f79357 | 686 | |
526278c9 VR |
687 | @cindex underscores in variables in macros |
688 | @cindex @samp{_} in variables in macros | |
689 | @cindex local variables in macros | |
690 | @cindex variables, local, in macros | |
691 | @cindex macros, local variables in | |
692 | ||
693 | The reason for using names that start with underscores for the local | |
694 | variables is to avoid conflicts with variable names that occur within the | |
695 | expressions that are substituted for @code{a} and @code{b}. Eventually we | |
696 | hope to design a new form of declaration syntax that allows you to declare | |
697 | variables whose scopes start only after their initializers; this will be a | |
698 | more reliable way to prevent such conflicts. | |
699 | ||
95f79357 ZW |
700 | @noindent |
701 | Some more examples of the use of @code{typeof}: | |
702 | ||
c1f7febf RK |
703 | @itemize @bullet |
704 | @item | |
705 | This declares @code{y} with the type of what @code{x} points to. | |
706 | ||
3ab51846 | 707 | @smallexample |
c1f7febf | 708 | typeof (*x) y; |
3ab51846 | 709 | @end smallexample |
c1f7febf RK |
710 | |
711 | @item | |
712 | This declares @code{y} as an array of such values. | |
713 | ||
3ab51846 | 714 | @smallexample |
c1f7febf | 715 | typeof (*x) y[4]; |
3ab51846 | 716 | @end smallexample |
c1f7febf RK |
717 | |
718 | @item | |
719 | This declares @code{y} as an array of pointers to characters: | |
720 | ||
3ab51846 | 721 | @smallexample |
c1f7febf | 722 | typeof (typeof (char *)[4]) y; |
3ab51846 | 723 | @end smallexample |
c1f7febf RK |
724 | |
725 | @noindent | |
726 | It is equivalent to the following traditional C declaration: | |
727 | ||
3ab51846 | 728 | @smallexample |
c1f7febf | 729 | char *y[4]; |
3ab51846 | 730 | @end smallexample |
c1f7febf RK |
731 | |
732 | To see the meaning of the declaration using @code{typeof}, and why it | |
962e6e00 | 733 | might be a useful way to write, rewrite it with these macros: |
c1f7febf | 734 | |
3ab51846 | 735 | @smallexample |
c1f7febf RK |
736 | #define pointer(T) typeof(T *) |
737 | #define array(T, N) typeof(T [N]) | |
3ab51846 | 738 | @end smallexample |
c1f7febf RK |
739 | |
740 | @noindent | |
741 | Now the declaration can be rewritten this way: | |
742 | ||
3ab51846 | 743 | @smallexample |
c1f7febf | 744 | array (pointer (char), 4) y; |
3ab51846 | 745 | @end smallexample |
c1f7febf RK |
746 | |
747 | @noindent | |
748 | Thus, @code{array (pointer (char), 4)} is the type of arrays of 4 | |
749 | pointers to @code{char}. | |
750 | @end itemize | |
751 | ||
95f79357 ZW |
752 | @emph{Compatibility Note:} In addition to @code{typeof}, GCC 2 supported |
753 | a more limited extension which permitted one to write | |
754 | ||
3ab51846 | 755 | @smallexample |
95f79357 | 756 | typedef @var{T} = @var{expr}; |
3ab51846 | 757 | @end smallexample |
95f79357 ZW |
758 | |
759 | @noindent | |
760 | with the effect of declaring @var{T} to have the type of the expression | |
761 | @var{expr}. This extension does not work with GCC 3 (versions between | |
762 | 3.0 and 3.2 will crash; 3.2.1 and later give an error). Code which | |
763 | relies on it should be rewritten to use @code{typeof}: | |
764 | ||
3ab51846 | 765 | @smallexample |
95f79357 | 766 | typedef typeof(@var{expr}) @var{T}; |
3ab51846 | 767 | @end smallexample |
95f79357 ZW |
768 | |
769 | @noindent | |
770 | This will work with all versions of GCC@. | |
771 | ||
c1f7febf RK |
772 | @node Conditionals |
773 | @section Conditionals with Omitted Operands | |
774 | @cindex conditional expressions, extensions | |
775 | @cindex omitted middle-operands | |
776 | @cindex middle-operands, omitted | |
777 | @cindex extensions, @code{?:} | |
778 | @cindex @code{?:} extensions | |
779 | ||
780 | The middle operand in a conditional expression may be omitted. Then | |
781 | if the first operand is nonzero, its value is the value of the conditional | |
782 | expression. | |
783 | ||
784 | Therefore, the expression | |
785 | ||
3ab51846 | 786 | @smallexample |
c1f7febf | 787 | x ? : y |
3ab51846 | 788 | @end smallexample |
c1f7febf RK |
789 | |
790 | @noindent | |
791 | has the value of @code{x} if that is nonzero; otherwise, the value of | |
792 | @code{y}. | |
793 | ||
794 | This example is perfectly equivalent to | |
795 | ||
3ab51846 | 796 | @smallexample |
c1f7febf | 797 | x ? x : y |
3ab51846 | 798 | @end smallexample |
c1f7febf | 799 | |
ab940b73 RW |
800 | @cindex side effect in @code{?:} |
801 | @cindex @code{?:} side effect | |
c1f7febf RK |
802 | @noindent |
803 | In this simple case, the ability to omit the middle operand is not | |
804 | especially useful. When it becomes useful is when the first operand does, | |
805 | or may (if it is a macro argument), contain a side effect. Then repeating | |
806 | the operand in the middle would perform the side effect twice. Omitting | |
807 | the middle operand uses the value already computed without the undesirable | |
808 | effects of recomputing it. | |
809 | ||
a6766312 KT |
810 | @node __int128 |
811 | @section 128-bits integers | |
812 | @cindex @code{__int128} data types | |
813 | ||
814 | As an extension the integer scalar type @code{__int128} is supported for | |
815 | targets having an integer mode wide enough to hold 128-bit. | |
816 | Simply write @code{__int128} for a signed 128-bit integer, or | |
817 | @code{unsigned __int128} for an unsigned 128-bit integer. There is no | |
818 | support in GCC to express an integer constant of type @code{__int128} | |
819 | for targets having @code{long long} integer with less then 128 bit width. | |
820 | ||
c1f7febf RK |
821 | @node Long Long |
822 | @section Double-Word Integers | |
823 | @cindex @code{long long} data types | |
824 | @cindex double-word arithmetic | |
825 | @cindex multiprecision arithmetic | |
4b404517 JM |
826 | @cindex @code{LL} integer suffix |
827 | @cindex @code{ULL} integer suffix | |
c1f7febf | 828 | |
4b404517 | 829 | ISO C99 supports data types for integers that are at least 64 bits wide, |
7e1542b9 | 830 | and as an extension GCC supports them in C90 mode and in C++. |
4b404517 | 831 | Simply write @code{long long int} for a signed integer, or |
c1f7febf | 832 | @code{unsigned long long int} for an unsigned integer. To make an |
84330467 | 833 | integer constant of type @code{long long int}, add the suffix @samp{LL} |
c1f7febf | 834 | to the integer. To make an integer constant of type @code{unsigned long |
84330467 | 835 | long int}, add the suffix @samp{ULL} to the integer. |
c1f7febf RK |
836 | |
837 | You can use these types in arithmetic like any other integer types. | |
838 | Addition, subtraction, and bitwise boolean operations on these types | |
839 | are open-coded on all types of machines. Multiplication is open-coded | |
840 | if the machine supports fullword-to-doubleword a widening multiply | |
841 | instruction. Division and shifts are open-coded only on machines that | |
842 | provide special support. The operations that are not open-coded use | |
161d7b59 | 843 | special library routines that come with GCC@. |
c1f7febf RK |
844 | |
845 | There may be pitfalls when you use @code{long long} types for function | |
846 | arguments, unless you declare function prototypes. If a function | |
847 | expects type @code{int} for its argument, and you pass a value of type | |
848 | @code{long long int}, confusion will result because the caller and the | |
849 | subroutine will disagree about the number of bytes for the argument. | |
850 | Likewise, if the function expects @code{long long int} and you pass | |
851 | @code{int}. The best way to avoid such problems is to use prototypes. | |
852 | ||
853 | @node Complex | |
854 | @section Complex Numbers | |
855 | @cindex complex numbers | |
4b404517 JM |
856 | @cindex @code{_Complex} keyword |
857 | @cindex @code{__complex__} keyword | |
c1f7febf | 858 | |
4b404517 | 859 | ISO C99 supports complex floating data types, and as an extension GCC |
7e1542b9 | 860 | supports them in C90 mode and in C++, and supports complex integer data |
4b404517 JM |
861 | types which are not part of ISO C99. You can declare complex types |
862 | using the keyword @code{_Complex}. As an extension, the older GNU | |
863 | keyword @code{__complex__} is also supported. | |
c1f7febf | 864 | |
4b404517 | 865 | For example, @samp{_Complex double x;} declares @code{x} as a |
c1f7febf | 866 | variable whose real part and imaginary part are both of type |
4b404517 | 867 | @code{double}. @samp{_Complex short int y;} declares @code{y} to |
c1f7febf RK |
868 | have real and imaginary parts of type @code{short int}; this is not |
869 | likely to be useful, but it shows that the set of complex types is | |
870 | complete. | |
871 | ||
872 | To write a constant with a complex data type, use the suffix @samp{i} or | |
873 | @samp{j} (either one; they are equivalent). For example, @code{2.5fi} | |
4b404517 JM |
874 | has type @code{_Complex float} and @code{3i} has type |
875 | @code{_Complex int}. Such a constant always has a pure imaginary | |
c1f7febf | 876 | value, but you can form any complex value you like by adding one to a |
4b404517 JM |
877 | real constant. This is a GNU extension; if you have an ISO C99 |
878 | conforming C library (such as GNU libc), and want to construct complex | |
879 | constants of floating type, you should include @code{<complex.h>} and | |
880 | use the macros @code{I} or @code{_Complex_I} instead. | |
c1f7febf | 881 | |
4b404517 JM |
882 | @cindex @code{__real__} keyword |
883 | @cindex @code{__imag__} keyword | |
c1f7febf RK |
884 | To extract the real part of a complex-valued expression @var{exp}, write |
885 | @code{__real__ @var{exp}}. Likewise, use @code{__imag__} to | |
4b404517 JM |
886 | extract the imaginary part. This is a GNU extension; for values of |
887 | floating type, you should use the ISO C99 functions @code{crealf}, | |
888 | @code{creal}, @code{creall}, @code{cimagf}, @code{cimag} and | |
889 | @code{cimagl}, declared in @code{<complex.h>} and also provided as | |
161d7b59 | 890 | built-in functions by GCC@. |
c1f7febf | 891 | |
4b404517 | 892 | @cindex complex conjugation |
c1f7febf | 893 | The operator @samp{~} performs complex conjugation when used on a value |
4b404517 JM |
894 | with a complex type. This is a GNU extension; for values of |
895 | floating type, you should use the ISO C99 functions @code{conjf}, | |
896 | @code{conj} and @code{conjl}, declared in @code{<complex.h>} and also | |
161d7b59 | 897 | provided as built-in functions by GCC@. |
c1f7febf | 898 | |
f0523f02 | 899 | GCC can allocate complex automatic variables in a noncontiguous |
c1f7febf | 900 | fashion; it's even possible for the real part to be in a register while |
580fb356 JW |
901 | the imaginary part is on the stack (or vice-versa). Only the DWARF2 |
902 | debug info format can represent this, so use of DWARF2 is recommended. | |
903 | If you are using the stabs debug info format, GCC describes a noncontiguous | |
904 | complex variable as if it were two separate variables of noncomplex type. | |
c1f7febf RK |
905 | If the variable's actual name is @code{foo}, the two fictitious |
906 | variables are named @code{foo$real} and @code{foo$imag}. You can | |
907 | examine and set these two fictitious variables with your debugger. | |
908 | ||
c77cd3d1 UB |
909 | @node Floating Types |
910 | @section Additional Floating Types | |
911 | @cindex additional floating types | |
912 | @cindex @code{__float80} data type | |
913 | @cindex @code{__float128} data type | |
914 | @cindex @code{w} floating point suffix | |
915 | @cindex @code{q} floating point suffix | |
916 | @cindex @code{W} floating point suffix | |
917 | @cindex @code{Q} floating point suffix | |
918 | ||
919 | As an extension, the GNU C compiler supports additional floating | |
920 | types, @code{__float80} and @code{__float128} to support 80bit | |
921 | (@code{XFmode}) and 128 bit (@code{TFmode}) floating types. | |
922 | Support for additional types includes the arithmetic operators: | |
923 | add, subtract, multiply, divide; unary arithmetic operators; | |
924 | relational operators; equality operators; and conversions to and from | |
925 | integer and other floating types. Use a suffix @samp{w} or @samp{W} | |
926 | in a literal constant of type @code{__float80} and @samp{q} or @samp{Q} | |
927 | for @code{_float128}. You can declare complex types using the | |
928 | corresponding internal complex type, @code{XCmode} for @code{__float80} | |
929 | type and @code{TCmode} for @code{__float128} type: | |
930 | ||
931 | @smallexample | |
932 | typedef _Complex float __attribute__((mode(TC))) _Complex128; | |
933 | typedef _Complex float __attribute__((mode(XC))) _Complex80; | |
934 | @end smallexample | |
935 | ||
936 | Not all targets support additional floating point types. @code{__float80} | |
897eef7b | 937 | and @code{__float128} types are supported on i386, x86_64 and ia64 targets. |
41a1208a | 938 | The @code{__float128} type is supported on hppa HP-UX targets. |
c77cd3d1 | 939 | |
0fd8c3ad SL |
940 | @node Half-Precision |
941 | @section Half-Precision Floating Point | |
942 | @cindex half-precision floating point | |
943 | @cindex @code{__fp16} data type | |
944 | ||
945 | On ARM targets, GCC supports half-precision (16-bit) floating point via | |
ff2ce160 | 946 | the @code{__fp16} type. You must enable this type explicitly |
0fd8c3ad SL |
947 | with the @option{-mfp16-format} command-line option in order to use it. |
948 | ||
949 | ARM supports two incompatible representations for half-precision | |
950 | floating-point values. You must choose one of the representations and | |
951 | use it consistently in your program. | |
952 | ||
953 | Specifying @option{-mfp16-format=ieee} selects the IEEE 754-2008 format. | |
954 | This format can represent normalized values in the range of @math{2^{-14}} to 65504. | |
955 | There are 11 bits of significand precision, approximately 3 | |
956 | decimal digits. | |
957 | ||
958 | Specifying @option{-mfp16-format=alternative} selects the ARM | |
959 | alternative format. This representation is similar to the IEEE | |
960 | format, but does not support infinities or NaNs. Instead, the range | |
961 | of exponents is extended, so that this format can represent normalized | |
962 | values in the range of @math{2^{-14}} to 131008. | |
963 | ||
964 | The @code{__fp16} type is a storage format only. For purposes | |
965 | of arithmetic and other operations, @code{__fp16} values in C or C++ | |
966 | expressions are automatically promoted to @code{float}. In addition, | |
ff2ce160 | 967 | you cannot declare a function with a return value or parameters |
0fd8c3ad SL |
968 | of type @code{__fp16}. |
969 | ||
970 | Note that conversions from @code{double} to @code{__fp16} | |
971 | involve an intermediate conversion to @code{float}. Because | |
972 | of rounding, this can sometimes produce a different result than a | |
973 | direct conversion. | |
974 | ||
ff2ce160 | 975 | ARM provides hardware support for conversions between |
0fd8c3ad SL |
976 | @code{__fp16} and @code{float} values |
977 | as an extension to VFP and NEON (Advanced SIMD). GCC generates | |
e0dc3601 | 978 | code using these hardware instructions if you compile with |
ff2ce160 | 979 | options to select an FPU that provides them; |
e0dc3601 | 980 | for example, @option{-mfpu=neon-fp16 -mfloat-abi=softfp}, |
0fd8c3ad | 981 | in addition to the @option{-mfp16-format} option to select |
ff2ce160 | 982 | a half-precision format. |
0fd8c3ad SL |
983 | |
984 | Language-level support for the @code{__fp16} data type is | |
985 | independent of whether GCC generates code using hardware floating-point | |
986 | instructions. In cases where hardware support is not specified, GCC | |
987 | implements conversions between @code{__fp16} and @code{float} values | |
988 | as library calls. | |
989 | ||
9a8ce21f | 990 | @node Decimal Float |
85a92f7e JJ |
991 | @section Decimal Floating Types |
992 | @cindex decimal floating types | |
9a8ce21f JG |
993 | @cindex @code{_Decimal32} data type |
994 | @cindex @code{_Decimal64} data type | |
995 | @cindex @code{_Decimal128} data type | |
996 | @cindex @code{df} integer suffix | |
997 | @cindex @code{dd} integer suffix | |
998 | @cindex @code{dl} integer suffix | |
999 | @cindex @code{DF} integer suffix | |
1000 | @cindex @code{DD} integer suffix | |
1001 | @cindex @code{DL} integer suffix | |
1002 | ||
85a92f7e | 1003 | As an extension, the GNU C compiler supports decimal floating types as |
853eda8d | 1004 | defined in the N1312 draft of ISO/IEC WDTR24732. Support for decimal |
85a92f7e JJ |
1005 | floating types in GCC will evolve as the draft technical report changes. |
1006 | Calling conventions for any target might also change. Not all targets | |
1007 | support decimal floating types. | |
9a8ce21f | 1008 | |
85a92f7e JJ |
1009 | The decimal floating types are @code{_Decimal32}, @code{_Decimal64}, and |
1010 | @code{_Decimal128}. They use a radix of ten, unlike the floating types | |
1011 | @code{float}, @code{double}, and @code{long double} whose radix is not | |
1012 | specified by the C standard but is usually two. | |
1013 | ||
1014 | Support for decimal floating types includes the arithmetic operators | |
9a8ce21f JG |
1015 | add, subtract, multiply, divide; unary arithmetic operators; |
1016 | relational operators; equality operators; and conversions to and from | |
85a92f7e | 1017 | integer and other floating types. Use a suffix @samp{df} or |
9a8ce21f JG |
1018 | @samp{DF} in a literal constant of type @code{_Decimal32}, @samp{dd} |
1019 | or @samp{DD} for @code{_Decimal64}, and @samp{dl} or @samp{DL} for | |
1020 | @code{_Decimal128}. | |
1021 | ||
85a92f7e JJ |
1022 | GCC support of decimal float as specified by the draft technical report |
1023 | is incomplete: | |
1024 | ||
1025 | @itemize @bullet | |
85a92f7e JJ |
1026 | @item |
1027 | When the value of a decimal floating type cannot be represented in the | |
1028 | integer type to which it is being converted, the result is undefined | |
1029 | rather than the result value specified by the draft technical report. | |
853eda8d JJ |
1030 | |
1031 | @item | |
1032 | GCC does not provide the C library functionality associated with | |
1033 | @file{math.h}, @file{fenv.h}, @file{stdio.h}, @file{stdlib.h}, and | |
1034 | @file{wchar.h}, which must come from a separate C library implementation. | |
1035 | Because of this the GNU C compiler does not define macro | |
1036 | @code{__STDC_DEC_FP__} to indicate that the implementation conforms to | |
1037 | the technical report. | |
85a92f7e | 1038 | @end itemize |
9a8ce21f JG |
1039 | |
1040 | Types @code{_Decimal32}, @code{_Decimal64}, and @code{_Decimal128} | |
1041 | are supported by the DWARF2 debug information format. | |
1042 | ||
6f4d7222 | 1043 | @node Hex Floats |
6b42b9ea UD |
1044 | @section Hex Floats |
1045 | @cindex hex floats | |
c5c76735 | 1046 | |
4b404517 | 1047 | ISO C99 supports floating-point numbers written not only in the usual |
6f4d7222 | 1048 | decimal notation, such as @code{1.55e1}, but also numbers such as |
4b404517 | 1049 | @code{0x1.fp3} written in hexadecimal format. As a GNU extension, GCC |
7e1542b9 | 1050 | supports this in C90 mode (except in some cases when strictly |
4b404517 | 1051 | conforming) and in C++. In that format the |
84330467 | 1052 | @samp{0x} hex introducer and the @samp{p} or @samp{P} exponent field are |
6f4d7222 | 1053 | mandatory. The exponent is a decimal number that indicates the power of |
84330467 | 1054 | 2 by which the significant part will be multiplied. Thus @samp{0x1.f} is |
aee96fe9 JM |
1055 | @tex |
1056 | $1 {15\over16}$, | |
1057 | @end tex | |
1058 | @ifnottex | |
1059 | 1 15/16, | |
1060 | @end ifnottex | |
1061 | @samp{p3} multiplies it by 8, and the value of @code{0x1.fp3} | |
6f4d7222 UD |
1062 | is the same as @code{1.55e1}. |
1063 | ||
1064 | Unlike for floating-point numbers in the decimal notation the exponent | |
1065 | is always required in the hexadecimal notation. Otherwise the compiler | |
1066 | would not be able to resolve the ambiguity of, e.g., @code{0x1.f}. This | |
84330467 | 1067 | could mean @code{1.0f} or @code{1.9375} since @samp{f} is also the |
6f4d7222 UD |
1068 | extension for floating-point constants of type @code{float}. |
1069 | ||
0f996086 CF |
1070 | @node Fixed-Point |
1071 | @section Fixed-Point Types | |
1072 | @cindex fixed-point types | |
1073 | @cindex @code{_Fract} data type | |
1074 | @cindex @code{_Accum} data type | |
1075 | @cindex @code{_Sat} data type | |
1076 | @cindex @code{hr} fixed-suffix | |
1077 | @cindex @code{r} fixed-suffix | |
1078 | @cindex @code{lr} fixed-suffix | |
1079 | @cindex @code{llr} fixed-suffix | |
1080 | @cindex @code{uhr} fixed-suffix | |
1081 | @cindex @code{ur} fixed-suffix | |
1082 | @cindex @code{ulr} fixed-suffix | |
1083 | @cindex @code{ullr} fixed-suffix | |
1084 | @cindex @code{hk} fixed-suffix | |
1085 | @cindex @code{k} fixed-suffix | |
1086 | @cindex @code{lk} fixed-suffix | |
1087 | @cindex @code{llk} fixed-suffix | |
1088 | @cindex @code{uhk} fixed-suffix | |
1089 | @cindex @code{uk} fixed-suffix | |
1090 | @cindex @code{ulk} fixed-suffix | |
1091 | @cindex @code{ullk} fixed-suffix | |
1092 | @cindex @code{HR} fixed-suffix | |
1093 | @cindex @code{R} fixed-suffix | |
1094 | @cindex @code{LR} fixed-suffix | |
1095 | @cindex @code{LLR} fixed-suffix | |
1096 | @cindex @code{UHR} fixed-suffix | |
1097 | @cindex @code{UR} fixed-suffix | |
1098 | @cindex @code{ULR} fixed-suffix | |
1099 | @cindex @code{ULLR} fixed-suffix | |
1100 | @cindex @code{HK} fixed-suffix | |
1101 | @cindex @code{K} fixed-suffix | |
1102 | @cindex @code{LK} fixed-suffix | |
1103 | @cindex @code{LLK} fixed-suffix | |
1104 | @cindex @code{UHK} fixed-suffix | |
1105 | @cindex @code{UK} fixed-suffix | |
1106 | @cindex @code{ULK} fixed-suffix | |
1107 | @cindex @code{ULLK} fixed-suffix | |
1108 | ||
1109 | As an extension, the GNU C compiler supports fixed-point types as | |
1110 | defined in the N1169 draft of ISO/IEC DTR 18037. Support for fixed-point | |
1111 | types in GCC will evolve as the draft technical report changes. | |
1112 | Calling conventions for any target might also change. Not all targets | |
1113 | support fixed-point types. | |
1114 | ||
1115 | The fixed-point types are | |
1116 | @code{short _Fract}, | |
1117 | @code{_Fract}, | |
1118 | @code{long _Fract}, | |
1119 | @code{long long _Fract}, | |
1120 | @code{unsigned short _Fract}, | |
1121 | @code{unsigned _Fract}, | |
1122 | @code{unsigned long _Fract}, | |
1123 | @code{unsigned long long _Fract}, | |
1124 | @code{_Sat short _Fract}, | |
1125 | @code{_Sat _Fract}, | |
1126 | @code{_Sat long _Fract}, | |
1127 | @code{_Sat long long _Fract}, | |
1128 | @code{_Sat unsigned short _Fract}, | |
1129 | @code{_Sat unsigned _Fract}, | |
1130 | @code{_Sat unsigned long _Fract}, | |
1131 | @code{_Sat unsigned long long _Fract}, | |
1132 | @code{short _Accum}, | |
1133 | @code{_Accum}, | |
1134 | @code{long _Accum}, | |
1135 | @code{long long _Accum}, | |
1136 | @code{unsigned short _Accum}, | |
1137 | @code{unsigned _Accum}, | |
1138 | @code{unsigned long _Accum}, | |
1139 | @code{unsigned long long _Accum}, | |
1140 | @code{_Sat short _Accum}, | |
1141 | @code{_Sat _Accum}, | |
1142 | @code{_Sat long _Accum}, | |
1143 | @code{_Sat long long _Accum}, | |
1144 | @code{_Sat unsigned short _Accum}, | |
1145 | @code{_Sat unsigned _Accum}, | |
1146 | @code{_Sat unsigned long _Accum}, | |
1147 | @code{_Sat unsigned long long _Accum}. | |
8fd94bda | 1148 | |
0f996086 CF |
1149 | Fixed-point data values contain fractional and optional integral parts. |
1150 | The format of fixed-point data varies and depends on the target machine. | |
1151 | ||
8fd94bda JJ |
1152 | Support for fixed-point types includes: |
1153 | @itemize @bullet | |
1154 | @item | |
1155 | prefix and postfix increment and decrement operators (@code{++}, @code{--}) | |
1156 | @item | |
1157 | unary arithmetic operators (@code{+}, @code{-}, @code{!}) | |
1158 | @item | |
1159 | binary arithmetic operators (@code{+}, @code{-}, @code{*}, @code{/}) | |
1160 | @item | |
1161 | binary shift operators (@code{<<}, @code{>>}) | |
1162 | @item | |
1163 | relational operators (@code{<}, @code{<=}, @code{>=}, @code{>}) | |
1164 | @item | |
1165 | equality operators (@code{==}, @code{!=}) | |
1166 | @item | |
1167 | assignment operators (@code{+=}, @code{-=}, @code{*=}, @code{/=}, | |
1168 | @code{<<=}, @code{>>=}) | |
1169 | @item | |
1170 | conversions to and from integer, floating-point, or fixed-point types | |
1171 | @end itemize | |
1172 | ||
1173 | Use a suffix in a fixed-point literal constant: | |
1174 | @itemize | |
1175 | @item @samp{hr} or @samp{HR} for @code{short _Fract} and | |
1176 | @code{_Sat short _Fract} | |
1177 | @item @samp{r} or @samp{R} for @code{_Fract} and @code{_Sat _Fract} | |
1178 | @item @samp{lr} or @samp{LR} for @code{long _Fract} and | |
1179 | @code{_Sat long _Fract} | |
1180 | @item @samp{llr} or @samp{LLR} for @code{long long _Fract} and | |
1181 | @code{_Sat long long _Fract} | |
1182 | @item @samp{uhr} or @samp{UHR} for @code{unsigned short _Fract} and | |
1183 | @code{_Sat unsigned short _Fract} | |
1184 | @item @samp{ur} or @samp{UR} for @code{unsigned _Fract} and | |
1185 | @code{_Sat unsigned _Fract} | |
1186 | @item @samp{ulr} or @samp{ULR} for @code{unsigned long _Fract} and | |
1187 | @code{_Sat unsigned long _Fract} | |
1188 | @item @samp{ullr} or @samp{ULLR} for @code{unsigned long long _Fract} | |
1189 | and @code{_Sat unsigned long long _Fract} | |
1190 | @item @samp{hk} or @samp{HK} for @code{short _Accum} and | |
1191 | @code{_Sat short _Accum} | |
1192 | @item @samp{k} or @samp{K} for @code{_Accum} and @code{_Sat _Accum} | |
1193 | @item @samp{lk} or @samp{LK} for @code{long _Accum} and | |
1194 | @code{_Sat long _Accum} | |
1195 | @item @samp{llk} or @samp{LLK} for @code{long long _Accum} and | |
1196 | @code{_Sat long long _Accum} | |
1197 | @item @samp{uhk} or @samp{UHK} for @code{unsigned short _Accum} and | |
1198 | @code{_Sat unsigned short _Accum} | |
1199 | @item @samp{uk} or @samp{UK} for @code{unsigned _Accum} and | |
1200 | @code{_Sat unsigned _Accum} | |
1201 | @item @samp{ulk} or @samp{ULK} for @code{unsigned long _Accum} and | |
1202 | @code{_Sat unsigned long _Accum} | |
1203 | @item @samp{ullk} or @samp{ULLK} for @code{unsigned long long _Accum} | |
1204 | and @code{_Sat unsigned long long _Accum} | |
1205 | @end itemize | |
0f996086 CF |
1206 | |
1207 | GCC support of fixed-point types as specified by the draft technical report | |
1208 | is incomplete: | |
1209 | ||
1210 | @itemize @bullet | |
1211 | @item | |
1212 | Pragmas to control overflow and rounding behaviors are not implemented. | |
1213 | @end itemize | |
1214 | ||
1215 | Fixed-point types are supported by the DWARF2 debug information format. | |
1216 | ||
09e881c9 | 1217 | @node Named Address Spaces |
542bf446 GJL |
1218 | @section Named Address Spaces |
1219 | @cindex Named Address Spaces | |
09e881c9 BE |
1220 | |
1221 | As an extension, the GNU C compiler supports named address spaces as | |
1222 | defined in the N1275 draft of ISO/IEC DTR 18037. Support for named | |
85b8555e DD |
1223 | address spaces in GCC will evolve as the draft technical report |
1224 | changes. Calling conventions for any target might also change. At | |
542bf446 GJL |
1225 | present, only the AVR, SPU, M32C, and RL78 targets support address |
1226 | spaces other than the generic address space. | |
1227 | ||
1228 | Address space identifiers may be used exactly like any other C type | |
1229 | qualifier (e.g., @code{const} or @code{volatile}). See the N1275 | |
1230 | document for more details. | |
1231 | ||
1232 | @anchor{AVR Named Address Spaces} | |
1233 | @subsection AVR Named Address Spaces | |
1234 | ||
1235 | On the AVR target, there are several address spaces that can be used | |
1236 | in order to put read-only data into the flash memory and access that | |
1237 | data by means of the special instructions @code{LPM} or @code{ELPM} | |
1238 | needed to read from flash. | |
1239 | ||
aa9ec4db GJL |
1240 | Per default, any data including read-only data is located in RAM |
1241 | (the generic address space) so that non-generic address spaces are | |
1242 | needed to locate read-only data in flash memory | |
1243 | @emph{and} to generate the right instructions to access this data | |
542bf446 GJL |
1244 | without using (inline) assembler code. |
1245 | ||
1246 | @table @code | |
3a840863 GJL |
1247 | @item __flash |
1248 | @cindex @code{__flash} AVR Named Address Spaces | |
1249 | The @code{__flash} qualifier will locate data in the | |
542bf446 GJL |
1250 | @code{.progmem.data} section. Data will be read using the @code{LPM} |
1251 | instruction. Pointers to this address space are 16 bits wide. | |
1252 | ||
3a840863 GJL |
1253 | @item __flash1 |
1254 | @item __flash2 | |
1255 | @item __flash3 | |
1256 | @item __flash4 | |
1257 | @item __flash5 | |
1258 | @cindex @code{__flash1} AVR Named Address Spaces | |
1259 | @cindex @code{__flash2} AVR Named Address Spaces | |
1260 | @cindex @code{__flash3} AVR Named Address Spaces | |
1261 | @cindex @code{__flash4} AVR Named Address Spaces | |
1262 | @cindex @code{__flash5} AVR Named Address Spaces | |
542bf446 GJL |
1263 | These are 16-bit address spaces locating data in section |
1264 | @code{.progmem@var{N}.data} where @var{N} refers to | |
3a840863 | 1265 | address space @code{__flash@var{N}}. |
542bf446 GJL |
1266 | The compiler will set the @code{RAMPZ} segment register approptiately |
1267 | before reading data by means of the @code{ELPM} instruction. | |
1268 | ||
aa9ec4db | 1269 | On devices with less 64@tie{}kiB flash segments as indicated by the address |
542bf446 | 1270 | space, the compiler will cut down the segment number to a number the |
aa9ec4db | 1271 | device actually supports. Counting starts at@tie{}@code{0} |
3a840863 GJL |
1272 | for space @code{__flash}. For example, if you access address space |
1273 | @code{__flash3} on an ATmega128 device with two 64@tie{}kiB flash segments, | |
1274 | the compiler will generate a read from @code{__flash1}, i.e.@: it | |
542bf446 GJL |
1275 | will load @code{RAMPZ} with@tie{}@code{1} before reading. |
1276 | ||
3a840863 GJL |
1277 | @item __memx |
1278 | @cindex @code{__memx} AVR Named Address Spaces | |
542bf446 GJL |
1279 | This is a 24-bit address space that linearizes flash and RAM: |
1280 | If the high bit of the address is set, data is read from | |
1281 | RAM using the lower two bytes as RAM address. | |
1282 | If the high bit of the address is clear, data is read from flash | |
1283 | with @code{RAMPZ} set according to the high byte of the address. | |
1284 | ||
1285 | Objects in this address space will be located in @code{.progmem.data}. | |
1286 | @end table | |
1287 | ||
aa9ec4db GJL |
1288 | @b{Example} |
1289 | ||
1290 | @example | |
3a840863 | 1291 | char my_read (const __flash char ** p) |
aa9ec4db GJL |
1292 | @{ |
1293 | /* p is a pointer to RAM that points to a pointer to flash. | |
1294 | The first indirection of p will read that flash pointer | |
1295 | from RAM and the second indirection reads a char from this | |
1296 | flash address. */ | |
1297 | ||
1298 | return **p; | |
1299 | @} | |
1300 | ||
1301 | /* Locate array[] in flash memory */ | |
3a840863 | 1302 | const __flash int array[] = @{ 3, 5, 7, 11, 13, 17, 19 @}; |
aa9ec4db GJL |
1303 | |
1304 | int i = 1; | |
1305 | ||
1306 | int main (void) | |
1307 | @{ | |
1308 | /* Return 17 by reading from flash memory */ | |
1309 | return array[array[i]]; | |
1310 | @} | |
1311 | @end example | |
1312 | ||
542bf446 GJL |
1313 | For each named address space supported by avr-gcc there is an equally |
1314 | named but uppercase built-in macro defined. | |
1315 | The purpose is to facilitate testing if respective address space | |
1316 | support is available or not: | |
1317 | ||
1318 | @example | |
3a840863 GJL |
1319 | #ifdef __FLASH |
1320 | const __flash int var = 1; | |
542bf446 GJL |
1321 | |
1322 | int read_i (void) | |
1323 | @{ | |
1324 | return i; | |
1325 | @} | |
1326 | #else | |
1327 | #include <avr/pgmspace.h> /* From avr-libc */ | |
1328 | ||
1329 | const int var PROGMEM = 1; | |
1330 | ||
1331 | int read_i (void) | |
1332 | @{ | |
1333 | return (int) pgm_read_word (&i); | |
1334 | @} | |
3a840863 | 1335 | #endif /* __FLASH */ |
542bf446 GJL |
1336 | @end example |
1337 | ||
1338 | Notice that attribute @ref{AVR Variable Attributes,@code{progmem}} | |
1339 | locates data in flash but | |
aa9ec4db GJL |
1340 | accesses to these data will read from generic address space, i.e.@: |
1341 | from RAM, | |
1342 | so that you need special accessors like @code{pgm_read_byte} | |
542bf446 GJL |
1343 | from @w{@uref{http://nongnu.org/avr-libc/user-manual,avr-libc}}. |
1344 | ||
1345 | @b{Limitations and caveats} | |
1346 | ||
1347 | @itemize | |
1348 | @item | |
1349 | Reading across the 64@tie{}KiB section boundary of | |
3a840863 | 1350 | the @code{__flash} or @code{__flash@var{N}} address spaces |
542bf446 GJL |
1351 | will show undefined behaviour. The only address space that |
1352 | supports reading across the 64@tie{}KiB flash segment boundaries is | |
3a840863 | 1353 | @code{__memx}. |
542bf446 GJL |
1354 | |
1355 | @item | |
3a840863 | 1356 | If you use one if the @code{__flash@var{N}} address spaces |
542bf446 GJL |
1357 | you will have to arrange your linker skript to locate the |
1358 | @code{.progmem@var{N}.data} sections according to your needs. | |
1359 | ||
1360 | @item | |
aa9ec4db GJL |
1361 | Any data or pointers to the non-generic address spaces must |
1362 | be qualified as @code{const}, i.e.@: as read-only data. | |
542bf446 | 1363 | This still applies if the data in one of these address |
aa9ec4db | 1364 | spaces like software version number or calibration lookup table are intended to |
542bf446 GJL |
1365 | be changed after load time by, say, a boot loader. In this case |
1366 | the right qualification is @code{const} @code{volatile} so that the compiler | |
1367 | must not optimize away known values or insert them | |
1368 | as immediates into operands of instructions. | |
1369 | ||
1370 | @item | |
1371 | Code like the following is not yet supported because of missing | |
1372 | support in avr-binutils, | |
1373 | see @w{@uref{http://sourceware.org/PR13503,PR13503}}. | |
1374 | @example | |
3a840863 GJL |
1375 | extern const __memx char foo; |
1376 | const __memx void *pfoo = &foo; | |
542bf446 GJL |
1377 | @end example |
1378 | The code will throw an assembler warning and the high byte of | |
aa9ec4db | 1379 | @code{pfoo} will be initialized with@tie{}@code{0}, i.e.@: the |
542bf446 GJL |
1380 | initialization will be as if @code{foo} was located in the first |
1381 | 64@tie{}KiB chunk of flash. | |
1382 | ||
542bf446 GJL |
1383 | @end itemize |
1384 | ||
542bf446 GJL |
1385 | @subsection M32C Named Address Spaces |
1386 | @cindex @code{__far} M32C Named Address Spaces | |
1387 | ||
1388 | On the M32C target, with the R8C and M16C cpu variants, variables | |
1389 | qualified with @code{__far} are accessed using 32-bit addresses in | |
1390 | order to access memory beyond the first 64@tie{}Ki bytes. If | |
1391 | @code{__far} is used with the M32CM or M32C cpu variants, it has no | |
1392 | effect. | |
1393 | ||
1394 | @subsection RL78 Named Address Spaces | |
1395 | @cindex @code{__far} RL78 Named Address Spaces | |
1396 | ||
1397 | On the RL78 target, variables qualified with @code{__far} are accessed | |
1398 | with 32-bit pointers (20-bit addresses) rather than the default 16-bit | |
1399 | addresses. Non-far variables are assumed to appear in the topmost | |
1400 | 64@tie{}KiB of the address space. | |
1401 | ||
1402 | @subsection SPU Named Address Spaces | |
1403 | @cindex @code{__ea} SPU Named Address Spaces | |
1404 | ||
1405 | On the SPU target variables may be declared as | |
85b8555e DD |
1406 | belonging to another address space by qualifying the type with the |
1407 | @code{__ea} address space identifier: | |
09e881c9 BE |
1408 | |
1409 | @smallexample | |
1410 | extern int __ea i; | |
1411 | @end smallexample | |
1412 | ||
1413 | When the variable @code{i} is accessed, the compiler will generate | |
1414 | special code to access this variable. It may use runtime library | |
1415 | support, or generate special machine instructions to access that address | |
1416 | space. | |
1417 | ||
c1f7febf RK |
1418 | @node Zero Length |
1419 | @section Arrays of Length Zero | |
1420 | @cindex arrays of length zero | |
1421 | @cindex zero-length arrays | |
1422 | @cindex length-zero arrays | |
ffc5c6a9 | 1423 | @cindex flexible array members |
c1f7febf | 1424 | |
161d7b59 | 1425 | Zero-length arrays are allowed in GNU C@. They are very useful as the |
584ef5fe | 1426 | last element of a structure which is really a header for a variable-length |
c1f7febf RK |
1427 | object: |
1428 | ||
3ab51846 | 1429 | @smallexample |
c1f7febf RK |
1430 | struct line @{ |
1431 | int length; | |
1432 | char contents[0]; | |
1433 | @}; | |
1434 | ||
584ef5fe RH |
1435 | struct line *thisline = (struct line *) |
1436 | malloc (sizeof (struct line) + this_length); | |
1437 | thisline->length = this_length; | |
3ab51846 | 1438 | @end smallexample |
c1f7febf | 1439 | |
3764f879 | 1440 | In ISO C90, you would have to give @code{contents} a length of 1, which |
c1f7febf RK |
1441 | means either you waste space or complicate the argument to @code{malloc}. |
1442 | ||
02f52e19 | 1443 | In ISO C99, you would use a @dfn{flexible array member}, which is |
584ef5fe RH |
1444 | slightly different in syntax and semantics: |
1445 | ||
1446 | @itemize @bullet | |
1447 | @item | |
1448 | Flexible array members are written as @code{contents[]} without | |
1449 | the @code{0}. | |
1450 | ||
1451 | @item | |
1452 | Flexible array members have incomplete type, and so the @code{sizeof} | |
1453 | operator may not be applied. As a quirk of the original implementation | |
1454 | of zero-length arrays, @code{sizeof} evaluates to zero. | |
1455 | ||
1456 | @item | |
1457 | Flexible array members may only appear as the last member of a | |
e7b6a0ee | 1458 | @code{struct} that is otherwise non-empty. |
2984fe64 JM |
1459 | |
1460 | @item | |
1461 | A structure containing a flexible array member, or a union containing | |
1462 | such a structure (possibly recursively), may not be a member of a | |
1463 | structure or an element of an array. (However, these uses are | |
1464 | permitted by GCC as extensions.) | |
ffc5c6a9 | 1465 | @end itemize |
a25f1211 | 1466 | |
ffc5c6a9 | 1467 | GCC versions before 3.0 allowed zero-length arrays to be statically |
e7b6a0ee DD |
1468 | initialized, as if they were flexible arrays. In addition to those |
1469 | cases that were useful, it also allowed initializations in situations | |
1470 | that would corrupt later data. Non-empty initialization of zero-length | |
1471 | arrays is now treated like any case where there are more initializer | |
1472 | elements than the array holds, in that a suitable warning about "excess | |
1473 | elements in array" is given, and the excess elements (all of them, in | |
1474 | this case) are ignored. | |
ffc5c6a9 RH |
1475 | |
1476 | Instead GCC allows static initialization of flexible array members. | |
1477 | This is equivalent to defining a new structure containing the original | |
1478 | structure followed by an array of sufficient size to contain the data. | |
e979f9e8 | 1479 | I.e.@: in the following, @code{f1} is constructed as if it were declared |
ffc5c6a9 | 1480 | like @code{f2}. |
a25f1211 | 1481 | |
3ab51846 | 1482 | @smallexample |
ffc5c6a9 RH |
1483 | struct f1 @{ |
1484 | int x; int y[]; | |
1485 | @} f1 = @{ 1, @{ 2, 3, 4 @} @}; | |
1486 | ||
1487 | struct f2 @{ | |
1488 | struct f1 f1; int data[3]; | |
1489 | @} f2 = @{ @{ 1 @}, @{ 2, 3, 4 @} @}; | |
3ab51846 | 1490 | @end smallexample |
584ef5fe | 1491 | |
ffc5c6a9 RH |
1492 | @noindent |
1493 | The convenience of this extension is that @code{f1} has the desired | |
1494 | type, eliminating the need to consistently refer to @code{f2.f1}. | |
1495 | ||
1496 | This has symmetry with normal static arrays, in that an array of | |
1497 | unknown size is also written with @code{[]}. | |
a25f1211 | 1498 | |
ffc5c6a9 RH |
1499 | Of course, this extension only makes sense if the extra data comes at |
1500 | the end of a top-level object, as otherwise we would be overwriting | |
1501 | data at subsequent offsets. To avoid undue complication and confusion | |
1502 | with initialization of deeply nested arrays, we simply disallow any | |
1503 | non-empty initialization except when the structure is the top-level | |
1504 | object. For example: | |
584ef5fe | 1505 | |
3ab51846 | 1506 | @smallexample |
ffc5c6a9 RH |
1507 | struct foo @{ int x; int y[]; @}; |
1508 | struct bar @{ struct foo z; @}; | |
1509 | ||
13ba36b4 JM |
1510 | struct foo a = @{ 1, @{ 2, 3, 4 @} @}; // @r{Valid.} |
1511 | struct bar b = @{ @{ 1, @{ 2, 3, 4 @} @} @}; // @r{Invalid.} | |
1512 | struct bar c = @{ @{ 1, @{ @} @} @}; // @r{Valid.} | |
1513 | struct foo d[1] = @{ @{ 1 @{ 2, 3, 4 @} @} @}; // @r{Invalid.} | |
3ab51846 | 1514 | @end smallexample |
4b606faf | 1515 | |
ba05abd3 GK |
1516 | @node Empty Structures |
1517 | @section Structures With No Members | |
1518 | @cindex empty structures | |
1519 | @cindex zero-size structures | |
1520 | ||
1521 | GCC permits a C structure to have no members: | |
1522 | ||
3ab51846 | 1523 | @smallexample |
ba05abd3 GK |
1524 | struct empty @{ |
1525 | @}; | |
3ab51846 | 1526 | @end smallexample |
ba05abd3 GK |
1527 | |
1528 | The structure will have size zero. In C++, empty structures are part | |
db0b376e MM |
1529 | of the language. G++ treats empty structures as if they had a single |
1530 | member of type @code{char}. | |
ba05abd3 | 1531 | |
c1f7febf RK |
1532 | @node Variable Length |
1533 | @section Arrays of Variable Length | |
1534 | @cindex variable-length arrays | |
1535 | @cindex arrays of variable length | |
4b404517 | 1536 | @cindex VLAs |
c1f7febf | 1537 | |
4b404517 | 1538 | Variable-length automatic arrays are allowed in ISO C99, and as an |
fbdaa0b2 | 1539 | extension GCC accepts them in C90 mode and in C++. These arrays are |
c1f7febf RK |
1540 | declared like any other automatic arrays, but with a length that is not |
1541 | a constant expression. The storage is allocated at the point of | |
1542 | declaration and deallocated when the brace-level is exited. For | |
1543 | example: | |
1544 | ||
3ab51846 | 1545 | @smallexample |
c1f7febf RK |
1546 | FILE * |
1547 | concat_fopen (char *s1, char *s2, char *mode) | |
1548 | @{ | |
1549 | char str[strlen (s1) + strlen (s2) + 1]; | |
1550 | strcpy (str, s1); | |
1551 | strcat (str, s2); | |
1552 | return fopen (str, mode); | |
1553 | @} | |
3ab51846 | 1554 | @end smallexample |
c1f7febf RK |
1555 | |
1556 | @cindex scope of a variable length array | |
1557 | @cindex variable-length array scope | |
1558 | @cindex deallocating variable length arrays | |
1559 | Jumping or breaking out of the scope of the array name deallocates the | |
1560 | storage. Jumping into the scope is not allowed; you get an error | |
1561 | message for it. | |
1562 | ||
1563 | @cindex @code{alloca} vs variable-length arrays | |
1564 | You can use the function @code{alloca} to get an effect much like | |
1565 | variable-length arrays. The function @code{alloca} is available in | |
1566 | many other C implementations (but not in all). On the other hand, | |
1567 | variable-length arrays are more elegant. | |
1568 | ||
1569 | There are other differences between these two methods. Space allocated | |
1570 | with @code{alloca} exists until the containing @emph{function} returns. | |
1571 | The space for a variable-length array is deallocated as soon as the array | |
1572 | name's scope ends. (If you use both variable-length arrays and | |
1573 | @code{alloca} in the same function, deallocation of a variable-length array | |
1574 | will also deallocate anything more recently allocated with @code{alloca}.) | |
1575 | ||
1576 | You can also use variable-length arrays as arguments to functions: | |
1577 | ||
3ab51846 | 1578 | @smallexample |
c1f7febf RK |
1579 | struct entry |
1580 | tester (int len, char data[len][len]) | |
1581 | @{ | |
0d893a63 | 1582 | /* @r{@dots{}} */ |
c1f7febf | 1583 | @} |
3ab51846 | 1584 | @end smallexample |
c1f7febf RK |
1585 | |
1586 | The length of an array is computed once when the storage is allocated | |
1587 | and is remembered for the scope of the array in case you access it with | |
1588 | @code{sizeof}. | |
1589 | ||
1590 | If you want to pass the array first and the length afterward, you can | |
1591 | use a forward declaration in the parameter list---another GNU extension. | |
1592 | ||
3ab51846 | 1593 | @smallexample |
c1f7febf RK |
1594 | struct entry |
1595 | tester (int len; char data[len][len], int len) | |
1596 | @{ | |
0d893a63 | 1597 | /* @r{@dots{}} */ |
c1f7febf | 1598 | @} |
3ab51846 | 1599 | @end smallexample |
c1f7febf RK |
1600 | |
1601 | @cindex parameter forward declaration | |
1602 | The @samp{int len} before the semicolon is a @dfn{parameter forward | |
1603 | declaration}, and it serves the purpose of making the name @code{len} | |
1604 | known when the declaration of @code{data} is parsed. | |
1605 | ||
1606 | You can write any number of such parameter forward declarations in the | |
1607 | parameter list. They can be separated by commas or semicolons, but the | |
1608 | last one must end with a semicolon, which is followed by the ``real'' | |
1609 | parameter declarations. Each forward declaration must match a ``real'' | |
4b404517 JM |
1610 | declaration in parameter name and data type. ISO C99 does not support |
1611 | parameter forward declarations. | |
c1f7febf | 1612 | |
ccd96f0a NB |
1613 | @node Variadic Macros |
1614 | @section Macros with a Variable Number of Arguments. | |
c1f7febf RK |
1615 | @cindex variable number of arguments |
1616 | @cindex macro with variable arguments | |
1617 | @cindex rest argument (in macro) | |
ccd96f0a | 1618 | @cindex variadic macros |
c1f7febf | 1619 | |
ccd96f0a NB |
1620 | In the ISO C standard of 1999, a macro can be declared to accept a |
1621 | variable number of arguments much as a function can. The syntax for | |
1622 | defining the macro is similar to that of a function. Here is an | |
1623 | example: | |
c1f7febf | 1624 | |
478c9e72 | 1625 | @smallexample |
ccd96f0a | 1626 | #define debug(format, ...) fprintf (stderr, format, __VA_ARGS__) |
478c9e72 | 1627 | @end smallexample |
c1f7febf | 1628 | |
ccd96f0a NB |
1629 | Here @samp{@dots{}} is a @dfn{variable argument}. In the invocation of |
1630 | such a macro, it represents the zero or more tokens until the closing | |
1631 | parenthesis that ends the invocation, including any commas. This set of | |
1632 | tokens replaces the identifier @code{__VA_ARGS__} in the macro body | |
1633 | wherever it appears. See the CPP manual for more information. | |
1634 | ||
1635 | GCC has long supported variadic macros, and used a different syntax that | |
1636 | allowed you to give a name to the variable arguments just like any other | |
1637 | argument. Here is an example: | |
c1f7febf | 1638 | |
3ab51846 | 1639 | @smallexample |
ccd96f0a | 1640 | #define debug(format, args...) fprintf (stderr, format, args) |
3ab51846 | 1641 | @end smallexample |
c1f7febf | 1642 | |
ccd96f0a NB |
1643 | This is in all ways equivalent to the ISO C example above, but arguably |
1644 | more readable and descriptive. | |
c1f7febf | 1645 | |
ccd96f0a NB |
1646 | GNU CPP has two further variadic macro extensions, and permits them to |
1647 | be used with either of the above forms of macro definition. | |
1648 | ||
1649 | In standard C, you are not allowed to leave the variable argument out | |
1650 | entirely; but you are allowed to pass an empty argument. For example, | |
1651 | this invocation is invalid in ISO C, because there is no comma after | |
1652 | the string: | |
c1f7febf | 1653 | |
3ab51846 | 1654 | @smallexample |
ccd96f0a | 1655 | debug ("A message") |
3ab51846 | 1656 | @end smallexample |
c1f7febf | 1657 | |
ccd96f0a NB |
1658 | GNU CPP permits you to completely omit the variable arguments in this |
1659 | way. In the above examples, the compiler would complain, though since | |
1660 | the expansion of the macro still has the extra comma after the format | |
1661 | string. | |
1662 | ||
1663 | To help solve this problem, CPP behaves specially for variable arguments | |
1664 | used with the token paste operator, @samp{##}. If instead you write | |
c1f7febf | 1665 | |
478c9e72 | 1666 | @smallexample |
ccd96f0a | 1667 | #define debug(format, ...) fprintf (stderr, format, ## __VA_ARGS__) |
478c9e72 | 1668 | @end smallexample |
c1f7febf | 1669 | |
ccd96f0a NB |
1670 | and if the variable arguments are omitted or empty, the @samp{##} |
1671 | operator causes the preprocessor to remove the comma before it. If you | |
1672 | do provide some variable arguments in your macro invocation, GNU CPP | |
1673 | does not complain about the paste operation and instead places the | |
1674 | variable arguments after the comma. Just like any other pasted macro | |
1675 | argument, these arguments are not macro expanded. | |
1676 | ||
1677 | @node Escaped Newlines | |
1678 | @section Slightly Looser Rules for Escaped Newlines | |
1679 | @cindex escaped newlines | |
1680 | @cindex newlines (escaped) | |
1681 | ||
f458d1d5 ZW |
1682 | Recently, the preprocessor has relaxed its treatment of escaped |
1683 | newlines. Previously, the newline had to immediately follow a | |
e6cc3a24 ZW |
1684 | backslash. The current implementation allows whitespace in the form |
1685 | of spaces, horizontal and vertical tabs, and form feeds between the | |
ccd96f0a NB |
1686 | backslash and the subsequent newline. The preprocessor issues a |
1687 | warning, but treats it as a valid escaped newline and combines the two | |
1688 | lines to form a single logical line. This works within comments and | |
e6cc3a24 ZW |
1689 | tokens, as well as between tokens. Comments are @emph{not} treated as |
1690 | whitespace for the purposes of this relaxation, since they have not | |
1691 | yet been replaced with spaces. | |
c1f7febf RK |
1692 | |
1693 | @node Subscripting | |
1694 | @section Non-Lvalue Arrays May Have Subscripts | |
1695 | @cindex subscripting | |
1696 | @cindex arrays, non-lvalue | |
1697 | ||
1698 | @cindex subscripting and function values | |
207bf485 JM |
1699 | In ISO C99, arrays that are not lvalues still decay to pointers, and |
1700 | may be subscripted, although they may not be modified or used after | |
1701 | the next sequence point and the unary @samp{&} operator may not be | |
1702 | applied to them. As an extension, GCC allows such arrays to be | |
7e1542b9 | 1703 | subscripted in C90 mode, though otherwise they do not decay to |
207bf485 | 1704 | pointers outside C99 mode. For example, |
7e1542b9 | 1705 | this is valid in GNU C though not valid in C90: |
c1f7febf | 1706 | |
3ab51846 | 1707 | @smallexample |
c1f7febf RK |
1708 | @group |
1709 | struct foo @{int a[4];@}; | |
1710 | ||
1711 | struct foo f(); | |
1712 | ||
1713 | bar (int index) | |
1714 | @{ | |
1715 | return f().a[index]; | |
1716 | @} | |
1717 | @end group | |
3ab51846 | 1718 | @end smallexample |
c1f7febf RK |
1719 | |
1720 | @node Pointer Arith | |
1721 | @section Arithmetic on @code{void}- and Function-Pointers | |
1722 | @cindex void pointers, arithmetic | |
1723 | @cindex void, size of pointer to | |
1724 | @cindex function pointers, arithmetic | |
1725 | @cindex function, size of pointer to | |
1726 | ||
1727 | In GNU C, addition and subtraction operations are supported on pointers to | |
1728 | @code{void} and on pointers to functions. This is done by treating the | |
1729 | size of a @code{void} or of a function as 1. | |
1730 | ||
1731 | A consequence of this is that @code{sizeof} is also allowed on @code{void} | |
1732 | and on function types, and returns 1. | |
1733 | ||
84330467 JM |
1734 | @opindex Wpointer-arith |
1735 | The option @option{-Wpointer-arith} requests a warning if these extensions | |
c1f7febf RK |
1736 | are used. |
1737 | ||
1738 | @node Initializers | |
1739 | @section Non-Constant Initializers | |
1740 | @cindex initializers, non-constant | |
1741 | @cindex non-constant initializers | |
1742 | ||
4b404517 | 1743 | As in standard C++ and ISO C99, the elements of an aggregate initializer for an |
161d7b59 | 1744 | automatic variable are not required to be constant expressions in GNU C@. |
c1f7febf RK |
1745 | Here is an example of an initializer with run-time varying elements: |
1746 | ||
3ab51846 | 1747 | @smallexample |
c1f7febf RK |
1748 | foo (float f, float g) |
1749 | @{ | |
1750 | float beat_freqs[2] = @{ f-g, f+g @}; | |
0d893a63 | 1751 | /* @r{@dots{}} */ |
c1f7febf | 1752 | @} |
3ab51846 | 1753 | @end smallexample |
c1f7febf | 1754 | |
4b404517 JM |
1755 | @node Compound Literals |
1756 | @section Compound Literals | |
c1f7febf RK |
1757 | @cindex constructor expressions |
1758 | @cindex initializations in expressions | |
1759 | @cindex structures, constructor expression | |
1760 | @cindex expressions, constructor | |
4b404517 JM |
1761 | @cindex compound literals |
1762 | @c The GNU C name for what C99 calls compound literals was "constructor expressions". | |
c1f7febf | 1763 | |
4b404517 | 1764 | ISO C99 supports compound literals. A compound literal looks like |
c1f7febf RK |
1765 | a cast containing an initializer. Its value is an object of the |
1766 | type specified in the cast, containing the elements specified in | |
db3acfa5 | 1767 | the initializer; it is an lvalue. As an extension, GCC supports |
7e1542b9 | 1768 | compound literals in C90 mode and in C++. |
c1f7febf RK |
1769 | |
1770 | Usually, the specified type is a structure. Assume that | |
1771 | @code{struct foo} and @code{structure} are declared as shown: | |
1772 | ||
3ab51846 | 1773 | @smallexample |
c1f7febf | 1774 | struct foo @{int a; char b[2];@} structure; |
3ab51846 | 1775 | @end smallexample |
c1f7febf RK |
1776 | |
1777 | @noindent | |
4b404517 | 1778 | Here is an example of constructing a @code{struct foo} with a compound literal: |
c1f7febf | 1779 | |
3ab51846 | 1780 | @smallexample |
c1f7febf | 1781 | structure = ((struct foo) @{x + y, 'a', 0@}); |
3ab51846 | 1782 | @end smallexample |
c1f7febf RK |
1783 | |
1784 | @noindent | |
1785 | This is equivalent to writing the following: | |
1786 | ||
3ab51846 | 1787 | @smallexample |
c1f7febf RK |
1788 | @{ |
1789 | struct foo temp = @{x + y, 'a', 0@}; | |
1790 | structure = temp; | |
1791 | @} | |
3ab51846 | 1792 | @end smallexample |
c1f7febf | 1793 | |
4b404517 | 1794 | You can also construct an array. If all the elements of the compound literal |
c1f7febf | 1795 | are (made up of) simple constant expressions, suitable for use in |
db3acfa5 JM |
1796 | initializers of objects of static storage duration, then the compound |
1797 | literal can be coerced to a pointer to its first element and used in | |
1798 | such an initializer, as shown here: | |
c1f7febf | 1799 | |
3ab51846 | 1800 | @smallexample |
c1f7febf | 1801 | char **foo = (char *[]) @{ "x", "y", "z" @}; |
3ab51846 | 1802 | @end smallexample |
c1f7febf | 1803 | |
49d6830d | 1804 | Compound literals for scalar types and union types are |
4b404517 | 1805 | also allowed, but then the compound literal is equivalent |
c1f7febf RK |
1806 | to a cast. |
1807 | ||
59c83dbf JJ |
1808 | As a GNU extension, GCC allows initialization of objects with static storage |
1809 | duration by compound literals (which is not possible in ISO C99, because | |
1810 | the initializer is not a constant). | |
1811 | It is handled as if the object was initialized only with the bracket | |
1eaf20ec | 1812 | enclosed list if the types of the compound literal and the object match. |
59c83dbf JJ |
1813 | The initializer list of the compound literal must be constant. |
1814 | If the object being initialized has array type of unknown size, the size is | |
ad47f1e5 | 1815 | determined by compound literal size. |
59c83dbf | 1816 | |
3ab51846 | 1817 | @smallexample |
59c83dbf JJ |
1818 | static struct foo x = (struct foo) @{1, 'a', 'b'@}; |
1819 | static int y[] = (int []) @{1, 2, 3@}; | |
1820 | static int z[] = (int [3]) @{1@}; | |
3ab51846 | 1821 | @end smallexample |
59c83dbf JJ |
1822 | |
1823 | @noindent | |
1824 | The above lines are equivalent to the following: | |
3ab51846 | 1825 | @smallexample |
59c83dbf JJ |
1826 | static struct foo x = @{1, 'a', 'b'@}; |
1827 | static int y[] = @{1, 2, 3@}; | |
ad47f1e5 | 1828 | static int z[] = @{1, 0, 0@}; |
3ab51846 | 1829 | @end smallexample |
59c83dbf | 1830 | |
4b404517 JM |
1831 | @node Designated Inits |
1832 | @section Designated Initializers | |
c1f7febf RK |
1833 | @cindex initializers with labeled elements |
1834 | @cindex labeled elements in initializers | |
1835 | @cindex case labels in initializers | |
4b404517 | 1836 | @cindex designated initializers |
c1f7febf | 1837 | |
7e1542b9 | 1838 | Standard C90 requires the elements of an initializer to appear in a fixed |
c1f7febf RK |
1839 | order, the same as the order of the elements in the array or structure |
1840 | being initialized. | |
1841 | ||
26d4fec7 JM |
1842 | In ISO C99 you can give the elements in any order, specifying the array |
1843 | indices or structure field names they apply to, and GNU C allows this as | |
7e1542b9 | 1844 | an extension in C90 mode as well. This extension is not |
c1f7febf RK |
1845 | implemented in GNU C++. |
1846 | ||
26d4fec7 | 1847 | To specify an array index, write |
c1f7febf RK |
1848 | @samp{[@var{index}] =} before the element value. For example, |
1849 | ||
3ab51846 | 1850 | @smallexample |
26d4fec7 | 1851 | int a[6] = @{ [4] = 29, [2] = 15 @}; |
3ab51846 | 1852 | @end smallexample |
c1f7febf RK |
1853 | |
1854 | @noindent | |
1855 | is equivalent to | |
1856 | ||
3ab51846 | 1857 | @smallexample |
c1f7febf | 1858 | int a[6] = @{ 0, 0, 15, 0, 29, 0 @}; |
3ab51846 | 1859 | @end smallexample |
c1f7febf RK |
1860 | |
1861 | @noindent | |
1862 | The index values must be constant expressions, even if the array being | |
1863 | initialized is automatic. | |
1864 | ||
26d4fec7 JM |
1865 | An alternative syntax for this which has been obsolete since GCC 2.5 but |
1866 | GCC still accepts is to write @samp{[@var{index}]} before the element | |
1867 | value, with no @samp{=}. | |
1868 | ||
c1f7febf | 1869 | To initialize a range of elements to the same value, write |
26d4fec7 JM |
1870 | @samp{[@var{first} ... @var{last}] = @var{value}}. This is a GNU |
1871 | extension. For example, | |
c1f7febf | 1872 | |
3ab51846 | 1873 | @smallexample |
c1f7febf | 1874 | int widths[] = @{ [0 ... 9] = 1, [10 ... 99] = 2, [100] = 3 @}; |
3ab51846 | 1875 | @end smallexample |
c1f7febf | 1876 | |
8b6a5902 JJ |
1877 | @noindent |
1878 | If the value in it has side-effects, the side-effects will happen only once, | |
1879 | not for each initialized field by the range initializer. | |
1880 | ||
c1f7febf RK |
1881 | @noindent |
1882 | Note that the length of the array is the highest value specified | |
1883 | plus one. | |
1884 | ||
1885 | In a structure initializer, specify the name of a field to initialize | |
26d4fec7 | 1886 | with @samp{.@var{fieldname} =} before the element value. For example, |
c1f7febf RK |
1887 | given the following structure, |
1888 | ||
3ab51846 | 1889 | @smallexample |
c1f7febf | 1890 | struct point @{ int x, y; @}; |
3ab51846 | 1891 | @end smallexample |
c1f7febf RK |
1892 | |
1893 | @noindent | |
1894 | the following initialization | |
1895 | ||
3ab51846 | 1896 | @smallexample |
26d4fec7 | 1897 | struct point p = @{ .y = yvalue, .x = xvalue @}; |
3ab51846 | 1898 | @end smallexample |
c1f7febf RK |
1899 | |
1900 | @noindent | |
1901 | is equivalent to | |
1902 | ||
3ab51846 | 1903 | @smallexample |
c1f7febf | 1904 | struct point p = @{ xvalue, yvalue @}; |
3ab51846 | 1905 | @end smallexample |
c1f7febf | 1906 | |
26d4fec7 JM |
1907 | Another syntax which has the same meaning, obsolete since GCC 2.5, is |
1908 | @samp{@var{fieldname}:}, as shown here: | |
c1f7febf | 1909 | |
3ab51846 | 1910 | @smallexample |
26d4fec7 | 1911 | struct point p = @{ y: yvalue, x: xvalue @}; |
3ab51846 | 1912 | @end smallexample |
c1f7febf | 1913 | |
4b404517 JM |
1914 | @cindex designators |
1915 | The @samp{[@var{index}]} or @samp{.@var{fieldname}} is known as a | |
1916 | @dfn{designator}. You can also use a designator (or the obsolete colon | |
1917 | syntax) when initializing a union, to specify which element of the union | |
1918 | should be used. For example, | |
c1f7febf | 1919 | |
3ab51846 | 1920 | @smallexample |
c1f7febf RK |
1921 | union foo @{ int i; double d; @}; |
1922 | ||
26d4fec7 | 1923 | union foo f = @{ .d = 4 @}; |
3ab51846 | 1924 | @end smallexample |
c1f7febf RK |
1925 | |
1926 | @noindent | |
1927 | will convert 4 to a @code{double} to store it in the union using | |
1928 | the second element. By contrast, casting 4 to type @code{union foo} | |
1929 | would store it into the union as the integer @code{i}, since it is | |
1930 | an integer. (@xref{Cast to Union}.) | |
1931 | ||
1932 | You can combine this technique of naming elements with ordinary C | |
1933 | initialization of successive elements. Each initializer element that | |
4b404517 | 1934 | does not have a designator applies to the next consecutive element of the |
c1f7febf RK |
1935 | array or structure. For example, |
1936 | ||
3ab51846 | 1937 | @smallexample |
c1f7febf | 1938 | int a[6] = @{ [1] = v1, v2, [4] = v4 @}; |
3ab51846 | 1939 | @end smallexample |
c1f7febf RK |
1940 | |
1941 | @noindent | |
1942 | is equivalent to | |
1943 | ||
3ab51846 | 1944 | @smallexample |
c1f7febf | 1945 | int a[6] = @{ 0, v1, v2, 0, v4, 0 @}; |
3ab51846 | 1946 | @end smallexample |
c1f7febf RK |
1947 | |
1948 | Labeling the elements of an array initializer is especially useful | |
1949 | when the indices are characters or belong to an @code{enum} type. | |
1950 | For example: | |
1951 | ||
3ab51846 | 1952 | @smallexample |
c1f7febf RK |
1953 | int whitespace[256] |
1954 | = @{ [' '] = 1, ['\t'] = 1, ['\h'] = 1, | |
1955 | ['\f'] = 1, ['\n'] = 1, ['\r'] = 1 @}; | |
3ab51846 | 1956 | @end smallexample |
c1f7febf | 1957 | |
4b404517 | 1958 | @cindex designator lists |
26d4fec7 | 1959 | You can also write a series of @samp{.@var{fieldname}} and |
4b404517 | 1960 | @samp{[@var{index}]} designators before an @samp{=} to specify a |
26d4fec7 JM |
1961 | nested subobject to initialize; the list is taken relative to the |
1962 | subobject corresponding to the closest surrounding brace pair. For | |
1963 | example, with the @samp{struct point} declaration above: | |
1964 | ||
478c9e72 | 1965 | @smallexample |
26d4fec7 | 1966 | struct point ptarray[10] = @{ [2].y = yv2, [2].x = xv2, [0].x = xv0 @}; |
478c9e72 | 1967 | @end smallexample |
26d4fec7 | 1968 | |
8b6a5902 JJ |
1969 | @noindent |
1970 | If the same field is initialized multiple times, it will have value from | |
1971 | the last initialization. If any such overridden initialization has | |
1972 | side-effect, it is unspecified whether the side-effect happens or not. | |
2dd76960 | 1973 | Currently, GCC will discard them and issue a warning. |
8b6a5902 | 1974 | |
c1f7febf RK |
1975 | @node Case Ranges |
1976 | @section Case Ranges | |
1977 | @cindex case ranges | |
1978 | @cindex ranges in case statements | |
1979 | ||
1980 | You can specify a range of consecutive values in a single @code{case} label, | |
1981 | like this: | |
1982 | ||
3ab51846 | 1983 | @smallexample |
c1f7febf | 1984 | case @var{low} ... @var{high}: |
3ab51846 | 1985 | @end smallexample |
c1f7febf RK |
1986 | |
1987 | @noindent | |
1988 | This has the same effect as the proper number of individual @code{case} | |
1989 | labels, one for each integer value from @var{low} to @var{high}, inclusive. | |
1990 | ||
1991 | This feature is especially useful for ranges of ASCII character codes: | |
1992 | ||
3ab51846 | 1993 | @smallexample |
c1f7febf | 1994 | case 'A' ... 'Z': |
3ab51846 | 1995 | @end smallexample |
c1f7febf RK |
1996 | |
1997 | @strong{Be careful:} Write spaces around the @code{...}, for otherwise | |
1998 | it may be parsed wrong when you use it with integer values. For example, | |
1999 | write this: | |
2000 | ||
3ab51846 | 2001 | @smallexample |
c1f7febf | 2002 | case 1 ... 5: |
3ab51846 | 2003 | @end smallexample |
c1f7febf RK |
2004 | |
2005 | @noindent | |
2006 | rather than this: | |
2007 | ||
3ab51846 | 2008 | @smallexample |
c1f7febf | 2009 | case 1...5: |
3ab51846 | 2010 | @end smallexample |
c1f7febf RK |
2011 | |
2012 | @node Cast to Union | |
2013 | @section Cast to a Union Type | |
2014 | @cindex cast to a union | |
2015 | @cindex union, casting to a | |
2016 | ||
2017 | A cast to union type is similar to other casts, except that the type | |
2018 | specified is a union type. You can specify the type either with | |
2019 | @code{union @var{tag}} or with a typedef name. A cast to union is actually | |
2020 | a constructor though, not a cast, and hence does not yield an lvalue like | |
4b404517 | 2021 | normal casts. (@xref{Compound Literals}.) |
c1f7febf RK |
2022 | |
2023 | The types that may be cast to the union type are those of the members | |
2024 | of the union. Thus, given the following union and variables: | |
2025 | ||
3ab51846 | 2026 | @smallexample |
c1f7febf RK |
2027 | union foo @{ int i; double d; @}; |
2028 | int x; | |
2029 | double y; | |
3ab51846 | 2030 | @end smallexample |
c1f7febf RK |
2031 | |
2032 | @noindent | |
aee96fe9 | 2033 | both @code{x} and @code{y} can be cast to type @code{union foo}. |
c1f7febf RK |
2034 | |
2035 | Using the cast as the right-hand side of an assignment to a variable of | |
2036 | union type is equivalent to storing in a member of the union: | |
2037 | ||
3ab51846 | 2038 | @smallexample |
c1f7febf | 2039 | union foo u; |
0d893a63 | 2040 | /* @r{@dots{}} */ |
c1f7febf RK |
2041 | u = (union foo) x @equiv{} u.i = x |
2042 | u = (union foo) y @equiv{} u.d = y | |
3ab51846 | 2043 | @end smallexample |
c1f7febf RK |
2044 | |
2045 | You can also use the union cast as a function argument: | |
2046 | ||
3ab51846 | 2047 | @smallexample |
c1f7febf | 2048 | void hack (union foo); |
0d893a63 | 2049 | /* @r{@dots{}} */ |
c1f7febf | 2050 | hack ((union foo) x); |
3ab51846 | 2051 | @end smallexample |
c1f7febf | 2052 | |
4b404517 JM |
2053 | @node Mixed Declarations |
2054 | @section Mixed Declarations and Code | |
2055 | @cindex mixed declarations and code | |
2056 | @cindex declarations, mixed with code | |
2057 | @cindex code, mixed with declarations | |
2058 | ||
2059 | ISO C99 and ISO C++ allow declarations and code to be freely mixed | |
2060 | within compound statements. As an extension, GCC also allows this in | |
7e1542b9 | 2061 | C90 mode. For example, you could do: |
4b404517 | 2062 | |
3ab51846 | 2063 | @smallexample |
4b404517 | 2064 | int i; |
0d893a63 | 2065 | /* @r{@dots{}} */ |
4b404517 JM |
2066 | i++; |
2067 | int j = i + 2; | |
3ab51846 | 2068 | @end smallexample |
4b404517 JM |
2069 | |
2070 | Each identifier is visible from where it is declared until the end of | |
2071 | the enclosing block. | |
2072 | ||
c1f7febf RK |
2073 | @node Function Attributes |
2074 | @section Declaring Attributes of Functions | |
2075 | @cindex function attributes | |
2076 | @cindex declaring attributes of functions | |
2077 | @cindex functions that never return | |
6e9a3221 | 2078 | @cindex functions that return more than once |
c1f7febf RK |
2079 | @cindex functions that have no side effects |
2080 | @cindex functions in arbitrary sections | |
2a59078d | 2081 | @cindex functions that behave like malloc |
c1f7febf RK |
2082 | @cindex @code{volatile} applied to function |
2083 | @cindex @code{const} applied to function | |
26f6672d | 2084 | @cindex functions with @code{printf}, @code{scanf}, @code{strftime} or @code{strfmon} style arguments |
b34c7881 | 2085 | @cindex functions with non-null pointer arguments |
c1f7febf RK |
2086 | @cindex functions that are passed arguments in registers on the 386 |
2087 | @cindex functions that pop the argument stack on the 386 | |
2088 | @cindex functions that do not pop the argument stack on the 386 | |
ab442df7 MM |
2089 | @cindex functions that have different compilation options on the 386 |
2090 | @cindex functions that have different optimization options | |
ba885ec5 | 2091 | @cindex functions that are dynamically resolved |
c1f7febf RK |
2092 | |
2093 | In GNU C, you declare certain things about functions called in your program | |
2094 | which help the compiler optimize function calls and check your code more | |
2095 | carefully. | |
2096 | ||
2097 | The keyword @code{__attribute__} allows you to specify special | |
2098 | attributes when making a declaration. This keyword is followed by an | |
9162542e | 2099 | attribute specification inside double parentheses. The following |
eacecf96 | 2100 | attributes are currently defined for functions on all targets: |
837edd5f | 2101 | @code{aligned}, @code{alloc_size}, @code{noreturn}, |
86631ea3 MJ |
2102 | @code{returns_twice}, @code{noinline}, @code{noclone}, |
2103 | @code{always_inline}, @code{flatten}, @code{pure}, @code{const}, | |
2104 | @code{nothrow}, @code{sentinel}, @code{format}, @code{format_arg}, | |
7458026b ILT |
2105 | @code{no_instrument_function}, @code{no_split_stack}, |
2106 | @code{section}, @code{constructor}, | |
51bc54a6 | 2107 | @code{destructor}, @code{used}, @code{unused}, @code{deprecated}, |
ba885ec5 NS |
2108 | @code{weak}, @code{malloc}, @code{alias}, @code{ifunc}, |
2109 | @code{warn_unused_result}, @code{nonnull}, @code{gnu_inline}, | |
2110 | @code{externally_visible}, @code{hot}, @code{cold}, @code{artificial}, | |
2111 | @code{error} and @code{warning}. Several other attributes are defined | |
2112 | for functions on particular target systems. Other attributes, | |
2113 | including @code{section} are supported for variables declarations | |
2114 | (@pxref{Variable Attributes}) and for types (@pxref{Type Attributes}). | |
c1f7febf | 2115 | |
110532c8 BS |
2116 | GCC plugins may provide their own attributes. |
2117 | ||
c1f7febf RK |
2118 | You may also specify attributes with @samp{__} preceding and following |
2119 | each keyword. This allows you to use them in header files without | |
2120 | being concerned about a possible macro of the same name. For example, | |
2121 | you may use @code{__noreturn__} instead of @code{noreturn}. | |
2122 | ||
2c5e91d2 JM |
2123 | @xref{Attribute Syntax}, for details of the exact syntax for using |
2124 | attributes. | |
2125 | ||
c1f7febf | 2126 | @table @code |
8a36672b | 2127 | @c Keep this table alphabetized by attribute name. Treat _ as space. |
c1f7febf | 2128 | |
c8619b90 NS |
2129 | @item alias ("@var{target}") |
2130 | @cindex @code{alias} attribute | |
2131 | The @code{alias} attribute causes the declaration to be emitted as an | |
2132 | alias for another symbol, which must be specified. For instance, | |
c1f7febf RK |
2133 | |
2134 | @smallexample | |
c8619b90 NS |
2135 | void __f () @{ /* @r{Do something.} */; @} |
2136 | void f () __attribute__ ((weak, alias ("__f"))); | |
c1f7febf RK |
2137 | @end smallexample |
2138 | ||
a9b0b825 | 2139 | defines @samp{f} to be a weak alias for @samp{__f}. In C++, the |
52eb57df RH |
2140 | mangled name for the target must be used. It is an error if @samp{__f} |
2141 | is not defined in the same translation unit. | |
c8619b90 NS |
2142 | |
2143 | Not all target machines support this attribute. | |
9162542e | 2144 | |
837edd5f GK |
2145 | @item aligned (@var{alignment}) |
2146 | @cindex @code{aligned} attribute | |
2147 | This attribute specifies a minimum alignment for the function, | |
2148 | measured in bytes. | |
2149 | ||
2150 | You cannot use this attribute to decrease the alignment of a function, | |
2151 | only to increase it. However, when you explicitly specify a function | |
2152 | alignment this will override the effect of the | |
2153 | @option{-falign-functions} (@pxref{Optimize Options}) option for this | |
2154 | function. | |
2155 | ||
2156 | Note that the effectiveness of @code{aligned} attributes may be | |
2157 | limited by inherent limitations in your linker. On many systems, the | |
2158 | linker is only able to arrange for functions to be aligned up to a | |
2159 | certain maximum alignment. (For some linkers, the maximum supported | |
2160 | alignment may be very very small.) See your linker documentation for | |
2161 | further information. | |
2162 | ||
2163 | The @code{aligned} attribute can also be used for variables and fields | |
2164 | (@pxref{Variable Attributes}.) | |
2165 | ||
51bc54a6 DM |
2166 | @item alloc_size |
2167 | @cindex @code{alloc_size} attribute | |
2168 | The @code{alloc_size} attribute is used to tell the compiler that the | |
2169 | function return value points to memory, where the size is given by | |
ff2ce160 | 2170 | one or two of the functions parameters. GCC uses this |
51bc54a6 DM |
2171 | information to improve the correctness of @code{__builtin_object_size}. |
2172 | ||
2173 | The function parameter(s) denoting the allocated size are specified by | |
2174 | one or two integer arguments supplied to the attribute. The allocated size | |
2175 | is either the value of the single function argument specified or the product | |
2176 | of the two function arguments specified. Argument numbering starts at | |
2177 | one. | |
2178 | ||
ff2ce160 | 2179 | For instance, |
51bc54a6 DM |
2180 | |
2181 | @smallexample | |
2182 | void* my_calloc(size_t, size_t) __attribute__((alloc_size(1,2))) | |
1c42f5c6 | 2183 | void my_realloc(void*, size_t) __attribute__((alloc_size(2))) |
51bc54a6 DM |
2184 | @end smallexample |
2185 | ||
2186 | declares that my_calloc will return memory of the size given by | |
2187 | the product of parameter 1 and 2 and that my_realloc will return memory | |
2188 | of the size given by parameter 2. | |
2189 | ||
6aa77e6c | 2190 | @item always_inline |
c8619b90 | 2191 | @cindex @code{always_inline} function attribute |
6aa77e6c AH |
2192 | Generally, functions are not inlined unless optimization is specified. |
2193 | For functions declared inline, this attribute inlines the function even | |
2194 | if no optimization level was specified. | |
2195 | ||
4eb7fd83 JJ |
2196 | @item gnu_inline |
2197 | @cindex @code{gnu_inline} function attribute | |
da1c7394 ILT |
2198 | This attribute should be used with a function which is also declared |
2199 | with the @code{inline} keyword. It directs GCC to treat the function | |
7e1542b9 | 2200 | as if it were defined in gnu90 mode even when compiling in C99 or |
da1c7394 ILT |
2201 | gnu99 mode. |
2202 | ||
2203 | If the function is declared @code{extern}, then this definition of the | |
2204 | function is used only for inlining. In no case is the function | |
2205 | compiled as a standalone function, not even if you take its address | |
2206 | explicitly. Such an address becomes an external reference, as if you | |
2207 | had only declared the function, and had not defined it. This has | |
2208 | almost the effect of a macro. The way to use this is to put a | |
2209 | function definition in a header file with this attribute, and put | |
2210 | another copy of the function, without @code{extern}, in a library | |
2211 | file. The definition in the header file will cause most calls to the | |
2212 | function to be inlined. If any uses of the function remain, they will | |
2213 | refer to the single copy in the library. Note that the two | |
2214 | definitions of the functions need not be precisely the same, although | |
2215 | if they do not have the same effect your program may behave oddly. | |
2216 | ||
3a47c4e4 AO |
2217 | In C, if the function is neither @code{extern} nor @code{static}, then |
2218 | the function is compiled as a standalone function, as well as being | |
da1c7394 ILT |
2219 | inlined where possible. |
2220 | ||
2221 | This is how GCC traditionally handled functions declared | |
2222 | @code{inline}. Since ISO C99 specifies a different semantics for | |
2223 | @code{inline}, this function attribute is provided as a transition | |
2224 | measure and as a useful feature in its own right. This attribute is | |
2225 | available in GCC 4.1.3 and later. It is available if either of the | |
2226 | preprocessor macros @code{__GNUC_GNU_INLINE__} or | |
2227 | @code{__GNUC_STDC_INLINE__} are defined. @xref{Inline,,An Inline | |
2228 | Function is As Fast As a Macro}. | |
4eb7fd83 | 2229 | |
3a47c4e4 AO |
2230 | In C++, this attribute does not depend on @code{extern} in any way, |
2231 | but it still requires the @code{inline} keyword to enable its special | |
2232 | behavior. | |
2233 | ||
d752cfdb | 2234 | @item artificial |
1df48f5c | 2235 | @cindex @code{artificial} function attribute |
d752cfdb JJ |
2236 | This attribute is useful for small inline wrappers which if possible |
2237 | should appear during debugging as a unit, depending on the debug | |
2238 | info format it will either mean marking the function as artificial | |
2239 | or using the caller location for all instructions within the inlined | |
2240 | body. | |
2241 | ||
65655f79 DD |
2242 | @item bank_switch |
2243 | @cindex interrupt handler functions | |
2244 | When added to an interrupt handler with the M32C port, causes the | |
2245 | prologue and epilogue to use bank switching to preserve the registers | |
2246 | rather than saving them on the stack. | |
2247 | ||
0691d1d4 | 2248 | @item flatten |
1df48f5c | 2249 | @cindex @code{flatten} function attribute |
0691d1d4 RG |
2250 | Generally, inlining into a function is limited. For a function marked with |
2251 | this attribute, every call inside this function will be inlined, if possible. | |
2252 | Whether the function itself is considered for inlining depends on its size and | |
d6cc6ec9 | 2253 | the current inlining parameters. |
0691d1d4 | 2254 | |
d2af6a68 JJ |
2255 | @item error ("@var{message}") |
2256 | @cindex @code{error} function attribute | |
2257 | If this attribute is used on a function declaration and a call to such a function | |
2258 | is not eliminated through dead code elimination or other optimizations, an error | |
2259 | which will include @var{message} will be diagnosed. This is useful | |
2260 | for compile time checking, especially together with @code{__builtin_constant_p} | |
2261 | and inline functions where checking the inline function arguments is not | |
2262 | possible through @code{extern char [(condition) ? 1 : -1];} tricks. | |
2263 | While it is possible to leave the function undefined and thus invoke | |
2264 | a link failure, when using this attribute the problem will be diagnosed | |
2265 | earlier and with exact location of the call even in presence of inline | |
2266 | functions or when not emitting debugging information. | |
2267 | ||
2268 | @item warning ("@var{message}") | |
2269 | @cindex @code{warning} function attribute | |
2270 | If this attribute is used on a function declaration and a call to such a function | |
2271 | is not eliminated through dead code elimination or other optimizations, a warning | |
2272 | which will include @var{message} will be diagnosed. This is useful | |
2273 | for compile time checking, especially together with @code{__builtin_constant_p} | |
2274 | and inline functions. While it is possible to define the function with | |
2275 | a message in @code{.gnu.warning*} section, when using this attribute the problem | |
2276 | will be diagnosed earlier and with exact location of the call even in presence | |
2277 | of inline functions or when not emitting debugging information. | |
2278 | ||
c8619b90 NS |
2279 | @item cdecl |
2280 | @cindex functions that do pop the argument stack on the 386 | |
2281 | @opindex mrtd | |
2282 | On the Intel 386, the @code{cdecl} attribute causes the compiler to | |
2283 | assume that the calling function will pop off the stack space used to | |
2284 | pass arguments. This is | |
2285 | useful to override the effects of the @option{-mrtd} switch. | |
2a8f6b90 | 2286 | |
2a8f6b90 | 2287 | @item const |
c8619b90 | 2288 | @cindex @code{const} function attribute |
2a8f6b90 JH |
2289 | Many functions do not examine any values except their arguments, and |
2290 | have no effects except the return value. Basically this is just slightly | |
50c177f7 | 2291 | more strict class than the @code{pure} attribute below, since function is not |
2a59078d | 2292 | allowed to read global memory. |
2a8f6b90 JH |
2293 | |
2294 | @cindex pointer arguments | |
2295 | Note that a function that has pointer arguments and examines the data | |
2296 | pointed to must @emph{not} be declared @code{const}. Likewise, a | |
2297 | function that calls a non-@code{const} function usually must not be | |
2298 | @code{const}. It does not make sense for a @code{const} function to | |
2299 | return @code{void}. | |
2300 | ||
f0523f02 | 2301 | The attribute @code{const} is not implemented in GCC versions earlier |
c1f7febf RK |
2302 | than 2.5. An alternative way to declare that a function has no side |
2303 | effects, which works in the current version and in some older versions, | |
2304 | is as follows: | |
2305 | ||
2306 | @smallexample | |
2307 | typedef int intfn (); | |
2308 | ||
2309 | extern const intfn square; | |
2310 | @end smallexample | |
2311 | ||
2312 | This approach does not work in GNU C++ from 2.6.0 on, since the language | |
2313 | specifies that the @samp{const} must be attached to the return value. | |
2314 | ||
c8619b90 NS |
2315 | @item constructor |
2316 | @itemx destructor | |
fc8600f9 MM |
2317 | @itemx constructor (@var{priority}) |
2318 | @itemx destructor (@var{priority}) | |
c8619b90 NS |
2319 | @cindex @code{constructor} function attribute |
2320 | @cindex @code{destructor} function attribute | |
2321 | The @code{constructor} attribute causes the function to be called | |
2322 | automatically before execution enters @code{main ()}. Similarly, the | |
2323 | @code{destructor} attribute causes the function to be called | |
2324 | automatically after @code{main ()} has completed or @code{exit ()} has | |
2325 | been called. Functions with these attributes are useful for | |
2326 | initializing data that will be used implicitly during the execution of | |
2327 | the program. | |
2328 | ||
fc8600f9 MM |
2329 | You may provide an optional integer priority to control the order in |
2330 | which constructor and destructor functions are run. A constructor | |
2331 | with a smaller priority number runs before a constructor with a larger | |
2332 | priority number; the opposite relationship holds for destructors. So, | |
2333 | if you have a constructor that allocates a resource and a destructor | |
2334 | that deallocates the same resource, both functions typically have the | |
2335 | same priority. The priorities for constructor and destructor | |
2336 | functions are the same as those specified for namespace-scope C++ | |
2337 | objects (@pxref{C++ Attributes}). | |
2338 | ||
c8619b90 NS |
2339 | These attributes are not currently implemented for Objective-C@. |
2340 | ||
2341 | @item deprecated | |
9b86d6bb | 2342 | @itemx deprecated (@var{msg}) |
c8619b90 NS |
2343 | @cindex @code{deprecated} attribute. |
2344 | The @code{deprecated} attribute results in a warning if the function | |
2345 | is used anywhere in the source file. This is useful when identifying | |
2346 | functions that are expected to be removed in a future version of a | |
2347 | program. The warning also includes the location of the declaration | |
2348 | of the deprecated function, to enable users to easily find further | |
2349 | information about why the function is deprecated, or what they should | |
2350 | do instead. Note that the warnings only occurs for uses: | |
2351 | ||
2352 | @smallexample | |
2353 | int old_fn () __attribute__ ((deprecated)); | |
2354 | int old_fn (); | |
2355 | int (*fn_ptr)() = old_fn; | |
2356 | @end smallexample | |
2357 | ||
9b86d6bb L |
2358 | results in a warning on line 3 but not line 2. The optional msg |
2359 | argument, which must be a string, will be printed in the warning if | |
2360 | present. | |
c8619b90 NS |
2361 | |
2362 | The @code{deprecated} attribute can also be used for variables and | |
2363 | types (@pxref{Variable Attributes}, @pxref{Type Attributes}.) | |
2364 | ||
e2491744 DD |
2365 | @item disinterrupt |
2366 | @cindex @code{disinterrupt} attribute | |
feeeff5c | 2367 | On Epiphany and MeP targets, this attribute causes the compiler to emit |
e2491744 DD |
2368 | instructions to disable interrupts for the duration of the given |
2369 | function. | |
2370 | ||
c8619b90 NS |
2371 | @item dllexport |
2372 | @cindex @code{__declspec(dllexport)} | |
b2ca3702 MM |
2373 | On Microsoft Windows targets and Symbian OS targets the |
2374 | @code{dllexport} attribute causes the compiler to provide a global | |
2375 | pointer to a pointer in a DLL, so that it can be referenced with the | |
2376 | @code{dllimport} attribute. On Microsoft Windows targets, the pointer | |
2377 | name is formed by combining @code{_imp__} and the function or variable | |
2378 | name. | |
2379 | ||
2380 | You can use @code{__declspec(dllexport)} as a synonym for | |
2381 | @code{__attribute__ ((dllexport))} for compatibility with other | |
2382 | compilers. | |
2383 | ||
2384 | On systems that support the @code{visibility} attribute, this | |
3a687f8b MM |
2385 | attribute also implies ``default'' visibility. It is an error to |
2386 | explicitly specify any other visibility. | |
c8619b90 | 2387 | |
ff2ce160 | 2388 | In previous versions of GCC, the @code{dllexport} attribute was ignored |
47ea1edf DK |
2389 | for inlined functions, unless the @option{-fkeep-inline-functions} flag |
2390 | had been used. The default behaviour now is to emit all dllexported | |
2391 | inline functions; however, this can cause object file-size bloat, in | |
2392 | which case the old behaviour can be restored by using | |
2393 | @option{-fno-keep-inline-dllexport}. | |
2394 | ||
2395 | The attribute is also ignored for undefined symbols. | |
c8619b90 | 2396 | |
8a36672b JM |
2397 | When applied to C++ classes, the attribute marks defined non-inlined |
2398 | member functions and static data members as exports. Static consts | |
c8619b90 NS |
2399 | initialized in-class are not marked unless they are also defined |
2400 | out-of-class. | |
2401 | ||
b55e3aad | 2402 | For Microsoft Windows targets there are alternative methods for |
b2ca3702 | 2403 | including the symbol in the DLL's export table such as using a |
b55e3aad NC |
2404 | @file{.def} file with an @code{EXPORTS} section or, with GNU ld, using |
2405 | the @option{--export-all} linker flag. | |
c8619b90 NS |
2406 | |
2407 | @item dllimport | |
2408 | @cindex @code{__declspec(dllimport)} | |
b2ca3702 | 2409 | On Microsoft Windows and Symbian OS targets, the @code{dllimport} |
b55e3aad | 2410 | attribute causes the compiler to reference a function or variable via |
b2ca3702 | 2411 | a global pointer to a pointer that is set up by the DLL exporting the |
3a687f8b MM |
2412 | symbol. The attribute implies @code{extern}. On Microsoft Windows |
2413 | targets, the pointer name is formed by combining @code{_imp__} and the | |
2414 | function or variable name. | |
b2ca3702 MM |
2415 | |
2416 | You can use @code{__declspec(dllimport)} as a synonym for | |
2417 | @code{__attribute__ ((dllimport))} for compatibility with other | |
2418 | compilers. | |
c8619b90 | 2419 | |
3a687f8b MM |
2420 | On systems that support the @code{visibility} attribute, this |
2421 | attribute also implies ``default'' visibility. It is an error to | |
2422 | explicitly specify any other visibility. | |
2423 | ||
8a36672b | 2424 | Currently, the attribute is ignored for inlined functions. If the |
c8619b90 NS |
2425 | attribute is applied to a symbol @emph{definition}, an error is reported. |
2426 | If a symbol previously declared @code{dllimport} is later defined, the | |
2427 | attribute is ignored in subsequent references, and a warning is emitted. | |
2428 | The attribute is also overridden by a subsequent declaration as | |
2429 | @code{dllexport}. | |
2430 | ||
2431 | When applied to C++ classes, the attribute marks non-inlined | |
2432 | member functions and static data members as imports. However, the | |
2433 | attribute is ignored for virtual methods to allow creation of vtables | |
2434 | using thunks. | |
2435 | ||
b2ca3702 | 2436 | On the SH Symbian OS target the @code{dllimport} attribute also has |
78466c0e | 2437 | another affect---it can cause the vtable and run-time type information |
b2ca3702 MM |
2438 | for a class to be exported. This happens when the class has a |
2439 | dllimport'ed constructor or a non-inline, non-pure virtual function | |
e4ae5e77 | 2440 | and, for either of those two conditions, the class also has an inline |
b2ca3702 MM |
2441 | constructor or destructor and has a key function that is defined in |
2442 | the current translation unit. | |
b55e3aad NC |
2443 | |
2444 | For Microsoft Windows based targets the use of the @code{dllimport} | |
2445 | attribute on functions is not necessary, but provides a small | |
8a36672b | 2446 | performance benefit by eliminating a thunk in the DLL@. The use of the |
b55e3aad | 2447 | @code{dllimport} attribute on imported variables was required on older |
b2ca3702 | 2448 | versions of the GNU linker, but can now be avoided by passing the |
8a36672b | 2449 | @option{--enable-auto-import} switch to the GNU linker. As with |
b2ca3702 | 2450 | functions, using the attribute for a variable eliminates a thunk in |
8a36672b | 2451 | the DLL@. |
b2ca3702 | 2452 | |
d32034a7 DS |
2453 | One drawback to using this attribute is that a pointer to a |
2454 | @emph{variable} marked as @code{dllimport} cannot be used as a constant | |
2455 | address. However, a pointer to a @emph{function} with the | |
2456 | @code{dllimport} attribute can be used as a constant initializer; in | |
2457 | this case, the address of a stub function in the import lib is | |
2458 | referenced. On Microsoft Windows targets, the attribute can be disabled | |
b2ca3702 | 2459 | for functions by setting the @option{-mnop-fun-dllimport} flag. |
c8619b90 NS |
2460 | |
2461 | @item eightbit_data | |
2462 | @cindex eight bit data on the H8/300, H8/300H, and H8S | |
2463 | Use this attribute on the H8/300, H8/300H, and H8S to indicate that the specified | |
2464 | variable should be placed into the eight bit data section. | |
2465 | The compiler will generate more efficient code for certain operations | |
2466 | on data in the eight bit data area. Note the eight bit data area is limited to | |
2467 | 256 bytes of data. | |
2468 | ||
2469 | You must use GAS and GLD from GNU binutils version 2.7 or later for | |
2470 | this attribute to work correctly. | |
2471 | ||
0d4a78eb BS |
2472 | @item exception_handler |
2473 | @cindex exception handler functions on the Blackfin processor | |
2474 | Use this attribute on the Blackfin to indicate that the specified function | |
2475 | is an exception handler. The compiler will generate function entry and | |
2476 | exit sequences suitable for use in an exception handler when this | |
2477 | attribute is present. | |
2478 | ||
1df48f5c JW |
2479 | @item externally_visible |
2480 | @cindex @code{externally_visible} attribute. | |
2481 | This attribute, attached to a global variable or function, nullifies | |
2482 | the effect of the @option{-fwhole-program} command-line option, so the | |
6d41cd02 | 2483 | object remains visible outside the current compilation unit. If @option{-fwhole-program} is used together with @option{-flto} and @command{gold} is used as the linker plugin, @code{externally_visible} attributes are automatically added to functions (not variable yet due to a current @command{gold} issue) that are accessed outside of LTO objects according to resolution file produced by @command{gold}. For other linkers that cannot generate resolution file, explicit @code{externally_visible} attributes are still necessary. |
1df48f5c | 2484 | |
c8619b90 NS |
2485 | @item far |
2486 | @cindex functions which handle memory bank switching | |
2487 | On 68HC11 and 68HC12 the @code{far} attribute causes the compiler to | |
2488 | use a calling convention that takes care of switching memory banks when | |
2489 | entering and leaving a function. This calling convention is also the | |
2490 | default when using the @option{-mlong-calls} option. | |
2491 | ||
2492 | On 68HC12 the compiler will use the @code{call} and @code{rtc} instructions | |
2493 | to call and return from a function. | |
2494 | ||
2495 | On 68HC11 the compiler will generate a sequence of instructions | |
2496 | to invoke a board-specific routine to switch the memory bank and call the | |
8a36672b | 2497 | real function. The board-specific routine simulates a @code{call}. |
c8619b90 | 2498 | At the end of a function, it will jump to a board-specific routine |
8a36672b | 2499 | instead of using @code{rts}. The board-specific return routine simulates |
c8619b90 NS |
2500 | the @code{rtc}. |
2501 | ||
e2491744 DD |
2502 | On MeP targets this causes the compiler to use a calling convention |
2503 | which assumes the called function is too far away for the built-in | |
2504 | addressing modes. | |
2505 | ||
65655f79 DD |
2506 | @item fast_interrupt |
2507 | @cindex interrupt handler functions | |
65a324b4 | 2508 | Use this attribute on the M32C and RX ports to indicate that the specified |
65655f79 DD |
2509 | function is a fast interrupt handler. This is just like the |
2510 | @code{interrupt} attribute, except that @code{freit} is used to return | |
2511 | instead of @code{reit}. | |
2512 | ||
c8619b90 NS |
2513 | @item fastcall |
2514 | @cindex functions that pop the argument stack on the 386 | |
2515 | On the Intel 386, the @code{fastcall} attribute causes the compiler to | |
2f84b963 RG |
2516 | pass the first argument (if of integral type) in the register ECX and |
2517 | the second argument (if of integral type) in the register EDX@. Subsequent | |
2518 | and other typed arguments are passed on the stack. The called function will | |
2519 | pop the arguments off the stack. If the number of arguments is variable all | |
c8619b90 | 2520 | arguments are pushed on the stack. |
c1f7febf | 2521 | |
3e65f251 KT |
2522 | @item thiscall |
2523 | @cindex functions that pop the argument stack on the 386 | |
2524 | On the Intel 386, the @code{thiscall} attribute causes the compiler to | |
2525 | pass the first argument (if of integral type) in the register ECX. | |
2526 | Subsequent and other typed arguments are passed on the stack. The called | |
2527 | function will pop the arguments off the stack. | |
2528 | If the number of arguments is variable all arguments are pushed on the | |
2529 | stack. | |
2530 | The @code{thiscall} attribute is intended for C++ non-static member functions. | |
2531 | As gcc extension this calling convention can be used for C-functions | |
2532 | and for static member methods. | |
2533 | ||
c1f7febf RK |
2534 | @item format (@var{archetype}, @var{string-index}, @var{first-to-check}) |
2535 | @cindex @code{format} function attribute | |
84330467 | 2536 | @opindex Wformat |
bb72a084 | 2537 | The @code{format} attribute specifies that a function takes @code{printf}, |
26f6672d JM |
2538 | @code{scanf}, @code{strftime} or @code{strfmon} style arguments which |
2539 | should be type-checked against a format string. For example, the | |
2540 | declaration: | |
c1f7febf RK |
2541 | |
2542 | @smallexample | |
2543 | extern int | |
2544 | my_printf (void *my_object, const char *my_format, ...) | |
2545 | __attribute__ ((format (printf, 2, 3))); | |
2546 | @end smallexample | |
2547 | ||
2548 | @noindent | |
2549 | causes the compiler to check the arguments in calls to @code{my_printf} | |
2550 | for consistency with the @code{printf} style format string argument | |
2551 | @code{my_format}. | |
2552 | ||
2553 | The parameter @var{archetype} determines how the format string is | |
6590fc9f KT |
2554 | interpreted, and should be @code{printf}, @code{scanf}, @code{strftime}, |
2555 | @code{gnu_printf}, @code{gnu_scanf}, @code{gnu_strftime} or | |
2556 | @code{strfmon}. (You can also use @code{__printf__}, | |
2557 | @code{__scanf__}, @code{__strftime__} or @code{__strfmon__}.) On | |
2558 | MinGW targets, @code{ms_printf}, @code{ms_scanf}, and | |
2559 | @code{ms_strftime} are also present. | |
2560 | @var{archtype} values such as @code{printf} refer to the formats accepted | |
2561 | by the system's C run-time library, while @code{gnu_} values always refer | |
2562 | to the formats accepted by the GNU C Library. On Microsoft Windows | |
2563 | targets, @code{ms_} values refer to the formats accepted by the | |
2564 | @file{msvcrt.dll} library. | |
2565 | The parameter @var{string-index} | |
2566 | specifies which argument is the format string argument (starting | |
2567 | from 1), while @var{first-to-check} is the number of the first | |
2568 | argument to check against the format string. For functions | |
2569 | where the arguments are not available to be checked (such as | |
c1f7febf | 2570 | @code{vprintf}), specify the third parameter as zero. In this case the |
b722c82c JM |
2571 | compiler only checks the format string for consistency. For |
2572 | @code{strftime} formats, the third parameter is required to be zero. | |
f57a2e3a BE |
2573 | Since non-static C++ methods have an implicit @code{this} argument, the |
2574 | arguments of such methods should be counted from two, not one, when | |
2575 | giving values for @var{string-index} and @var{first-to-check}. | |
c1f7febf RK |
2576 | |
2577 | In the example above, the format string (@code{my_format}) is the second | |
2578 | argument of the function @code{my_print}, and the arguments to check | |
2579 | start with the third argument, so the correct parameters for the format | |
2580 | attribute are 2 and 3. | |
2581 | ||
84330467 | 2582 | @opindex ffreestanding |
e6e931b7 | 2583 | @opindex fno-builtin |
c1f7febf | 2584 | The @code{format} attribute allows you to identify your own functions |
f0523f02 | 2585 | which take format strings as arguments, so that GCC can check the |
b722c82c | 2586 | calls to these functions for errors. The compiler always (unless |
e6e931b7 | 2587 | @option{-ffreestanding} or @option{-fno-builtin} is used) checks formats |
b722c82c | 2588 | for the standard library functions @code{printf}, @code{fprintf}, |
bb72a084 | 2589 | @code{sprintf}, @code{scanf}, @code{fscanf}, @code{sscanf}, @code{strftime}, |
c1f7febf | 2590 | @code{vprintf}, @code{vfprintf} and @code{vsprintf} whenever such |
84330467 | 2591 | warnings are requested (using @option{-Wformat}), so there is no need to |
b722c82c JM |
2592 | modify the header file @file{stdio.h}. In C99 mode, the functions |
2593 | @code{snprintf}, @code{vsnprintf}, @code{vscanf}, @code{vfscanf} and | |
26f6672d | 2594 | @code{vsscanf} are also checked. Except in strictly conforming C |
b4c984fb KG |
2595 | standard modes, the X/Open function @code{strfmon} is also checked as |
2596 | are @code{printf_unlocked} and @code{fprintf_unlocked}. | |
b722c82c | 2597 | @xref{C Dialect Options,,Options Controlling C Dialect}. |
c1f7febf | 2598 | |
ff2ce160 | 2599 | For Objective-C dialects, @code{NSString} (or @code{__NSString__}) is |
91ebb981 IS |
2600 | recognized in the same context. Declarations including these format attributes |
2601 | will be parsed for correct syntax, however the result of checking of such format | |
ff2ce160 | 2602 | strings is not yet defined, and will not be carried out by this version of the |
91ebb981 IS |
2603 | compiler. |
2604 | ||
2605 | The target may also provide additional types of format checks. | |
a2bec818 DJ |
2606 | @xref{Target Format Checks,,Format Checks Specific to Particular |
2607 | Target Machines}. | |
2608 | ||
c1f7febf RK |
2609 | @item format_arg (@var{string-index}) |
2610 | @cindex @code{format_arg} function attribute | |
84330467 | 2611 | @opindex Wformat-nonliteral |
26f6672d JM |
2612 | The @code{format_arg} attribute specifies that a function takes a format |
2613 | string for a @code{printf}, @code{scanf}, @code{strftime} or | |
2614 | @code{strfmon} style function and modifies it (for example, to translate | |
2615 | it into another language), so the result can be passed to a | |
2616 | @code{printf}, @code{scanf}, @code{strftime} or @code{strfmon} style | |
2617 | function (with the remaining arguments to the format function the same | |
2618 | as they would have been for the unmodified string). For example, the | |
2619 | declaration: | |
c1f7febf RK |
2620 | |
2621 | @smallexample | |
2622 | extern char * | |
2623 | my_dgettext (char *my_domain, const char *my_format) | |
2624 | __attribute__ ((format_arg (2))); | |
2625 | @end smallexample | |
2626 | ||
2627 | @noindent | |
26f6672d JM |
2628 | causes the compiler to check the arguments in calls to a @code{printf}, |
2629 | @code{scanf}, @code{strftime} or @code{strfmon} type function, whose | |
2630 | format string argument is a call to the @code{my_dgettext} function, for | |
2631 | consistency with the format string argument @code{my_format}. If the | |
2632 | @code{format_arg} attribute had not been specified, all the compiler | |
2633 | could tell in such calls to format functions would be that the format | |
2634 | string argument is not constant; this would generate a warning when | |
84330467 | 2635 | @option{-Wformat-nonliteral} is used, but the calls could not be checked |
26f6672d | 2636 | without the attribute. |
c1f7febf RK |
2637 | |
2638 | The parameter @var{string-index} specifies which argument is the format | |
f57a2e3a BE |
2639 | string argument (starting from one). Since non-static C++ methods have |
2640 | an implicit @code{this} argument, the arguments of such methods should | |
2641 | be counted from two. | |
c1f7febf RK |
2642 | |
2643 | The @code{format-arg} attribute allows you to identify your own | |
f0523f02 | 2644 | functions which modify format strings, so that GCC can check the |
26f6672d JM |
2645 | calls to @code{printf}, @code{scanf}, @code{strftime} or @code{strfmon} |
2646 | type function whose operands are a call to one of your own function. | |
2647 | The compiler always treats @code{gettext}, @code{dgettext}, and | |
2648 | @code{dcgettext} in this manner except when strict ISO C support is | |
84330467 | 2649 | requested by @option{-ansi} or an appropriate @option{-std} option, or |
e6e931b7 JM |
2650 | @option{-ffreestanding} or @option{-fno-builtin} |
2651 | is used. @xref{C Dialect Options,,Options | |
26f6672d | 2652 | Controlling C Dialect}. |
c1f7febf | 2653 | |
91ebb981 IS |
2654 | For Objective-C dialects, the @code{format-arg} attribute may refer to an |
2655 | @code{NSString} reference for compatibility with the @code{format} attribute | |
2656 | above. | |
2657 | ||
2658 | The target may also allow additional types in @code{format-arg} attributes. | |
2659 | @xref{Target Format Checks,,Format Checks Specific to Particular | |
2660 | Target Machines}. | |
2661 | ||
c8619b90 | 2662 | @item function_vector |
561642fa | 2663 | @cindex calling functions through the function vector on H8/300, M16C, M32C and SH2A processors |
c8619b90 NS |
2664 | Use this attribute on the H8/300, H8/300H, and H8S to indicate that the specified |
2665 | function should be called through the function vector. Calling a | |
2666 | function through the function vector will reduce code size, however; | |
2667 | the function vector has a limited size (maximum 128 entries on the H8/300 | |
2668 | and 64 entries on the H8/300H and H8S) and shares space with the interrupt vector. | |
b34c7881 | 2669 | |
561642fa AP |
2670 | In SH2A target, this attribute declares a function to be called using the |
2671 | TBR relative addressing mode. The argument to this attribute is the entry | |
2672 | number of the same function in a vector table containing all the TBR | |
2673 | relative addressable functions. For the successful jump, register TBR | |
2674 | should contain the start address of this TBR relative vector table. | |
2675 | In the startup routine of the user application, user needs to care of this | |
2676 | TBR register initialization. The TBR relative vector table can have at | |
2677 | max 256 function entries. The jumps to these functions will be generated | |
2678 | using a SH2A specific, non delayed branch instruction JSR/N @@(disp8,TBR). | |
c8619b90 NS |
2679 | You must use GAS and GLD from GNU binutils version 2.7 or later for |
2680 | this attribute to work correctly. | |
b34c7881 | 2681 | |
561642fa AP |
2682 | Please refer the example of M16C target, to see the use of this |
2683 | attribute while declaring a function, | |
2684 | ||
2685 | In an application, for a function being called once, this attribute will | |
2686 | save at least 8 bytes of code; and if other successive calls are being | |
2687 | made to the same function, it will save 2 bytes of code per each of these | |
2688 | calls. | |
2689 | ||
5abd2125 JS |
2690 | On M16C/M32C targets, the @code{function_vector} attribute declares a |
2691 | special page subroutine call function. Use of this attribute reduces | |
2692 | the code size by 2 bytes for each call generated to the | |
2693 | subroutine. The argument to the attribute is the vector number entry | |
2694 | from the special page vector table which contains the 16 low-order | |
2695 | bits of the subroutine's entry address. Each vector table has special | |
2696 | page number (18 to 255) which are used in @code{jsrs} instruction. | |
2697 | Jump addresses of the routines are generated by adding 0x0F0000 (in | |
2698 | case of M16C targets) or 0xFF0000 (in case of M32C targets), to the 2 | |
2699 | byte addresses set in the vector table. Therefore you need to ensure | |
2700 | that all the special page vector routines should get mapped within the | |
2701 | address range 0x0F0000 to 0x0FFFFF (for M16C) and 0xFF0000 to 0xFFFFFF | |
2702 | (for M32C). | |
2703 | ||
2704 | In the following example 2 bytes will be saved for each call to | |
2705 | function @code{foo}. | |
2706 | ||
2707 | @smallexample | |
2708 | void foo (void) __attribute__((function_vector(0x18))); | |
2709 | void foo (void) | |
2710 | @{ | |
2711 | @} | |
2712 | ||
2713 | void bar (void) | |
2714 | @{ | |
2715 | foo(); | |
2716 | @} | |
2717 | @end smallexample | |
2718 | ||
2719 | If functions are defined in one file and are called in another file, | |
2720 | then be sure to write this declaration in both files. | |
2721 | ||
2722 | This attribute is ignored for R8C target. | |
2723 | ||
c8619b90 NS |
2724 | @item interrupt |
2725 | @cindex interrupt handler functions | |
b25364a0 | 2726 | Use this attribute on the ARM, AVR, CR16, Epiphany, M32C, M32R/D, m68k, MeP, MIPS, |
85b8555e | 2727 | RL78, RX and Xstormy16 ports to indicate that the specified function is an |
2bccb817 KH |
2728 | interrupt handler. The compiler will generate function entry and exit |
2729 | sequences suitable for use in an interrupt handler when this attribute | |
2730 | is present. | |
b34c7881 | 2731 | |
80920132 ME |
2732 | Note, interrupt handlers for the Blackfin, H8/300, H8/300H, H8S, MicroBlaze, |
2733 | and SH processors can be specified via the @code{interrupt_handler} attribute. | |
b34c7881 | 2734 | |
c8619b90 | 2735 | Note, on the AVR, interrupts will be enabled inside the function. |
9162542e | 2736 | |
c8619b90 NS |
2737 | Note, for the ARM, you can specify the kind of interrupt to be handled by |
2738 | adding an optional parameter to the interrupt attribute like this: | |
e23bd218 IR |
2739 | |
2740 | @smallexample | |
c8619b90 | 2741 | void f () __attribute__ ((interrupt ("IRQ"))); |
e23bd218 IR |
2742 | @end smallexample |
2743 | ||
c8619b90 | 2744 | Permissible values for this parameter are: IRQ, FIQ, SWI, ABORT and UNDEF@. |
e23bd218 | 2745 | |
7a085dce | 2746 | On ARMv7-M the interrupt type is ignored, and the attribute means the function |
5b3e6663 PB |
2747 | may be called with a word aligned stack pointer. |
2748 | ||
e19da24c CF |
2749 | On MIPS targets, you can use the following attributes to modify the behavior |
2750 | of an interrupt handler: | |
2751 | @table @code | |
2752 | @item use_shadow_register_set | |
2753 | @cindex @code{use_shadow_register_set} attribute | |
2754 | Assume that the handler uses a shadow register set, instead of | |
2755 | the main general-purpose registers. | |
2756 | ||
2757 | @item keep_interrupts_masked | |
2758 | @cindex @code{keep_interrupts_masked} attribute | |
2759 | Keep interrupts masked for the whole function. Without this attribute, | |
2760 | GCC tries to reenable interrupts for as much of the function as it can. | |
2761 | ||
2762 | @item use_debug_exception_return | |
2763 | @cindex @code{use_debug_exception_return} attribute | |
2764 | Return using the @code{deret} instruction. Interrupt handlers that don't | |
2765 | have this attribute return using @code{eret} instead. | |
2766 | @end table | |
2767 | ||
2768 | You can use any combination of these attributes, as shown below: | |
2769 | @smallexample | |
2770 | void __attribute__ ((interrupt)) v0 (); | |
2771 | void __attribute__ ((interrupt, use_shadow_register_set)) v1 (); | |
2772 | void __attribute__ ((interrupt, keep_interrupts_masked)) v2 (); | |
2773 | void __attribute__ ((interrupt, use_debug_exception_return)) v3 (); | |
2774 | void __attribute__ ((interrupt, use_shadow_register_set, | |
73b8bfe1 | 2775 | keep_interrupts_masked)) v4 (); |
e19da24c | 2776 | void __attribute__ ((interrupt, use_shadow_register_set, |
73b8bfe1 | 2777 | use_debug_exception_return)) v5 (); |
e19da24c | 2778 | void __attribute__ ((interrupt, keep_interrupts_masked, |
73b8bfe1 | 2779 | use_debug_exception_return)) v6 (); |
e19da24c | 2780 | void __attribute__ ((interrupt, use_shadow_register_set, |
73b8bfe1 RW |
2781 | keep_interrupts_masked, |
2782 | use_debug_exception_return)) v7 (); | |
e19da24c CF |
2783 | @end smallexample |
2784 | ||
85b8555e DD |
2785 | On RL78, use @code{brk_interrupt} instead of @code{interrupt} for |
2786 | handlers intended to be used with the @code{BRK} opcode (i.e. those | |
2787 | that must end with @code{RETB} instead of @code{RETI}). | |
2788 | ||
ba885ec5 NS |
2789 | @item ifunc ("@var{resolver}") |
2790 | @cindex @code{ifunc} attribute | |
2791 | The @code{ifunc} attribute is used to mark a function as an indirect | |
2792 | function using the STT_GNU_IFUNC symbol type extension to the ELF | |
2793 | standard. This allows the resolution of the symbol value to be | |
2794 | determined dynamically at load time, and an optimized version of the | |
2795 | routine can be selected for the particular processor or other system | |
2796 | characteristics determined then. To use this attribute, first define | |
2797 | the implementation functions available, and a resolver function that | |
2798 | returns a pointer to the selected implementation function. The | |
2799 | implementation functions' declarations must match the API of the | |
2800 | function being implemented, the resolver's declaration is be a | |
2801 | function returning pointer to void function returning void: | |
2802 | ||
2803 | @smallexample | |
2804 | void *my_memcpy (void *dst, const void *src, size_t len) | |
2805 | @{ | |
2806 | @dots{} | |
2807 | @} | |
2808 | ||
2809 | static void (*resolve_memcpy (void)) (void) | |
2810 | @{ | |
2811 | return my_memcpy; // we'll just always select this routine | |
2812 | @} | |
2813 | @end smallexample | |
2814 | ||
2815 | The exported header file declaring the function the user calls would | |
2816 | contain: | |
2817 | ||
2818 | @smallexample | |
2819 | extern void *memcpy (void *, const void *, size_t); | |
2820 | @end smallexample | |
2821 | ||
2822 | allowing the user to call this as a regular function, unaware of the | |
2823 | implementation. Finally, the indirect function needs to be defined in | |
2824 | the same translation unit as the resolver function: | |
2825 | ||
2826 | @smallexample | |
2827 | void *memcpy (void *, const void *, size_t) | |
2828 | __attribute__ ((ifunc ("resolve_memcpy"))); | |
2829 | @end smallexample | |
2830 | ||
2831 | Indirect functions cannot be weak, and require a recent binutils (at | |
2832 | least version 2.20.1), and GNU C library (at least version 2.11.1). | |
2833 | ||
c8619b90 | 2834 | @item interrupt_handler |
0d4a78eb BS |
2835 | @cindex interrupt handler functions on the Blackfin, m68k, H8/300 and SH processors |
2836 | Use this attribute on the Blackfin, m68k, H8/300, H8/300H, H8S, and SH to | |
2837 | indicate that the specified function is an interrupt handler. The compiler | |
2838 | will generate function entry and exit sequences suitable for use in an | |
2839 | interrupt handler when this attribute is present. | |
2840 | ||
a4242737 KH |
2841 | @item interrupt_thread |
2842 | @cindex interrupt thread functions on fido | |
2843 | Use this attribute on fido, a subarchitecture of the m68k, to indicate | |
2844 | that the specified function is an interrupt handler that is designed | |
2845 | to run as a thread. The compiler omits generate prologue/epilogue | |
2846 | sequences and replaces the return instruction with a @code{sleep} | |
2847 | instruction. This attribute is available only on fido. | |
2848 | ||
d8f8ca80 RR |
2849 | @item isr |
2850 | @cindex interrupt service routines on ARM | |
2851 | Use this attribute on ARM to write Interrupt Service Routines. This is an | |
2852 | alias to the @code{interrupt} attribute above. | |
2853 | ||
0d4a78eb BS |
2854 | @item kspisusp |
2855 | @cindex User stack pointer in interrupts on the Blackfin | |
2856 | When used together with @code{interrupt_handler}, @code{exception_handler} | |
2857 | or @code{nmi_handler}, code will be generated to load the stack pointer | |
2858 | from the USP register in the function prologue. | |
72954a4f | 2859 | |
4af797b5 JZ |
2860 | @item l1_text |
2861 | @cindex @code{l1_text} function attribute | |
2862 | This attribute specifies a function to be placed into L1 Instruction | |
0ee2ea09 | 2863 | SRAM@. The function will be put into a specific section named @code{.l1.text}. |
4af797b5 JZ |
2864 | With @option{-mfdpic}, function calls with a such function as the callee |
2865 | or caller will use inlined PLT. | |
2866 | ||
603bb63e BS |
2867 | @item l2 |
2868 | @cindex @code{l2} function attribute | |
2869 | On the Blackfin, this attribute specifies a function to be placed into L2 | |
2870 | SRAM. The function will be put into a specific section named | |
2871 | @code{.l1.text}. With @option{-mfdpic}, callers of such functions will use | |
2872 | an inlined PLT. | |
2873 | ||
46a4da10 JH |
2874 | @item leaf |
2875 | @cindex @code{leaf} function attribute | |
2876 | Calls to external functions with this attribute must return to the current | |
2b0d3573 RW |
2877 | compilation unit only by return or by exception handling. In particular, leaf |
2878 | functions are not allowed to call callback function passed to it from the current | |
46a4da10 | 2879 | compilation unit or directly call functions exported by the unit or longjmp |
2b0d3573 RW |
2880 | into the unit. Leaf function might still call functions from other compilation |
2881 | units and thus they are not necessarily leaf in the sense that they contain no | |
46a4da10 JH |
2882 | function calls at all. |
2883 | ||
2884 | The attribute is intended for library functions to improve dataflow analysis. | |
2b0d3573 RW |
2885 | The compiler takes the hint that any data not escaping the current compilation unit can |
2886 | not be used or modified by the leaf function. For example, the @code{sin} function | |
2887 | is a leaf function, but @code{qsort} is not. | |
46a4da10 | 2888 | |
2b0d3573 RW |
2889 | Note that leaf functions might invoke signals and signal handlers might be |
2890 | defined in the current compilation unit and use static variables. The only | |
46a4da10 JH |
2891 | compliant way to write such a signal handler is to declare such variables |
2892 | @code{volatile}. | |
2893 | ||
2b0d3573 | 2894 | The attribute has no effect on functions defined within the current compilation |
46a4da10 JH |
2895 | unit. This is to allow easy merging of multiple compilation units into one, |
2896 | for example, by using the link time optimization. For this reason the | |
2897 | attribute is not allowed on types to annotate indirect calls. | |
2898 | ||
c8619b90 NS |
2899 | @item long_call/short_call |
2900 | @cindex indirect calls on ARM | |
2901 | This attribute specifies how a particular function is called on | |
feeeff5c JR |
2902 | ARM and Epiphany. Both attributes override the |
2903 | @option{-mlong-calls} (@pxref{ARM Options}) | |
bcbc9564 | 2904 | command-line switch and @code{#pragma long_calls} settings. The |
87c365a4 NS |
2905 | @code{long_call} attribute indicates that the function might be far |
2906 | away from the call site and require a different (more expensive) | |
2907 | calling sequence. The @code{short_call} attribute always places | |
c8619b90 NS |
2908 | the offset to the function from the call site into the @samp{BL} |
2909 | instruction directly. | |
72954a4f | 2910 | |
c8619b90 NS |
2911 | @item longcall/shortcall |
2912 | @cindex functions called via pointer on the RS/6000 and PowerPC | |
87c365a4 NS |
2913 | On the Blackfin, RS/6000 and PowerPC, the @code{longcall} attribute |
2914 | indicates that the function might be far away from the call site and | |
2915 | require a different (more expensive) calling sequence. The | |
2916 | @code{shortcall} attribute indicates that the function is always close | |
2917 | enough for the shorter calling sequence to be used. These attributes | |
2918 | override both the @option{-mlongcall} switch and, on the RS/6000 and | |
2919 | PowerPC, the @code{#pragma longcall} setting. | |
72954a4f | 2920 | |
c8619b90 NS |
2921 | @xref{RS/6000 and PowerPC Options}, for more information on whether long |
2922 | calls are necessary. | |
c1f7febf | 2923 | |
cd3a59b3 | 2924 | @item long_call/near/far |
4dbdb061 | 2925 | @cindex indirect calls on MIPS |
cd3a59b3 SL |
2926 | These attributes specify how a particular function is called on MIPS@. |
2927 | The attributes override the @option{-mlong-calls} (@pxref{MIPS Options}) | |
2928 | command-line switch. The @code{long_call} and @code{far} attributes are | |
2929 | synonyms, and cause the compiler to always call | |
4dbdb061 | 2930 | the function by first loading its address into a register, and then using |
cd3a59b3 | 2931 | the contents of that register. The @code{near} attribute has the opposite |
ff2ce160 | 2932 | effect; it specifies that non-PIC calls should be made using the more |
cd3a59b3 | 2933 | efficient @code{jal} instruction. |
4dbdb061 | 2934 | |
140592a0 AG |
2935 | @item malloc |
2936 | @cindex @code{malloc} attribute | |
2937 | The @code{malloc} attribute is used to tell the compiler that a function | |
928a5ba9 | 2938 | may be treated as if any non-@code{NULL} pointer it returns cannot |
65d5c485 RG |
2939 | alias any other pointer valid when the function returns and that the memory |
2940 | has undefined content. | |
140592a0 | 2941 | This will often improve optimization. |
928a5ba9 | 2942 | Standard functions with this property include @code{malloc} and |
65d5c485 RG |
2943 | @code{calloc}. @code{realloc}-like functions do not have this |
2944 | property as the memory pointed to does not have undefined content. | |
140592a0 | 2945 | |
f9e4a411 SL |
2946 | @item mips16/nomips16 |
2947 | @cindex @code{mips16} attribute | |
2948 | @cindex @code{nomips16} attribute | |
2949 | ||
2950 | On MIPS targets, you can use the @code{mips16} and @code{nomips16} | |
2951 | function attributes to locally select or turn off MIPS16 code generation. | |
ff2ce160 MS |
2952 | A function with the @code{mips16} attribute is emitted as MIPS16 code, |
2953 | while MIPS16 code generation is disabled for functions with the | |
2954 | @code{nomips16} attribute. These attributes override the | |
f9e4a411 | 2955 | @option{-mips16} and @option{-mno-mips16} options on the command line |
ff2ce160 | 2956 | (@pxref{MIPS Options}). |
f9e4a411 SL |
2957 | |
2958 | When compiling files containing mixed MIPS16 and non-MIPS16 code, the | |
2959 | preprocessor symbol @code{__mips16} reflects the setting on the command line, | |
2960 | not that within individual functions. Mixed MIPS16 and non-MIPS16 code | |
2961 | may interact badly with some GCC extensions such as @code{__builtin_apply} | |
2962 | (@pxref{Constructing Calls}). | |
2963 | ||
c8619b90 NS |
2964 | @item model (@var{model-name}) |
2965 | @cindex function addressability on the M32R/D | |
2966 | @cindex variable addressability on the IA-64 | |
2967 | ||
2968 | On the M32R/D, use this attribute to set the addressability of an | |
2969 | object, and of the code generated for a function. The identifier | |
2970 | @var{model-name} is one of @code{small}, @code{medium}, or | |
2971 | @code{large}, representing each of the code models. | |
2972 | ||
2973 | Small model objects live in the lower 16MB of memory (so that their | |
2974 | addresses can be loaded with the @code{ld24} instruction), and are | |
2975 | callable with the @code{bl} instruction. | |
2976 | ||
2977 | Medium model objects may live anywhere in the 32-bit address space (the | |
2978 | compiler will generate @code{seth/add3} instructions to load their addresses), | |
2979 | and are callable with the @code{bl} instruction. | |
2980 | ||
2981 | Large model objects may live anywhere in the 32-bit address space (the | |
2982 | compiler will generate @code{seth/add3} instructions to load their addresses), | |
2983 | and may not be reachable with the @code{bl} instruction (the compiler will | |
2984 | generate the much slower @code{seth/add3/jl} instruction sequence). | |
2985 | ||
2986 | On IA-64, use this attribute to set the addressability of an object. | |
2987 | At present, the only supported identifier for @var{model-name} is | |
2988 | @code{small}, indicating addressability via ``small'' (22-bit) | |
2989 | addresses (so that their addresses can be loaded with the @code{addl} | |
2990 | instruction). Caveat: such addressing is by definition not position | |
2991 | independent and hence this attribute must not be used for objects | |
2992 | defined by shared libraries. | |
2993 | ||
7c800926 | 2994 | @item ms_abi/sysv_abi |
f9ac6b1e | 2995 | @cindex @code{ms_abi} attribute |
7c800926 KT |
2996 | @cindex @code{sysv_abi} attribute |
2997 | ||
2fe83a0c KT |
2998 | On 32-bit and 64-bit (i?86|x86_64)-*-* targets, you can use an ABI attribute |
2999 | to indicate which calling convention should be used for a function. The | |
3000 | @code{ms_abi} attribute tells the compiler to use the Microsoft ABI, | |
3001 | while the @code{sysv_abi} attribute tells the compiler to use the ABI | |
3002 | used on GNU/Linux and other systems. The default is to use the Microsoft ABI | |
3003 | when targeting Windows. On all other systems, the default is the x86/AMD ABI. | |
7c800926 | 3004 | |
2fe83a0c KT |
3005 | Note, the @code{ms_abi} attribute for Windows 64-bit targets currently |
3006 | requires the @option{-maccumulate-outgoing-args} option. | |
7c800926 | 3007 | |
628c4eee KT |
3008 | @item callee_pop_aggregate_return (@var{number}) |
3009 | @cindex @code{callee_pop_aggregate_return} attribute | |
3010 | ||
3011 | On 32-bit i?86-*-* targets, you can control by those attribute for | |
3012 | aggregate return in memory, if the caller is responsible to pop the hidden | |
3013 | pointer together with the rest of the arguments - @var{number} equal to | |
3014 | zero -, or if the callee is responsible to pop hidden pointer - @var{number} | |
e44dbbe1 RO |
3015 | equal to one. The default i386 ABI assumes that the callee pops the |
3016 | stack for hidden pointer. | |
628c4eee | 3017 | |
2fe83a0c KT |
3018 | Note, that on 32-bit i386 Windows targets the compiler assumes that the |
3019 | caller pops the stack for hidden pointer. | |
3020 | ||
afd2c302 SD |
3021 | @item ms_hook_prologue |
3022 | @cindex @code{ms_hook_prologue} attribute | |
3023 | ||
135a687e KT |
3024 | On 32 bit i[34567]86-*-* targets and 64 bit x86_64-*-* targets, you can use |
3025 | this function attribute to make gcc generate the "hot-patching" function | |
3026 | prologue used in Win32 API functions in Microsoft Windows XP Service Pack 2 | |
3027 | and newer. | |
afd2c302 | 3028 | |
c8619b90 NS |
3029 | @item naked |
3030 | @cindex function without a prologue/epilogue code | |
ed3100b2 | 3031 | Use this attribute on the ARM, AVR, MCORE, RX and SPU ports to indicate that |
85d9c13c | 3032 | the specified function does not need prologue/epilogue sequences generated by |
ff2ce160 MS |
3033 | the compiler. It is up to the programmer to provide these sequences. The |
3034 | only statements that can be safely included in naked functions are | |
007e61c2 | 3035 | @code{asm} statements that do not have operands. All other statements, |
ff2ce160 MS |
3036 | including declarations of local variables, @code{if} statements, and so |
3037 | forth, should be avoided. Naked functions should be used to implement the | |
007e61c2 PB |
3038 | body of an assembly function, while allowing the compiler to construct |
3039 | the requisite function declaration for the assembler. | |
c8619b90 NS |
3040 | |
3041 | @item near | |
3042 | @cindex functions which do not handle memory bank switching on 68HC11/68HC12 | |
3043 | On 68HC11 and 68HC12 the @code{near} attribute causes the compiler to | |
3044 | use the normal calling convention based on @code{jsr} and @code{rts}. | |
3045 | This attribute can be used to cancel the effect of the @option{-mlong-calls} | |
3046 | option. | |
3047 | ||
e2491744 DD |
3048 | On MeP targets this attribute causes the compiler to assume the called |
3049 | function is close enough to use the normal calling convention, | |
3050 | overriding the @code{-mtf} command line option. | |
3051 | ||
0d4a78eb BS |
3052 | @item nesting |
3053 | @cindex Allow nesting in an interrupt handler on the Blackfin processor. | |
3054 | Use this attribute together with @code{interrupt_handler}, | |
3055 | @code{exception_handler} or @code{nmi_handler} to indicate that the function | |
3056 | entry code should enable nested interrupts or exceptions. | |
3057 | ||
3058 | @item nmi_handler | |
3059 | @cindex NMI handler functions on the Blackfin processor | |
3060 | Use this attribute on the Blackfin to indicate that the specified function | |
3061 | is an NMI handler. The compiler will generate function entry and | |
3062 | exit sequences suitable for use in an NMI handler when this | |
3063 | attribute is present. | |
3064 | ||
c8619b90 NS |
3065 | @item no_instrument_function |
3066 | @cindex @code{no_instrument_function} function attribute | |
3067 | @opindex finstrument-functions | |
3068 | If @option{-finstrument-functions} is given, profiling function calls will | |
3069 | be generated at entry and exit of most user-compiled functions. | |
3070 | Functions with this attribute will not be so instrumented. | |
3071 | ||
7458026b ILT |
3072 | @item no_split_stack |
3073 | @cindex @code{no_split_stack} function attribute | |
3074 | @opindex fsplit-stack | |
3075 | If @option{-fsplit-stack} is given, functions will have a small | |
3076 | prologue which decides whether to split the stack. Functions with the | |
3077 | @code{no_split_stack} attribute will not have that prologue, and thus | |
3078 | may run with only a small amount of stack space available. | |
3079 | ||
c8619b90 NS |
3080 | @item noinline |
3081 | @cindex @code{noinline} function attribute | |
3082 | This function attribute prevents a function from being considered for | |
3083 | inlining. | |
ccd2a21e HPN |
3084 | @c Don't enumerate the optimizations by name here; we try to be |
3085 | @c future-compatible with this mechanism. | |
3086 | If the function does not have side-effects, there are optimizations | |
3087 | other than inlining that causes function calls to be optimized away, | |
3088 | although the function call is live. To keep such calls from being | |
3089 | optimized away, put | |
3090 | @smallexample | |
3091 | asm (""); | |
3092 | @end smallexample | |
3093 | (@pxref{Extended Asm}) in the called function, to serve as a special | |
3094 | side-effect. | |
c8619b90 | 3095 | |
86631ea3 MJ |
3096 | @item noclone |
3097 | @cindex @code{noclone} function attribute | |
3098 | This function attribute prevents a function from being considered for | |
3099 | cloning - a mechanism which produces specialized copies of functions | |
3100 | and which is (currently) performed by interprocedural constant | |
3101 | propagation. | |
3102 | ||
c8619b90 NS |
3103 | @item nonnull (@var{arg-index}, @dots{}) |
3104 | @cindex @code{nonnull} function attribute | |
3105 | The @code{nonnull} attribute specifies that some function parameters should | |
3106 | be non-null pointers. For instance, the declaration: | |
c1f7febf RK |
3107 | |
3108 | @smallexample | |
c8619b90 NS |
3109 | extern void * |
3110 | my_memcpy (void *dest, const void *src, size_t len) | |
6ccde948 | 3111 | __attribute__((nonnull (1, 2))); |
c1f7febf RK |
3112 | @end smallexample |
3113 | ||
c8619b90 NS |
3114 | @noindent |
3115 | causes the compiler to check that, in calls to @code{my_memcpy}, | |
3116 | arguments @var{dest} and @var{src} are non-null. If the compiler | |
3117 | determines that a null pointer is passed in an argument slot marked | |
3118 | as non-null, and the @option{-Wnonnull} option is enabled, a warning | |
3119 | is issued. The compiler may also choose to make optimizations based | |
3120 | on the knowledge that certain function arguments will not be null. | |
af3e86c2 | 3121 | |
c8619b90 NS |
3122 | If no argument index list is given to the @code{nonnull} attribute, |
3123 | all pointer arguments are marked as non-null. To illustrate, the | |
3124 | following declaration is equivalent to the previous example: | |
47bd70b5 JJ |
3125 | |
3126 | @smallexample | |
c8619b90 NS |
3127 | extern void * |
3128 | my_memcpy (void *dest, const void *src, size_t len) | |
6ccde948 | 3129 | __attribute__((nonnull)); |
47bd70b5 JJ |
3130 | @end smallexample |
3131 | ||
c8619b90 NS |
3132 | @item noreturn |
3133 | @cindex @code{noreturn} function attribute | |
3134 | A few standard library functions, such as @code{abort} and @code{exit}, | |
3135 | cannot return. GCC knows this automatically. Some programs define | |
3136 | their own functions that never return. You can declare them | |
3137 | @code{noreturn} to tell the compiler this fact. For example, | |
9e8aab55 | 3138 | |
c8619b90 NS |
3139 | @smallexample |
3140 | @group | |
3141 | void fatal () __attribute__ ((noreturn)); | |
d5c4db17 | 3142 | |
c8619b90 NS |
3143 | void |
3144 | fatal (/* @r{@dots{}} */) | |
3145 | @{ | |
3146 | /* @r{@dots{}} */ /* @r{Print error message.} */ /* @r{@dots{}} */ | |
3147 | exit (1); | |
3148 | @} | |
3149 | @end group | |
3150 | @end smallexample | |
9e8aab55 | 3151 | |
c8619b90 NS |
3152 | The @code{noreturn} keyword tells the compiler to assume that |
3153 | @code{fatal} cannot return. It can then optimize without regard to what | |
3154 | would happen if @code{fatal} ever did return. This makes slightly | |
3155 | better code. More importantly, it helps avoid spurious warnings of | |
3156 | uninitialized variables. | |
9e8aab55 | 3157 | |
c8619b90 NS |
3158 | The @code{noreturn} keyword does not affect the exceptional path when that |
3159 | applies: a @code{noreturn}-marked function may still return to the caller | |
2e9522f4 | 3160 | by throwing an exception or calling @code{longjmp}. |
9e8aab55 | 3161 | |
c8619b90 NS |
3162 | Do not assume that registers saved by the calling function are |
3163 | restored before calling the @code{noreturn} function. | |
47bd70b5 | 3164 | |
c8619b90 NS |
3165 | It does not make sense for a @code{noreturn} function to have a return |
3166 | type other than @code{void}. | |
c1f7febf | 3167 | |
c8619b90 NS |
3168 | The attribute @code{noreturn} is not implemented in GCC versions |
3169 | earlier than 2.5. An alternative way to declare that a function does | |
3170 | not return, which works in the current version and in some older | |
3171 | versions, is as follows: | |
5d34c8e9 | 3172 | |
c8619b90 NS |
3173 | @smallexample |
3174 | typedef void voidfn (); | |
c1f7febf | 3175 | |
c8619b90 NS |
3176 | volatile voidfn fatal; |
3177 | @end smallexample | |
e91f04de | 3178 | |
a1e73046 PC |
3179 | This approach does not work in GNU C++. |
3180 | ||
c8619b90 NS |
3181 | @item nothrow |
3182 | @cindex @code{nothrow} function attribute | |
3183 | The @code{nothrow} attribute is used to inform the compiler that a | |
3184 | function cannot throw an exception. For example, most functions in | |
3185 | the standard C library can be guaranteed not to throw an exception | |
3186 | with the notable exceptions of @code{qsort} and @code{bsearch} that | |
3187 | take function pointer arguments. The @code{nothrow} attribute is not | |
3f3174b6 | 3188 | implemented in GCC versions earlier than 3.3. |
c1f7febf | 3189 | |
ab442df7 MM |
3190 | @item optimize |
3191 | @cindex @code{optimize} function attribute | |
3192 | The @code{optimize} attribute is used to specify that a function is to | |
3193 | be compiled with different optimization options than specified on the | |
3194 | command line. Arguments can either be numbers or strings. Numbers | |
3195 | are assumed to be an optimization level. Strings that begin with | |
3196 | @code{O} are assumed to be an optimization option, while other options | |
3197 | are assumed to be used with a @code{-f} prefix. You can also use the | |
3198 | @samp{#pragma GCC optimize} pragma to set the optimization options | |
3199 | that affect more than one function. | |
3200 | @xref{Function Specific Option Pragmas}, for details about the | |
e3606f3b | 3201 | @samp{#pragma GCC optimize} pragma. |
ab442df7 MM |
3202 | |
3203 | This can be used for instance to have frequently executed functions | |
3204 | compiled with more aggressive optimization options that produce faster | |
3205 | and larger code, while other functions can be called with less | |
5779e713 | 3206 | aggressive options. |
ab442df7 | 3207 | |
3d33d151 AS |
3208 | @item OS_main/OS_task |
3209 | @cindex @code{OS_main} AVR function attribute | |
3210 | @cindex @code{OS_task} AVR function attribute | |
3211 | On AVR, functions with the @code{OS_main} or @code{OS_task} attribute | |
3212 | do not save/restore any call-saved register in their prologue/epilogue. | |
3213 | ||
3214 | The @code{OS_main} attribute can be used when there @emph{is | |
3215 | guarantee} that interrupts are disabled at the time when the function | |
3216 | is entered. This will save resources when the stack pointer has to be | |
3217 | changed to set up a frame for local variables. | |
3218 | ||
3219 | The @code{OS_task} attribute can be used when there is @emph{no | |
3220 | guarantee} that interrupts are disabled at that time when the function | |
3221 | is entered like for, e@.g@. task functions in a multi-threading operating | |
3222 | system. In that case, changing the stack pointer register will be | |
3223 | guarded by save/clear/restore of the global interrupt enable flag. | |
3224 | ||
aa9ec4db | 3225 | The differences to the @code{naked} function attribute are: |
3d33d151 AS |
3226 | @itemize @bullet |
3227 | @item @code{naked} functions do not have a return instruction whereas | |
3228 | @code{OS_main} and @code{OS_task} functions will have a @code{RET} or | |
3229 | @code{RETI} return instruction. | |
3230 | @item @code{naked} functions do not set up a frame for local variables | |
3231 | or a frame pointer whereas @code{OS_main} and @code{OS_task} do this | |
3232 | as needed. | |
3233 | @end itemize | |
3234 | ||
14a782c8 RE |
3235 | @item pcs |
3236 | @cindex @code{pcs} function attribute | |
3237 | ||
3238 | The @code{pcs} attribute can be used to control the calling convention | |
3239 | used for a function on ARM. The attribute takes an argument that specifies | |
3240 | the calling convention to use. | |
3241 | ||
3242 | When compiling using the AAPCS ABI (or a variant of that) then valid | |
3243 | values for the argument are @code{"aapcs"} and @code{"aapcs-vfp"}. In | |
3244 | order to use a variant other than @code{"aapcs"} then the compiler must | |
3245 | be permitted to use the appropriate co-processor registers (i.e., the | |
3246 | VFP registers must be available in order to use @code{"aapcs-vfp"}). | |
3247 | For example, | |
3248 | ||
3249 | @smallexample | |
3250 | /* Argument passed in r0, and result returned in r0+r1. */ | |
3251 | double f2d (float) __attribute__((pcs("aapcs"))); | |
3252 | @end smallexample | |
3253 | ||
3254 | Variadic functions always use the @code{"aapcs"} calling convention and | |
3255 | the compiler will reject attempts to specify an alternative. | |
3256 | ||
c8619b90 NS |
3257 | @item pure |
3258 | @cindex @code{pure} function attribute | |
3259 | Many functions have no effects except the return value and their | |
3260 | return value depends only on the parameters and/or global variables. | |
3261 | Such a function can be subject | |
3262 | to common subexpression elimination and loop optimization just as an | |
3263 | arithmetic operator would be. These functions should be declared | |
3264 | with the attribute @code{pure}. For example, | |
a5c76ee6 | 3265 | |
c8619b90 NS |
3266 | @smallexample |
3267 | int square (int) __attribute__ ((pure)); | |
3268 | @end smallexample | |
c1f7febf | 3269 | |
c8619b90 NS |
3270 | @noindent |
3271 | says that the hypothetical function @code{square} is safe to call | |
3272 | fewer times than the program says. | |
c27ba912 | 3273 | |
c8619b90 NS |
3274 | Some of common examples of pure functions are @code{strlen} or @code{memcmp}. |
3275 | Interesting non-pure functions are functions with infinite loops or those | |
3276 | depending on volatile memory or other system resource, that may change between | |
3277 | two consecutive calls (such as @code{feof} in a multithreading environment). | |
c1f7febf | 3278 | |
c8619b90 NS |
3279 | The attribute @code{pure} is not implemented in GCC versions earlier |
3280 | than 2.96. | |
c1f7febf | 3281 | |
52bf96d2 JH |
3282 | @item hot |
3283 | @cindex @code{hot} function attribute | |
3284 | The @code{hot} attribute is used to inform the compiler that a function is a | |
3285 | hot spot of the compiled program. The function is optimized more aggressively | |
3286 | and on many target it is placed into special subsection of the text section so | |
3287 | all hot functions appears close together improving locality. | |
3288 | ||
3289 | When profile feedback is available, via @option{-fprofile-use}, hot functions | |
3290 | are automatically detected and this attribute is ignored. | |
3291 | ||
ab442df7 MM |
3292 | The @code{hot} attribute is not implemented in GCC versions earlier |
3293 | than 4.3. | |
3294 | ||
52bf96d2 JH |
3295 | @item cold |
3296 | @cindex @code{cold} function attribute | |
3297 | The @code{cold} attribute is used to inform the compiler that a function is | |
3298 | unlikely executed. The function is optimized for size rather than speed and on | |
3299 | many targets it is placed into special subsection of the text section so all | |
3300 | cold functions appears close together improving code locality of non-cold parts | |
3301 | of program. The paths leading to call of cold functions within code are marked | |
44c7bd63 | 3302 | as unlikely by the branch prediction mechanism. It is thus useful to mark |
52bf96d2 JH |
3303 | functions used to handle unlikely conditions, such as @code{perror}, as cold to |
3304 | improve optimization of hot functions that do call marked functions in rare | |
3305 | occasions. | |
3306 | ||
3307 | When profile feedback is available, via @option{-fprofile-use}, hot functions | |
3308 | are automatically detected and this attribute is ignored. | |
3309 | ||
ab442df7 MM |
3310 | The @code{cold} attribute is not implemented in GCC versions earlier than 4.3. |
3311 | ||
c8619b90 NS |
3312 | @item regparm (@var{number}) |
3313 | @cindex @code{regparm} attribute | |
3314 | @cindex functions that are passed arguments in registers on the 386 | |
3315 | On the Intel 386, the @code{regparm} attribute causes the compiler to | |
2f84b963 RG |
3316 | pass arguments number one to @var{number} if they are of integral type |
3317 | in registers EAX, EDX, and ECX instead of on the stack. Functions that | |
3318 | take a variable number of arguments will continue to be passed all of their | |
c8619b90 | 3319 | arguments on the stack. |
6d3d9133 | 3320 | |
c8619b90 NS |
3321 | Beware that on some ELF systems this attribute is unsuitable for |
3322 | global functions in shared libraries with lazy binding (which is the | |
3323 | default). Lazy binding will send the first call via resolving code in | |
3324 | the loader, which might assume EAX, EDX and ECX can be clobbered, as | |
3325 | per the standard calling conventions. Solaris 8 is affected by this. | |
3326 | GNU systems with GLIBC 2.1 or higher, and FreeBSD, are believed to be | |
21440b2d | 3327 | safe since the loaders there save EAX, EDX and ECX. (Lazy binding can be |
c8619b90 NS |
3328 | disabled with the linker or the loader if desired, to avoid the |
3329 | problem.) | |
6d3d9133 | 3330 | |
2f84b963 RG |
3331 | @item sseregparm |
3332 | @cindex @code{sseregparm} attribute | |
3333 | On the Intel 386 with SSE support, the @code{sseregparm} attribute | |
56829cae | 3334 | causes the compiler to pass up to 3 floating point arguments in |
2f84b963 RG |
3335 | SSE registers instead of on the stack. Functions that take a |
3336 | variable number of arguments will continue to pass all of their | |
3337 | floating point arguments on the stack. | |
3338 | ||
33932946 SH |
3339 | @item force_align_arg_pointer |
3340 | @cindex @code{force_align_arg_pointer} attribute | |
3341 | On the Intel x86, the @code{force_align_arg_pointer} attribute may be | |
3342 | applied to individual function definitions, generating an alternate | |
2e3f842f L |
3343 | prologue and epilogue that realigns the runtime stack if necessary. |
3344 | This supports mixing legacy codes that run with a 4-byte aligned stack | |
3345 | with modern codes that keep a 16-byte stack for SSE compatibility. | |
33932946 | 3346 | |
561642fa AP |
3347 | @item resbank |
3348 | @cindex @code{resbank} attribute | |
3349 | On the SH2A target, this attribute enables the high-speed register | |
3350 | saving and restoration using a register bank for @code{interrupt_handler} | |
a640c13b | 3351 | routines. Saving to the bank is performed automatically after the CPU |
561642fa AP |
3352 | accepts an interrupt that uses a register bank. |
3353 | ||
3354 | The nineteen 32-bit registers comprising general register R0 to R14, | |
3355 | control register GBR, and system registers MACH, MACL, and PR and the | |
3356 | vector table address offset are saved into a register bank. Register | |
3357 | banks are stacked in first-in last-out (FILO) sequence. Restoration | |
3358 | from the bank is executed by issuing a RESBANK instruction. | |
3359 | ||
6e9a3221 AN |
3360 | @item returns_twice |
3361 | @cindex @code{returns_twice} attribute | |
3362 | The @code{returns_twice} attribute tells the compiler that a function may | |
3363 | return more than one time. The compiler will ensure that all registers | |
3364 | are dead before calling such a function and will emit a warning about | |
3365 | the variables that may be clobbered after the second return from the | |
3366 | function. Examples of such functions are @code{setjmp} and @code{vfork}. | |
3367 | The @code{longjmp}-like counterpart of such function, if any, might need | |
3368 | to be marked with the @code{noreturn} attribute. | |
3369 | ||
c8619b90 | 3370 | @item saveall |
0d4a78eb BS |
3371 | @cindex save all registers on the Blackfin, H8/300, H8/300H, and H8S |
3372 | Use this attribute on the Blackfin, H8/300, H8/300H, and H8S to indicate that | |
c8619b90 NS |
3373 | all registers except the stack pointer should be saved in the prologue |
3374 | regardless of whether they are used or not. | |
6d3d9133 | 3375 | |
80920132 ME |
3376 | @item save_volatiles |
3377 | @cindex save volatile registers on the MicroBlaze | |
3378 | Use this attribute on the MicroBlaze to indicate that the function is | |
ff2ce160 MS |
3379 | an interrupt handler. All volatile registers (in addition to non-volatile |
3380 | registers) will be saved in the function prologue. If the function is a leaf | |
3381 | function, only volatiles used by the function are saved. A normal function | |
3382 | return is generated instead of a return from interrupt. | |
80920132 | 3383 | |
c8619b90 NS |
3384 | @item section ("@var{section-name}") |
3385 | @cindex @code{section} function attribute | |
3386 | Normally, the compiler places the code it generates in the @code{text} section. | |
3387 | Sometimes, however, you need additional sections, or you need certain | |
3388 | particular functions to appear in special sections. The @code{section} | |
3389 | attribute specifies that a function lives in a particular section. | |
3390 | For example, the declaration: | |
6d3d9133 NC |
3391 | |
3392 | @smallexample | |
c8619b90 | 3393 | extern void foobar (void) __attribute__ ((section ("bar"))); |
6d3d9133 NC |
3394 | @end smallexample |
3395 | ||
c8619b90 NS |
3396 | @noindent |
3397 | puts the function @code{foobar} in the @code{bar} section. | |
6d3d9133 | 3398 | |
c8619b90 NS |
3399 | Some file formats do not support arbitrary sections so the @code{section} |
3400 | attribute is not available on all platforms. | |
3401 | If you need to map the entire contents of a module to a particular | |
3402 | section, consider using the facilities of the linker instead. | |
3403 | ||
3d091dac KG |
3404 | @item sentinel |
3405 | @cindex @code{sentinel} function attribute | |
254986c7 KG |
3406 | This function attribute ensures that a parameter in a function call is |
3407 | an explicit @code{NULL}. The attribute is only valid on variadic | |
3408 | functions. By default, the sentinel is located at position zero, the | |
3409 | last parameter of the function call. If an optional integer position | |
3410 | argument P is supplied to the attribute, the sentinel must be located at | |
3411 | position P counting backwards from the end of the argument list. | |
3412 | ||
3413 | @smallexample | |
3414 | __attribute__ ((sentinel)) | |
3415 | is equivalent to | |
3416 | __attribute__ ((sentinel(0))) | |
3417 | @end smallexample | |
3418 | ||
3419 | The attribute is automatically set with a position of 0 for the built-in | |
3420 | functions @code{execl} and @code{execlp}. The built-in function | |
254ea84c | 3421 | @code{execle} has the attribute set with a position of 1. |
254986c7 KG |
3422 | |
3423 | A valid @code{NULL} in this context is defined as zero with any pointer | |
3424 | type. If your system defines the @code{NULL} macro with an integer type | |
3425 | then you need to add an explicit cast. GCC replaces @code{stddef.h} | |
3426 | with a copy that redefines NULL appropriately. | |
3427 | ||
3428 | The warnings for missing or incorrect sentinels are enabled with | |
3429 | @option{-Wformat}. | |
3d091dac | 3430 | |
c8619b90 NS |
3431 | @item short_call |
3432 | See long_call/short_call. | |
3433 | ||
3434 | @item shortcall | |
3435 | See longcall/shortcall. | |
3436 | ||
3437 | @item signal | |
3438 | @cindex signal handler functions on the AVR processors | |
3439 | Use this attribute on the AVR to indicate that the specified | |
3440 | function is a signal handler. The compiler will generate function | |
3441 | entry and exit sequences suitable for use in a signal handler when this | |
3442 | attribute is present. Interrupts will be disabled inside the function. | |
b93e3893 AO |
3443 | |
3444 | @item sp_switch | |
88ab0d1c | 3445 | Use this attribute on the SH to indicate an @code{interrupt_handler} |
b93e3893 AO |
3446 | function should switch to an alternate stack. It expects a string |
3447 | argument that names a global variable holding the address of the | |
3448 | alternate stack. | |
3449 | ||
3450 | @smallexample | |
3451 | void *alt_stack; | |
aee96fe9 JM |
3452 | void f () __attribute__ ((interrupt_handler, |
3453 | sp_switch ("alt_stack"))); | |
b93e3893 AO |
3454 | @end smallexample |
3455 | ||
c8619b90 NS |
3456 | @item stdcall |
3457 | @cindex functions that pop the argument stack on the 386 | |
3458 | On the Intel 386, the @code{stdcall} attribute causes the compiler to | |
3459 | assume that the called function will pop off the stack space used to | |
3460 | pass arguments, unless it takes a variable number of arguments. | |
c1f7febf | 3461 | |
4b84f3de SE |
3462 | @item syscall_linkage |
3463 | @cindex @code{syscall_linkage} attribute | |
3464 | This attribute is used to modify the IA64 calling convention by marking | |
3465 | all input registers as live at all function exits. This makes it possible | |
3466 | to restart a system call after an interrupt without having to save/restore | |
3467 | the input registers. This also prevents kernel data from leaking into | |
3468 | application code. | |
3469 | ||
1df48f5c JW |
3470 | @item target |
3471 | @cindex @code{target} function attribute | |
3472 | The @code{target} attribute is used to specify that a function is to | |
3473 | be compiled with different target options than specified on the | |
3474 | command line. This can be used for instance to have functions | |
3475 | compiled with a different ISA (instruction set architecture) than the | |
3476 | default. You can also use the @samp{#pragma GCC target} pragma to set | |
3477 | more than one function to be compiled with specific target options. | |
3478 | @xref{Function Specific Option Pragmas}, for details about the | |
3479 | @samp{#pragma GCC target} pragma. | |
3480 | ||
3481 | For instance on a 386, you could compile one function with | |
3482 | @code{target("sse4.1,arch=core2")} and another with | |
3483 | @code{target("sse4a,arch=amdfam10")} that would be equivalent to | |
3484 | compiling the first function with @option{-msse4.1} and | |
3485 | @option{-march=core2} options, and the second function with | |
3486 | @option{-msse4a} and @option{-march=amdfam10} options. It is up to the | |
3487 | user to make sure that a function is only invoked on a machine that | |
3488 | supports the particular ISA it was compiled for (for example by using | |
3489 | @code{cpuid} on 386 to determine what feature bits and architecture | |
3490 | family are used). | |
3491 | ||
3492 | @smallexample | |
3493 | int core2_func (void) __attribute__ ((__target__ ("arch=core2"))); | |
3494 | int sse3_func (void) __attribute__ ((__target__ ("sse3"))); | |
3495 | @end smallexample | |
3496 | ||
3497 | On the 386, the following options are allowed: | |
3498 | ||
3499 | @table @samp | |
3500 | @item abm | |
3501 | @itemx no-abm | |
3502 | @cindex @code{target("abm")} attribute | |
3503 | Enable/disable the generation of the advanced bit instructions. | |
3504 | ||
3505 | @item aes | |
3506 | @itemx no-aes | |
3507 | @cindex @code{target("aes")} attribute | |
3508 | Enable/disable the generation of the AES instructions. | |
3509 | ||
3510 | @item mmx | |
3511 | @itemx no-mmx | |
3512 | @cindex @code{target("mmx")} attribute | |
3513 | Enable/disable the generation of the MMX instructions. | |
3514 | ||
3515 | @item pclmul | |
3516 | @itemx no-pclmul | |
3517 | @cindex @code{target("pclmul")} attribute | |
3518 | Enable/disable the generation of the PCLMUL instructions. | |
3519 | ||
3520 | @item popcnt | |
3521 | @itemx no-popcnt | |
3522 | @cindex @code{target("popcnt")} attribute | |
3523 | Enable/disable the generation of the POPCNT instruction. | |
3524 | ||
3525 | @item sse | |
3526 | @itemx no-sse | |
3527 | @cindex @code{target("sse")} attribute | |
3528 | Enable/disable the generation of the SSE instructions. | |
3529 | ||
3530 | @item sse2 | |
3531 | @itemx no-sse2 | |
3532 | @cindex @code{target("sse2")} attribute | |
3533 | Enable/disable the generation of the SSE2 instructions. | |
3534 | ||
3535 | @item sse3 | |
3536 | @itemx no-sse3 | |
3537 | @cindex @code{target("sse3")} attribute | |
3538 | Enable/disable the generation of the SSE3 instructions. | |
3539 | ||
3540 | @item sse4 | |
3541 | @itemx no-sse4 | |
3542 | @cindex @code{target("sse4")} attribute | |
3543 | Enable/disable the generation of the SSE4 instructions (both SSE4.1 | |
3544 | and SSE4.2). | |
3545 | ||
3546 | @item sse4.1 | |
3547 | @itemx no-sse4.1 | |
3548 | @cindex @code{target("sse4.1")} attribute | |
3549 | Enable/disable the generation of the sse4.1 instructions. | |
3550 | ||
3551 | @item sse4.2 | |
3552 | @itemx no-sse4.2 | |
3553 | @cindex @code{target("sse4.2")} attribute | |
3554 | Enable/disable the generation of the sse4.2 instructions. | |
3555 | ||
3556 | @item sse4a | |
3557 | @itemx no-sse4a | |
3558 | @cindex @code{target("sse4a")} attribute | |
3559 | Enable/disable the generation of the SSE4A instructions. | |
3560 | ||
cbf2e4d4 HJ |
3561 | @item fma4 |
3562 | @itemx no-fma4 | |
3563 | @cindex @code{target("fma4")} attribute | |
3564 | Enable/disable the generation of the FMA4 instructions. | |
3565 | ||
43a8b705 HJ |
3566 | @item xop |
3567 | @itemx no-xop | |
3568 | @cindex @code{target("xop")} attribute | |
3569 | Enable/disable the generation of the XOP instructions. | |
3570 | ||
3e901069 HJ |
3571 | @item lwp |
3572 | @itemx no-lwp | |
3573 | @cindex @code{target("lwp")} attribute | |
3574 | Enable/disable the generation of the LWP instructions. | |
3575 | ||
1df48f5c JW |
3576 | @item ssse3 |
3577 | @itemx no-ssse3 | |
3578 | @cindex @code{target("ssse3")} attribute | |
3579 | Enable/disable the generation of the SSSE3 instructions. | |
3580 | ||
3581 | @item cld | |
3582 | @itemx no-cld | |
3583 | @cindex @code{target("cld")} attribute | |
3584 | Enable/disable the generation of the CLD before string moves. | |
3585 | ||
3586 | @item fancy-math-387 | |
3587 | @itemx no-fancy-math-387 | |
3588 | @cindex @code{target("fancy-math-387")} attribute | |
3589 | Enable/disable the generation of the @code{sin}, @code{cos}, and | |
3590 | @code{sqrt} instructions on the 387 floating point unit. | |
3591 | ||
3592 | @item fused-madd | |
3593 | @itemx no-fused-madd | |
3594 | @cindex @code{target("fused-madd")} attribute | |
3595 | Enable/disable the generation of the fused multiply/add instructions. | |
3596 | ||
3597 | @item ieee-fp | |
3598 | @itemx no-ieee-fp | |
3599 | @cindex @code{target("ieee-fp")} attribute | |
3600 | Enable/disable the generation of floating point that depends on IEEE arithmetic. | |
3601 | ||
3602 | @item inline-all-stringops | |
3603 | @itemx no-inline-all-stringops | |
3604 | @cindex @code{target("inline-all-stringops")} attribute | |
3605 | Enable/disable inlining of string operations. | |
3606 | ||
3607 | @item inline-stringops-dynamically | |
3608 | @itemx no-inline-stringops-dynamically | |
3609 | @cindex @code{target("inline-stringops-dynamically")} attribute | |
3610 | Enable/disable the generation of the inline code to do small string | |
3611 | operations and calling the library routines for large operations. | |
3612 | ||
3613 | @item align-stringops | |
3614 | @itemx no-align-stringops | |
3615 | @cindex @code{target("align-stringops")} attribute | |
3616 | Do/do not align destination of inlined string operations. | |
3617 | ||
3618 | @item recip | |
3619 | @itemx no-recip | |
3620 | @cindex @code{target("recip")} attribute | |
3621 | Enable/disable the generation of RCPSS, RCPPS, RSQRTSS and RSQRTPS | |
048fd785 | 3622 | instructions followed an additional Newton-Raphson step instead of |
1df48f5c JW |
3623 | doing a floating point division. |
3624 | ||
3625 | @item arch=@var{ARCH} | |
3626 | @cindex @code{target("arch=@var{ARCH}")} attribute | |
3627 | Specify the architecture to generate code for in compiling the function. | |
3628 | ||
3629 | @item tune=@var{TUNE} | |
3630 | @cindex @code{target("tune=@var{TUNE}")} attribute | |
3631 | Specify the architecture to tune for in compiling the function. | |
3632 | ||
3633 | @item fpmath=@var{FPMATH} | |
3634 | @cindex @code{target("fpmath=@var{FPMATH}")} attribute | |
3635 | Specify which floating point unit to use. The | |
3636 | @code{target("fpmath=sse,387")} option must be specified as | |
3637 | @code{target("fpmath=sse+387")} because the comma would separate | |
3638 | different options. | |
15bf6f3a | 3639 | @end table |
fd438373 | 3640 | |
fd438373 MM |
3641 | On the PowerPC, the following options are allowed: |
3642 | ||
3643 | @table @samp | |
3644 | @item altivec | |
3645 | @itemx no-altivec | |
3646 | @cindex @code{target("altivec")} attribute | |
3647 | Generate code that uses (does not use) AltiVec instructions. In | |
3648 | 32-bit code, you cannot enable Altivec instructions unless | |
3649 | @option{-mabi=altivec} was used on the command line. | |
3650 | ||
3651 | @item cmpb | |
3652 | @itemx no-cmpb | |
3653 | @cindex @code{target("cmpb")} attribute | |
3654 | Generate code that uses (does not use) the compare bytes instruction | |
3655 | implemented on the POWER6 processor and other processors that support | |
3656 | the PowerPC V2.05 architecture. | |
3657 | ||
3658 | @item dlmzb | |
3659 | @itemx no-dlmzb | |
3660 | @cindex @code{target("dlmzb")} attribute | |
3661 | Generate code that uses (does not use) the string-search @samp{dlmzb} | |
3662 | instruction on the IBM 405, 440, 464 and 476 processors. This instruction is | |
3663 | generated by default when targetting those processors. | |
3664 | ||
3665 | @item fprnd | |
3666 | @itemx no-fprnd | |
3667 | @cindex @code{target("fprnd")} attribute | |
3668 | Generate code that uses (does not use) the FP round to integer | |
3669 | instructions implemented on the POWER5+ processor and other processors | |
3670 | that support the PowerPC V2.03 architecture. | |
3671 | ||
3672 | @item hard-dfp | |
3673 | @itemx no-hard-dfp | |
3674 | @cindex @code{target("hard-dfp")} attribute | |
3675 | Generate code that uses (does not use) the decimal floating point | |
3676 | instructions implemented on some POWER processors. | |
3677 | ||
3678 | @item isel | |
3679 | @itemx no-isel | |
3680 | @cindex @code{target("isel")} attribute | |
3681 | Generate code that uses (does not use) ISEL instruction. | |
3682 | ||
3683 | @item mfcrf | |
3684 | @itemx no-mfcrf | |
3685 | @cindex @code{target("mfcrf")} attribute | |
3686 | Generate code that uses (does not use) the move from condition | |
3687 | register field instruction implemented on the POWER4 processor and | |
3688 | other processors that support the PowerPC V2.01 architecture. | |
3689 | ||
3690 | @item mfpgpr | |
3691 | @itemx no-mfpgpr | |
3692 | @cindex @code{target("mfpgpr")} attribute | |
3693 | Generate code that uses (does not use) the FP move to/from general | |
3694 | purpose register instructions implemented on the POWER6X processor and | |
3695 | other processors that support the extended PowerPC V2.05 architecture. | |
3696 | ||
3697 | @item mulhw | |
3698 | @itemx no-mulhw | |
3699 | @cindex @code{target("mulhw")} attribute | |
3700 | Generate code that uses (does not use) the half-word multiply and | |
3701 | multiply-accumulate instructions on the IBM 405, 440, 464 and 476 processors. | |
3702 | These instructions are generated by default when targetting those | |
3703 | processors. | |
3704 | ||
3705 | @item multiple | |
3706 | @itemx no-multiple | |
3707 | @cindex @code{target("multiple")} attribute | |
3708 | Generate code that uses (does not use) the load multiple word | |
3709 | instructions and the store multiple word instructions. | |
3710 | ||
3711 | @item update | |
3712 | @itemx no-update | |
3713 | @cindex @code{target("update")} attribute | |
3714 | Generate code that uses (does not use) the load or store instructions | |
3715 | that update the base register to the address of the calculated memory | |
3716 | location. | |
3717 | ||
3718 | @item popcntb | |
3719 | @itemx no-popcntb | |
3720 | @cindex @code{target("popcntb")} attribute | |
3721 | Generate code that uses (does not use) the popcount and double | |
3722 | precision FP reciprocal estimate instruction implemented on the POWER5 | |
3723 | processor and other processors that support the PowerPC V2.02 | |
3724 | architecture. | |
3725 | ||
3726 | @item popcntd | |
3727 | @itemx no-popcntd | |
3728 | @cindex @code{target("popcntd")} attribute | |
3729 | Generate code that uses (does not use) the popcount instruction | |
3730 | implemented on the POWER7 processor and other processors that support | |
3731 | the PowerPC V2.06 architecture. | |
3732 | ||
3733 | @item powerpc-gfxopt | |
3734 | @itemx no-powerpc-gfxopt | |
3735 | @cindex @code{target("powerpc-gfxopt")} attribute | |
3736 | Generate code that uses (does not use) the optional PowerPC | |
3737 | architecture instructions in the Graphics group, including | |
3738 | floating-point select. | |
3739 | ||
3740 | @item powerpc-gpopt | |
3741 | @itemx no-powerpc-gpopt | |
3742 | @cindex @code{target("powerpc-gpopt")} attribute | |
3743 | Generate code that uses (does not use) the optional PowerPC | |
3744 | architecture instructions in the General Purpose group, including | |
3745 | floating-point square root. | |
3746 | ||
3747 | @item recip-precision | |
3748 | @itemx no-recip-precision | |
3749 | @cindex @code{target("recip-precision")} attribute | |
3750 | Assume (do not assume) that the reciprocal estimate instructions | |
3751 | provide higher precision estimates than is mandated by the powerpc | |
3752 | ABI. | |
3753 | ||
3754 | @item string | |
3755 | @itemx no-string | |
3756 | @cindex @code{target("string")} attribute | |
3757 | Generate code that uses (does not use) the load string instructions | |
3758 | and the store string word instructions to save multiple registers and | |
3759 | do small block moves. | |
3760 | ||
3761 | @item vsx | |
3762 | @itemx no-vsx | |
3763 | @cindex @code{target("vsx")} attribute | |
3764 | Generate code that uses (does not use) vector/scalar (VSX) | |
3765 | instructions, and also enable the use of built-in functions that allow | |
3766 | more direct access to the VSX instruction set. In 32-bit code, you | |
3767 | cannot enable VSX or Altivec instructions unless | |
3768 | @option{-mabi=altivec} was used on the command line. | |
3769 | ||
3770 | @item friz | |
3771 | @itemx no-friz | |
3772 | @cindex @code{target("friz")} attribute | |
3773 | Generate (do not generate) the @code{friz} instruction when the | |
3774 | @option{-funsafe-math-optimizations} option is used to optimize | |
3775 | rounding a floating point value to 64-bit integer and back to floating | |
3776 | point. The @code{friz} instruction does not return the same value if | |
3777 | the floating point number is too large to fit in an integer. | |
3778 | ||
3779 | @item avoid-indexed-addresses | |
3780 | @itemx no-avoid-indexed-addresses | |
3781 | @cindex @code{target("avoid-indexed-addresses")} attribute | |
3782 | Generate code that tries to avoid (not avoid) the use of indexed load | |
3783 | or store instructions. | |
3784 | ||
3785 | @item paired | |
3786 | @itemx no-paired | |
3787 | @cindex @code{target("paired")} attribute | |
3788 | Generate code that uses (does not use) the generation of PAIRED simd | |
3789 | instructions. | |
3790 | ||
3791 | @item longcall | |
3792 | @itemx no-longcall | |
3793 | @cindex @code{target("longcall")} attribute | |
3794 | Generate code that assumes (does not assume) that all calls are far | |
3795 | away so that a longer more expensive calling sequence is required. | |
3796 | ||
3797 | @item cpu=@var{CPU} | |
3798 | @cindex @code{target("cpu=@var{CPU}")} attribute | |
2b0d3573 | 3799 | Specify the architecture to generate code for when compiling the |
76f59013 | 3800 | function. If you select the @code{target("cpu=power7")} attribute when |
fd438373 MM |
3801 | generating 32-bit code, VSX and Altivec instructions are not generated |
3802 | unless you use the @option{-mabi=altivec} option on the command line. | |
3803 | ||
3804 | @item tune=@var{TUNE} | |
3805 | @cindex @code{target("tune=@var{TUNE}")} attribute | |
2b0d3573 | 3806 | Specify the architecture to tune for when compiling the function. If |
fd438373 | 3807 | you do not specify the @code{target("tune=@var{TUNE}")} attribute and |
2b0d3573 | 3808 | you do specify the @code{target("cpu=@var{CPU}")} attribute, |
fd438373 MM |
3809 | compilation will tune for the @var{CPU} architecture, and not the |
3810 | default tuning specified on the command line. | |
3811 | @end table | |
1df48f5c | 3812 | |
fd438373 MM |
3813 | On the 386/x86_64 and PowerPC backends, you can use either multiple |
3814 | strings to specify multiple options, or you can separate the option | |
3815 | with a comma (@code{,}). | |
1df48f5c | 3816 | |
fd438373 MM |
3817 | On the 386/x86_64 and PowerPC backends, the inliner will not inline a |
3818 | function that has different target options than the caller, unless the | |
3819 | callee has a subset of the target options of the caller. For example | |
3820 | a function declared with @code{target("sse3")} can inline a function | |
3821 | with @code{target("sse2")}, since @code{-msse3} implies @code{-msse2}. | |
1df48f5c JW |
3822 | |
3823 | The @code{target} attribute is not implemented in GCC versions earlier | |
fd438373 MM |
3824 | than 4.4 for the i386/x86_64 and 4.6 for the PowerPC backends. It is |
3825 | not currently implemented for other backends. | |
1df48f5c | 3826 | |
c1f7febf | 3827 | @item tiny_data |
dbacaa98 KH |
3828 | @cindex tiny data section on the H8/300H and H8S |
3829 | Use this attribute on the H8/300H and H8S to indicate that the specified | |
c1f7febf RK |
3830 | variable should be placed into the tiny data section. |
3831 | The compiler will generate more efficient code for loads and stores | |
3832 | on data in the tiny data section. Note the tiny data area is limited to | |
3833 | slightly under 32kbytes of data. | |
845da534 | 3834 | |
c8619b90 NS |
3835 | @item trap_exit |
3836 | Use this attribute on the SH for an @code{interrupt_handler} to return using | |
3837 | @code{trapa} instead of @code{rte}. This attribute expects an integer | |
3838 | argument specifying the trap number to be used. | |
845da534 | 3839 | |
c8619b90 NS |
3840 | @item unused |
3841 | @cindex @code{unused} attribute. | |
3842 | This attribute, attached to a function, means that the function is meant | |
3843 | to be possibly unused. GCC will not produce a warning for this | |
3844 | function. | |
a32767e4 | 3845 | |
c8619b90 NS |
3846 | @item used |
3847 | @cindex @code{used} attribute. | |
3848 | This attribute, attached to a function, means that code must be emitted | |
3849 | for the function even if it appears that the function is not referenced. | |
3850 | This is useful, for example, when the function is referenced only in | |
3851 | inline assembly. | |
5936c7e7 | 3852 | |
4951efb6 JM |
3853 | When applied to a member function of a C++ class template, the |
3854 | attribute also means that the function will be instantiated if the | |
3855 | class itself is instantiated. | |
3856 | ||
812b587e | 3857 | @item version_id |
4b84f3de SE |
3858 | @cindex @code{version_id} attribute |
3859 | This IA64 HP-UX attribute, attached to a global variable or function, renames a | |
812b587e SE |
3860 | symbol to contain a version string, thus allowing for function level |
3861 | versioning. HP-UX system header files may use version level functioning | |
3862 | for some system calls. | |
3863 | ||
3864 | @smallexample | |
3865 | extern int foo () __attribute__((version_id ("20040821"))); | |
3866 | @end smallexample | |
3867 | ||
3868 | Calls to @var{foo} will be mapped to calls to @var{foo@{20040821@}}. | |
3869 | ||
c8619b90 NS |
3870 | @item visibility ("@var{visibility_type}") |
3871 | @cindex @code{visibility} attribute | |
46bdbc00 GK |
3872 | This attribute affects the linkage of the declaration to which it is attached. |
3873 | There are four supported @var{visibility_type} values: default, | |
3874 | hidden, protected or internal visibility. | |
5936c7e7 | 3875 | |
c8619b90 NS |
3876 | @smallexample |
3877 | void __attribute__ ((visibility ("protected"))) | |
3878 | f () @{ /* @r{Do something.} */; @} | |
3879 | int i __attribute__ ((visibility ("hidden"))); | |
3880 | @end smallexample | |
5936c7e7 | 3881 | |
46bdbc00 GK |
3882 | The possible values of @var{visibility_type} correspond to the |
3883 | visibility settings in the ELF gABI. | |
5936c7e7 | 3884 | |
c8619b90 | 3885 | @table @dfn |
63c5b495 | 3886 | @c keep this list of visibilities in alphabetical order. |
6b6cb52e | 3887 | |
c8619b90 | 3888 | @item default |
46bdbc00 GK |
3889 | Default visibility is the normal case for the object file format. |
3890 | This value is available for the visibility attribute to override other | |
3891 | options that may change the assumed visibility of entities. | |
3892 | ||
3893 | On ELF, default visibility means that the declaration is visible to other | |
3894 | modules and, in shared libraries, means that the declared entity may be | |
3895 | overridden. | |
3896 | ||
3897 | On Darwin, default visibility means that the declaration is visible to | |
3898 | other modules. | |
3899 | ||
3900 | Default visibility corresponds to ``external linkage'' in the language. | |
6b6cb52e | 3901 | |
c8619b90 | 3902 | @item hidden |
46bdbc00 GK |
3903 | Hidden visibility indicates that the entity declared will have a new |
3904 | form of linkage, which we'll call ``hidden linkage''. Two | |
3905 | declarations of an object with hidden linkage refer to the same object | |
3906 | if they are in the same shared object. | |
6b6cb52e | 3907 | |
c8619b90 NS |
3908 | @item internal |
3909 | Internal visibility is like hidden visibility, but with additional | |
46bdbc00 GK |
3910 | processor specific semantics. Unless otherwise specified by the |
3911 | psABI, GCC defines internal visibility to mean that a function is | |
3912 | @emph{never} called from another module. Compare this with hidden | |
3913 | functions which, while they cannot be referenced directly by other | |
3914 | modules, can be referenced indirectly via function pointers. By | |
3915 | indicating that a function cannot be called from outside the module, | |
3916 | GCC may for instance omit the load of a PIC register since it is known | |
3917 | that the calling function loaded the correct value. | |
6b6cb52e | 3918 | |
c8619b90 | 3919 | @item protected |
46bdbc00 GK |
3920 | Protected visibility is like default visibility except that it |
3921 | indicates that references within the defining module will bind to the | |
3922 | definition in that module. That is, the declared entity cannot be | |
3923 | overridden by another module. | |
6b6cb52e | 3924 | |
c8619b90 | 3925 | @end table |
6b6cb52e | 3926 | |
46bdbc00 GK |
3927 | All visibilities are supported on many, but not all, ELF targets |
3928 | (supported when the assembler supports the @samp{.visibility} | |
3929 | pseudo-op). Default visibility is supported everywhere. Hidden | |
3930 | visibility is supported on Darwin targets. | |
3931 | ||
3932 | The visibility attribute should be applied only to declarations which | |
3933 | would otherwise have external linkage. The attribute should be applied | |
3934 | consistently, so that the same entity should not be declared with | |
3935 | different settings of the attribute. | |
3936 | ||
3937 | In C++, the visibility attribute applies to types as well as functions | |
b9e75696 JM |
3938 | and objects, because in C++ types have linkage. A class must not have |
3939 | greater visibility than its non-static data member types and bases, | |
3940 | and class members default to the visibility of their class. Also, a | |
b70f0f48 JM |
3941 | declaration without explicit visibility is limited to the visibility |
3942 | of its type. | |
46bdbc00 GK |
3943 | |
3944 | In C++, you can mark member functions and static member variables of a | |
d1facce0 | 3945 | class with the visibility attribute. This is useful if you know a |
46bdbc00 GK |
3946 | particular method or static member variable should only be used from |
3947 | one shared object; then you can mark it hidden while the rest of the | |
3948 | class has default visibility. Care must be taken to avoid breaking | |
b70f0f48 JM |
3949 | the One Definition Rule; for example, it is usually not useful to mark |
3950 | an inline method as hidden without marking the whole class as hidden. | |
6b6cb52e | 3951 | |
b9e75696 JM |
3952 | A C++ namespace declaration can also have the visibility attribute. |
3953 | This attribute applies only to the particular namespace body, not to | |
3954 | other definitions of the same namespace; it is equivalent to using | |
3955 | @samp{#pragma GCC visibility} before and after the namespace | |
3956 | definition (@pxref{Visibility Pragmas}). | |
3957 | ||
3958 | In C++, if a template argument has limited visibility, this | |
3959 | restriction is implicitly propagated to the template instantiation. | |
3960 | Otherwise, template instantiations and specializations default to the | |
3961 | visibility of their template. | |
3962 | ||
b70f0f48 JM |
3963 | If both the template and enclosing class have explicit visibility, the |
3964 | visibility from the template is used. | |
3965 | ||
e2491744 DD |
3966 | @item vliw |
3967 | @cindex @code{vliw} attribute | |
3968 | On MeP, the @code{vliw} attribute tells the compiler to emit | |
3969 | instructions in VLIW mode instead of core mode. Note that this | |
3970 | attribute is not allowed unless a VLIW coprocessor has been configured | |
3971 | and enabled through command line options. | |
3972 | ||
c8619b90 NS |
3973 | @item warn_unused_result |
3974 | @cindex @code{warn_unused_result} attribute | |
3975 | The @code{warn_unused_result} attribute causes a warning to be emitted | |
3976 | if a caller of the function with this attribute does not use its | |
3977 | return value. This is useful for functions where not checking | |
3978 | the result is either a security problem or always a bug, such as | |
3979 | @code{realloc}. | |
6b6cb52e | 3980 | |
c8619b90 NS |
3981 | @smallexample |
3982 | int fn () __attribute__ ((warn_unused_result)); | |
3983 | int foo () | |
3984 | @{ | |
3985 | if (fn () < 0) return -1; | |
3986 | fn (); | |
3987 | return 0; | |
3988 | @} | |
3989 | @end smallexample | |
6b6cb52e | 3990 | |
c8619b90 | 3991 | results in warning on line 5. |
6b6cb52e | 3992 | |
c8619b90 NS |
3993 | @item weak |
3994 | @cindex @code{weak} attribute | |
3995 | The @code{weak} attribute causes the declaration to be emitted as a weak | |
3996 | symbol rather than a global. This is primarily useful in defining | |
3997 | library functions which can be overridden in user code, though it can | |
3998 | also be used with non-function declarations. Weak symbols are supported | |
3999 | for ELF targets, and also for a.out targets when using the GNU assembler | |
4000 | and linker. | |
6b6cb52e | 4001 | |
a0203ca7 AO |
4002 | @item weakref |
4003 | @itemx weakref ("@var{target}") | |
4004 | @cindex @code{weakref} attribute | |
4005 | The @code{weakref} attribute marks a declaration as a weak reference. | |
4006 | Without arguments, it should be accompanied by an @code{alias} attribute | |
4007 | naming the target symbol. Optionally, the @var{target} may be given as | |
4008 | an argument to @code{weakref} itself. In either case, @code{weakref} | |
4009 | implicitly marks the declaration as @code{weak}. Without a | |
4010 | @var{target}, given as an argument to @code{weakref} or to @code{alias}, | |
4011 | @code{weakref} is equivalent to @code{weak}. | |
4012 | ||
4013 | @smallexample | |
a9b0b825 | 4014 | static int x() __attribute__ ((weakref ("y"))); |
a0203ca7 | 4015 | /* is equivalent to... */ |
a9b0b825 | 4016 | static int x() __attribute__ ((weak, weakref, alias ("y"))); |
a0203ca7 | 4017 | /* and to... */ |
a9b0b825 GK |
4018 | static int x() __attribute__ ((weakref)); |
4019 | static int x() __attribute__ ((alias ("y"))); | |
a0203ca7 AO |
4020 | @end smallexample |
4021 | ||
4022 | A weak reference is an alias that does not by itself require a | |
4023 | definition to be given for the target symbol. If the target symbol is | |
4896c7b8 | 4024 | only referenced through weak references, then it becomes a @code{weak} |
a0203ca7 AO |
4025 | undefined symbol. If it is directly referenced, however, then such |
4026 | strong references prevail, and a definition will be required for the | |
4027 | symbol, not necessarily in the same translation unit. | |
4028 | ||
4029 | The effect is equivalent to moving all references to the alias to a | |
4030 | separate translation unit, renaming the alias to the aliased symbol, | |
4031 | declaring it as weak, compiling the two separate translation units and | |
4032 | performing a reloadable link on them. | |
4033 | ||
a9b0b825 GK |
4034 | At present, a declaration to which @code{weakref} is attached can |
4035 | only be @code{static}. | |
4036 | ||
c1f7febf RK |
4037 | @end table |
4038 | ||
4039 | You can specify multiple attributes in a declaration by separating them | |
4040 | by commas within the double parentheses or by immediately following an | |
4041 | attribute declaration with another attribute declaration. | |
4042 | ||
4043 | @cindex @code{#pragma}, reason for not using | |
4044 | @cindex pragma, reason for not using | |
9f1bbeaa JM |
4045 | Some people object to the @code{__attribute__} feature, suggesting that |
4046 | ISO C's @code{#pragma} should be used instead. At the time | |
4047 | @code{__attribute__} was designed, there were two reasons for not doing | |
4048 | this. | |
c1f7febf RK |
4049 | |
4050 | @enumerate | |
4051 | @item | |
4052 | It is impossible to generate @code{#pragma} commands from a macro. | |
4053 | ||
4054 | @item | |
4055 | There is no telling what the same @code{#pragma} might mean in another | |
4056 | compiler. | |
4057 | @end enumerate | |
4058 | ||
9f1bbeaa JM |
4059 | These two reasons applied to almost any application that might have been |
4060 | proposed for @code{#pragma}. It was basically a mistake to use | |
4061 | @code{#pragma} for @emph{anything}. | |
4062 | ||
4063 | The ISO C99 standard includes @code{_Pragma}, which now allows pragmas | |
4064 | to be generated from macros. In addition, a @code{#pragma GCC} | |
4065 | namespace is now in use for GCC-specific pragmas. However, it has been | |
4066 | found convenient to use @code{__attribute__} to achieve a natural | |
4067 | attachment of attributes to their corresponding declarations, whereas | |
4068 | @code{#pragma GCC} is of use for constructs that do not naturally form | |
4069 | part of the grammar. @xref{Other Directives,,Miscellaneous | |
48795525 | 4070 | Preprocessing Directives, cpp, The GNU C Preprocessor}. |
c1f7febf | 4071 | |
2c5e91d2 JM |
4072 | @node Attribute Syntax |
4073 | @section Attribute Syntax | |
4074 | @cindex attribute syntax | |
4075 | ||
4076 | This section describes the syntax with which @code{__attribute__} may be | |
4077 | used, and the constructs to which attribute specifiers bind, for the C | |
161d7b59 | 4078 | language. Some details may vary for C++ and Objective-C@. Because of |
2c5e91d2 JM |
4079 | infelicities in the grammar for attributes, some forms described here |
4080 | may not be successfully parsed in all cases. | |
4081 | ||
91d231cb JM |
4082 | There are some problems with the semantics of attributes in C++. For |
4083 | example, there are no manglings for attributes, although they may affect | |
4084 | code generation, so problems may arise when attributed types are used in | |
4085 | conjunction with templates or overloading. Similarly, @code{typeid} | |
4086 | does not distinguish between types with different attributes. Support | |
4087 | for attributes in C++ may be restricted in future to attributes on | |
4088 | declarations only, but not on nested declarators. | |
4089 | ||
2c5e91d2 JM |
4090 | @xref{Function Attributes}, for details of the semantics of attributes |
4091 | applying to functions. @xref{Variable Attributes}, for details of the | |
4092 | semantics of attributes applying to variables. @xref{Type Attributes}, | |
4093 | for details of the semantics of attributes applying to structure, union | |
4094 | and enumerated types. | |
4095 | ||
4096 | An @dfn{attribute specifier} is of the form | |
4097 | @code{__attribute__ ((@var{attribute-list}))}. An @dfn{attribute list} | |
4098 | is a possibly empty comma-separated sequence of @dfn{attributes}, where | |
4099 | each attribute is one of the following: | |
4100 | ||
4101 | @itemize @bullet | |
4102 | @item | |
4103 | Empty. Empty attributes are ignored. | |
4104 | ||
4105 | @item | |
4106 | A word (which may be an identifier such as @code{unused}, or a reserved | |
4107 | word such as @code{const}). | |
4108 | ||
4109 | @item | |
4110 | A word, followed by, in parentheses, parameters for the attribute. | |
4111 | These parameters take one of the following forms: | |
4112 | ||
4113 | @itemize @bullet | |
4114 | @item | |
4115 | An identifier. For example, @code{mode} attributes use this form. | |
4116 | ||
4117 | @item | |
4118 | An identifier followed by a comma and a non-empty comma-separated list | |
4119 | of expressions. For example, @code{format} attributes use this form. | |
4120 | ||
4121 | @item | |
4122 | A possibly empty comma-separated list of expressions. For example, | |
4123 | @code{format_arg} attributes use this form with the list being a single | |
4124 | integer constant expression, and @code{alias} attributes use this form | |
4125 | with the list being a single string constant. | |
4126 | @end itemize | |
4127 | @end itemize | |
4128 | ||
4129 | An @dfn{attribute specifier list} is a sequence of one or more attribute | |
4130 | specifiers, not separated by any other tokens. | |
4131 | ||
50fc59e7 | 4132 | In GNU C, an attribute specifier list may appear after the colon following a |
2c5e91d2 JM |
4133 | label, other than a @code{case} or @code{default} label. The only |
4134 | attribute it makes sense to use after a label is @code{unused}. This | |
4135 | feature is intended for code generated by programs which contains labels | |
4136 | that may be unused but which is compiled with @option{-Wall}. It would | |
4137 | not normally be appropriate to use in it human-written code, though it | |
4138 | could be useful in cases where the code that jumps to the label is | |
5bca4e80 ILT |
4139 | contained within an @code{#ifdef} conditional. GNU C++ only permits |
4140 | attributes on labels if the attribute specifier is immediately | |
4141 | followed by a semicolon (i.e., the label applies to an empty | |
4142 | statement). If the semicolon is missing, C++ label attributes are | |
4143 | ambiguous, as it is permissible for a declaration, which could begin | |
4144 | with an attribute list, to be labelled in C++. Declarations cannot be | |
4145 | labelled in C90 or C99, so the ambiguity does not arise there. | |
2c5e91d2 JM |
4146 | |
4147 | An attribute specifier list may appear as part of a @code{struct}, | |
4148 | @code{union} or @code{enum} specifier. It may go either immediately | |
4149 | after the @code{struct}, @code{union} or @code{enum} keyword, or after | |
b9e75696 | 4150 | the closing brace. The former syntax is preferred. |
2c5e91d2 JM |
4151 | Where attribute specifiers follow the closing brace, they are considered |
4152 | to relate to the structure, union or enumerated type defined, not to any | |
4153 | enclosing declaration the type specifier appears in, and the type | |
4154 | defined is not complete until after the attribute specifiers. | |
4155 | @c Otherwise, there would be the following problems: a shift/reduce | |
4fe9b91c | 4156 | @c conflict between attributes binding the struct/union/enum and |
2c5e91d2 JM |
4157 | @c binding to the list of specifiers/qualifiers; and "aligned" |
4158 | @c attributes could use sizeof for the structure, but the size could be | |
4159 | @c changed later by "packed" attributes. | |
4160 | ||
4161 | Otherwise, an attribute specifier appears as part of a declaration, | |
4162 | counting declarations of unnamed parameters and type names, and relates | |
4163 | to that declaration (which may be nested in another declaration, for | |
91d231cb JM |
4164 | example in the case of a parameter declaration), or to a particular declarator |
4165 | within a declaration. Where an | |
ff867905 JM |
4166 | attribute specifier is applied to a parameter declared as a function or |
4167 | an array, it should apply to the function or array rather than the | |
4168 | pointer to which the parameter is implicitly converted, but this is not | |
4169 | yet correctly implemented. | |
2c5e91d2 JM |
4170 | |
4171 | Any list of specifiers and qualifiers at the start of a declaration may | |
4172 | contain attribute specifiers, whether or not such a list may in that | |
4173 | context contain storage class specifiers. (Some attributes, however, | |
4174 | are essentially in the nature of storage class specifiers, and only make | |
4175 | sense where storage class specifiers may be used; for example, | |
4176 | @code{section}.) There is one necessary limitation to this syntax: the | |
4177 | first old-style parameter declaration in a function definition cannot | |
4178 | begin with an attribute specifier, because such an attribute applies to | |
4179 | the function instead by syntax described below (which, however, is not | |
4180 | yet implemented in this case). In some other cases, attribute | |
4181 | specifiers are permitted by this grammar but not yet supported by the | |
4182 | compiler. All attribute specifiers in this place relate to the | |
c771326b | 4183 | declaration as a whole. In the obsolescent usage where a type of |
2c5e91d2 JM |
4184 | @code{int} is implied by the absence of type specifiers, such a list of |
4185 | specifiers and qualifiers may be an attribute specifier list with no | |
4186 | other specifiers or qualifiers. | |
4187 | ||
7dcb0442 JM |
4188 | At present, the first parameter in a function prototype must have some |
4189 | type specifier which is not an attribute specifier; this resolves an | |
4190 | ambiguity in the interpretation of @code{void f(int | |
4191 | (__attribute__((foo)) x))}, but is subject to change. At present, if | |
4192 | the parentheses of a function declarator contain only attributes then | |
4193 | those attributes are ignored, rather than yielding an error or warning | |
4194 | or implying a single parameter of type int, but this is subject to | |
4195 | change. | |
4196 | ||
2c5e91d2 JM |
4197 | An attribute specifier list may appear immediately before a declarator |
4198 | (other than the first) in a comma-separated list of declarators in a | |
4199 | declaration of more than one identifier using a single list of | |
4b01f8d8 | 4200 | specifiers and qualifiers. Such attribute specifiers apply |
9c34dbbf ZW |
4201 | only to the identifier before whose declarator they appear. For |
4202 | example, in | |
4203 | ||
4204 | @smallexample | |
4205 | __attribute__((noreturn)) void d0 (void), | |
4206 | __attribute__((format(printf, 1, 2))) d1 (const char *, ...), | |
4207 | d2 (void) | |
4208 | @end smallexample | |
4209 | ||
4210 | @noindent | |
4211 | the @code{noreturn} attribute applies to all the functions | |
4b01f8d8 | 4212 | declared; the @code{format} attribute only applies to @code{d1}. |
2c5e91d2 JM |
4213 | |
4214 | An attribute specifier list may appear immediately before the comma, | |
4215 | @code{=} or semicolon terminating the declaration of an identifier other | |
770a9950 JM |
4216 | than a function definition. Such attribute specifiers apply |
4217 | to the declared object or function. Where an | |
9c34dbbf | 4218 | assembler name for an object or function is specified (@pxref{Asm |
770a9950 JM |
4219 | Labels}), the attribute must follow the @code{asm} |
4220 | specification. | |
2c5e91d2 JM |
4221 | |
4222 | An attribute specifier list may, in future, be permitted to appear after | |
4223 | the declarator in a function definition (before any old-style parameter | |
4224 | declarations or the function body). | |
4225 | ||
0e03329a JM |
4226 | Attribute specifiers may be mixed with type qualifiers appearing inside |
4227 | the @code{[]} of a parameter array declarator, in the C99 construct by | |
4228 | which such qualifiers are applied to the pointer to which the array is | |
4229 | implicitly converted. Such attribute specifiers apply to the pointer, | |
4230 | not to the array, but at present this is not implemented and they are | |
4231 | ignored. | |
4232 | ||
2c5e91d2 JM |
4233 | An attribute specifier list may appear at the start of a nested |
4234 | declarator. At present, there are some limitations in this usage: the | |
91d231cb JM |
4235 | attributes correctly apply to the declarator, but for most individual |
4236 | attributes the semantics this implies are not implemented. | |
4237 | When attribute specifiers follow the @code{*} of a pointer | |
4b01f8d8 | 4238 | declarator, they may be mixed with any type qualifiers present. |
91d231cb | 4239 | The following describes the formal semantics of this syntax. It will make the |
2c5e91d2 JM |
4240 | most sense if you are familiar with the formal specification of |
4241 | declarators in the ISO C standard. | |
4242 | ||
4243 | Consider (as in C99 subclause 6.7.5 paragraph 4) a declaration @code{T | |
4244 | D1}, where @code{T} contains declaration specifiers that specify a type | |
4245 | @var{Type} (such as @code{int}) and @code{D1} is a declarator that | |
4246 | contains an identifier @var{ident}. The type specified for @var{ident} | |
4247 | for derived declarators whose type does not include an attribute | |
4248 | specifier is as in the ISO C standard. | |
4249 | ||
4250 | If @code{D1} has the form @code{( @var{attribute-specifier-list} D )}, | |
4251 | and the declaration @code{T D} specifies the type | |
4252 | ``@var{derived-declarator-type-list} @var{Type}'' for @var{ident}, then | |
4253 | @code{T D1} specifies the type ``@var{derived-declarator-type-list} | |
4254 | @var{attribute-specifier-list} @var{Type}'' for @var{ident}. | |
4255 | ||
4256 | If @code{D1} has the form @code{* | |
4257 | @var{type-qualifier-and-attribute-specifier-list} D}, and the | |
4258 | declaration @code{T D} specifies the type | |
4259 | ``@var{derived-declarator-type-list} @var{Type}'' for @var{ident}, then | |
4260 | @code{T D1} specifies the type ``@var{derived-declarator-type-list} | |
197ef306 | 4261 | @var{type-qualifier-and-attribute-specifier-list} pointer to @var{Type}'' for |
2c5e91d2 JM |
4262 | @var{ident}. |
4263 | ||
f282ffb3 | 4264 | For example, |
9c34dbbf ZW |
4265 | |
4266 | @smallexample | |
4267 | void (__attribute__((noreturn)) ****f) (void); | |
4268 | @end smallexample | |
4269 | ||
4270 | @noindent | |
4271 | specifies the type ``pointer to pointer to pointer to pointer to | |
4272 | non-returning function returning @code{void}''. As another example, | |
4273 | ||
4274 | @smallexample | |
4275 | char *__attribute__((aligned(8))) *f; | |
4276 | @end smallexample | |
4277 | ||
4278 | @noindent | |
4279 | specifies the type ``pointer to 8-byte-aligned pointer to @code{char}''. | |
91d231cb JM |
4280 | Note again that this does not work with most attributes; for example, |
4281 | the usage of @samp{aligned} and @samp{noreturn} attributes given above | |
4282 | is not yet supported. | |
4283 | ||
4284 | For compatibility with existing code written for compiler versions that | |
4285 | did not implement attributes on nested declarators, some laxity is | |
4286 | allowed in the placing of attributes. If an attribute that only applies | |
4287 | to types is applied to a declaration, it will be treated as applying to | |
4288 | the type of that declaration. If an attribute that only applies to | |
4289 | declarations is applied to the type of a declaration, it will be treated | |
4290 | as applying to that declaration; and, for compatibility with code | |
4291 | placing the attributes immediately before the identifier declared, such | |
4292 | an attribute applied to a function return type will be treated as | |
4293 | applying to the function type, and such an attribute applied to an array | |
4294 | element type will be treated as applying to the array type. If an | |
4295 | attribute that only applies to function types is applied to a | |
4296 | pointer-to-function type, it will be treated as applying to the pointer | |
4297 | target type; if such an attribute is applied to a function return type | |
4298 | that is not a pointer-to-function type, it will be treated as applying | |
4299 | to the function type. | |
2c5e91d2 | 4300 | |
c1f7febf RK |
4301 | @node Function Prototypes |
4302 | @section Prototypes and Old-Style Function Definitions | |
4303 | @cindex function prototype declarations | |
4304 | @cindex old-style function definitions | |
4305 | @cindex promotion of formal parameters | |
4306 | ||
5490d604 | 4307 | GNU C extends ISO C to allow a function prototype to override a later |
c1f7febf RK |
4308 | old-style non-prototype definition. Consider the following example: |
4309 | ||
3ab51846 | 4310 | @smallexample |
c1f7febf | 4311 | /* @r{Use prototypes unless the compiler is old-fashioned.} */ |
d863830b | 4312 | #ifdef __STDC__ |
c1f7febf RK |
4313 | #define P(x) x |
4314 | #else | |
4315 | #define P(x) () | |
4316 | #endif | |
4317 | ||
4318 | /* @r{Prototype function declaration.} */ | |
4319 | int isroot P((uid_t)); | |
4320 | ||
4321 | /* @r{Old-style function definition.} */ | |
4322 | int | |
12bcfaa1 | 4323 | isroot (x) /* @r{??? lossage here ???} */ |
c1f7febf RK |
4324 | uid_t x; |
4325 | @{ | |
4326 | return x == 0; | |
4327 | @} | |
3ab51846 | 4328 | @end smallexample |
c1f7febf | 4329 | |
5490d604 | 4330 | Suppose the type @code{uid_t} happens to be @code{short}. ISO C does |
c1f7febf RK |
4331 | not allow this example, because subword arguments in old-style |
4332 | non-prototype definitions are promoted. Therefore in this example the | |
4333 | function definition's argument is really an @code{int}, which does not | |
4334 | match the prototype argument type of @code{short}. | |
4335 | ||
5490d604 | 4336 | This restriction of ISO C makes it hard to write code that is portable |
c1f7febf RK |
4337 | to traditional C compilers, because the programmer does not know |
4338 | whether the @code{uid_t} type is @code{short}, @code{int}, or | |
4339 | @code{long}. Therefore, in cases like these GNU C allows a prototype | |
4340 | to override a later old-style definition. More precisely, in GNU C, a | |
4341 | function prototype argument type overrides the argument type specified | |
4342 | by a later old-style definition if the former type is the same as the | |
4343 | latter type before promotion. Thus in GNU C the above example is | |
4344 | equivalent to the following: | |
4345 | ||
3ab51846 | 4346 | @smallexample |
c1f7febf RK |
4347 | int isroot (uid_t); |
4348 | ||
4349 | int | |
4350 | isroot (uid_t x) | |
4351 | @{ | |
4352 | return x == 0; | |
4353 | @} | |
3ab51846 | 4354 | @end smallexample |
c1f7febf | 4355 | |
9c34dbbf | 4356 | @noindent |
c1f7febf RK |
4357 | GNU C++ does not support old-style function definitions, so this |
4358 | extension is irrelevant. | |
4359 | ||
4360 | @node C++ Comments | |
4361 | @section C++ Style Comments | |
ab940b73 | 4362 | @cindex @code{//} |
c1f7febf RK |
4363 | @cindex C++ comments |
4364 | @cindex comments, C++ style | |
4365 | ||
4366 | In GNU C, you may use C++ style comments, which start with @samp{//} and | |
4367 | continue until the end of the line. Many other C implementations allow | |
f458d1d5 ZW |
4368 | such comments, and they are included in the 1999 C standard. However, |
4369 | C++ style comments are not recognized if you specify an @option{-std} | |
4370 | option specifying a version of ISO C before C99, or @option{-ansi} | |
7e1542b9 | 4371 | (equivalent to @option{-std=c90}). |
c1f7febf RK |
4372 | |
4373 | @node Dollar Signs | |
4374 | @section Dollar Signs in Identifier Names | |
4375 | @cindex $ | |
4376 | @cindex dollar signs in identifier names | |
4377 | @cindex identifier names, dollar signs in | |
4378 | ||
79188db9 RK |
4379 | In GNU C, you may normally use dollar signs in identifier names. |
4380 | This is because many traditional C implementations allow such identifiers. | |
4381 | However, dollar signs in identifiers are not supported on a few target | |
4382 | machines, typically because the target assembler does not allow them. | |
c1f7febf RK |
4383 | |
4384 | @node Character Escapes | |
4385 | @section The Character @key{ESC} in Constants | |
4386 | ||
4387 | You can use the sequence @samp{\e} in a string or character constant to | |
4388 | stand for the ASCII character @key{ESC}. | |
4389 | ||
c1f7febf RK |
4390 | @node Variable Attributes |
4391 | @section Specifying Attributes of Variables | |
4392 | @cindex attribute of variables | |
4393 | @cindex variable attributes | |
4394 | ||
4395 | The keyword @code{__attribute__} allows you to specify special | |
4396 | attributes of variables or structure fields. This keyword is followed | |
905e8651 RH |
4397 | by an attribute specification inside double parentheses. Some |
4398 | attributes are currently defined generically for variables. | |
4399 | Other attributes are defined for variables on particular target | |
4400 | systems. Other attributes are available for functions | |
4401 | (@pxref{Function Attributes}) and for types (@pxref{Type Attributes}). | |
4402 | Other front ends might define more attributes | |
4403 | (@pxref{C++ Extensions,,Extensions to the C++ Language}). | |
c1f7febf RK |
4404 | |
4405 | You may also specify attributes with @samp{__} preceding and following | |
4406 | each keyword. This allows you to use them in header files without | |
4407 | being concerned about a possible macro of the same name. For example, | |
4408 | you may use @code{__aligned__} instead of @code{aligned}. | |
4409 | ||
2c5e91d2 JM |
4410 | @xref{Attribute Syntax}, for details of the exact syntax for using |
4411 | attributes. | |
4412 | ||
c1f7febf RK |
4413 | @table @code |
4414 | @cindex @code{aligned} attribute | |
4415 | @item aligned (@var{alignment}) | |
4416 | This attribute specifies a minimum alignment for the variable or | |
4417 | structure field, measured in bytes. For example, the declaration: | |
4418 | ||
4419 | @smallexample | |
4420 | int x __attribute__ ((aligned (16))) = 0; | |
4421 | @end smallexample | |
4422 | ||
4423 | @noindent | |
4424 | causes the compiler to allocate the global variable @code{x} on a | |
4425 | 16-byte boundary. On a 68040, this could be used in conjunction with | |
4426 | an @code{asm} expression to access the @code{move16} instruction which | |
4427 | requires 16-byte aligned operands. | |
4428 | ||
4429 | You can also specify the alignment of structure fields. For example, to | |
4430 | create a double-word aligned @code{int} pair, you could write: | |
4431 | ||
4432 | @smallexample | |
4433 | struct foo @{ int x[2] __attribute__ ((aligned (8))); @}; | |
4434 | @end smallexample | |
4435 | ||
4436 | @noindent | |
4437 | This is an alternative to creating a union with a @code{double} member | |
4438 | that forces the union to be double-word aligned. | |
4439 | ||
c1f7febf RK |
4440 | As in the preceding examples, you can explicitly specify the alignment |
4441 | (in bytes) that you wish the compiler to use for a given variable or | |
4442 | structure field. Alternatively, you can leave out the alignment factor | |
6e4f1168 L |
4443 | and just ask the compiler to align a variable or field to the |
4444 | default alignment for the target architecture you are compiling for. | |
4445 | The default alignment is sufficient for all scalar types, but may not be | |
4446 | enough for all vector types on a target which supports vector operations. | |
4447 | The default alignment is fixed for a particular target ABI. | |
4448 | ||
4449 | Gcc also provides a target specific macro @code{__BIGGEST_ALIGNMENT__}, | |
4450 | which is the largest alignment ever used for any data type on the | |
4451 | target machine you are compiling for. For example, you could write: | |
c1f7febf RK |
4452 | |
4453 | @smallexample | |
6e4f1168 | 4454 | short array[3] __attribute__ ((aligned (__BIGGEST_ALIGNMENT__))); |
c1f7febf RK |
4455 | @end smallexample |
4456 | ||
6e4f1168 L |
4457 | The compiler automatically sets the alignment for the declared |
4458 | variable or field to @code{__BIGGEST_ALIGNMENT__}. Doing this can | |
4459 | often make copy operations more efficient, because the compiler can | |
4460 | use whatever instructions copy the biggest chunks of memory when | |
4461 | performing copies to or from the variables or fields that you have | |
4462 | aligned this way. Note that the value of @code{__BIGGEST_ALIGNMENT__} | |
4463 | may change depending on command line options. | |
c1f7febf | 4464 | |
e9f9692b MW |
4465 | When used on a struct, or struct member, the @code{aligned} attribute can |
4466 | only increase the alignment; in order to decrease it, the @code{packed} | |
4467 | attribute must be specified as well. When used as part of a typedef, the | |
4468 | @code{aligned} attribute can both increase and decrease alignment, and | |
4469 | specifying the @code{packed} attribute will generate a warning. | |
c1f7febf RK |
4470 | |
4471 | Note that the effectiveness of @code{aligned} attributes may be limited | |
4472 | by inherent limitations in your linker. On many systems, the linker is | |
4473 | only able to arrange for variables to be aligned up to a certain maximum | |
4474 | alignment. (For some linkers, the maximum supported alignment may | |
4475 | be very very small.) If your linker is only able to align variables | |
4476 | up to a maximum of 8 byte alignment, then specifying @code{aligned(16)} | |
4477 | in an @code{__attribute__} will still only provide you with 8 byte | |
4478 | alignment. See your linker documentation for further information. | |
4479 | ||
ff2ce160 | 4480 | The @code{aligned} attribute can also be used for functions |
837edd5f GK |
4481 | (@pxref{Function Attributes}.) |
4482 | ||
0bfa5f65 RH |
4483 | @item cleanup (@var{cleanup_function}) |
4484 | @cindex @code{cleanup} attribute | |
4485 | The @code{cleanup} attribute runs a function when the variable goes | |
4486 | out of scope. This attribute can only be applied to auto function | |
4487 | scope variables; it may not be applied to parameters or variables | |
4488 | with static storage duration. The function must take one parameter, | |
4489 | a pointer to a type compatible with the variable. The return value | |
4490 | of the function (if any) is ignored. | |
4491 | ||
4492 | If @option{-fexceptions} is enabled, then @var{cleanup_function} | |
4493 | will be run during the stack unwinding that happens during the | |
4494 | processing of the exception. Note that the @code{cleanup} attribute | |
4495 | does not allow the exception to be caught, only to perform an action. | |
4496 | It is undefined what happens if @var{cleanup_function} does not | |
4497 | return normally. | |
4498 | ||
905e8651 RH |
4499 | @item common |
4500 | @itemx nocommon | |
4501 | @cindex @code{common} attribute | |
4502 | @cindex @code{nocommon} attribute | |
4503 | @opindex fcommon | |
4504 | @opindex fno-common | |
4505 | The @code{common} attribute requests GCC to place a variable in | |
4506 | ``common'' storage. The @code{nocommon} attribute requests the | |
78466c0e | 4507 | opposite---to allocate space for it directly. |
905e8651 | 4508 | |
daf2f129 | 4509 | These attributes override the default chosen by the |
905e8651 RH |
4510 | @option{-fno-common} and @option{-fcommon} flags respectively. |
4511 | ||
4512 | @item deprecated | |
9b86d6bb | 4513 | @itemx deprecated (@var{msg}) |
905e8651 RH |
4514 | @cindex @code{deprecated} attribute |
4515 | The @code{deprecated} attribute results in a warning if the variable | |
4516 | is used anywhere in the source file. This is useful when identifying | |
4517 | variables that are expected to be removed in a future version of a | |
4518 | program. The warning also includes the location of the declaration | |
4519 | of the deprecated variable, to enable users to easily find further | |
4520 | information about why the variable is deprecated, or what they should | |
64c18e57 | 4521 | do instead. Note that the warning only occurs for uses: |
905e8651 RH |
4522 | |
4523 | @smallexample | |
4524 | extern int old_var __attribute__ ((deprecated)); | |
4525 | extern int old_var; | |
4526 | int new_fn () @{ return old_var; @} | |
4527 | @end smallexample | |
4528 | ||
9b86d6bb L |
4529 | results in a warning on line 3 but not line 2. The optional msg |
4530 | argument, which must be a string, will be printed in the warning if | |
4531 | present. | |
905e8651 RH |
4532 | |
4533 | The @code{deprecated} attribute can also be used for functions and | |
4534 | types (@pxref{Function Attributes}, @pxref{Type Attributes}.) | |
4535 | ||
c1f7febf RK |
4536 | @item mode (@var{mode}) |
4537 | @cindex @code{mode} attribute | |
4538 | This attribute specifies the data type for the declaration---whichever | |
4539 | type corresponds to the mode @var{mode}. This in effect lets you | |
4540 | request an integer or floating point type according to its width. | |
4541 | ||
4542 | You may also specify a mode of @samp{byte} or @samp{__byte__} to | |
4543 | indicate the mode corresponding to a one-byte integer, @samp{word} or | |
4544 | @samp{__word__} for the mode of a one-word integer, and @samp{pointer} | |
4545 | or @samp{__pointer__} for the mode used to represent pointers. | |
4546 | ||
c1f7febf RK |
4547 | @item packed |
4548 | @cindex @code{packed} attribute | |
4549 | The @code{packed} attribute specifies that a variable or structure field | |
4550 | should have the smallest possible alignment---one byte for a variable, | |
4551 | and one bit for a field, unless you specify a larger value with the | |
4552 | @code{aligned} attribute. | |
4553 | ||
4554 | Here is a structure in which the field @code{x} is packed, so that it | |
4555 | immediately follows @code{a}: | |
4556 | ||
3ab51846 | 4557 | @smallexample |
c1f7febf RK |
4558 | struct foo |
4559 | @{ | |
4560 | char a; | |
4561 | int x[2] __attribute__ ((packed)); | |
4562 | @}; | |
3ab51846 | 4563 | @end smallexample |
c1f7febf | 4564 | |
2cd36c22 AN |
4565 | @emph{Note:} The 4.1, 4.2 and 4.3 series of GCC ignore the |
4566 | @code{packed} attribute on bit-fields of type @code{char}. This has | |
4567 | been fixed in GCC 4.4 but the change can lead to differences in the | |
048fd785 | 4568 | structure layout. See the documentation of |
2cd36c22 AN |
4569 | @option{-Wpacked-bitfield-compat} for more information. |
4570 | ||
84330467 | 4571 | @item section ("@var{section-name}") |
c1f7febf RK |
4572 | @cindex @code{section} variable attribute |
4573 | Normally, the compiler places the objects it generates in sections like | |
4574 | @code{data} and @code{bss}. Sometimes, however, you need additional sections, | |
4575 | or you need certain particular variables to appear in special sections, | |
4576 | for example to map to special hardware. The @code{section} | |
4577 | attribute specifies that a variable (or function) lives in a particular | |
4578 | section. For example, this small program uses several specific section names: | |
4579 | ||
4580 | @smallexample | |
4581 | struct duart a __attribute__ ((section ("DUART_A"))) = @{ 0 @}; | |
4582 | struct duart b __attribute__ ((section ("DUART_B"))) = @{ 0 @}; | |
4583 | char stack[10000] __attribute__ ((section ("STACK"))) = @{ 0 @}; | |
8b9d598f | 4584 | int init_data __attribute__ ((section ("INITDATA"))); |
c1f7febf RK |
4585 | |
4586 | main() | |
4587 | @{ | |
12bcfaa1 | 4588 | /* @r{Initialize stack pointer} */ |
c1f7febf RK |
4589 | init_sp (stack + sizeof (stack)); |
4590 | ||
12bcfaa1 | 4591 | /* @r{Initialize initialized data} */ |
c1f7febf RK |
4592 | memcpy (&init_data, &data, &edata - &data); |
4593 | ||
12bcfaa1 | 4594 | /* @r{Turn on the serial ports} */ |
c1f7febf RK |
4595 | init_duart (&a); |
4596 | init_duart (&b); | |
4597 | @} | |
4598 | @end smallexample | |
4599 | ||
4600 | @noindent | |
8b9d598f SE |
4601 | Use the @code{section} attribute with |
4602 | @emph{global} variables and not @emph{local} variables, | |
4603 | as shown in the example. | |
c1f7febf | 4604 | |
8b9d598f SE |
4605 | You may use the @code{section} attribute with initialized or |
4606 | uninitialized global variables but the linker requires | |
c1f7febf RK |
4607 | each object be defined once, with the exception that uninitialized |
4608 | variables tentatively go in the @code{common} (or @code{bss}) section | |
8b9d598f SE |
4609 | and can be multiply ``defined''. Using the @code{section} attribute |
4610 | will change what section the variable goes into and may cause the | |
4611 | linker to issue an error if an uninitialized variable has multiple | |
4612 | definitions. You can force a variable to be initialized with the | |
4613 | @option{-fno-common} flag or the @code{nocommon} attribute. | |
c1f7febf RK |
4614 | |
4615 | Some file formats do not support arbitrary sections so the @code{section} | |
4616 | attribute is not available on all platforms. | |
4617 | If you need to map the entire contents of a module to a particular | |
4618 | section, consider using the facilities of the linker instead. | |
4619 | ||
593d3a34 MK |
4620 | @item shared |
4621 | @cindex @code{shared} variable attribute | |
95fef11f | 4622 | On Microsoft Windows, in addition to putting variable definitions in a named |
02f52e19 | 4623 | section, the section can also be shared among all running copies of an |
161d7b59 | 4624 | executable or DLL@. For example, this small program defines shared data |
84330467 | 4625 | by putting it in a named section @code{shared} and marking the section |
593d3a34 MK |
4626 | shareable: |
4627 | ||
4628 | @smallexample | |
4629 | int foo __attribute__((section ("shared"), shared)) = 0; | |
4630 | ||
4631 | int | |
4632 | main() | |
4633 | @{ | |
12bcfaa1 JM |
4634 | /* @r{Read and write foo. All running |
4635 | copies see the same value.} */ | |
593d3a34 MK |
4636 | return 0; |
4637 | @} | |
4638 | @end smallexample | |
4639 | ||
4640 | @noindent | |
4641 | You may only use the @code{shared} attribute along with @code{section} | |
02f52e19 | 4642 | attribute with a fully initialized global definition because of the way |
593d3a34 MK |
4643 | linkers work. See @code{section} attribute for more information. |
4644 | ||
95fef11f | 4645 | The @code{shared} attribute is only available on Microsoft Windows@. |
593d3a34 | 4646 | |
905e8651 RH |
4647 | @item tls_model ("@var{tls_model}") |
4648 | @cindex @code{tls_model} attribute | |
4649 | The @code{tls_model} attribute sets thread-local storage model | |
4650 | (@pxref{Thread-Local}) of a particular @code{__thread} variable, | |
bcbc9564 | 4651 | overriding @option{-ftls-model=} command-line switch on a per-variable |
905e8651 RH |
4652 | basis. |
4653 | The @var{tls_model} argument should be one of @code{global-dynamic}, | |
4654 | @code{local-dynamic}, @code{initial-exec} or @code{local-exec}. | |
4655 | ||
4656 | Not all targets support this attribute. | |
4657 | ||
c1f7febf RK |
4658 | @item unused |
4659 | This attribute, attached to a variable, means that the variable is meant | |
f0523f02 | 4660 | to be possibly unused. GCC will not produce a warning for this |
c1f7febf RK |
4661 | variable. |
4662 | ||
5f79d643 RM |
4663 | @item used |
4664 | This attribute, attached to a variable, means that the variable must be | |
4665 | emitted even if it appears that the variable is not referenced. | |
4666 | ||
4951efb6 JM |
4667 | When applied to a static data member of a C++ class template, the |
4668 | attribute also means that the member will be instantiated if the | |
4669 | class itself is instantiated. | |
4670 | ||
1b9191d2 AH |
4671 | @item vector_size (@var{bytes}) |
4672 | This attribute specifies the vector size for the variable, measured in | |
4673 | bytes. For example, the declaration: | |
4674 | ||
4675 | @smallexample | |
4676 | int foo __attribute__ ((vector_size (16))); | |
4677 | @end smallexample | |
4678 | ||
4679 | @noindent | |
4680 | causes the compiler to set the mode for @code{foo}, to be 16 bytes, | |
4681 | divided into @code{int} sized units. Assuming a 32-bit int (a vector of | |
4682 | 4 units of 4 bytes), the corresponding mode of @code{foo} will be V4SI@. | |
4683 | ||
4684 | This attribute is only applicable to integral and float scalars, | |
4685 | although arrays, pointers, and function return values are allowed in | |
4686 | conjunction with this construct. | |
4687 | ||
4688 | Aggregates with this attribute are invalid, even if they are of the same | |
4689 | size as a corresponding scalar. For example, the declaration: | |
4690 | ||
4691 | @smallexample | |
ad706f54 | 4692 | struct S @{ int a; @}; |
1b9191d2 AH |
4693 | struct S __attribute__ ((vector_size (16))) foo; |
4694 | @end smallexample | |
4695 | ||
4696 | @noindent | |
4697 | is invalid even if the size of the structure is the same as the size of | |
4698 | the @code{int}. | |
4699 | ||
a20f6f00 DS |
4700 | @item selectany |
4701 | The @code{selectany} attribute causes an initialized global variable to | |
4702 | have link-once semantics. When multiple definitions of the variable are | |
4703 | encountered by the linker, the first is selected and the remainder are | |
4704 | discarded. Following usage by the Microsoft compiler, the linker is told | |
4705 | @emph{not} to warn about size or content differences of the multiple | |
4706 | definitions. | |
4707 | ||
4708 | Although the primary usage of this attribute is for POD types, the | |
4709 | attribute can also be applied to global C++ objects that are initialized | |
4710 | by a constructor. In this case, the static initialization and destruction | |
4711 | code for the object is emitted in each translation defining the object, | |
4712 | but the calls to the constructor and destructor are protected by a | |
0ac11108 | 4713 | link-once guard variable. |
a20f6f00 DS |
4714 | |
4715 | The @code{selectany} attribute is only available on Microsoft Windows | |
4716 | targets. You can use @code{__declspec (selectany)} as a synonym for | |
4717 | @code{__attribute__ ((selectany))} for compatibility with other | |
4718 | compilers. | |
4719 | ||
c1f7febf | 4720 | @item weak |
38bb2b65 | 4721 | The @code{weak} attribute is described in @ref{Function Attributes}. |
6b6cb52e DS |
4722 | |
4723 | @item dllimport | |
38bb2b65 | 4724 | The @code{dllimport} attribute is described in @ref{Function Attributes}. |
6b6cb52e | 4725 | |
9baf8aea | 4726 | @item dllexport |
38bb2b65 | 4727 | The @code{dllexport} attribute is described in @ref{Function Attributes}. |
6b6cb52e | 4728 | |
905e8651 RH |
4729 | @end table |
4730 | ||
542bf446 | 4731 | @anchor{AVR Variable Attributes} |
3d33d151 AS |
4732 | @subsection AVR Variable Attributes |
4733 | ||
4734 | @table @code | |
4735 | @item progmem | |
4736 | @cindex @code{progmem} AVR variable attribute | |
542bf446 GJL |
4737 | The @code{progmem} attribute is used on the AVR to place read-only |
4738 | data in the non-volatile program memory (flash). The @code{progmem} | |
4739 | attribute accomplishes this by putting respective variables into a | |
4740 | section whose name starts with @code{.progmem}. | |
4741 | ||
aa9ec4db | 4742 | This attribute works similar to the @code{section} attribute |
542bf446 GJL |
4743 | but adds additional checking. Notice that just like the |
4744 | @code{section} attribute, @code{progmem} affects the location | |
4745 | of the data but not how this data is accessed. | |
4746 | ||
aa9ec4db GJL |
4747 | In order to read data located with the @code{progmem} attribute |
4748 | (inline) assembler must be used. | |
4749 | @example | |
4750 | /* Use custom macros from @w{@uref{http://nongnu.org/avr-libc/user-manual,avr-libc}} */ | |
4751 | #include <avr/pgmspace.h> | |
4752 | ||
4753 | /* Locate var in flash memory */ | |
4754 | const int var[2] PROGMEM = @{ 1, 2 @}; | |
4755 | ||
4756 | int read_var (int i) | |
4757 | @{ | |
4758 | /* Access var[] by accessor macro from avr/pgmspace.h */ | |
4759 | return (int) pgm_read_word (& var[i]); | |
4760 | @} | |
4761 | @end example | |
4762 | ||
542bf446 GJL |
4763 | AVR is a Harvard architecture processor and data and read-only data |
4764 | normally resides in the data memory (RAM). | |
aa9ec4db GJL |
4765 | |
4766 | See also the @ref{AVR Named Address Spaces} section for | |
4767 | an alternate way to locate and access data in flash memory. | |
3d33d151 AS |
4768 | @end table |
4769 | ||
4af797b5 JZ |
4770 | @subsection Blackfin Variable Attributes |
4771 | ||
4772 | Three attributes are currently defined for the Blackfin. | |
4773 | ||
4774 | @table @code | |
4775 | @item l1_data | |
1588fb31 RW |
4776 | @itemx l1_data_A |
4777 | @itemx l1_data_B | |
4af797b5 JZ |
4778 | @cindex @code{l1_data} variable attribute |
4779 | @cindex @code{l1_data_A} variable attribute | |
4780 | @cindex @code{l1_data_B} variable attribute | |
4781 | Use these attributes on the Blackfin to place the variable into L1 Data SRAM. | |
4782 | Variables with @code{l1_data} attribute will be put into the specific section | |
4783 | named @code{.l1.data}. Those with @code{l1_data_A} attribute will be put into | |
4784 | the specific section named @code{.l1.data.A}. Those with @code{l1_data_B} | |
4785 | attribute will be put into the specific section named @code{.l1.data.B}. | |
603bb63e BS |
4786 | |
4787 | @item l2 | |
4788 | @cindex @code{l2} variable attribute | |
4789 | Use this attribute on the Blackfin to place the variable into L2 SRAM. | |
4790 | Variables with @code{l2} attribute will be put into the specific section | |
4791 | named @code{.l2.data}. | |
4af797b5 JZ |
4792 | @end table |
4793 | ||
905e8651 | 4794 | @subsection M32R/D Variable Attributes |
845da534 | 4795 | |
8a36672b | 4796 | One attribute is currently defined for the M32R/D@. |
905e8651 RH |
4797 | |
4798 | @table @code | |
845da534 DE |
4799 | @item model (@var{model-name}) |
4800 | @cindex variable addressability on the M32R/D | |
4801 | Use this attribute on the M32R/D to set the addressability of an object. | |
4802 | The identifier @var{model-name} is one of @code{small}, @code{medium}, | |
4803 | or @code{large}, representing each of the code models. | |
4804 | ||
4805 | Small model objects live in the lower 16MB of memory (so that their | |
4806 | addresses can be loaded with the @code{ld24} instruction). | |
4807 | ||
02f52e19 | 4808 | Medium and large model objects may live anywhere in the 32-bit address space |
845da534 DE |
4809 | (the compiler will generate @code{seth/add3} instructions to load their |
4810 | addresses). | |
905e8651 | 4811 | @end table |
845da534 | 4812 | |
e2491744 DD |
4813 | @anchor{MeP Variable Attributes} |
4814 | @subsection MeP Variable Attributes | |
4815 | ||
4816 | The MeP target has a number of addressing modes and busses. The | |
4817 | @code{near} space spans the standard memory space's first 16 megabytes | |
4818 | (24 bits). The @code{far} space spans the entire 32-bit memory space. | |
4819 | The @code{based} space is a 128 byte region in the memory space which | |
4820 | is addressed relative to the @code{$tp} register. The @code{tiny} | |
4821 | space is a 65536 byte region relative to the @code{$gp} register. In | |
4822 | addition to these memory regions, the MeP target has a separate 16-bit | |
4823 | control bus which is specified with @code{cb} attributes. | |
4824 | ||
4825 | @table @code | |
4826 | ||
4827 | @item based | |
4828 | Any variable with the @code{based} attribute will be assigned to the | |
4829 | @code{.based} section, and will be accessed with relative to the | |
4830 | @code{$tp} register. | |
4831 | ||
4832 | @item tiny | |
4833 | Likewise, the @code{tiny} attribute assigned variables to the | |
4834 | @code{.tiny} section, relative to the @code{$gp} register. | |
4835 | ||
4836 | @item near | |
4837 | Variables with the @code{near} attribute are assumed to have addresses | |
4838 | that fit in a 24-bit addressing mode. This is the default for large | |
4839 | variables (@code{-mtiny=4} is the default) but this attribute can | |
4840 | override @code{-mtiny=} for small variables, or override @code{-ml}. | |
4841 | ||
4842 | @item far | |
4843 | Variables with the @code{far} attribute are addressed using a full | |
4844 | 32-bit address. Since this covers the entire memory space, this | |
4845 | allows modules to make no assumptions about where variables might be | |
4846 | stored. | |
4847 | ||
4848 | @item io | |
1588fb31 | 4849 | @itemx io (@var{addr}) |
e2491744 DD |
4850 | Variables with the @code{io} attribute are used to address |
4851 | memory-mapped peripherals. If an address is specified, the variable | |
4852 | is assigned that address, else it is not assigned an address (it is | |
4853 | assumed some other module will assign an address). Example: | |
4854 | ||
4855 | @example | |
4856 | int timer_count __attribute__((io(0x123))); | |
4857 | @end example | |
4858 | ||
4859 | @item cb | |
1588fb31 | 4860 | @itemx cb (@var{addr}) |
e2491744 DD |
4861 | Variables with the @code{cb} attribute are used to access the control |
4862 | bus, using special instructions. @code{addr} indicates the control bus | |
4863 | address. Example: | |
4864 | ||
4865 | @example | |
4866 | int cpu_clock __attribute__((cb(0x123))); | |
4867 | @end example | |
4868 | ||
4869 | @end table | |
4870 | ||
1ccbef77 | 4871 | @anchor{i386 Variable Attributes} |
fe77449a DR |
4872 | @subsection i386 Variable Attributes |
4873 | ||
4874 | Two attributes are currently defined for i386 configurations: | |
4875 | @code{ms_struct} and @code{gcc_struct} | |
4876 | ||
905e8651 | 4877 | @table @code |
fe77449a DR |
4878 | @item ms_struct |
4879 | @itemx gcc_struct | |
905e8651 RH |
4880 | @cindex @code{ms_struct} attribute |
4881 | @cindex @code{gcc_struct} attribute | |
fe77449a DR |
4882 | |
4883 | If @code{packed} is used on a structure, or if bit-fields are used | |
4884 | it may be that the Microsoft ABI packs them differently | |
4885 | than GCC would normally pack them. Particularly when moving packed | |
4886 | data between functions compiled with GCC and the native Microsoft compiler | |
4887 | (either via function call or as data in a file), it may be necessary to access | |
4888 | either format. | |
4889 | ||
95fef11f | 4890 | Currently @option{-m[no-]ms-bitfields} is provided for the Microsoft Windows X86 |
fe77449a | 4891 | compilers to match the native Microsoft compiler. |
0ac11108 EC |
4892 | |
4893 | The Microsoft structure layout algorithm is fairly simple with the exception | |
4894 | of the bitfield packing: | |
4895 | ||
4896 | The padding and alignment of members of structures and whether a bit field | |
4897 | can straddle a storage-unit boundary | |
4898 | ||
4899 | @enumerate | |
4900 | @item Structure members are stored sequentially in the order in which they are | |
4901 | declared: the first member has the lowest memory address and the last member | |
4902 | the highest. | |
4903 | ||
4904 | @item Every data object has an alignment-requirement. The alignment-requirement | |
4905 | for all data except structures, unions, and arrays is either the size of the | |
4906 | object or the current packing size (specified with either the aligned attribute | |
4907 | or the pack pragma), whichever is less. For structures, unions, and arrays, | |
4908 | the alignment-requirement is the largest alignment-requirement of its members. | |
4909 | Every object is allocated an offset so that: | |
4910 | ||
4911 | offset % alignment-requirement == 0 | |
4912 | ||
4913 | @item Adjacent bit fields are packed into the same 1-, 2-, or 4-byte allocation | |
4914 | unit if the integral types are the same size and if the next bit field fits | |
4915 | into the current allocation unit without crossing the boundary imposed by the | |
4916 | common alignment requirements of the bit fields. | |
4917 | @end enumerate | |
4918 | ||
4919 | Handling of zero-length bitfields: | |
4920 | ||
4921 | MSVC interprets zero-length bitfields in the following ways: | |
4922 | ||
4923 | @enumerate | |
4924 | @item If a zero-length bitfield is inserted between two bitfields that would | |
4925 | normally be coalesced, the bitfields will not be coalesced. | |
4926 | ||
4927 | For example: | |
4928 | ||
4929 | @smallexample | |
4930 | struct | |
4931 | @{ | |
4932 | unsigned long bf_1 : 12; | |
4933 | unsigned long : 0; | |
4934 | unsigned long bf_2 : 12; | |
4935 | @} t1; | |
4936 | @end smallexample | |
4937 | ||
4938 | The size of @code{t1} would be 8 bytes with the zero-length bitfield. If the | |
4939 | zero-length bitfield were removed, @code{t1}'s size would be 4 bytes. | |
4940 | ||
4941 | @item If a zero-length bitfield is inserted after a bitfield, @code{foo}, and the | |
4942 | alignment of the zero-length bitfield is greater than the member that follows it, | |
4943 | @code{bar}, @code{bar} will be aligned as the type of the zero-length bitfield. | |
4944 | ||
4945 | For example: | |
4946 | ||
4947 | @smallexample | |
4948 | struct | |
4949 | @{ | |
4950 | char foo : 4; | |
4951 | short : 0; | |
4952 | char bar; | |
4953 | @} t2; | |
4954 | ||
4955 | struct | |
4956 | @{ | |
4957 | char foo : 4; | |
4958 | short : 0; | |
4959 | double bar; | |
4960 | @} t3; | |
4961 | @end smallexample | |
4962 | ||
4963 | For @code{t2}, @code{bar} will be placed at offset 2, rather than offset 1. | |
4964 | Accordingly, the size of @code{t2} will be 4. For @code{t3}, the zero-length | |
4965 | bitfield will not affect the alignment of @code{bar} or, as a result, the size | |
4966 | of the structure. | |
4967 | ||
4968 | Taking this into account, it is important to note the following: | |
4969 | ||
4970 | @enumerate | |
4971 | @item If a zero-length bitfield follows a normal bitfield, the type of the | |
4972 | zero-length bitfield may affect the alignment of the structure as whole. For | |
4973 | example, @code{t2} has a size of 4 bytes, since the zero-length bitfield follows a | |
4974 | normal bitfield, and is of type short. | |
4975 | ||
4976 | @item Even if a zero-length bitfield is not followed by a normal bitfield, it may | |
4977 | still affect the alignment of the structure: | |
4978 | ||
4979 | @smallexample | |
4980 | struct | |
4981 | @{ | |
4982 | char foo : 6; | |
4983 | long : 0; | |
4984 | @} t4; | |
4985 | @end smallexample | |
4986 | ||
4987 | Here, @code{t4} will take up 4 bytes. | |
4988 | @end enumerate | |
4989 | ||
4990 | @item Zero-length bitfields following non-bitfield members are ignored: | |
4991 | ||
4992 | @smallexample | |
4993 | struct | |
4994 | @{ | |
4995 | char foo; | |
4996 | long : 0; | |
4997 | char bar; | |
4998 | @} t5; | |
4999 | @end smallexample | |
5000 | ||
5001 | Here, @code{t5} will take up 2 bytes. | |
5002 | @end enumerate | |
c1f7febf RK |
5003 | @end table |
5004 | ||
1ccbef77 EC |
5005 | @subsection PowerPC Variable Attributes |
5006 | ||
63d0dca4 DE |
5007 | Three attributes currently are defined for PowerPC configurations: |
5008 | @code{altivec}, @code{ms_struct} and @code{gcc_struct}. | |
1ccbef77 | 5009 | |
63d0dca4 | 5010 | For full documentation of the struct attributes please see the |
38bb2b65 | 5011 | documentation in @ref{i386 Variable Attributes}. |
63d0dca4 DE |
5012 | |
5013 | For documentation of @code{altivec} attribute please see the | |
38bb2b65 | 5014 | documentation in @ref{PowerPC Type Attributes}. |
1ccbef77 | 5015 | |
85d9c13c TS |
5016 | @subsection SPU Variable Attributes |
5017 | ||
5018 | The SPU supports the @code{spu_vector} attribute for variables. For | |
38bb2b65 SL |
5019 | documentation of this attribute please see the documentation in |
5020 | @ref{SPU Type Attributes}. | |
85d9c13c | 5021 | |
54e9a19d DD |
5022 | @subsection Xstormy16 Variable Attributes |
5023 | ||
5024 | One attribute is currently defined for xstormy16 configurations: | |
38bb2b65 | 5025 | @code{below100}. |
54e9a19d DD |
5026 | |
5027 | @table @code | |
5028 | @item below100 | |
5029 | @cindex @code{below100} attribute | |
5030 | ||
5031 | If a variable has the @code{below100} attribute (@code{BELOW100} is | |
5032 | allowed also), GCC will place the variable in the first 0x100 bytes of | |
5033 | memory and use special opcodes to access it. Such variables will be | |
5034 | placed in either the @code{.bss_below100} section or the | |
5035 | @code{.data_below100} section. | |
5036 | ||
5037 | @end table | |
5038 | ||
c1f7febf RK |
5039 | @node Type Attributes |
5040 | @section Specifying Attributes of Types | |
5041 | @cindex attribute of types | |
5042 | @cindex type attributes | |
5043 | ||
5044 | The keyword @code{__attribute__} allows you to specify special | |
b9e75696 JM |
5045 | attributes of @code{struct} and @code{union} types when you define |
5046 | such types. This keyword is followed by an attribute specification | |
5047 | inside double parentheses. Seven attributes are currently defined for | |
5048 | types: @code{aligned}, @code{packed}, @code{transparent_union}, | |
5049 | @code{unused}, @code{deprecated}, @code{visibility}, and | |
5050 | @code{may_alias}. Other attributes are defined for functions | |
5051 | (@pxref{Function Attributes}) and for variables (@pxref{Variable | |
5052 | Attributes}). | |
c1f7febf RK |
5053 | |
5054 | You may also specify any one of these attributes with @samp{__} | |
5055 | preceding and following its keyword. This allows you to use these | |
5056 | attributes in header files without being concerned about a possible | |
5057 | macro of the same name. For example, you may use @code{__aligned__} | |
5058 | instead of @code{aligned}. | |
5059 | ||
4009f2e7 JM |
5060 | You may specify type attributes in an enum, struct or union type |
5061 | declaration or definition, or for other types in a @code{typedef} | |
5062 | declaration. | |
c1f7febf | 5063 | |
b9e75696 JM |
5064 | For an enum, struct or union type, you may specify attributes either |
5065 | between the enum, struct or union tag and the name of the type, or | |
5066 | just past the closing curly brace of the @emph{definition}. The | |
5067 | former syntax is preferred. | |
4051959b | 5068 | |
2c5e91d2 JM |
5069 | @xref{Attribute Syntax}, for details of the exact syntax for using |
5070 | attributes. | |
5071 | ||
c1f7febf RK |
5072 | @table @code |
5073 | @cindex @code{aligned} attribute | |
5074 | @item aligned (@var{alignment}) | |
5075 | This attribute specifies a minimum alignment (in bytes) for variables | |
5076 | of the specified type. For example, the declarations: | |
5077 | ||
5078 | @smallexample | |
f69eecfb JL |
5079 | struct S @{ short f[3]; @} __attribute__ ((aligned (8))); |
5080 | typedef int more_aligned_int __attribute__ ((aligned (8))); | |
c1f7febf RK |
5081 | @end smallexample |
5082 | ||
5083 | @noindent | |
d863830b | 5084 | force the compiler to insure (as far as it can) that each variable whose |
c1f7febf | 5085 | type is @code{struct S} or @code{more_aligned_int} will be allocated and |
981f6289 | 5086 | aligned @emph{at least} on a 8-byte boundary. On a SPARC, having all |
c1f7febf RK |
5087 | variables of type @code{struct S} aligned to 8-byte boundaries allows |
5088 | the compiler to use the @code{ldd} and @code{std} (doubleword load and | |
5089 | store) instructions when copying one variable of type @code{struct S} to | |
5090 | another, thus improving run-time efficiency. | |
5091 | ||
5092 | Note that the alignment of any given @code{struct} or @code{union} type | |
5490d604 | 5093 | is required by the ISO C standard to be at least a perfect multiple of |
c1f7febf RK |
5094 | the lowest common multiple of the alignments of all of the members of |
5095 | the @code{struct} or @code{union} in question. This means that you @emph{can} | |
5096 | effectively adjust the alignment of a @code{struct} or @code{union} | |
5097 | type by attaching an @code{aligned} attribute to any one of the members | |
5098 | of such a type, but the notation illustrated in the example above is a | |
5099 | more obvious, intuitive, and readable way to request the compiler to | |
5100 | adjust the alignment of an entire @code{struct} or @code{union} type. | |
5101 | ||
5102 | As in the preceding example, you can explicitly specify the alignment | |
5103 | (in bytes) that you wish the compiler to use for a given @code{struct} | |
5104 | or @code{union} type. Alternatively, you can leave out the alignment factor | |
5105 | and just ask the compiler to align a type to the maximum | |
5106 | useful alignment for the target machine you are compiling for. For | |
5107 | example, you could write: | |
5108 | ||
5109 | @smallexample | |
5110 | struct S @{ short f[3]; @} __attribute__ ((aligned)); | |
5111 | @end smallexample | |
5112 | ||
5113 | Whenever you leave out the alignment factor in an @code{aligned} | |
5114 | attribute specification, the compiler automatically sets the alignment | |
5115 | for the type to the largest alignment which is ever used for any data | |
5116 | type on the target machine you are compiling for. Doing this can often | |
5117 | make copy operations more efficient, because the compiler can use | |
5118 | whatever instructions copy the biggest chunks of memory when performing | |
5119 | copies to or from the variables which have types that you have aligned | |
5120 | this way. | |
5121 | ||
5122 | In the example above, if the size of each @code{short} is 2 bytes, then | |
5123 | the size of the entire @code{struct S} type is 6 bytes. The smallest | |
5124 | power of two which is greater than or equal to that is 8, so the | |
5125 | compiler sets the alignment for the entire @code{struct S} type to 8 | |
5126 | bytes. | |
5127 | ||
5128 | Note that although you can ask the compiler to select a time-efficient | |
5129 | alignment for a given type and then declare only individual stand-alone | |
5130 | objects of that type, the compiler's ability to select a time-efficient | |
5131 | alignment is primarily useful only when you plan to create arrays of | |
5132 | variables having the relevant (efficiently aligned) type. If you | |
5133 | declare or use arrays of variables of an efficiently-aligned type, then | |
5134 | it is likely that your program will also be doing pointer arithmetic (or | |
5135 | subscripting, which amounts to the same thing) on pointers to the | |
5136 | relevant type, and the code that the compiler generates for these | |
5137 | pointer arithmetic operations will often be more efficient for | |
5138 | efficiently-aligned types than for other types. | |
5139 | ||
5140 | The @code{aligned} attribute can only increase the alignment; but you | |
5141 | can decrease it by specifying @code{packed} as well. See below. | |
5142 | ||
5143 | Note that the effectiveness of @code{aligned} attributes may be limited | |
5144 | by inherent limitations in your linker. On many systems, the linker is | |
5145 | only able to arrange for variables to be aligned up to a certain maximum | |
5146 | alignment. (For some linkers, the maximum supported alignment may | |
5147 | be very very small.) If your linker is only able to align variables | |
5148 | up to a maximum of 8 byte alignment, then specifying @code{aligned(16)} | |
5149 | in an @code{__attribute__} will still only provide you with 8 byte | |
5150 | alignment. See your linker documentation for further information. | |
5151 | ||
5152 | @item packed | |
a5bcc582 | 5153 | This attribute, attached to @code{struct} or @code{union} type |
d1a701eb MM |
5154 | definition, specifies that each member (other than zero-width bitfields) |
5155 | of the structure or union is placed to minimize the memory required. When | |
5156 | attached to an @code{enum} definition, it indicates that the smallest | |
5157 | integral type should be used. | |
c1f7febf | 5158 | |
84330467 | 5159 | @opindex fshort-enums |
c1f7febf RK |
5160 | Specifying this attribute for @code{struct} and @code{union} types is |
5161 | equivalent to specifying the @code{packed} attribute on each of the | |
84330467 | 5162 | structure or union members. Specifying the @option{-fshort-enums} |
c1f7febf RK |
5163 | flag on the line is equivalent to specifying the @code{packed} |
5164 | attribute on all @code{enum} definitions. | |
5165 | ||
a5bcc582 NS |
5166 | In the following example @code{struct my_packed_struct}'s members are |
5167 | packed closely together, but the internal layout of its @code{s} member | |
78466c0e | 5168 | is not packed---to do that, @code{struct my_unpacked_struct} would need to |
a5bcc582 NS |
5169 | be packed too. |
5170 | ||
5171 | @smallexample | |
5172 | struct my_unpacked_struct | |
5173 | @{ | |
5174 | char c; | |
5175 | int i; | |
5176 | @}; | |
5177 | ||
75b66a16 | 5178 | struct __attribute__ ((__packed__)) my_packed_struct |
a5bcc582 NS |
5179 | @{ |
5180 | char c; | |
5181 | int i; | |
5182 | struct my_unpacked_struct s; | |
5183 | @}; | |
5184 | @end smallexample | |
5185 | ||
e4ae5e77 | 5186 | You may only specify this attribute on the definition of an @code{enum}, |
a5bcc582 NS |
5187 | @code{struct} or @code{union}, not on a @code{typedef} which does not |
5188 | also define the enumerated type, structure or union. | |
c1f7febf RK |
5189 | |
5190 | @item transparent_union | |
5191 | This attribute, attached to a @code{union} type definition, indicates | |
5192 | that any function parameter having that union type causes calls to that | |
5193 | function to be treated in a special way. | |
5194 | ||
5195 | First, the argument corresponding to a transparent union type can be of | |
5196 | any type in the union; no cast is required. Also, if the union contains | |
5197 | a pointer type, the corresponding argument can be a null pointer | |
5198 | constant or a void pointer expression; and if the union contains a void | |
5199 | pointer type, the corresponding argument can be any pointer expression. | |
5200 | If the union member type is a pointer, qualifiers like @code{const} on | |
5201 | the referenced type must be respected, just as with normal pointer | |
5202 | conversions. | |
5203 | ||
5204 | Second, the argument is passed to the function using the calling | |
64c18e57 | 5205 | conventions of the first member of the transparent union, not the calling |
c1f7febf RK |
5206 | conventions of the union itself. All members of the union must have the |
5207 | same machine representation; this is necessary for this argument passing | |
5208 | to work properly. | |
5209 | ||
5210 | Transparent unions are designed for library functions that have multiple | |
5211 | interfaces for compatibility reasons. For example, suppose the | |
5212 | @code{wait} function must accept either a value of type @code{int *} to | |
5213 | comply with Posix, or a value of type @code{union wait *} to comply with | |
5214 | the 4.1BSD interface. If @code{wait}'s parameter were @code{void *}, | |
5215 | @code{wait} would accept both kinds of arguments, but it would also | |
5216 | accept any other pointer type and this would make argument type checking | |
5217 | less useful. Instead, @code{<sys/wait.h>} might define the interface | |
5218 | as follows: | |
5219 | ||
5220 | @smallexample | |
4009f2e7 | 5221 | typedef union __attribute__ ((__transparent_union__)) |
c1f7febf RK |
5222 | @{ |
5223 | int *__ip; | |
5224 | union wait *__up; | |
4009f2e7 | 5225 | @} wait_status_ptr_t; |
c1f7febf RK |
5226 | |
5227 | pid_t wait (wait_status_ptr_t); | |
5228 | @end smallexample | |
5229 | ||
5230 | This interface allows either @code{int *} or @code{union wait *} | |
5231 | arguments to be passed, using the @code{int *} calling convention. | |
5232 | The program can call @code{wait} with arguments of either type: | |
5233 | ||
3ab51846 | 5234 | @smallexample |
c1f7febf RK |
5235 | int w1 () @{ int w; return wait (&w); @} |
5236 | int w2 () @{ union wait w; return wait (&w); @} | |
3ab51846 | 5237 | @end smallexample |
c1f7febf RK |
5238 | |
5239 | With this interface, @code{wait}'s implementation might look like this: | |
5240 | ||
3ab51846 | 5241 | @smallexample |
c1f7febf RK |
5242 | pid_t wait (wait_status_ptr_t p) |
5243 | @{ | |
5244 | return waitpid (-1, p.__ip, 0); | |
5245 | @} | |
3ab51846 | 5246 | @end smallexample |
d863830b JL |
5247 | |
5248 | @item unused | |
5249 | When attached to a type (including a @code{union} or a @code{struct}), | |
5250 | this attribute means that variables of that type are meant to appear | |
f0523f02 | 5251 | possibly unused. GCC will not produce a warning for any variables of |
d863830b JL |
5252 | that type, even if the variable appears to do nothing. This is often |
5253 | the case with lock or thread classes, which are usually defined and then | |
5254 | not referenced, but contain constructors and destructors that have | |
956d6950 | 5255 | nontrivial bookkeeping functions. |
d863830b | 5256 | |
e23bd218 | 5257 | @item deprecated |
9b86d6bb | 5258 | @itemx deprecated (@var{msg}) |
e23bd218 IR |
5259 | The @code{deprecated} attribute results in a warning if the type |
5260 | is used anywhere in the source file. This is useful when identifying | |
5261 | types that are expected to be removed in a future version of a program. | |
5262 | If possible, the warning also includes the location of the declaration | |
5263 | of the deprecated type, to enable users to easily find further | |
5264 | information about why the type is deprecated, or what they should do | |
5265 | instead. Note that the warnings only occur for uses and then only | |
adc9fe67 | 5266 | if the type is being applied to an identifier that itself is not being |
e23bd218 IR |
5267 | declared as deprecated. |
5268 | ||
5269 | @smallexample | |
5270 | typedef int T1 __attribute__ ((deprecated)); | |
5271 | T1 x; | |
5272 | typedef T1 T2; | |
5273 | T2 y; | |
5274 | typedef T1 T3 __attribute__ ((deprecated)); | |
5275 | T3 z __attribute__ ((deprecated)); | |
5276 | @end smallexample | |
5277 | ||
5278 | results in a warning on line 2 and 3 but not lines 4, 5, or 6. No | |
5279 | warning is issued for line 4 because T2 is not explicitly | |
5280 | deprecated. Line 5 has no warning because T3 is explicitly | |
9b86d6bb L |
5281 | deprecated. Similarly for line 6. The optional msg |
5282 | argument, which must be a string, will be printed in the warning if | |
5283 | present. | |
e23bd218 IR |
5284 | |
5285 | The @code{deprecated} attribute can also be used for functions and | |
5286 | variables (@pxref{Function Attributes}, @pxref{Variable Attributes}.) | |
5287 | ||
d18b1ed8 | 5288 | @item may_alias |
ac7ee6ad RG |
5289 | Accesses through pointers to types with this attribute are not subject |
5290 | to type-based alias analysis, but are instead assumed to be able to alias | |
5291 | any other type of objects. In the context of 6.5/7 an lvalue expression | |
5292 | dereferencing such a pointer is treated like having a character type. | |
5293 | See @option{-fstrict-aliasing} for more information on aliasing issues. | |
5294 | This extension exists to support some vector APIs, in which pointers to | |
5295 | one vector type are permitted to alias pointers to a different vector type. | |
5296 | ||
5297 | Note that an object of a type with this attribute does not have any | |
5298 | special semantics. | |
d18b1ed8 OS |
5299 | |
5300 | Example of use: | |
5301 | ||
478c9e72 | 5302 | @smallexample |
d18b1ed8 OS |
5303 | typedef short __attribute__((__may_alias__)) short_a; |
5304 | ||
5305 | int | |
5306 | main (void) | |
5307 | @{ | |
5308 | int a = 0x12345678; | |
5309 | short_a *b = (short_a *) &a; | |
5310 | ||
5311 | b[1] = 0; | |
5312 | ||
5313 | if (a == 0x12345678) | |
5314 | abort(); | |
5315 | ||
5316 | exit(0); | |
5317 | @} | |
478c9e72 | 5318 | @end smallexample |
d18b1ed8 OS |
5319 | |
5320 | If you replaced @code{short_a} with @code{short} in the variable | |
5321 | declaration, the above program would abort when compiled with | |
5322 | @option{-fstrict-aliasing}, which is on by default at @option{-O2} or | |
5323 | above in recent GCC versions. | |
fe77449a | 5324 | |
b9e75696 | 5325 | @item visibility |
b9e75696 JM |
5326 | In C++, attribute visibility (@pxref{Function Attributes}) can also be |
5327 | applied to class, struct, union and enum types. Unlike other type | |
5328 | attributes, the attribute must appear between the initial keyword and | |
5329 | the name of the type; it cannot appear after the body of the type. | |
5330 | ||
b70f0f48 JM |
5331 | Note that the type visibility is applied to vague linkage entities |
5332 | associated with the class (vtable, typeinfo node, etc.). In | |
5333 | particular, if a class is thrown as an exception in one shared object | |
5334 | and caught in another, the class must have default visibility. | |
5335 | Otherwise the two shared objects will be unable to use the same | |
5336 | typeinfo node and exception handling will break. | |
5337 | ||
38bb2b65 SL |
5338 | @end table |
5339 | ||
04fb56d5 MM |
5340 | @subsection ARM Type Attributes |
5341 | ||
5342 | On those ARM targets that support @code{dllimport} (such as Symbian | |
f0eb93a8 | 5343 | OS), you can use the @code{notshared} attribute to indicate that the |
04fb56d5 | 5344 | virtual table and other similar data for a class should not be |
8a36672b | 5345 | exported from a DLL@. For example: |
04fb56d5 MM |
5346 | |
5347 | @smallexample | |
5348 | class __declspec(notshared) C @{ | |
5349 | public: | |
f0eb93a8 | 5350 | __declspec(dllimport) C(); |
04fb56d5 MM |
5351 | virtual void f(); |
5352 | @} | |
5353 | ||
5354 | __declspec(dllexport) | |
5355 | C::C() @{@} | |
5356 | @end smallexample | |
5357 | ||
5358 | In this code, @code{C::C} is exported from the current DLL, but the | |
5359 | virtual table for @code{C} is not exported. (You can use | |
5360 | @code{__attribute__} instead of @code{__declspec} if you prefer, but | |
5361 | most Symbian OS code uses @code{__declspec}.) | |
5362 | ||
e2491744 DD |
5363 | @anchor{MeP Type Attributes} |
5364 | @subsection MeP Type Attributes | |
5365 | ||
5366 | Many of the MeP variable attributes may be applied to types as well. | |
5367 | Specifically, the @code{based}, @code{tiny}, @code{near}, and | |
5368 | @code{far} attributes may be applied to either. The @code{io} and | |
5369 | @code{cb} attributes may not be applied to types. | |
5370 | ||
63d0dca4 | 5371 | @anchor{i386 Type Attributes} |
fe77449a DR |
5372 | @subsection i386 Type Attributes |
5373 | ||
5374 | Two attributes are currently defined for i386 configurations: | |
38bb2b65 SL |
5375 | @code{ms_struct} and @code{gcc_struct}. |
5376 | ||
5377 | @table @code | |
fe77449a DR |
5378 | |
5379 | @item ms_struct | |
5380 | @itemx gcc_struct | |
5381 | @cindex @code{ms_struct} | |
5382 | @cindex @code{gcc_struct} | |
5383 | ||
5384 | If @code{packed} is used on a structure, or if bit-fields are used | |
5385 | it may be that the Microsoft ABI packs them differently | |
5386 | than GCC would normally pack them. Particularly when moving packed | |
5387 | data between functions compiled with GCC and the native Microsoft compiler | |
5388 | (either via function call or as data in a file), it may be necessary to access | |
5389 | either format. | |
5390 | ||
95fef11f | 5391 | Currently @option{-m[no-]ms-bitfields} is provided for the Microsoft Windows X86 |
fe77449a | 5392 | compilers to match the native Microsoft compiler. |
c1f7febf RK |
5393 | @end table |
5394 | ||
5395 | To specify multiple attributes, separate them by commas within the | |
5396 | double parentheses: for example, @samp{__attribute__ ((aligned (16), | |
5397 | packed))}. | |
5398 | ||
63d0dca4 DE |
5399 | @anchor{PowerPC Type Attributes} |
5400 | @subsection PowerPC Type Attributes | |
5401 | ||
5402 | Three attributes currently are defined for PowerPC configurations: | |
5403 | @code{altivec}, @code{ms_struct} and @code{gcc_struct}. | |
5404 | ||
ff2ce160 | 5405 | For full documentation of the @code{ms_struct} and @code{gcc_struct} |
38bb2b65 | 5406 | attributes please see the documentation in @ref{i386 Type Attributes}. |
63d0dca4 DE |
5407 | |
5408 | The @code{altivec} attribute allows one to declare AltiVec vector data | |
5409 | types supported by the AltiVec Programming Interface Manual. The | |
5410 | attribute requires an argument to specify one of three vector types: | |
5411 | @code{vector__}, @code{pixel__} (always followed by unsigned short), | |
5412 | and @code{bool__} (always followed by unsigned). | |
5413 | ||
5414 | @smallexample | |
5415 | __attribute__((altivec(vector__))) | |
5416 | __attribute__((altivec(pixel__))) unsigned short | |
5417 | __attribute__((altivec(bool__))) unsigned | |
5418 | @end smallexample | |
5419 | ||
5420 | These attributes mainly are intended to support the @code{__vector}, | |
5421 | @code{__pixel}, and @code{__bool} AltiVec keywords. | |
5422 | ||
85d9c13c TS |
5423 | @anchor{SPU Type Attributes} |
5424 | @subsection SPU Type Attributes | |
5425 | ||
5426 | The SPU supports the @code{spu_vector} attribute for types. This attribute | |
5427 | allows one to declare vector data types supported by the Sony/Toshiba/IBM SPU | |
5428 | Language Extensions Specification. It is intended to support the | |
5429 | @code{__vector} keyword. | |
5430 | ||
2be478a2 JW |
5431 | @node Alignment |
5432 | @section Inquiring on Alignment of Types or Variables | |
5433 | @cindex alignment | |
5434 | @cindex type alignment | |
5435 | @cindex variable alignment | |
5436 | ||
5437 | The keyword @code{__alignof__} allows you to inquire about how an object | |
5438 | is aligned, or the minimum alignment usually required by a type. Its | |
5439 | syntax is just like @code{sizeof}. | |
5440 | ||
5441 | For example, if the target machine requires a @code{double} value to be | |
5442 | aligned on an 8-byte boundary, then @code{__alignof__ (double)} is 8. | |
5443 | This is true on many RISC machines. On more traditional machine | |
5444 | designs, @code{__alignof__ (double)} is 4 or even 2. | |
5445 | ||
5446 | Some machines never actually require alignment; they allow reference to any | |
5447 | data type even at an odd address. For these machines, @code{__alignof__} | |
5448 | reports the smallest alignment that GCC will give the data type, usually as | |
5449 | mandated by the target ABI. | |
5450 | ||
5451 | If the operand of @code{__alignof__} is an lvalue rather than a type, | |
5452 | its value is the required alignment for its type, taking into account | |
5453 | any minimum alignment specified with GCC's @code{__attribute__} | |
5454 | extension (@pxref{Variable Attributes}). For example, after this | |
5455 | declaration: | |
5456 | ||
5457 | @smallexample | |
5458 | struct foo @{ int x; char y; @} foo1; | |
5459 | @end smallexample | |
5460 | ||
5461 | @noindent | |
5462 | the value of @code{__alignof__ (foo1.y)} is 1, even though its actual | |
5463 | alignment is probably 2 or 4, the same as @code{__alignof__ (int)}. | |
5464 | ||
5465 | It is an error to ask for the alignment of an incomplete type. | |
5466 | ||
85d9c13c | 5467 | |
c1f7febf RK |
5468 | @node Inline |
5469 | @section An Inline Function is As Fast As a Macro | |
5470 | @cindex inline functions | |
5471 | @cindex integrating function code | |
5472 | @cindex open coding | |
5473 | @cindex macros, inline alternative | |
5474 | ||
0a052b16 GK |
5475 | By declaring a function inline, you can direct GCC to make |
5476 | calls to that function faster. One way GCC can achieve this is to | |
c1f7febf RK |
5477 | integrate that function's code into the code for its callers. This |
5478 | makes execution faster by eliminating the function-call overhead; in | |
0a052b16 GK |
5479 | addition, if any of the actual argument values are constant, their |
5480 | known values may permit simplifications at compile time so that not | |
5481 | all of the inline function's code needs to be included. The effect on | |
5482 | code size is less predictable; object code may be larger or smaller | |
5483 | with function inlining, depending on the particular case. You can | |
5484 | also direct GCC to try to integrate all ``simple enough'' functions | |
5485 | into their callers with the option @option{-finline-functions}. | |
5486 | ||
5487 | GCC implements three different semantics of declaring a function | |
da1c7394 ILT |
5488 | inline. One is available with @option{-std=gnu89} or |
5489 | @option{-fgnu89-inline} or when @code{gnu_inline} attribute is present | |
2778d766 | 5490 | on all inline declarations, another when |
48b0b196 JM |
5491 | @option{-std=c99}, @option{-std=c11}, |
5492 | @option{-std=gnu99} or @option{-std=gnu11} | |
2778d766 | 5493 | (without @option{-fgnu89-inline}), and the third |
da1c7394 | 5494 | is used when compiling C++. |
4b404517 | 5495 | |
c1f7febf RK |
5496 | To declare a function inline, use the @code{inline} keyword in its |
5497 | declaration, like this: | |
5498 | ||
3ab51846 | 5499 | @smallexample |
0a052b16 | 5500 | static inline int |
c1f7febf RK |
5501 | inc (int *a) |
5502 | @{ | |
bcbc9564 | 5503 | return (*a)++; |
c1f7febf | 5504 | @} |
3ab51846 | 5505 | @end smallexample |
c1f7febf | 5506 | |
7e1542b9 | 5507 | If you are writing a header file to be included in ISO C90 programs, write |
0a052b16 | 5508 | @code{__inline__} instead of @code{inline}. @xref{Alternate Keywords}. |
247b14bd | 5509 | |
0a052b16 GK |
5510 | The three types of inlining behave similarly in two important cases: |
5511 | when the @code{inline} keyword is used on a @code{static} function, | |
5512 | like the example above, and when a function is first declared without | |
5513 | using the @code{inline} keyword and then is defined with | |
5514 | @code{inline}, like this: | |
c1f7febf | 5515 | |
0a052b16 GK |
5516 | @smallexample |
5517 | extern int inc (int *a); | |
5518 | inline int | |
5519 | inc (int *a) | |
5520 | @{ | |
bcbc9564 | 5521 | return (*a)++; |
0a052b16 GK |
5522 | @} |
5523 | @end smallexample | |
c1f7febf | 5524 | |
0a052b16 GK |
5525 | In both of these common cases, the program behaves the same as if you |
5526 | had not used the @code{inline} keyword, except for its speed. | |
c1f7febf RK |
5527 | |
5528 | @cindex inline functions, omission of | |
84330467 | 5529 | @opindex fkeep-inline-functions |
c1f7febf RK |
5530 | When a function is both inline and @code{static}, if all calls to the |
5531 | function are integrated into the caller, and the function's address is | |
5532 | never used, then the function's own assembler code is never referenced. | |
f0523f02 | 5533 | In this case, GCC does not actually output assembler code for the |
84330467 | 5534 | function, unless you specify the option @option{-fkeep-inline-functions}. |
c1f7febf RK |
5535 | Some calls cannot be integrated for various reasons (in particular, |
5536 | calls that precede the function's definition cannot be integrated, and | |
5537 | neither can recursive calls within the definition). If there is a | |
5538 | nonintegrated call, then the function is compiled to assembler code as | |
5539 | usual. The function must also be compiled as usual if the program | |
5540 | refers to its address, because that can't be inlined. | |
5541 | ||
0a052b16 GK |
5542 | @opindex Winline |
5543 | Note that certain usages in a function definition can make it unsuitable | |
5544 | for inline substitution. Among these usages are: use of varargs, use of | |
5545 | alloca, use of variable sized data types (@pxref{Variable Length}), | |
5546 | use of computed goto (@pxref{Labels as Values}), use of nonlocal goto, | |
5547 | and nested functions (@pxref{Nested Functions}). Using @option{-Winline} | |
5548 | will warn when a function marked @code{inline} could not be substituted, | |
5549 | and will give the reason for the failure. | |
5550 | ||
5551 | @cindex automatic @code{inline} for C++ member fns | |
5552 | @cindex @code{inline} automatic for C++ member fns | |
5553 | @cindex member fns, automatically @code{inline} | |
5554 | @cindex C++ member fns, automatically @code{inline} | |
5555 | @opindex fno-default-inline | |
5556 | As required by ISO C++, GCC considers member functions defined within | |
5557 | the body of a class to be marked inline even if they are | |
5558 | not explicitly declared with the @code{inline} keyword. You can | |
5559 | override this with @option{-fno-default-inline}; @pxref{C++ Dialect | |
5560 | Options,,Options Controlling C++ Dialect}. | |
5561 | ||
5562 | GCC does not inline any functions when not optimizing unless you specify | |
5563 | the @samp{always_inline} attribute for the function, like this: | |
5564 | ||
5565 | @smallexample | |
5566 | /* @r{Prototype.} */ | |
5567 | inline void foo (const char) __attribute__((always_inline)); | |
5568 | @end smallexample | |
5569 | ||
7e1542b9 | 5570 | The remainder of this section is specific to GNU C90 inlining. |
0a052b16 | 5571 | |
c1f7febf RK |
5572 | @cindex non-static inline function |
5573 | When an inline function is not @code{static}, then the compiler must assume | |
5574 | that there may be calls from other source files; since a global symbol can | |
5575 | be defined only once in any program, the function must not be defined in | |
5576 | the other source files, so the calls therein cannot be integrated. | |
5577 | Therefore, a non-@code{static} inline function is always compiled on its | |
5578 | own in the usual fashion. | |
5579 | ||
5580 | If you specify both @code{inline} and @code{extern} in the function | |
5581 | definition, then the definition is used only for inlining. In no case | |
5582 | is the function compiled on its own, not even if you refer to its | |
5583 | address explicitly. Such an address becomes an external reference, as | |
5584 | if you had only declared the function, and had not defined it. | |
5585 | ||
5586 | This combination of @code{inline} and @code{extern} has almost the | |
5587 | effect of a macro. The way to use it is to put a function definition in | |
5588 | a header file with these keywords, and put another copy of the | |
5589 | definition (lacking @code{inline} and @code{extern}) in a library file. | |
5590 | The definition in the header file will cause most calls to the function | |
5591 | to be inlined. If any uses of the function remain, they will refer to | |
5592 | the single copy in the library. | |
5593 | ||
8f0fe813 NS |
5594 | @node Volatiles |
5595 | @section When is a Volatile Object Accessed? | |
5596 | @cindex accessing volatiles | |
5597 | @cindex volatile read | |
5598 | @cindex volatile write | |
5599 | @cindex volatile access | |
5600 | ||
5601 | C has the concept of volatile objects. These are normally accessed by | |
5602 | pointers and used for accessing hardware or inter-thread | |
2b0d3573 | 5603 | communication. The standard encourages compilers to refrain from |
8f0fe813 NS |
5604 | optimizations concerning accesses to volatile objects, but leaves it |
5605 | implementation defined as to what constitutes a volatile access. The | |
5606 | minimum requirement is that at a sequence point all previous accesses | |
5607 | to volatile objects have stabilized and no subsequent accesses have | |
5608 | occurred. Thus an implementation is free to reorder and combine | |
5609 | volatile accesses which occur between sequence points, but cannot do | |
2b0d3573 | 5610 | so for accesses across a sequence point. The use of volatile does |
8f0fe813 NS |
5611 | not allow you to violate the restriction on updating objects multiple |
5612 | times between two sequence points. | |
5613 | ||
5614 | Accesses to non-volatile objects are not ordered with respect to | |
5615 | volatile accesses. You cannot use a volatile object as a memory | |
5616 | barrier to order a sequence of writes to non-volatile memory. For | |
5617 | instance: | |
5618 | ||
5619 | @smallexample | |
5620 | int *ptr = @var{something}; | |
5621 | volatile int vobj; | |
5622 | *ptr = @var{something}; | |
5623 | vobj = 1; | |
5624 | @end smallexample | |
5625 | ||
5626 | Unless @var{*ptr} and @var{vobj} can be aliased, it is not guaranteed | |
5627 | that the write to @var{*ptr} will have occurred by the time the update | |
5628 | of @var{vobj} has happened. If you need this guarantee, you must use | |
5629 | a stronger memory barrier such as: | |
5630 | ||
5631 | @smallexample | |
5632 | int *ptr = @var{something}; | |
5633 | volatile int vobj; | |
5634 | *ptr = @var{something}; | |
5635 | asm volatile ("" : : : "memory"); | |
5636 | vobj = 1; | |
5637 | @end smallexample | |
5638 | ||
2b0d3573 | 5639 | A scalar volatile object is read when it is accessed in a void context: |
8f0fe813 NS |
5640 | |
5641 | @smallexample | |
5642 | volatile int *src = @var{somevalue}; | |
5643 | *src; | |
5644 | @end smallexample | |
5645 | ||
5646 | Such expressions are rvalues, and GCC implements this as a | |
5647 | read of the volatile object being pointed to. | |
5648 | ||
5649 | Assignments are also expressions and have an rvalue. However when | |
5650 | assigning to a scalar volatile, the volatile object is not reread, | |
5651 | regardless of whether the assignment expression's rvalue is used or | |
5652 | not. If the assignment's rvalue is used, the value is that assigned | |
5653 | to the volatile object. For instance, there is no read of @var{vobj} | |
5654 | in all the following cases: | |
5655 | ||
5656 | @smallexample | |
5657 | int obj; | |
5658 | volatile int vobj; | |
5659 | vobj = @var{something}; | |
5660 | obj = vobj = @var{something}; | |
5661 | obj ? vobj = @var{onething} : vobj = @var{anotherthing}; | |
5662 | obj = (@var{something}, vobj = @var{anotherthing}); | |
5663 | @end smallexample | |
5664 | ||
5665 | If you need to read the volatile object after an assignment has | |
5666 | occurred, you must use a separate expression with an intervening | |
5667 | sequence point. | |
5668 | ||
5669 | As bitfields are not individually addressable, volatile bitfields may | |
5670 | be implicitly read when written to, or when adjacent bitfields are | |
5671 | accessed. Bitfield operations may be optimized such that adjacent | |
5672 | bitfields are only partially accessed, if they straddle a storage unit | |
5673 | boundary. For these reasons it is unwise to use volatile bitfields to | |
5674 | access hardware. | |
5675 | ||
c1f7febf RK |
5676 | @node Extended Asm |
5677 | @section Assembler Instructions with C Expression Operands | |
5678 | @cindex extended @code{asm} | |
5679 | @cindex @code{asm} expressions | |
5680 | @cindex assembler instructions | |
5681 | @cindex registers | |
5682 | ||
c85f7c16 JL |
5683 | In an assembler instruction using @code{asm}, you can specify the |
5684 | operands of the instruction using C expressions. This means you need not | |
5685 | guess which registers or memory locations will contain the data you want | |
c1f7febf RK |
5686 | to use. |
5687 | ||
c85f7c16 JL |
5688 | You must specify an assembler instruction template much like what |
5689 | appears in a machine description, plus an operand constraint string for | |
5690 | each operand. | |
c1f7febf RK |
5691 | |
5692 | For example, here is how to use the 68881's @code{fsinx} instruction: | |
5693 | ||
3ab51846 | 5694 | @smallexample |
c1f7febf | 5695 | asm ("fsinx %1,%0" : "=f" (result) : "f" (angle)); |
3ab51846 | 5696 | @end smallexample |
c1f7febf RK |
5697 | |
5698 | @noindent | |
5699 | Here @code{angle} is the C expression for the input operand while | |
5700 | @code{result} is that of the output operand. Each has @samp{"f"} as its | |
c85f7c16 JL |
5701 | operand constraint, saying that a floating point register is required. |
5702 | The @samp{=} in @samp{=f} indicates that the operand is an output; all | |
5703 | output operands' constraints must use @samp{=}. The constraints use the | |
5704 | same language used in the machine description (@pxref{Constraints}). | |
5705 | ||
5706 | Each operand is described by an operand-constraint string followed by | |
5707 | the C expression in parentheses. A colon separates the assembler | |
5708 | template from the first output operand and another separates the last | |
5709 | output operand from the first input, if any. Commas separate the | |
84b72302 RH |
5710 | operands within each group. The total number of operands is currently |
5711 | limited to 30; this limitation may be lifted in some future version of | |
8a36672b | 5712 | GCC@. |
c85f7c16 JL |
5713 | |
5714 | If there are no output operands but there are input operands, you must | |
5715 | place two consecutive colons surrounding the place where the output | |
c1f7febf RK |
5716 | operands would go. |
5717 | ||
84b72302 RH |
5718 | As of GCC version 3.1, it is also possible to specify input and output |
5719 | operands using symbolic names which can be referenced within the | |
5720 | assembler code. These names are specified inside square brackets | |
5721 | preceding the constraint string, and can be referenced inside the | |
5722 | assembler code using @code{%[@var{name}]} instead of a percentage sign | |
5723 | followed by the operand number. Using named operands the above example | |
5724 | could look like: | |
5725 | ||
3ab51846 | 5726 | @smallexample |
84b72302 RH |
5727 | asm ("fsinx %[angle],%[output]" |
5728 | : [output] "=f" (result) | |
5729 | : [angle] "f" (angle)); | |
3ab51846 | 5730 | @end smallexample |
84b72302 RH |
5731 | |
5732 | @noindent | |
5733 | Note that the symbolic operand names have no relation whatsoever to | |
5734 | other C identifiers. You may use any name you like, even those of | |
64c18e57 | 5735 | existing C symbols, but you must ensure that no two operands within the same |
84b72302 RH |
5736 | assembler construct use the same symbolic name. |
5737 | ||
c1f7febf | 5738 | Output operand expressions must be lvalues; the compiler can check this. |
c85f7c16 JL |
5739 | The input operands need not be lvalues. The compiler cannot check |
5740 | whether the operands have data types that are reasonable for the | |
5741 | instruction being executed. It does not parse the assembler instruction | |
5742 | template and does not know what it means or even whether it is valid | |
5743 | assembler input. The extended @code{asm} feature is most often used for | |
5744 | machine instructions the compiler itself does not know exist. If | |
5745 | the output expression cannot be directly addressed (for example, it is a | |
f0523f02 | 5746 | bit-field), your constraint must allow a register. In that case, GCC |
c85f7c16 JL |
5747 | will use the register as the output of the @code{asm}, and then store |
5748 | that register into the output. | |
5749 | ||
f0523f02 | 5750 | The ordinary output operands must be write-only; GCC will assume that |
c85f7c16 JL |
5751 | the values in these operands before the instruction are dead and need |
5752 | not be generated. Extended asm supports input-output or read-write | |
5753 | operands. Use the constraint character @samp{+} to indicate such an | |
373a04f1 JM |
5754 | operand and list it with the output operands. You should only use |
5755 | read-write operands when the constraints for the operand (or the | |
5756 | operand in which only some of the bits are to be changed) allow a | |
5757 | register. | |
5758 | ||
5759 | You may, as an alternative, logically split its function into two | |
5760 | separate operands, one input operand and one write-only output | |
5761 | operand. The connection between them is expressed by constraints | |
5762 | which say they need to be in the same location when the instruction | |
5763 | executes. You can use the same C expression for both operands, or | |
5764 | different expressions. For example, here we write the (fictitious) | |
5765 | @samp{combine} instruction with @code{bar} as its read-only source | |
5766 | operand and @code{foo} as its read-write destination: | |
c1f7febf | 5767 | |
3ab51846 | 5768 | @smallexample |
c1f7febf | 5769 | asm ("combine %2,%0" : "=r" (foo) : "0" (foo), "g" (bar)); |
3ab51846 | 5770 | @end smallexample |
c1f7febf RK |
5771 | |
5772 | @noindent | |
c85f7c16 | 5773 | The constraint @samp{"0"} for operand 1 says that it must occupy the |
84b72302 RH |
5774 | same location as operand 0. A number in constraint is allowed only in |
5775 | an input operand and it must refer to an output operand. | |
c1f7febf | 5776 | |
84b72302 | 5777 | Only a number in the constraint can guarantee that one operand will be in |
c85f7c16 JL |
5778 | the same place as another. The mere fact that @code{foo} is the value |
5779 | of both operands is not enough to guarantee that they will be in the | |
5780 | same place in the generated assembler code. The following would not | |
5781 | work reliably: | |
c1f7febf | 5782 | |
3ab51846 | 5783 | @smallexample |
c1f7febf | 5784 | asm ("combine %2,%0" : "=r" (foo) : "r" (foo), "g" (bar)); |
3ab51846 | 5785 | @end smallexample |
c1f7febf RK |
5786 | |
5787 | Various optimizations or reloading could cause operands 0 and 1 to be in | |
f0523f02 | 5788 | different registers; GCC knows no reason not to do so. For example, the |
c1f7febf RK |
5789 | compiler might find a copy of the value of @code{foo} in one register and |
5790 | use it for operand 1, but generate the output operand 0 in a different | |
5791 | register (copying it afterward to @code{foo}'s own address). Of course, | |
5792 | since the register for operand 1 is not even mentioned in the assembler | |
f0523f02 | 5793 | code, the result will not work, but GCC can't tell that. |
c1f7febf | 5794 | |
84b72302 RH |
5795 | As of GCC version 3.1, one may write @code{[@var{name}]} instead of |
5796 | the operand number for a matching constraint. For example: | |
5797 | ||
3ab51846 | 5798 | @smallexample |
84b72302 RH |
5799 | asm ("cmoveq %1,%2,%[result]" |
5800 | : [result] "=r"(result) | |
5801 | : "r" (test), "r"(new), "[result]"(old)); | |
3ab51846 | 5802 | @end smallexample |
84b72302 | 5803 | |
805c33df HPN |
5804 | Sometimes you need to make an @code{asm} operand be a specific register, |
5805 | but there's no matching constraint letter for that register @emph{by | |
5806 | itself}. To force the operand into that register, use a local variable | |
5807 | for the operand and specify the register in the variable declaration. | |
5808 | @xref{Explicit Reg Vars}. Then for the @code{asm} operand, use any | |
5809 | register constraint letter that matches the register: | |
5810 | ||
5811 | @smallexample | |
5812 | register int *p1 asm ("r0") = @dots{}; | |
5813 | register int *p2 asm ("r1") = @dots{}; | |
5814 | register int *result asm ("r0"); | |
5815 | asm ("sysint" : "=r" (result) : "0" (p1), "r" (p2)); | |
5816 | @end smallexample | |
5817 | ||
b55d5746 HPN |
5818 | @anchor{Example of asm with clobbered asm reg} |
5819 | In the above example, beware that a register that is call-clobbered by | |
5820 | the target ABI will be overwritten by any function call in the | |
5821 | assignment, including library calls for arithmetic operators. | |
0c6390fa L |
5822 | Also a register may be clobbered when generating some operations, |
5823 | like variable shift, memory copy or memory move on x86. | |
b55d5746 HPN |
5824 | Assuming it is a call-clobbered register, this may happen to @code{r0} |
5825 | above by the assignment to @code{p2}. If you have to use such a | |
5826 | register, use temporary variables for expressions between the register | |
5827 | assignment and use: | |
5828 | ||
5829 | @smallexample | |
5830 | int t1 = @dots{}; | |
5831 | register int *p1 asm ("r0") = @dots{}; | |
5832 | register int *p2 asm ("r1") = t1; | |
5833 | register int *result asm ("r0"); | |
5834 | asm ("sysint" : "=r" (result) : "0" (p1), "r" (p2)); | |
5835 | @end smallexample | |
5836 | ||
c85f7c16 JL |
5837 | Some instructions clobber specific hard registers. To describe this, |
5838 | write a third colon after the input operands, followed by the names of | |
5839 | the clobbered hard registers (given as strings). Here is a realistic | |
5840 | example for the VAX: | |
c1f7febf | 5841 | |
3ab51846 | 5842 | @smallexample |
c1f7febf | 5843 | asm volatile ("movc3 %0,%1,%2" |
12bcfaa1 | 5844 | : /* @r{no outputs} */ |
c1f7febf RK |
5845 | : "g" (from), "g" (to), "g" (count) |
5846 | : "r0", "r1", "r2", "r3", "r4", "r5"); | |
3ab51846 | 5847 | @end smallexample |
c1f7febf | 5848 | |
c5c76735 JL |
5849 | You may not write a clobber description in a way that overlaps with an |
5850 | input or output operand. For example, you may not have an operand | |
5851 | describing a register class with one member if you mention that register | |
acb5d088 HPN |
5852 | in the clobber list. Variables declared to live in specific registers |
5853 | (@pxref{Explicit Reg Vars}), and used as asm input or output operands must | |
5854 | have no part mentioned in the clobber description. | |
5855 | There is no way for you to specify that an input | |
c5c76735 JL |
5856 | operand is modified without also specifying it as an output |
5857 | operand. Note that if all the output operands you specify are for this | |
5858 | purpose (and hence unused), you will then also need to specify | |
5859 | @code{volatile} for the @code{asm} construct, as described below, to | |
f0523f02 | 5860 | prevent GCC from deleting the @code{asm} statement as unused. |
8fe1938e | 5861 | |
c1f7febf | 5862 | If you refer to a particular hardware register from the assembler code, |
c85f7c16 JL |
5863 | you will probably have to list the register after the third colon to |
5864 | tell the compiler the register's value is modified. In some assemblers, | |
5865 | the register names begin with @samp{%}; to produce one @samp{%} in the | |
5866 | assembler code, you must write @samp{%%} in the input. | |
5867 | ||
5868 | If your assembler instruction can alter the condition code register, add | |
f0523f02 | 5869 | @samp{cc} to the list of clobbered registers. GCC on some machines |
c85f7c16 JL |
5870 | represents the condition codes as a specific hardware register; |
5871 | @samp{cc} serves to name this register. On other machines, the | |
5872 | condition code is handled differently, and specifying @samp{cc} has no | |
5873 | effect. But it is valid no matter what the machine. | |
c1f7febf | 5874 | |
bbf5a54d | 5875 | If your assembler instructions access memory in an unpredictable |
c85f7c16 | 5876 | fashion, add @samp{memory} to the list of clobbered registers. This |
bbf5a54d AJ |
5877 | will cause GCC to not keep memory values cached in registers across the |
5878 | assembler instruction and not optimize stores or loads to that memory. | |
5879 | You will also want to add the @code{volatile} keyword if the memory | |
5880 | affected is not listed in the inputs or outputs of the @code{asm}, as | |
5881 | the @samp{memory} clobber does not count as a side-effect of the | |
5882 | @code{asm}. If you know how large the accessed memory is, you can add | |
5883 | it as input or output but if this is not known, you should add | |
5884 | @samp{memory}. As an example, if you access ten bytes of a string, you | |
5885 | can use a memory input like: | |
5886 | ||
cd1a8088 | 5887 | @smallexample |
bbf5a54d | 5888 | @{"m"( (@{ struct @{ char x[10]; @} *p = (void *)ptr ; *p; @}) )@}. |
cd1a8088 | 5889 | @end smallexample |
bbf5a54d AJ |
5890 | |
5891 | Note that in the following example the memory input is necessary, | |
5892 | otherwise GCC might optimize the store to @code{x} away: | |
cd1a8088 | 5893 | @smallexample |
bbf5a54d AJ |
5894 | int foo () |
5895 | @{ | |
5896 | int x = 42; | |
5897 | int *y = &x; | |
5898 | int result; | |
5899 | asm ("magic stuff accessing an 'int' pointed to by '%1'" | |
5900 | "=&d" (r) : "a" (y), "m" (*y)); | |
f0eb93a8 | 5901 | return result; |
bbf5a54d | 5902 | @} |
cd1a8088 | 5903 | @end smallexample |
c1f7febf | 5904 | |
c85f7c16 | 5905 | You can put multiple assembler instructions together in a single |
8720914b HPN |
5906 | @code{asm} template, separated by the characters normally used in assembly |
5907 | code for the system. A combination that works in most places is a newline | |
5908 | to break the line, plus a tab character to move to the instruction field | |
5909 | (written as @samp{\n\t}). Sometimes semicolons can be used, if the | |
5910 | assembler allows semicolons as a line-breaking character. Note that some | |
5911 | assembler dialects use semicolons to start a comment. | |
5912 | The input operands are guaranteed not to use any of the clobbered | |
c85f7c16 JL |
5913 | registers, and neither will the output operands' addresses, so you can |
5914 | read and write the clobbered registers as many times as you like. Here | |
5915 | is an example of multiple instructions in a template; it assumes the | |
5916 | subroutine @code{_foo} accepts arguments in registers 9 and 10: | |
c1f7febf | 5917 | |
3ab51846 | 5918 | @smallexample |
8720914b | 5919 | asm ("movl %0,r9\n\tmovl %1,r10\n\tcall _foo" |
c1f7febf RK |
5920 | : /* no outputs */ |
5921 | : "g" (from), "g" (to) | |
5922 | : "r9", "r10"); | |
3ab51846 | 5923 | @end smallexample |
c1f7febf | 5924 | |
f0523f02 | 5925 | Unless an output operand has the @samp{&} constraint modifier, GCC |
c85f7c16 JL |
5926 | may allocate it in the same register as an unrelated input operand, on |
5927 | the assumption the inputs are consumed before the outputs are produced. | |
c1f7febf RK |
5928 | This assumption may be false if the assembler code actually consists of |
5929 | more than one instruction. In such a case, use @samp{&} for each output | |
c85f7c16 | 5930 | operand that may not overlap an input. @xref{Modifiers}. |
c1f7febf | 5931 | |
c85f7c16 JL |
5932 | If you want to test the condition code produced by an assembler |
5933 | instruction, you must include a branch and a label in the @code{asm} | |
5934 | construct, as follows: | |
c1f7febf | 5935 | |
3ab51846 | 5936 | @smallexample |
8720914b | 5937 | asm ("clr %0\n\tfrob %1\n\tbeq 0f\n\tmov #1,%0\n0:" |
c1f7febf RK |
5938 | : "g" (result) |
5939 | : "g" (input)); | |
3ab51846 | 5940 | @end smallexample |
c1f7febf RK |
5941 | |
5942 | @noindent | |
5943 | This assumes your assembler supports local labels, as the GNU assembler | |
5944 | and most Unix assemblers do. | |
5945 | ||
5946 | Speaking of labels, jumps from one @code{asm} to another are not | |
c85f7c16 JL |
5947 | supported. The compiler's optimizers do not know about these jumps, and |
5948 | therefore they cannot take account of them when deciding how to | |
1c384bf1 | 5949 | optimize. @xref{Extended asm with goto}. |
c1f7febf RK |
5950 | |
5951 | @cindex macros containing @code{asm} | |
5952 | Usually the most convenient way to use these @code{asm} instructions is to | |
5953 | encapsulate them in macros that look like functions. For example, | |
5954 | ||
3ab51846 | 5955 | @smallexample |
c1f7febf RK |
5956 | #define sin(x) \ |
5957 | (@{ double __value, __arg = (x); \ | |
5958 | asm ("fsinx %1,%0": "=f" (__value): "f" (__arg)); \ | |
5959 | __value; @}) | |
3ab51846 | 5960 | @end smallexample |
c1f7febf RK |
5961 | |
5962 | @noindent | |
5963 | Here the variable @code{__arg} is used to make sure that the instruction | |
5964 | operates on a proper @code{double} value, and to accept only those | |
5965 | arguments @code{x} which can convert automatically to a @code{double}. | |
5966 | ||
c85f7c16 JL |
5967 | Another way to make sure the instruction operates on the correct data |
5968 | type is to use a cast in the @code{asm}. This is different from using a | |
c1f7febf RK |
5969 | variable @code{__arg} in that it converts more different types. For |
5970 | example, if the desired type were @code{int}, casting the argument to | |
5971 | @code{int} would accept a pointer with no complaint, while assigning the | |
5972 | argument to an @code{int} variable named @code{__arg} would warn about | |
5973 | using a pointer unless the caller explicitly casts it. | |
5974 | ||
f0523f02 | 5975 | If an @code{asm} has output operands, GCC assumes for optimization |
c85f7c16 JL |
5976 | purposes the instruction has no side effects except to change the output |
5977 | operands. This does not mean instructions with a side effect cannot be | |
5978 | used, but you must be careful, because the compiler may eliminate them | |
5979 | if the output operands aren't used, or move them out of loops, or | |
5980 | replace two with one if they constitute a common subexpression. Also, | |
5981 | if your instruction does have a side effect on a variable that otherwise | |
5982 | appears not to change, the old value of the variable may be reused later | |
5983 | if it happens to be found in a register. | |
c1f7febf | 5984 | |
2f59e40e DJ |
5985 | You can prevent an @code{asm} instruction from being deleted |
5986 | by writing the keyword @code{volatile} after | |
c1f7febf RK |
5987 | the @code{asm}. For example: |
5988 | ||
3ab51846 | 5989 | @smallexample |
310668e8 JM |
5990 | #define get_and_set_priority(new) \ |
5991 | (@{ int __old; \ | |
5992 | asm volatile ("get_and_set_priority %0, %1" \ | |
5993 | : "=g" (__old) : "g" (new)); \ | |
c85f7c16 | 5994 | __old; @}) |
3ab51846 | 5995 | @end smallexample |
c1f7febf RK |
5996 | |
5997 | @noindent | |
e71b34aa MM |
5998 | The @code{volatile} keyword indicates that the instruction has |
5999 | important side-effects. GCC will not delete a volatile @code{asm} if | |
6000 | it is reachable. (The instruction can still be deleted if GCC can | |
6001 | prove that control-flow will never reach the location of the | |
f0eb93a8 | 6002 | instruction.) Note that even a volatile @code{asm} instruction |
2f59e40e | 6003 | can be moved relative to other code, including across jump |
f0eb93a8 JM |
6004 | instructions. For example, on many targets there is a system |
6005 | register which can be set to control the rounding mode of | |
2f59e40e DJ |
6006 | floating point operations. You might try |
6007 | setting it with a volatile @code{asm}, like this PowerPC example: | |
e71b34aa | 6008 | |
3ab51846 | 6009 | @smallexample |
2f59e40e DJ |
6010 | asm volatile("mtfsf 255,%0" : : "f" (fpenv)); |
6011 | sum = x + y; | |
3ab51846 | 6012 | @end smallexample |
e71b34aa | 6013 | |
ebb48a4d | 6014 | @noindent |
2f59e40e DJ |
6015 | This will not work reliably, as the compiler may move the addition back |
6016 | before the volatile @code{asm}. To make it work you need to add an | |
6017 | artificial dependency to the @code{asm} referencing a variable in the code | |
6018 | you don't want moved, for example: | |
6019 | ||
6020 | @smallexample | |
6021 | asm volatile ("mtfsf 255,%1" : "=X"(sum): "f"(fpenv)); | |
6022 | sum = x + y; | |
6023 | @end smallexample | |
6024 | ||
6025 | Similarly, you can't expect a | |
6026 | sequence of volatile @code{asm} instructions to remain perfectly | |
6027 | consecutive. If you want consecutive output, use a single @code{asm}. | |
6028 | Also, GCC will perform some optimizations across a volatile @code{asm} | |
6029 | instruction; GCC does not ``forget everything'' when it encounters | |
6030 | a volatile @code{asm} instruction the way some other compilers do. | |
6031 | ||
6032 | An @code{asm} instruction without any output operands will be treated | |
6033 | identically to a volatile @code{asm} instruction. | |
c1f7febf RK |
6034 | |
6035 | It is a natural idea to look for a way to give access to the condition | |
6036 | code left by the assembler instruction. However, when we attempted to | |
6037 | implement this, we found no way to make it work reliably. The problem | |
6038 | is that output operands might need reloading, which would result in | |
6039 | additional following ``store'' instructions. On most machines, these | |
6040 | instructions would alter the condition code before there was time to | |
6041 | test it. This problem doesn't arise for ordinary ``test'' and | |
6042 | ``compare'' instructions because they don't have any output operands. | |
6043 | ||
eda3fbbe GB |
6044 | For reasons similar to those described above, it is not possible to give |
6045 | an assembler instruction access to the condition code left by previous | |
6046 | instructions. | |
6047 | ||
1c384bf1 RH |
6048 | @anchor{Extended asm with goto} |
6049 | As of GCC version 4.5, @code{asm goto} may be used to have the assembly | |
6050 | jump to one or more C labels. In this form, a fifth section after the | |
6051 | clobber list contains a list of all C labels to which the assembly may jump. | |
6052 | Each label operand is implicitly self-named. The @code{asm} is also assumed | |
6053 | to fall through to the next statement. | |
6054 | ||
6055 | This form of @code{asm} is restricted to not have outputs. This is due | |
6056 | to a internal restriction in the compiler that control transfer instructions | |
6057 | cannot have outputs. This restriction on @code{asm goto} may be lifted | |
6058 | in some future version of the compiler. In the mean time, @code{asm goto} | |
6059 | may include a memory clobber, and so leave outputs in memory. | |
6060 | ||
6061 | @smallexample | |
6062 | int frob(int x) | |
6063 | @{ | |
6064 | int y; | |
6065 | asm goto ("frob %%r5, %1; jc %l[error]; mov (%2), %%r5" | |
6066 | : : "r"(x), "r"(&y) : "r5", "memory" : error); | |
6067 | return y; | |
6068 | error: | |
6069 | return -1; | |
6070 | @} | |
6071 | @end smallexample | |
6072 | ||
6073 | In this (inefficient) example, the @code{frob} instruction sets the | |
6074 | carry bit to indicate an error. The @code{jc} instruction detects | |
ff2ce160 | 6075 | this and branches to the @code{error} label. Finally, the output |
1c384bf1 RH |
6076 | of the @code{frob} instruction (@code{%r5}) is stored into the memory |
6077 | for variable @code{y}, which is later read by the @code{return} statement. | |
6078 | ||
6079 | @smallexample | |
6080 | void doit(void) | |
6081 | @{ | |
6082 | int i = 0; | |
6083 | asm goto ("mfsr %%r1, 123; jmp %%r1;" | |
6084 | ".pushsection doit_table;" | |
73b8bfe1 RW |
6085 | ".long %l0, %l1, %l2, %l3;" |
6086 | ".popsection" | |
6087 | : : : "r1" : label1, label2, label3, label4); | |
1c384bf1 RH |
6088 | __builtin_unreachable (); |
6089 | ||
6090 | label1: | |
6091 | f1(); | |
6092 | return; | |
6093 | label2: | |
6094 | f2(); | |
6095 | return; | |
6096 | label3: | |
6097 | i = 1; | |
6098 | label4: | |
6099 | f3(i); | |
6100 | @} | |
6101 | @end smallexample | |
6102 | ||
6103 | In this (also inefficient) example, the @code{mfsr} instruction reads | |
6104 | an address from some out-of-band machine register, and the following | |
6105 | @code{jmp} instruction branches to that address. The address read by | |
6106 | the @code{mfsr} instruction is assumed to have been previously set via | |
6107 | some application-specific mechanism to be one of the four values stored | |
6108 | in the @code{doit_table} section. Finally, the @code{asm} is followed | |
6109 | by a call to @code{__builtin_unreachable} to indicate that the @code{asm} | |
6110 | does not in fact fall through. | |
6111 | ||
6112 | @smallexample | |
6113 | #define TRACE1(NUM) \ | |
6114 | do @{ \ | |
6115 | asm goto ("0: nop;" \ | |
6116 | ".pushsection trace_table;" \ | |
6117 | ".long 0b, %l0;" \ | |
6118 | ".popsection" \ | |
6119 | : : : : trace#NUM); \ | |
6120 | if (0) @{ trace#NUM: trace(); @} \ | |
6121 | @} while (0) | |
6122 | #define TRACE TRACE1(__COUNTER__) | |
6123 | @end smallexample | |
6124 | ||
6125 | In this example (which in fact inspired the @code{asm goto} feature) | |
6126 | we want on rare occasions to call the @code{trace} function; on other | |
6127 | occasions we'd like to keep the overhead to the absolute minimum. | |
6128 | The normal code path consists of a single @code{nop} instruction. | |
6129 | However, we record the address of this @code{nop} together with the | |
6130 | address of a label that calls the @code{trace} function. This allows | |
ff2ce160 | 6131 | the @code{nop} instruction to be patched at runtime to be an |
1c384bf1 RH |
6132 | unconditional branch to the stored label. It is assumed that an |
6133 | optimizing compiler will move the labeled block out of line, to | |
6134 | optimize the fall through path from the @code{asm}. | |
6135 | ||
5490d604 | 6136 | If you are writing a header file that should be includable in ISO C |
c1f7febf RK |
6137 | programs, write @code{__asm__} instead of @code{asm}. @xref{Alternate |
6138 | Keywords}. | |
6139 | ||
ece7fc1c RE |
6140 | @subsection Size of an @code{asm} |
6141 | ||
6142 | Some targets require that GCC track the size of each instruction used in | |
6143 | order to generate correct code. Because the final length of an | |
6144 | @code{asm} is only known by the assembler, GCC must make an estimate as | |
6145 | to how big it will be. The estimate is formed by counting the number of | |
6146 | statements in the pattern of the @code{asm} and multiplying that by the | |
6147 | length of the longest instruction on that processor. Statements in the | |
6148 | @code{asm} are identified by newline characters and whatever statement | |
6149 | separator characters are supported by the assembler; on most processors | |
6150 | this is the `@code{;}' character. | |
6151 | ||
6152 | Normally, GCC's estimate is perfectly adequate to ensure that correct | |
6153 | code is generated, but it is possible to confuse the compiler if you use | |
6154 | pseudo instructions or assembler macros that expand into multiple real | |
6155 | instructions or if you use assembler directives that expand to more | |
6156 | space in the object file than would be needed for a single instruction. | |
6157 | If this happens then the assembler will produce a diagnostic saying that | |
6158 | a label is unreachable. | |
6159 | ||
fe0ce426 JH |
6160 | @subsection i386 floating point asm operands |
6161 | ||
6162 | There are several rules on the usage of stack-like regs in | |
6163 | asm_operands insns. These rules apply only to the operands that are | |
6164 | stack-like regs: | |
6165 | ||
6166 | @enumerate | |
6167 | @item | |
6168 | Given a set of input regs that die in an asm_operands, it is | |
6169 | necessary to know which are implicitly popped by the asm, and | |
6170 | which must be explicitly popped by gcc. | |
6171 | ||
6172 | An input reg that is implicitly popped by the asm must be | |
6173 | explicitly clobbered, unless it is constrained to match an | |
6174 | output operand. | |
6175 | ||
6176 | @item | |
6177 | For any input reg that is implicitly popped by an asm, it is | |
6178 | necessary to know how to adjust the stack to compensate for the pop. | |
6179 | If any non-popped input is closer to the top of the reg-stack than | |
6180 | the implicitly popped reg, it would not be possible to know what the | |
84330467 | 6181 | stack looked like---it's not clear how the rest of the stack ``slides |
fe0ce426 JH |
6182 | up''. |
6183 | ||
6184 | All implicitly popped input regs must be closer to the top of | |
6185 | the reg-stack than any input that is not implicitly popped. | |
6186 | ||
6187 | It is possible that if an input dies in an insn, reload might | |
6188 | use the input reg for an output reload. Consider this example: | |
6189 | ||
3ab51846 | 6190 | @smallexample |
fe0ce426 | 6191 | asm ("foo" : "=t" (a) : "f" (b)); |
3ab51846 | 6192 | @end smallexample |
fe0ce426 JH |
6193 | |
6194 | This asm says that input B is not popped by the asm, and that | |
c771326b | 6195 | the asm pushes a result onto the reg-stack, i.e., the stack is one |
fe0ce426 JH |
6196 | deeper after the asm than it was before. But, it is possible that |
6197 | reload will think that it can use the same reg for both the input and | |
6198 | the output, if input B dies in this insn. | |
6199 | ||
6200 | If any input operand uses the @code{f} constraint, all output reg | |
6201 | constraints must use the @code{&} earlyclobber. | |
6202 | ||
6203 | The asm above would be written as | |
6204 | ||
3ab51846 | 6205 | @smallexample |
fe0ce426 | 6206 | asm ("foo" : "=&t" (a) : "f" (b)); |
3ab51846 | 6207 | @end smallexample |
fe0ce426 JH |
6208 | |
6209 | @item | |
6210 | Some operands need to be in particular places on the stack. All | |
84330467 | 6211 | output operands fall in this category---there is no other way to |
fe0ce426 JH |
6212 | know which regs the outputs appear in unless the user indicates |
6213 | this in the constraints. | |
6214 | ||
6215 | Output operands must specifically indicate which reg an output | |
6216 | appears in after an asm. @code{=f} is not allowed: the operand | |
6217 | constraints must select a class with a single reg. | |
6218 | ||
6219 | @item | |
6220 | Output operands may not be ``inserted'' between existing stack regs. | |
6221 | Since no 387 opcode uses a read/write operand, all output operands | |
6222 | are dead before the asm_operands, and are pushed by the asm_operands. | |
6223 | It makes no sense to push anywhere but the top of the reg-stack. | |
6224 | ||
6225 | Output operands must start at the top of the reg-stack: output | |
6226 | operands may not ``skip'' a reg. | |
6227 | ||
6228 | @item | |
6229 | Some asm statements may need extra stack space for internal | |
6230 | calculations. This can be guaranteed by clobbering stack registers | |
6231 | unrelated to the inputs and outputs. | |
6232 | ||
6233 | @end enumerate | |
6234 | ||
6235 | Here are a couple of reasonable asms to want to write. This asm | |
6236 | takes one input, which is internally popped, and produces two outputs. | |
6237 | ||
3ab51846 | 6238 | @smallexample |
fe0ce426 | 6239 | asm ("fsincos" : "=t" (cos), "=u" (sin) : "0" (inp)); |
3ab51846 | 6240 | @end smallexample |
fe0ce426 JH |
6241 | |
6242 | This asm takes two inputs, which are popped by the @code{fyl2xp1} opcode, | |
6243 | and replaces them with one output. The user must code the @code{st(1)} | |
6244 | clobber for reg-stack.c to know that @code{fyl2xp1} pops both inputs. | |
6245 | ||
3ab51846 | 6246 | @smallexample |
fe0ce426 | 6247 | asm ("fyl2xp1" : "=t" (result) : "0" (x), "u" (y) : "st(1)"); |
3ab51846 | 6248 | @end smallexample |
fe0ce426 | 6249 | |
c1f7febf | 6250 | @include md.texi |
c1f7febf RK |
6251 | |
6252 | @node Asm Labels | |
6253 | @section Controlling Names Used in Assembler Code | |
6254 | @cindex assembler names for identifiers | |
6255 | @cindex names used in assembler code | |
6256 | @cindex identifiers, names in assembler code | |
6257 | ||
6258 | You can specify the name to be used in the assembler code for a C | |
6259 | function or variable by writing the @code{asm} (or @code{__asm__}) | |
6260 | keyword after the declarator as follows: | |
6261 | ||
3ab51846 | 6262 | @smallexample |
c1f7febf | 6263 | int foo asm ("myfoo") = 2; |
3ab51846 | 6264 | @end smallexample |
c1f7febf RK |
6265 | |
6266 | @noindent | |
6267 | This specifies that the name to be used for the variable @code{foo} in | |
6268 | the assembler code should be @samp{myfoo} rather than the usual | |
6269 | @samp{_foo}. | |
6270 | ||
6271 | On systems where an underscore is normally prepended to the name of a C | |
6272 | function or variable, this feature allows you to define names for the | |
6273 | linker that do not start with an underscore. | |
6274 | ||
0adc3c19 MM |
6275 | It does not make sense to use this feature with a non-static local |
6276 | variable since such variables do not have assembler names. If you are | |
6277 | trying to put the variable in a particular register, see @ref{Explicit | |
6278 | Reg Vars}. GCC presently accepts such code with a warning, but will | |
6279 | probably be changed to issue an error, rather than a warning, in the | |
6280 | future. | |
6281 | ||
c1f7febf RK |
6282 | You cannot use @code{asm} in this way in a function @emph{definition}; but |
6283 | you can get the same effect by writing a declaration for the function | |
6284 | before its definition and putting @code{asm} there, like this: | |
6285 | ||
3ab51846 | 6286 | @smallexample |
c1f7febf RK |
6287 | extern func () asm ("FUNC"); |
6288 | ||
6289 | func (x, y) | |
6290 | int x, y; | |
0d893a63 | 6291 | /* @r{@dots{}} */ |
3ab51846 | 6292 | @end smallexample |
c1f7febf RK |
6293 | |
6294 | It is up to you to make sure that the assembler names you choose do not | |
6295 | conflict with any other assembler symbols. Also, you must not use a | |
f0523f02 JM |
6296 | register name; that would produce completely invalid assembler code. GCC |
6297 | does not as yet have the ability to store static variables in registers. | |
c1f7febf RK |
6298 | Perhaps that will be added. |
6299 | ||
6300 | @node Explicit Reg Vars | |
6301 | @section Variables in Specified Registers | |
6302 | @cindex explicit register variables | |
6303 | @cindex variables in specified registers | |
6304 | @cindex specified registers | |
6305 | @cindex registers, global allocation | |
6306 | ||
6307 | GNU C allows you to put a few global variables into specified hardware | |
6308 | registers. You can also specify the register in which an ordinary | |
6309 | register variable should be allocated. | |
6310 | ||
6311 | @itemize @bullet | |
6312 | @item | |
6313 | Global register variables reserve registers throughout the program. | |
6314 | This may be useful in programs such as programming language | |
6315 | interpreters which have a couple of global variables that are accessed | |
6316 | very often. | |
6317 | ||
6318 | @item | |
6319 | Local register variables in specific registers do not reserve the | |
805c33df HPN |
6320 | registers, except at the point where they are used as input or output |
6321 | operands in an @code{asm} statement and the @code{asm} statement itself is | |
6322 | not deleted. The compiler's data flow analysis is capable of determining | |
c1f7febf | 6323 | where the specified registers contain live values, and where they are |
8d344fbc | 6324 | available for other uses. Stores into local register variables may be deleted |
0deaf590 JL |
6325 | when they appear to be dead according to dataflow analysis. References |
6326 | to local register variables may be deleted or moved or simplified. | |
c1f7febf RK |
6327 | |
6328 | These local variables are sometimes convenient for use with the extended | |
6329 | @code{asm} feature (@pxref{Extended Asm}), if you want to write one | |
6330 | output of the assembler instruction directly into a particular register. | |
6331 | (This will work provided the register you specify fits the constraints | |
6332 | specified for that operand in the @code{asm}.) | |
6333 | @end itemize | |
6334 | ||
6335 | @menu | |
6336 | * Global Reg Vars:: | |
6337 | * Local Reg Vars:: | |
6338 | @end menu | |
6339 | ||
6340 | @node Global Reg Vars | |
6341 | @subsection Defining Global Register Variables | |
6342 | @cindex global register variables | |
6343 | @cindex registers, global variables in | |
6344 | ||
6345 | You can define a global register variable in GNU C like this: | |
6346 | ||
3ab51846 | 6347 | @smallexample |
c1f7febf | 6348 | register int *foo asm ("a5"); |
3ab51846 | 6349 | @end smallexample |
c1f7febf RK |
6350 | |
6351 | @noindent | |
6352 | Here @code{a5} is the name of the register which should be used. Choose a | |
6353 | register which is normally saved and restored by function calls on your | |
6354 | machine, so that library routines will not clobber it. | |
6355 | ||
6356 | Naturally the register name is cpu-dependent, so you would need to | |
6357 | conditionalize your program according to cpu type. The register | |
6358 | @code{a5} would be a good choice on a 68000 for a variable of pointer | |
6359 | type. On machines with register windows, be sure to choose a ``global'' | |
6360 | register that is not affected magically by the function call mechanism. | |
6361 | ||
6362 | In addition, operating systems on one type of cpu may differ in how they | |
6363 | name the registers; then you would need additional conditionals. For | |
6364 | example, some 68000 operating systems call this register @code{%a5}. | |
6365 | ||
6366 | Eventually there may be a way of asking the compiler to choose a register | |
6367 | automatically, but first we need to figure out how it should choose and | |
6368 | how to enable you to guide the choice. No solution is evident. | |
6369 | ||
6370 | Defining a global register variable in a certain register reserves that | |
6371 | register entirely for this use, at least within the current compilation. | |
6372 | The register will not be allocated for any other purpose in the functions | |
6373 | in the current compilation. The register will not be saved and restored by | |
6374 | these functions. Stores into this register are never deleted even if they | |
6375 | would appear to be dead, but references may be deleted or moved or | |
6376 | simplified. | |
6377 | ||
6378 | It is not safe to access the global register variables from signal | |
6379 | handlers, or from more than one thread of control, because the system | |
6380 | library routines may temporarily use the register for other things (unless | |
6381 | you recompile them specially for the task at hand). | |
6382 | ||
6383 | @cindex @code{qsort}, and global register variables | |
6384 | It is not safe for one function that uses a global register variable to | |
6385 | call another such function @code{foo} by way of a third function | |
e979f9e8 | 6386 | @code{lose} that was compiled without knowledge of this variable (i.e.@: in a |
c1f7febf RK |
6387 | different source file in which the variable wasn't declared). This is |
6388 | because @code{lose} might save the register and put some other value there. | |
6389 | For example, you can't expect a global register variable to be available in | |
6390 | the comparison-function that you pass to @code{qsort}, since @code{qsort} | |
6391 | might have put something else in that register. (If you are prepared to | |
6392 | recompile @code{qsort} with the same global register variable, you can | |
6393 | solve this problem.) | |
6394 | ||
6395 | If you want to recompile @code{qsort} or other source files which do not | |
6396 | actually use your global register variable, so that they will not use that | |
6397 | register for any other purpose, then it suffices to specify the compiler | |
84330467 | 6398 | option @option{-ffixed-@var{reg}}. You need not actually add a global |
c1f7febf RK |
6399 | register declaration to their source code. |
6400 | ||
6401 | A function which can alter the value of a global register variable cannot | |
6402 | safely be called from a function compiled without this variable, because it | |
6403 | could clobber the value the caller expects to find there on return. | |
6404 | Therefore, the function which is the entry point into the part of the | |
6405 | program that uses the global register variable must explicitly save and | |
6406 | restore the value which belongs to its caller. | |
6407 | ||
6408 | @cindex register variable after @code{longjmp} | |
6409 | @cindex global register after @code{longjmp} | |
6410 | @cindex value after @code{longjmp} | |
6411 | @findex longjmp | |
6412 | @findex setjmp | |
6413 | On most machines, @code{longjmp} will restore to each global register | |
6414 | variable the value it had at the time of the @code{setjmp}. On some | |
6415 | machines, however, @code{longjmp} will not change the value of global | |
6416 | register variables. To be portable, the function that called @code{setjmp} | |
6417 | should make other arrangements to save the values of the global register | |
6418 | variables, and to restore them in a @code{longjmp}. This way, the same | |
6419 | thing will happen regardless of what @code{longjmp} does. | |
6420 | ||
6421 | All global register variable declarations must precede all function | |
6422 | definitions. If such a declaration could appear after function | |
6423 | definitions, the declaration would be too late to prevent the register from | |
6424 | being used for other purposes in the preceding functions. | |
6425 | ||
6426 | Global register variables may not have initial values, because an | |
6427 | executable file has no means to supply initial contents for a register. | |
6428 | ||
981f6289 | 6429 | On the SPARC, there are reports that g3 @dots{} g7 are suitable |
c1f7febf RK |
6430 | registers, but certain library functions, such as @code{getwd}, as well |
6431 | as the subroutines for division and remainder, modify g3 and g4. g1 and | |
6432 | g2 are local temporaries. | |
6433 | ||
6434 | On the 68000, a2 @dots{} a5 should be suitable, as should d2 @dots{} d7. | |
6435 | Of course, it will not do to use more than a few of those. | |
6436 | ||
6437 | @node Local Reg Vars | |
6438 | @subsection Specifying Registers for Local Variables | |
6439 | @cindex local variables, specifying registers | |
6440 | @cindex specifying registers for local variables | |
6441 | @cindex registers for local variables | |
6442 | ||
6443 | You can define a local register variable with a specified register | |
6444 | like this: | |
6445 | ||
3ab51846 | 6446 | @smallexample |
c1f7febf | 6447 | register int *foo asm ("a5"); |
3ab51846 | 6448 | @end smallexample |
c1f7febf RK |
6449 | |
6450 | @noindent | |
6451 | Here @code{a5} is the name of the register which should be used. Note | |
6452 | that this is the same syntax used for defining global register | |
6453 | variables, but for a local variable it would appear within a function. | |
6454 | ||
6455 | Naturally the register name is cpu-dependent, but this is not a | |
6456 | problem, since specific registers are most often useful with explicit | |
6457 | assembler instructions (@pxref{Extended Asm}). Both of these things | |
6458 | generally require that you conditionalize your program according to | |
6459 | cpu type. | |
6460 | ||
6461 | In addition, operating systems on one type of cpu may differ in how they | |
6462 | name the registers; then you would need additional conditionals. For | |
6463 | example, some 68000 operating systems call this register @code{%a5}. | |
6464 | ||
c1f7febf RK |
6465 | Defining such a register variable does not reserve the register; it |
6466 | remains available for other uses in places where flow control determines | |
d754127f | 6467 | the variable's value is not live. |
e5e809f4 | 6468 | |
f0523f02 | 6469 | This option does not guarantee that GCC will generate code that has |
e5e809f4 | 6470 | this variable in the register you specify at all times. You may not |
805c33df HPN |
6471 | code an explicit reference to this register in the @emph{assembler |
6472 | instruction template} part of an @code{asm} statement and assume it will | |
6473 | always refer to this variable. However, using the variable as an | |
6474 | @code{asm} @emph{operand} guarantees that the specified register is used | |
6475 | for the operand. | |
c1f7febf | 6476 | |
8d344fbc | 6477 | Stores into local register variables may be deleted when they appear to be dead |
0deaf590 JL |
6478 | according to dataflow analysis. References to local register variables may |
6479 | be deleted or moved or simplified. | |
6480 | ||
b55d5746 HPN |
6481 | As for global register variables, it's recommended that you choose a |
6482 | register which is normally saved and restored by function calls on | |
6483 | your machine, so that library routines will not clobber it. A common | |
6484 | pitfall is to initialize multiple call-clobbered registers with | |
6485 | arbitrary expressions, where a function call or library call for an | |
6486 | arithmetic operator will overwrite a register value from a previous | |
6487 | assignment, for example @code{r0} below: | |
6488 | @smallexample | |
6489 | register int *p1 asm ("r0") = @dots{}; | |
6490 | register int *p2 asm ("r1") = @dots{}; | |
6491 | @end smallexample | |
6492 | In those cases, a solution is to use a temporary variable for | |
6493 | each arbitrary expression. @xref{Example of asm with clobbered asm reg}. | |
6494 | ||
c1f7febf RK |
6495 | @node Alternate Keywords |
6496 | @section Alternate Keywords | |
6497 | @cindex alternate keywords | |
6498 | @cindex keywords, alternate | |
6499 | ||
5490d604 | 6500 | @option{-ansi} and the various @option{-std} options disable certain |
f458d1d5 ZW |
6501 | keywords. This causes trouble when you want to use GNU C extensions, or |
6502 | a general-purpose header file that should be usable by all programs, | |
6503 | including ISO C programs. The keywords @code{asm}, @code{typeof} and | |
6504 | @code{inline} are not available in programs compiled with | |
6505 | @option{-ansi} or @option{-std} (although @code{inline} can be used in a | |
48b0b196 | 6506 | program compiled with @option{-std=c99} or @option{-std=c11}). The |
2778d766 | 6507 | ISO C99 keyword |
5490d604 JM |
6508 | @code{restrict} is only available when @option{-std=gnu99} (which will |
6509 | eventually be the default) or @option{-std=c99} (or the equivalent | |
2778d766 JM |
6510 | @option{-std=iso9899:1999}), or an option for a later standard |
6511 | version, is used. | |
c1f7febf RK |
6512 | |
6513 | The way to solve these problems is to put @samp{__} at the beginning and | |
6514 | end of each problematical keyword. For example, use @code{__asm__} | |
f458d1d5 | 6515 | instead of @code{asm}, and @code{__inline__} instead of @code{inline}. |
c1f7febf RK |
6516 | |
6517 | Other C compilers won't accept these alternative keywords; if you want to | |
6518 | compile with another compiler, you can define the alternate keywords as | |
6519 | macros to replace them with the customary keywords. It looks like this: | |
6520 | ||
3ab51846 | 6521 | @smallexample |
c1f7febf RK |
6522 | #ifndef __GNUC__ |
6523 | #define __asm__ asm | |
6524 | #endif | |
3ab51846 | 6525 | @end smallexample |
c1f7febf | 6526 | |
6e6b0525 | 6527 | @findex __extension__ |
84330467 JM |
6528 | @opindex pedantic |
6529 | @option{-pedantic} and other options cause warnings for many GNU C extensions. | |
dbe519e0 | 6530 | You can |
c1f7febf RK |
6531 | prevent such warnings within one expression by writing |
6532 | @code{__extension__} before the expression. @code{__extension__} has no | |
6533 | effect aside from this. | |
6534 | ||
6535 | @node Incomplete Enums | |
6536 | @section Incomplete @code{enum} Types | |
6537 | ||
6538 | You can define an @code{enum} tag without specifying its possible values. | |
6539 | This results in an incomplete type, much like what you get if you write | |
6540 | @code{struct foo} without describing the elements. A later declaration | |
6541 | which does specify the possible values completes the type. | |
6542 | ||
6543 | You can't allocate variables or storage using the type while it is | |
6544 | incomplete. However, you can work with pointers to that type. | |
6545 | ||
6546 | This extension may not be very useful, but it makes the handling of | |
6547 | @code{enum} more consistent with the way @code{struct} and @code{union} | |
6548 | are handled. | |
6549 | ||
6550 | This extension is not supported by GNU C++. | |
6551 | ||
6552 | @node Function Names | |
6553 | @section Function Names as Strings | |
e6cc3a24 | 6554 | @cindex @code{__func__} identifier |
4b404517 JM |
6555 | @cindex @code{__FUNCTION__} identifier |
6556 | @cindex @code{__PRETTY_FUNCTION__} identifier | |
c1f7febf | 6557 | |
e6cc3a24 ZW |
6558 | GCC provides three magic variables which hold the name of the current |
6559 | function, as a string. The first of these is @code{__func__}, which | |
6560 | is part of the C99 standard: | |
6561 | ||
e6cc3a24 ZW |
6562 | The identifier @code{__func__} is implicitly declared by the translator |
6563 | as if, immediately following the opening brace of each function | |
6564 | definition, the declaration | |
6565 | ||
6566 | @smallexample | |
6567 | static const char __func__[] = "function-name"; | |
6568 | @end smallexample | |
c1f7febf | 6569 | |
38bb2b65 | 6570 | @noindent |
e6cc3a24 ZW |
6571 | appeared, where function-name is the name of the lexically-enclosing |
6572 | function. This name is the unadorned name of the function. | |
e6cc3a24 ZW |
6573 | |
6574 | @code{__FUNCTION__} is another name for @code{__func__}. Older | |
6575 | versions of GCC recognize only this name. However, it is not | |
6576 | standardized. For maximum portability, we recommend you use | |
6577 | @code{__func__}, but provide a fallback definition with the | |
6578 | preprocessor: | |
6579 | ||
6580 | @smallexample | |
6581 | #if __STDC_VERSION__ < 199901L | |
6582 | # if __GNUC__ >= 2 | |
6583 | # define __func__ __FUNCTION__ | |
6584 | # else | |
6585 | # define __func__ "<unknown>" | |
6586 | # endif | |
6587 | #endif | |
6588 | @end smallexample | |
6589 | ||
6590 | In C, @code{__PRETTY_FUNCTION__} is yet another name for | |
6591 | @code{__func__}. However, in C++, @code{__PRETTY_FUNCTION__} contains | |
6592 | the type signature of the function as well as its bare name. For | |
6593 | example, this program: | |
c1f7febf RK |
6594 | |
6595 | @smallexample | |
6596 | extern "C" @{ | |
6597 | extern int printf (char *, ...); | |
6598 | @} | |
6599 | ||
6600 | class a @{ | |
6601 | public: | |
a721a601 | 6602 | void sub (int i) |
c1f7febf RK |
6603 | @{ |
6604 | printf ("__FUNCTION__ = %s\n", __FUNCTION__); | |
6605 | printf ("__PRETTY_FUNCTION__ = %s\n", __PRETTY_FUNCTION__); | |
6606 | @} | |
6607 | @}; | |
6608 | ||
6609 | int | |
6610 | main (void) | |
6611 | @{ | |
6612 | a ax; | |
6613 | ax.sub (0); | |
6614 | return 0; | |
6615 | @} | |
6616 | @end smallexample | |
6617 | ||
6618 | @noindent | |
6619 | gives this output: | |
6620 | ||
6621 | @smallexample | |
6622 | __FUNCTION__ = sub | |
e6cc3a24 | 6623 | __PRETTY_FUNCTION__ = void a::sub(int) |
22acfb79 NM |
6624 | @end smallexample |
6625 | ||
e6cc3a24 ZW |
6626 | These identifiers are not preprocessor macros. In GCC 3.3 and |
6627 | earlier, in C only, @code{__FUNCTION__} and @code{__PRETTY_FUNCTION__} | |
6628 | were treated as string literals; they could be used to initialize | |
6629 | @code{char} arrays, and they could be concatenated with other string | |
6630 | literals. GCC 3.4 and later treat them as variables, like | |
6631 | @code{__func__}. In C++, @code{__FUNCTION__} and | |
6632 | @code{__PRETTY_FUNCTION__} have always been variables. | |
22acfb79 | 6633 | |
c1f7febf RK |
6634 | @node Return Address |
6635 | @section Getting the Return or Frame Address of a Function | |
6636 | ||
6637 | These functions may be used to get information about the callers of a | |
6638 | function. | |
6639 | ||
84330467 | 6640 | @deftypefn {Built-in Function} {void *} __builtin_return_address (unsigned int @var{level}) |
c1f7febf RK |
6641 | This function returns the return address of the current function, or of |
6642 | one of its callers. The @var{level} argument is number of frames to | |
6643 | scan up the call stack. A value of @code{0} yields the return address | |
6644 | of the current function, a value of @code{1} yields the return address | |
8a36672b | 6645 | of the caller of the current function, and so forth. When inlining |
95b1627e EC |
6646 | the expected behavior is that the function will return the address of |
6647 | the function that will be returned to. To work around this behavior use | |
6648 | the @code{noinline} function attribute. | |
c1f7febf RK |
6649 | |
6650 | The @var{level} argument must be a constant integer. | |
6651 | ||
6652 | On some machines it may be impossible to determine the return address of | |
6653 | any function other than the current one; in such cases, or when the top | |
dd96fbc5 | 6654 | of the stack has been reached, this function will return @code{0} or a |
8a36672b | 6655 | random value. In addition, @code{__builtin_frame_address} may be used |
dd96fbc5 | 6656 | to determine if the top of the stack has been reached. |
c1f7febf | 6657 | |
48c4de16 TS |
6658 | Additional post-processing of the returned value may be needed, see |
6659 | @code{__builtin_extract_return_address}. | |
6660 | ||
df2a54e9 | 6661 | This function should only be used with a nonzero argument for debugging |
c1f7febf | 6662 | purposes. |
84330467 | 6663 | @end deftypefn |
c1f7febf | 6664 | |
48c4de16 TS |
6665 | @deftypefn {Built-in Function} {void *} __builtin_extract_return_address (void *@var{addr}) |
6666 | The address as returned by @code{__builtin_return_address} may have to be fed | |
6667 | through this function to get the actual encoded address. For example, on the | |
6668 | 31-bit S/390 platform the highest bit has to be masked out, or on SPARC | |
6669 | platforms an offset has to be added for the true next instruction to be | |
6670 | executed. | |
6671 | ||
6672 | If no fixup is needed, this function simply passes through @var{addr}. | |
6673 | @end deftypefn | |
6674 | ||
6675 | @deftypefn {Built-in Function} {void *} __builtin_frob_return_address (void *@var{addr}) | |
6676 | This function does the reverse of @code{__builtin_extract_return_address}. | |
6677 | @end deftypefn | |
6678 | ||
84330467 | 6679 | @deftypefn {Built-in Function} {void *} __builtin_frame_address (unsigned int @var{level}) |
c1f7febf RK |
6680 | This function is similar to @code{__builtin_return_address}, but it |
6681 | returns the address of the function frame rather than the return address | |
6682 | of the function. Calling @code{__builtin_frame_address} with a value of | |
6683 | @code{0} yields the frame address of the current function, a value of | |
6684 | @code{1} yields the frame address of the caller of the current function, | |
6685 | and so forth. | |
6686 | ||
6687 | The frame is the area on the stack which holds local variables and saved | |
6688 | registers. The frame address is normally the address of the first word | |
6689 | pushed on to the stack by the function. However, the exact definition | |
6690 | depends upon the processor and the calling convention. If the processor | |
6691 | has a dedicated frame pointer register, and the function has a frame, | |
6692 | then @code{__builtin_frame_address} will return the value of the frame | |
6693 | pointer register. | |
6694 | ||
dd96fbc5 L |
6695 | On some machines it may be impossible to determine the frame address of |
6696 | any function other than the current one; in such cases, or when the top | |
6697 | of the stack has been reached, this function will return @code{0} if | |
6698 | the first frame pointer is properly initialized by the startup code. | |
6699 | ||
df2a54e9 | 6700 | This function should only be used with a nonzero argument for debugging |
dd96fbc5 | 6701 | purposes. |
84330467 | 6702 | @end deftypefn |
c1f7febf | 6703 | |
1255c85c BS |
6704 | @node Vector Extensions |
6705 | @section Using vector instructions through built-in functions | |
6706 | ||
6707 | On some targets, the instruction set contains SIMD vector instructions that | |
6708 | operate on multiple values contained in one large register at the same time. | |
f8723eb6 | 6709 | For example, on the i386 the MMX, 3DNow!@: and SSE extensions can be used |
1255c85c BS |
6710 | this way. |
6711 | ||
6712 | The first step in using these extensions is to provide the necessary data | |
6713 | types. This should be done using an appropriate @code{typedef}: | |
6714 | ||
3ab51846 | 6715 | @smallexample |
4a5eab38 | 6716 | typedef int v4si __attribute__ ((vector_size (16))); |
3ab51846 | 6717 | @end smallexample |
1255c85c | 6718 | |
4a5eab38 PB |
6719 | The @code{int} type specifies the base type, while the attribute specifies |
6720 | the vector size for the variable, measured in bytes. For example, the | |
6721 | declaration above causes the compiler to set the mode for the @code{v4si} | |
6722 | type to be 16 bytes wide and divided into @code{int} sized units. For | |
6723 | a 32-bit @code{int} this means a vector of 4 units of 4 bytes, and the | |
6724 | corresponding mode of @code{foo} will be @acronym{V4SI}. | |
1255c85c | 6725 | |
4a5eab38 PB |
6726 | The @code{vector_size} attribute is only applicable to integral and |
6727 | float scalars, although arrays, pointers, and function return values | |
6728 | are allowed in conjunction with this construct. | |
6729 | ||
6730 | All the basic integer types can be used as base types, both as signed | |
6731 | and as unsigned: @code{char}, @code{short}, @code{int}, @code{long}, | |
6732 | @code{long long}. In addition, @code{float} and @code{double} can be | |
6733 | used to build floating-point vector types. | |
1255c85c | 6734 | |
cb2a532e | 6735 | Specifying a combination that is not valid for the current architecture |
2dd76960 | 6736 | will cause GCC to synthesize the instructions using a narrower mode. |
cb2a532e | 6737 | For example, if you specify a variable of type @code{V4SI} and your |
2dd76960 | 6738 | architecture does not allow for this specific SIMD type, GCC will |
cb2a532e AH |
6739 | produce code that uses 4 @code{SIs}. |
6740 | ||
6741 | The types defined in this manner can be used with a subset of normal C | |
2dd76960 | 6742 | operations. Currently, GCC will allow using the following operators |
5cfd5d9b | 6743 | on these types: @code{+, -, *, /, unary minus, ^, |, &, ~, %}@. |
cb2a532e AH |
6744 | |
6745 | The operations behave like C++ @code{valarrays}. Addition is defined as | |
6746 | the addition of the corresponding elements of the operands. For | |
6747 | example, in the code below, each of the 4 elements in @var{a} will be | |
6748 | added to the corresponding 4 elements in @var{b} and the resulting | |
6749 | vector will be stored in @var{c}. | |
6750 | ||
3ab51846 | 6751 | @smallexample |
4a5eab38 | 6752 | typedef int v4si __attribute__ ((vector_size (16))); |
cb2a532e AH |
6753 | |
6754 | v4si a, b, c; | |
6755 | ||
6756 | c = a + b; | |
3ab51846 | 6757 | @end smallexample |
cb2a532e | 6758 | |
3a3e1600 GK |
6759 | Subtraction, multiplication, division, and the logical operations |
6760 | operate in a similar manner. Likewise, the result of using the unary | |
6761 | minus or complement operators on a vector type is a vector whose | |
6762 | elements are the negative or complemented values of the corresponding | |
cb2a532e AH |
6763 | elements in the operand. |
6764 | ||
f87bd04b AS |
6765 | In C it is possible to use shifting operators @code{<<}, @code{>>} on |
6766 | integer-type vectors. The operation is defined as following: @code{@{a0, | |
6767 | a1, @dots{}, an@} >> @{b0, b1, @dots{}, bn@} == @{a0 >> b0, a1 >> b1, | |
6768 | @dots{}, an >> bn@}}@. Vector operands must have the same number of | |
0e3a99ae AS |
6769 | elements. |
6770 | ||
6771 | For the convenience in C it is allowed to use a binary vector operation | |
6772 | where one operand is a scalar. In that case the compiler will transform | |
6773 | the scalar operand into a vector where each element is the scalar from | |
6774 | the operation. The transformation will happen only if the scalar could be | |
6775 | safely converted to the vector-element type. | |
f87bd04b AS |
6776 | Consider the following code. |
6777 | ||
6778 | @smallexample | |
6779 | typedef int v4si __attribute__ ((vector_size (16))); | |
6780 | ||
0e3a99ae AS |
6781 | v4si a, b, c; |
6782 | long l; | |
6783 | ||
6784 | a = b + 1; /* a = b + @{1,1,1,1@}; */ | |
6785 | a = 2 * b; /* a = @{2,2,2,2@} * b; */ | |
f87bd04b | 6786 | |
0e3a99ae | 6787 | a = l + a; /* Error, cannot convert long to int. */ |
f87bd04b AS |
6788 | @end smallexample |
6789 | ||
30cd1c5d AS |
6790 | In C vectors can be subscripted as if the vector were an array with |
6791 | the same number of elements and base type. Out of bound accesses | |
6792 | invoke undefined behavior at runtime. Warnings for out of bound | |
6793 | accesses for vector subscription can be enabled with | |
6794 | @option{-Warray-bounds}. | |
6795 | ||
d246ab4f AS |
6796 | In GNU C vector comparison is supported within standard comparison |
6797 | operators: @code{==, !=, <, <=, >, >=}. Comparison operands can be | |
6798 | vector expressions of integer-type or real-type. Comparison between | |
6799 | integer-type vectors and real-type vectors are not supported. The | |
6800 | result of the comparison is a vector of the same width and number of | |
6801 | elements as the comparison operands with a signed integral element | |
6802 | type. | |
6803 | ||
6804 | Vectors are compared element-wise producing 0 when comparison is false | |
6805 | and -1 (constant of the appropriate type where all bits are set) | |
6806 | otherwise. Consider the following example. | |
6807 | ||
6808 | @smallexample | |
6809 | typedef int v4si __attribute__ ((vector_size (16))); | |
6810 | ||
6811 | v4si a = @{1,2,3,4@}; | |
6812 | v4si b = @{3,2,1,4@}; | |
6813 | v4si c; | |
6814 | ||
6815 | c = a > b; /* The result would be @{0, 0,-1, 0@} */ | |
6816 | c = a == b; /* The result would be @{0,-1, 0,-1@} */ | |
6817 | @end smallexample | |
6818 | ||
f90e8e2e AS |
6819 | Vector shuffling is available using functions |
6820 | @code{__builtin_shuffle (vec, mask)} and | |
2205ed25 RH |
6821 | @code{__builtin_shuffle (vec0, vec1, mask)}. |
6822 | Both functions construct a permutation of elements from one or two | |
6823 | vectors and return a vector of the same type as the input vector(s). | |
6824 | The @var{mask} is an integral vector with the same width (@var{W}) | |
6825 | and element count (@var{N}) as the output vector. | |
f90e8e2e | 6826 | |
2205ed25 RH |
6827 | The elements of the input vectors are numbered in memory ordering of |
6828 | @var{vec0} beginning at 0 and @var{vec1} beginning at @var{N}. The | |
6829 | elements of @var{mask} are considered modulo @var{N} in the single-operand | |
6830 | case and modulo @math{2*@var{N}} in the two-operand case. | |
6831 | ||
6832 | Consider the following example, | |
f90e8e2e AS |
6833 | |
6834 | @smallexample | |
6835 | typedef int v4si __attribute__ ((vector_size (16))); | |
6836 | ||
6837 | v4si a = @{1,2,3,4@}; | |
6838 | v4si b = @{5,6,7,8@}; | |
6839 | v4si mask1 = @{0,1,1,3@}; | |
6840 | v4si mask2 = @{0,4,2,5@}; | |
6841 | v4si res; | |
6842 | ||
6843 | res = __builtin_shuffle (a, mask1); /* res is @{1,2,2,4@} */ | |
6844 | res = __builtin_shuffle (a, b, mask2); /* res is @{1,5,3,6@} */ | |
6845 | @end smallexample | |
6846 | ||
2205ed25 RH |
6847 | Note that @code{__builtin_shuffle} is intentionally semantically |
6848 | compatible with the OpenCL @code{shuffle} and @code{shuffle2} functions. | |
6849 | ||
cb2a532e AH |
6850 | You can declare variables and use them in function calls and returns, as |
6851 | well as in assignments and some casts. You can specify a vector type as | |
6852 | a return type for a function. Vector types can also be used as function | |
6853 | arguments. It is possible to cast from one vector type to another, | |
6854 | provided they are of the same size (in fact, you can also cast vectors | |
6855 | to and from other datatypes of the same size). | |
6856 | ||
6857 | You cannot operate between vectors of different lengths or different | |
90a21764 | 6858 | signedness without a cast. |
cb2a532e | 6859 | |
7a3ea201 RH |
6860 | @node Offsetof |
6861 | @section Offsetof | |
6862 | @findex __builtin_offsetof | |
6863 | ||
6864 | GCC implements for both C and C++ a syntactic extension to implement | |
6865 | the @code{offsetof} macro. | |
6866 | ||
6867 | @smallexample | |
6868 | primary: | |
6ccde948 | 6869 | "__builtin_offsetof" "(" @code{typename} "," offsetof_member_designator ")" |
7a3ea201 RH |
6870 | |
6871 | offsetof_member_designator: | |
6ccde948 RW |
6872 | @code{identifier} |
6873 | | offsetof_member_designator "." @code{identifier} | |
6874 | | offsetof_member_designator "[" @code{expr} "]" | |
7a3ea201 RH |
6875 | @end smallexample |
6876 | ||
6877 | This extension is sufficient such that | |
6878 | ||
6879 | @smallexample | |
6880 | #define offsetof(@var{type}, @var{member}) __builtin_offsetof (@var{type}, @var{member}) | |
6881 | @end smallexample | |
6882 | ||
6883 | is a suitable definition of the @code{offsetof} macro. In C++, @var{type} | |
6884 | may be dependent. In either case, @var{member} may consist of a single | |
6885 | identifier, or a sequence of member accesses and array references. | |
6886 | ||
86951993 AM |
6887 | @node __sync Builtins |
6888 | @section Legacy __sync built-in functions for atomic memory access | |
48ae6c13 RH |
6889 | |
6890 | The following builtins are intended to be compatible with those described | |
6891 | in the @cite{Intel Itanium Processor-specific Application Binary Interface}, | |
6892 | section 7.4. As such, they depart from the normal GCC practice of using | |
6893 | the ``__builtin_'' prefix, and further that they are overloaded such that | |
6894 | they work on multiple types. | |
6895 | ||
6896 | The definition given in the Intel documentation allows only for the use of | |
6897 | the types @code{int}, @code{long}, @code{long long} as well as their unsigned | |
6898 | counterparts. GCC will allow any integral scalar or pointer type that is | |
6899 | 1, 2, 4 or 8 bytes in length. | |
6900 | ||
6901 | Not all operations are supported by all target processors. If a particular | |
6902 | operation cannot be implemented on the target processor, a warning will be | |
6903 | generated and a call an external function will be generated. The external | |
6904 | function will carry the same name as the builtin, with an additional suffix | |
6905 | @samp{_@var{n}} where @var{n} is the size of the data type. | |
6906 | ||
6907 | @c ??? Should we have a mechanism to suppress this warning? This is almost | |
6908 | @c useful for implementing the operation under the control of an external | |
6909 | @c mutex. | |
6910 | ||
6911 | In most cases, these builtins are considered a @dfn{full barrier}. That is, | |
6912 | no memory operand will be moved across the operation, either forward or | |
6913 | backward. Further, instructions will be issued as necessary to prevent the | |
6914 | processor from speculating loads across the operation and from queuing stores | |
6915 | after the operation. | |
6916 | ||
d1facce0 | 6917 | All of the routines are described in the Intel documentation to take |
48ae6c13 RH |
6918 | ``an optional list of variables protected by the memory barrier''. It's |
6919 | not clear what is meant by that; it could mean that @emph{only} the | |
6920 | following variables are protected, or it could mean that these variables | |
6921 | should in addition be protected. At present GCC ignores this list and | |
6922 | protects all variables which are globally accessible. If in the future | |
6923 | we make some use of this list, an empty list will continue to mean all | |
6924 | globally accessible variables. | |
6925 | ||
6926 | @table @code | |
6927 | @item @var{type} __sync_fetch_and_add (@var{type} *ptr, @var{type} value, ...) | |
6928 | @itemx @var{type} __sync_fetch_and_sub (@var{type} *ptr, @var{type} value, ...) | |
6929 | @itemx @var{type} __sync_fetch_and_or (@var{type} *ptr, @var{type} value, ...) | |
6930 | @itemx @var{type} __sync_fetch_and_and (@var{type} *ptr, @var{type} value, ...) | |
6931 | @itemx @var{type} __sync_fetch_and_xor (@var{type} *ptr, @var{type} value, ...) | |
6932 | @itemx @var{type} __sync_fetch_and_nand (@var{type} *ptr, @var{type} value, ...) | |
6933 | @findex __sync_fetch_and_add | |
6934 | @findex __sync_fetch_and_sub | |
6935 | @findex __sync_fetch_and_or | |
6936 | @findex __sync_fetch_and_and | |
6937 | @findex __sync_fetch_and_xor | |
6938 | @findex __sync_fetch_and_nand | |
6939 | These builtins perform the operation suggested by the name, and | |
6940 | returns the value that had previously been in memory. That is, | |
6941 | ||
6942 | @smallexample | |
6943 | @{ tmp = *ptr; *ptr @var{op}= value; return tmp; @} | |
23462d4d | 6944 | @{ tmp = *ptr; *ptr = ~(tmp & value); return tmp; @} // nand |
48ae6c13 RH |
6945 | @end smallexample |
6946 | ||
23462d4d UB |
6947 | @emph{Note:} GCC 4.4 and later implement @code{__sync_fetch_and_nand} |
6948 | builtin as @code{*ptr = ~(tmp & value)} instead of @code{*ptr = ~tmp & value}. | |
6949 | ||
48ae6c13 RH |
6950 | @item @var{type} __sync_add_and_fetch (@var{type} *ptr, @var{type} value, ...) |
6951 | @itemx @var{type} __sync_sub_and_fetch (@var{type} *ptr, @var{type} value, ...) | |
6952 | @itemx @var{type} __sync_or_and_fetch (@var{type} *ptr, @var{type} value, ...) | |
6953 | @itemx @var{type} __sync_and_and_fetch (@var{type} *ptr, @var{type} value, ...) | |
6954 | @itemx @var{type} __sync_xor_and_fetch (@var{type} *ptr, @var{type} value, ...) | |
6955 | @itemx @var{type} __sync_nand_and_fetch (@var{type} *ptr, @var{type} value, ...) | |
6956 | @findex __sync_add_and_fetch | |
6957 | @findex __sync_sub_and_fetch | |
6958 | @findex __sync_or_and_fetch | |
6959 | @findex __sync_and_and_fetch | |
6960 | @findex __sync_xor_and_fetch | |
6961 | @findex __sync_nand_and_fetch | |
6962 | These builtins perform the operation suggested by the name, and | |
6963 | return the new value. That is, | |
6964 | ||
6965 | @smallexample | |
6966 | @{ *ptr @var{op}= value; return *ptr; @} | |
23462d4d | 6967 | @{ *ptr = ~(*ptr & value); return *ptr; @} // nand |
48ae6c13 RH |
6968 | @end smallexample |
6969 | ||
23462d4d UB |
6970 | @emph{Note:} GCC 4.4 and later implement @code{__sync_nand_and_fetch} |
6971 | builtin as @code{*ptr = ~(*ptr & value)} instead of | |
6972 | @code{*ptr = ~*ptr & value}. | |
6973 | ||
06ef8c2e L |
6974 | @item bool __sync_bool_compare_and_swap (@var{type} *ptr, @var{type} oldval, @var{type} newval, ...) |
6975 | @itemx @var{type} __sync_val_compare_and_swap (@var{type} *ptr, @var{type} oldval, @var{type} newval, ...) | |
48ae6c13 RH |
6976 | @findex __sync_bool_compare_and_swap |
6977 | @findex __sync_val_compare_and_swap | |
6978 | These builtins perform an atomic compare and swap. That is, if the current | |
6979 | value of @code{*@var{ptr}} is @var{oldval}, then write @var{newval} into | |
6980 | @code{*@var{ptr}}. | |
6981 | ||
0ac11108 | 6982 | The ``bool'' version returns true if the comparison is successful and |
48ae6c13 | 6983 | @var{newval} was written. The ``val'' version returns the contents |
f12b785d | 6984 | of @code{*@var{ptr}} before the operation. |
48ae6c13 RH |
6985 | |
6986 | @item __sync_synchronize (...) | |
6987 | @findex __sync_synchronize | |
6988 | This builtin issues a full memory barrier. | |
6989 | ||
6990 | @item @var{type} __sync_lock_test_and_set (@var{type} *ptr, @var{type} value, ...) | |
6991 | @findex __sync_lock_test_and_set | |
6992 | This builtin, as described by Intel, is not a traditional test-and-set | |
6993 | operation, but rather an atomic exchange operation. It writes @var{value} | |
6994 | into @code{*@var{ptr}}, and returns the previous contents of | |
6995 | @code{*@var{ptr}}. | |
6996 | ||
6997 | Many targets have only minimal support for such locks, and do not support | |
6998 | a full exchange operation. In this case, a target may support reduced | |
6999 | functionality here by which the @emph{only} valid value to store is the | |
7000 | immediate constant 1. The exact value actually stored in @code{*@var{ptr}} | |
7001 | is implementation defined. | |
7002 | ||
7003 | This builtin is not a full barrier, but rather an @dfn{acquire barrier}. | |
7004 | This means that references after the builtin cannot move to (or be | |
7005 | speculated to) before the builtin, but previous memory stores may not | |
0ac11108 | 7006 | be globally visible yet, and previous memory loads may not yet be |
48ae6c13 RH |
7007 | satisfied. |
7008 | ||
7009 | @item void __sync_lock_release (@var{type} *ptr, ...) | |
7010 | @findex __sync_lock_release | |
7011 | This builtin releases the lock acquired by @code{__sync_lock_test_and_set}. | |
7012 | Normally this means writing the constant 0 to @code{*@var{ptr}}. | |
7013 | ||
7014 | This builtin is not a full barrier, but rather a @dfn{release barrier}. | |
7015 | This means that all previous memory stores are globally visible, and all | |
7016 | previous memory loads have been satisfied, but following memory reads | |
7017 | are not prevented from being speculated to before the barrier. | |
7018 | @end table | |
7019 | ||
86951993 AM |
7020 | @node __atomic Builtins |
7021 | @section Built-in functions for memory model aware atomic operations | |
7022 | ||
7023 | The following built-in functions approximately match the requirements for | |
7024 | C++11 memory model. Many are similar to the @samp{__sync} prefixed built-in | |
7025 | functions, but all also have a memory model parameter. These are all | |
7026 | identified by being prefixed with @samp{__atomic}, and most are overloaded | |
7027 | such that they work with multiple types. | |
7028 | ||
7029 | GCC will allow any integral scalar or pointer type that is 1, 2, 4, or 8 | |
7030 | bytes in length. 16-byte integral types are also allowed if | |
7031 | @samp{__int128} (@pxref{__int128}) is supported by the architecture. | |
7032 | ||
7033 | Target architectures are encouraged to provide their own patterns for | |
7034 | each of these built-in functions. If no target is provided, the original | |
7035 | non-memory model set of @samp{__sync} atomic built-in functions will be | |
7036 | utilized, along with any required synchronization fences surrounding it in | |
7037 | order to achieve the proper behaviour. Execution in this case is subject | |
7038 | to the same restrictions as those built-in functions. | |
7039 | ||
7040 | If there is no pattern or mechanism to provide a lock free instruction | |
7041 | sequence, a call is made to an external routine with the same parameters | |
7042 | to be resolved at runtime. | |
7043 | ||
7044 | The four non-arithmetic functions (load, store, exchange, and | |
7045 | compare_exchange) all have a generic version as well. This generic | |
7046 | version will work on any data type. If the data type size maps to one | |
7047 | of the integral sizes which may have lock free support, the generic | |
7048 | version will utilize the lock free built-in function. Otherwise an | |
7049 | external call is left to be resolved at runtime. This external call will | |
7050 | be the same format with the addition of a @samp{size_t} parameter inserted | |
7051 | as the first parameter indicating the size of the object being pointed to. | |
7052 | All objects must be the same size. | |
7053 | ||
7054 | There are 6 different memory models which can be specified. These map | |
7055 | to the same names in the C++11 standard. Refer there or to the | |
7056 | @uref{http://gcc.gnu.org/wiki/Atomic/GCCMM/AtomicSync,GCC wiki on | |
7057 | atomic synchronization} for more detailed definitions. These memory | |
7058 | models integrate both barriers to code motion as well as synchronization | |
7059 | requirements with other threads. These are listed in approximately | |
7060 | ascending order of strength. | |
7061 | ||
7062 | @table @code | |
7063 | @item __ATOMIC_RELAXED | |
7064 | No barriers or synchronization. | |
7065 | @item __ATOMIC_CONSUME | |
7066 | Data dependency only for both barrier and synchronization with another | |
7067 | thread. | |
7068 | @item __ATOMIC_ACQUIRE | |
7069 | Barrier to hoisting of code and synchronizes with release (or stronger) | |
7070 | semantic stores from another thread. | |
7071 | @item __ATOMIC_RELEASE | |
7072 | Barrier to sinking of code and synchronizes with acquire (or stronger) | |
7073 | semantic loads from another thread. | |
7074 | @item __ATOMIC_ACQ_REL | |
7075 | Full barrier in both directions and synchronizes with acquire loads and | |
7076 | release stores in another thread. | |
7077 | @item __ATOMIC_SEQ_CST | |
7078 | Full barrier in both directions and synchronizes with acquire loads and | |
7079 | release stores in all threads. | |
7080 | @end table | |
7081 | ||
7082 | When implementing patterns for these built-in functions , the memory model | |
7083 | parameter can be ignored as long as the pattern implements the most | |
7084 | restrictive @code{__ATOMIC_SEQ_CST} model. Any of the other memory models | |
7085 | will execute correctly with this memory model but they may not execute as | |
7086 | efficiently as they could with a more appropriate implemention of the | |
7087 | relaxed requirements. | |
7088 | ||
7089 | Note that the C++11 standard allows for the memory model parameter to be | |
7090 | determined at runtime rather than at compile time. These built-in | |
7091 | functions will map any runtime value to @code{__ATOMIC_SEQ_CST} rather | |
7092 | than invoke a runtime library call or inline a switch statement. This is | |
7093 | standard compliant, safe, and the simplest approach for now. | |
7094 | ||
7095 | @deftypefn {Built-in Function} @var{type} __atomic_load_n (@var{type} *ptr, int memmodel) | |
7096 | This built-in function implements an atomic load operation. It returns the | |
7097 | contents of @code{*@var{ptr}}. | |
7098 | ||
7099 | The valid memory model variants are | |
7100 | @code{__ATOMIC_RELAXED}, @code{__ATOMIC_SEQ_CST}, @code{__ATOMIC_ACQUIRE}, | |
7101 | and @code{__ATOMIC_CONSUME}. | |
7102 | ||
7103 | @end deftypefn | |
7104 | ||
7105 | @deftypefn {Built-in Function} void __atomic_load (@var{type} *ptr, @var{type} *ret, int memmodel) | |
7106 | This is the generic version of an atomic load. It will return the | |
7107 | contents of @code{*@var{ptr}} in @code{*@var{ret}}. | |
7108 | ||
7109 | @end deftypefn | |
7110 | ||
7111 | @deftypefn {Built-in Function} void __atomic_store_n (@var{type} *ptr, @var{type} val, int memmodel) | |
7112 | This built-in function implements an atomic store operation. It writes | |
0669295b | 7113 | @code{@var{val}} into @code{*@var{ptr}}. |
86951993 AM |
7114 | |
7115 | The valid memory model variants are | |
7116 | @code{__ATOMIC_RELAXED}, @code{__ATOMIC_SEQ_CST}, and @code{__ATOMIC_RELEASE}. | |
7117 | ||
7118 | @end deftypefn | |
7119 | ||
7120 | @deftypefn {Built-in Function} void __atomic_store (@var{type} *ptr, @var{type} *val, int memmodel) | |
7121 | This is the generic version of an atomic store. It will store the value | |
7122 | of @code{*@var{val}} into @code{*@var{ptr}}. | |
7123 | ||
7124 | @end deftypefn | |
7125 | ||
7126 | @deftypefn {Built-in Function} @var{type} __atomic_exchange_n (@var{type} *ptr, @var{type} val, int memmodel) | |
7127 | This built-in function implements an atomic exchange operation. It writes | |
7128 | @var{val} into @code{*@var{ptr}}, and returns the previous contents of | |
7129 | @code{*@var{ptr}}. | |
7130 | ||
86951993 AM |
7131 | The valid memory model variants are |
7132 | @code{__ATOMIC_RELAXED}, @code{__ATOMIC_SEQ_CST}, @code{__ATOMIC_ACQUIRE}, | |
7133 | @code{__ATOMIC_RELEASE}, and @code{__ATOMIC_ACQ_REL}. | |
7134 | ||
7135 | @end deftypefn | |
7136 | ||
7137 | @deftypefn {Built-in Function} void __atomic_exchange (@var{type} *ptr, @var{type} *val, @var{type} *ret, int memmodel) | |
7138 | This is the generic version of an atomic exchange. It will store the | |
7139 | contents of @code{*@var{val}} into @code{*@var{ptr}}. The original value | |
7140 | of @code{*@var{ptr}} will be copied into @code{*@var{ret}}. | |
7141 | ||
7142 | @end deftypefn | |
7143 | ||
7144 | @deftypefn {Built-in Function} bool __atomic_compare_exchange_n (@var{type} *ptr, @var{type} *expected, @var{type} desired, bool weak, int success_memmodel, int failure_memmodel) | |
7145 | This built-in function implements an atomic compare and exchange operation. | |
7146 | This compares the contents of @code{*@var{ptr}} with the contents of | |
7147 | @code{*@var{expected}} and if equal, writes @var{desired} into | |
7148 | @code{*@var{ptr}}. If they are not equal, the current contents of | |
7149 | @code{*@var{ptr}} is written into @code{*@var{expected}}. | |
7150 | ||
7151 | True is returned if @code{*@var{desired}} is written into | |
7152 | @code{*@var{ptr}} and the execution is considered to conform to the | |
7153 | memory model specified by @var{success_memmodel}. There are no | |
7154 | restrictions on what memory model can be used here. | |
7155 | ||
7156 | False is returned otherwise, and the execution is considered to conform | |
7157 | to @var{failure_memmodel}. This memory model cannot be | |
7158 | @code{__ATOMIC_RELEASE} nor @code{__ATOMIC_ACQ_REL}. It also cannot be a | |
7159 | stronger model than that specified by @var{success_memmodel}. | |
7160 | ||
7161 | @end deftypefn | |
7162 | ||
7163 | @deftypefn {Built-in Function} bool __atomic_compare_exchange (@var{type} *ptr, @var{type} *expected, @var{type} *desired, bool weak, int success_memmodel, int failure_memmodel) | |
7164 | This built-in function implements the generic version of | |
7165 | @code{__atomic_compare_exchange}. The function is virtually identical to | |
7166 | @code{__atomic_compare_exchange_n}, except the desired value is also a | |
7167 | pointer. | |
7168 | ||
7169 | @end deftypefn | |
7170 | ||
7171 | @deftypefn {Built-in Function} @var{type} __atomic_add_fetch (@var{type} *ptr, @var{type} val, int memmodel) | |
7172 | @deftypefnx {Built-in Function} @var{type} __atomic_sub_fetch (@var{type} *ptr, @var{type} val, int memmodel) | |
7173 | @deftypefnx {Built-in Function} @var{type} __atomic_and_fetch (@var{type} *ptr, @var{type} val, int memmodel) | |
7174 | @deftypefnx {Built-in Function} @var{type} __atomic_xor_fetch (@var{type} *ptr, @var{type} val, int memmodel) | |
7175 | @deftypefnx {Built-in Function} @var{type} __atomic_or_fetch (@var{type} *ptr, @var{type} val, int memmodel) | |
7176 | @deftypefnx {Built-in Function} @var{type} __atomic_nand_fetch (@var{type} *ptr, @var{type} val, int memmodel) | |
7177 | These built-in functions perform the operation suggested by the name, and | |
7178 | return the result of the operation. That is, | |
7179 | ||
7180 | @smallexample | |
7181 | @{ *ptr @var{op}= val; return *ptr; @} | |
7182 | @end smallexample | |
7183 | ||
7184 | All memory models are valid. | |
7185 | ||
7186 | @end deftypefn | |
7187 | ||
7188 | @deftypefn {Built-in Function} @var{type} __atomic_fetch_add (@var{type} *ptr, @var{type} val, int memmodel) | |
7189 | @deftypefnx {Built-in Function} @var{type} __atomic_fetch_sub (@var{type} *ptr, @var{type} val, int memmodel) | |
7190 | @deftypefnx {Built-in Function} @var{type} __atomic_fetch_and (@var{type} *ptr, @var{type} val, int memmodel) | |
7191 | @deftypefnx {Built-in Function} @var{type} __atomic_fetch_xor (@var{type} *ptr, @var{type} val, int memmodel) | |
7192 | @deftypefnx {Built-in Function} @var{type} __atomic_fetch_or (@var{type} *ptr, @var{type} val, int memmodel) | |
7193 | @deftypefnx {Built-in Function} @var{type} __atomic_fetch_nand (@var{type} *ptr, @var{type} val, int memmodel) | |
7194 | These built-in functions perform the operation suggested by the name, and | |
7195 | return the value that had previously been in @code{*@var{ptr}}. That is, | |
7196 | ||
7197 | @smallexample | |
7198 | @{ tmp = *ptr; *ptr @var{op}= val; return tmp; @} | |
7199 | @end smallexample | |
7200 | ||
7201 | All memory models are valid. | |
7202 | ||
7203 | @end deftypefn | |
7204 | ||
f8a27aa6 | 7205 | @deftypefn {Built-in Function} bool __atomic_test_and_set (void *ptr, int memmodel) |
1aabd05e AM |
7206 | |
7207 | This built-in function performs an atomic test-and-set operation on | |
f8a27aa6 RH |
7208 | the byte at @code{*@var{ptr}}. The byte is set to some implementation |
7209 | defined non-zero "set" value and the return value is @code{true} if and only | |
7210 | if the previous contents were "set". | |
1aabd05e AM |
7211 | |
7212 | All memory models are valid. | |
7213 | ||
7214 | @end deftypefn | |
7215 | ||
7216 | @deftypefn {Built-in Function} void __atomic_clear (bool *ptr, int memmodel) | |
7217 | ||
7218 | This built-in function performs an atomic clear operation on | |
7219 | @code{*@var{ptr}}. After the operation, @code{*@var{ptr}} will contain 0. | |
7220 | ||
7221 | The valid memory model variants are | |
7222 | @code{__ATOMIC_RELAXED}, @code{__ATOMIC_SEQ_CST}, and | |
7223 | @code{__ATOMIC_RELEASE}. | |
7224 | ||
7225 | @end deftypefn | |
7226 | ||
86951993 AM |
7227 | @deftypefn {Built-in Function} void __atomic_thread_fence (int memmodel) |
7228 | ||
7229 | This built-in function acts as a synchronization fence between threads | |
7230 | based on the specified memory model. | |
7231 | ||
7232 | All memory orders are valid. | |
7233 | ||
7234 | @end deftypefn | |
7235 | ||
7236 | @deftypefn {Built-in Function} void __atomic_signal_fence (int memmodel) | |
7237 | ||
7238 | This built-in function acts as a synchronization fence between a thread | |
7239 | and signal handlers based in the same thread. | |
7240 | ||
7241 | All memory orders are valid. | |
7242 | ||
7243 | @end deftypefn | |
7244 | ||
7245 | @deftypefn {Built-in Function} bool __atomic_always_lock_free (size_t size) | |
7246 | ||
7247 | This built-in function returns true if objects of size bytes will always | |
7248 | generate lock free atomic instructions for the target architecture. | |
7249 | Otherwise false is returned. | |
7250 | ||
7251 | size must resolve to a compile time constant. | |
7252 | ||
7253 | @smallexample | |
7254 | if (_atomic_always_lock_free (sizeof (long long))) | |
7255 | @end smallexample | |
7256 | ||
7257 | @end deftypefn | |
7258 | ||
7259 | @deftypefn {Built-in Function} bool __atomic_is_lock_free (size_t size) | |
7260 | ||
7261 | This built-in function returns true if objects of size bytes will always | |
7262 | generate lock free atomic instructions for the target architecture. If | |
7263 | it is not known to be lock free a call is made to a runtime routine named | |
7264 | @code{__atomic_is_lock_free}. | |
7265 | ||
7266 | @end deftypefn | |
7267 | ||
10a0d495 JJ |
7268 | @node Object Size Checking |
7269 | @section Object Size Checking Builtins | |
7270 | @findex __builtin_object_size | |
7271 | @findex __builtin___memcpy_chk | |
7272 | @findex __builtin___mempcpy_chk | |
7273 | @findex __builtin___memmove_chk | |
7274 | @findex __builtin___memset_chk | |
7275 | @findex __builtin___strcpy_chk | |
7276 | @findex __builtin___stpcpy_chk | |
7277 | @findex __builtin___strncpy_chk | |
7278 | @findex __builtin___strcat_chk | |
7279 | @findex __builtin___strncat_chk | |
7280 | @findex __builtin___sprintf_chk | |
7281 | @findex __builtin___snprintf_chk | |
7282 | @findex __builtin___vsprintf_chk | |
7283 | @findex __builtin___vsnprintf_chk | |
7284 | @findex __builtin___printf_chk | |
7285 | @findex __builtin___vprintf_chk | |
7286 | @findex __builtin___fprintf_chk | |
7287 | @findex __builtin___vfprintf_chk | |
7288 | ||
7289 | GCC implements a limited buffer overflow protection mechanism | |
7290 | that can prevent some buffer overflow attacks. | |
7291 | ||
7292 | @deftypefn {Built-in Function} {size_t} __builtin_object_size (void * @var{ptr}, int @var{type}) | |
7293 | is a built-in construct that returns a constant number of bytes from | |
7294 | @var{ptr} to the end of the object @var{ptr} pointer points to | |
7295 | (if known at compile time). @code{__builtin_object_size} never evaluates | |
7296 | its arguments for side-effects. If there are any side-effects in them, it | |
7297 | returns @code{(size_t) -1} for @var{type} 0 or 1 and @code{(size_t) 0} | |
7298 | for @var{type} 2 or 3. If there are multiple objects @var{ptr} can | |
7299 | point to and all of them are known at compile time, the returned number | |
7300 | is the maximum of remaining byte counts in those objects if @var{type} & 2 is | |
a4d05547 | 7301 | 0 and minimum if nonzero. If it is not possible to determine which objects |
10a0d495 JJ |
7302 | @var{ptr} points to at compile time, @code{__builtin_object_size} should |
7303 | return @code{(size_t) -1} for @var{type} 0 or 1 and @code{(size_t) 0} | |
7304 | for @var{type} 2 or 3. | |
7305 | ||
7306 | @var{type} is an integer constant from 0 to 3. If the least significant | |
7307 | bit is clear, objects are whole variables, if it is set, a closest | |
7308 | surrounding subobject is considered the object a pointer points to. | |
7309 | The second bit determines if maximum or minimum of remaining bytes | |
7310 | is computed. | |
7311 | ||
7312 | @smallexample | |
7313 | struct V @{ char buf1[10]; int b; char buf2[10]; @} var; | |
7314 | char *p = &var.buf1[1], *q = &var.b; | |
7315 | ||
7316 | /* Here the object p points to is var. */ | |
7317 | assert (__builtin_object_size (p, 0) == sizeof (var) - 1); | |
7318 | /* The subobject p points to is var.buf1. */ | |
7319 | assert (__builtin_object_size (p, 1) == sizeof (var.buf1) - 1); | |
7320 | /* The object q points to is var. */ | |
7321 | assert (__builtin_object_size (q, 0) | |
6ccde948 | 7322 | == (char *) (&var + 1) - (char *) &var.b); |
10a0d495 JJ |
7323 | /* The subobject q points to is var.b. */ |
7324 | assert (__builtin_object_size (q, 1) == sizeof (var.b)); | |
7325 | @end smallexample | |
7326 | @end deftypefn | |
7327 | ||
7328 | There are built-in functions added for many common string operation | |
021efafc | 7329 | functions, e.g., for @code{memcpy} @code{__builtin___memcpy_chk} |
10a0d495 JJ |
7330 | built-in is provided. This built-in has an additional last argument, |
7331 | which is the number of bytes remaining in object the @var{dest} | |
7332 | argument points to or @code{(size_t) -1} if the size is not known. | |
7333 | ||
7334 | The built-in functions are optimized into the normal string functions | |
7335 | like @code{memcpy} if the last argument is @code{(size_t) -1} or if | |
7336 | it is known at compile time that the destination object will not | |
7337 | be overflown. If the compiler can determine at compile time the | |
7338 | object will be always overflown, it issues a warning. | |
7339 | ||
7340 | The intended use can be e.g. | |
7341 | ||
7342 | @smallexample | |
7343 | #undef memcpy | |
7344 | #define bos0(dest) __builtin_object_size (dest, 0) | |
7345 | #define memcpy(dest, src, n) \ | |
7346 | __builtin___memcpy_chk (dest, src, n, bos0 (dest)) | |
7347 | ||
7348 | char *volatile p; | |
7349 | char buf[10]; | |
7350 | /* It is unknown what object p points to, so this is optimized | |
7351 | into plain memcpy - no checking is possible. */ | |
7352 | memcpy (p, "abcde", n); | |
7353 | /* Destination is known and length too. It is known at compile | |
7354 | time there will be no overflow. */ | |
7355 | memcpy (&buf[5], "abcde", 5); | |
7356 | /* Destination is known, but the length is not known at compile time. | |
7357 | This will result in __memcpy_chk call that can check for overflow | |
7358 | at runtime. */ | |
7359 | memcpy (&buf[5], "abcde", n); | |
7360 | /* Destination is known and it is known at compile time there will | |
7361 | be overflow. There will be a warning and __memcpy_chk call that | |
7362 | will abort the program at runtime. */ | |
7363 | memcpy (&buf[6], "abcde", 5); | |
7364 | @end smallexample | |
7365 | ||
7366 | Such built-in functions are provided for @code{memcpy}, @code{mempcpy}, | |
7367 | @code{memmove}, @code{memset}, @code{strcpy}, @code{stpcpy}, @code{strncpy}, | |
7368 | @code{strcat} and @code{strncat}. | |
7369 | ||
7370 | There are also checking built-in functions for formatted output functions. | |
7371 | @smallexample | |
7372 | int __builtin___sprintf_chk (char *s, int flag, size_t os, const char *fmt, ...); | |
7373 | int __builtin___snprintf_chk (char *s, size_t maxlen, int flag, size_t os, | |
6ccde948 | 7374 | const char *fmt, ...); |
10a0d495 | 7375 | int __builtin___vsprintf_chk (char *s, int flag, size_t os, const char *fmt, |
6ccde948 | 7376 | va_list ap); |
10a0d495 | 7377 | int __builtin___vsnprintf_chk (char *s, size_t maxlen, int flag, size_t os, |
6ccde948 | 7378 | const char *fmt, va_list ap); |
10a0d495 JJ |
7379 | @end smallexample |
7380 | ||
7381 | The added @var{flag} argument is passed unchanged to @code{__sprintf_chk} | |
021efafc | 7382 | etc.@: functions and can contain implementation specific flags on what |
10a0d495 JJ |
7383 | additional security measures the checking function might take, such as |
7384 | handling @code{%n} differently. | |
7385 | ||
7386 | The @var{os} argument is the object size @var{s} points to, like in the | |
a4d05547 | 7387 | other built-in functions. There is a small difference in the behavior |
10a0d495 JJ |
7388 | though, if @var{os} is @code{(size_t) -1}, the built-in functions are |
7389 | optimized into the non-checking functions only if @var{flag} is 0, otherwise | |
7390 | the checking function is called with @var{os} argument set to | |
7391 | @code{(size_t) -1}. | |
7392 | ||
7393 | In addition to this, there are checking built-in functions | |
7394 | @code{__builtin___printf_chk}, @code{__builtin___vprintf_chk}, | |
7395 | @code{__builtin___fprintf_chk} and @code{__builtin___vfprintf_chk}. | |
7396 | These have just one additional argument, @var{flag}, right before | |
7397 | format string @var{fmt}. If the compiler is able to optimize them to | |
021efafc | 7398 | @code{fputc} etc.@: functions, it will, otherwise the checking function |
10a0d495 JJ |
7399 | should be called and the @var{flag} argument passed to it. |
7400 | ||
185ebd6c | 7401 | @node Other Builtins |
f0523f02 | 7402 | @section Other built-in functions provided by GCC |
c771326b | 7403 | @cindex built-in functions |
3bf5906b | 7404 | @findex __builtin_fpclassify |
0c8d3c2b | 7405 | @findex __builtin_isfinite |
8a91c45b | 7406 | @findex __builtin_isnormal |
01702459 JM |
7407 | @findex __builtin_isgreater |
7408 | @findex __builtin_isgreaterequal | |
05f41289 | 7409 | @findex __builtin_isinf_sign |
01702459 JM |
7410 | @findex __builtin_isless |
7411 | @findex __builtin_islessequal | |
7412 | @findex __builtin_islessgreater | |
7413 | @findex __builtin_isunordered | |
17684d46 RG |
7414 | @findex __builtin_powi |
7415 | @findex __builtin_powif | |
7416 | @findex __builtin_powil | |
98ff7c4d KG |
7417 | @findex _Exit |
7418 | @findex _exit | |
01702459 JM |
7419 | @findex abort |
7420 | @findex abs | |
98ff7c4d KG |
7421 | @findex acos |
7422 | @findex acosf | |
7423 | @findex acosh | |
7424 | @findex acoshf | |
7425 | @findex acoshl | |
7426 | @findex acosl | |
01702459 | 7427 | @findex alloca |
98ff7c4d KG |
7428 | @findex asin |
7429 | @findex asinf | |
7430 | @findex asinh | |
7431 | @findex asinhf | |
7432 | @findex asinhl | |
7433 | @findex asinl | |
29f523be | 7434 | @findex atan |
46847aa6 RS |
7435 | @findex atan2 |
7436 | @findex atan2f | |
7437 | @findex atan2l | |
29f523be | 7438 | @findex atanf |
98ff7c4d KG |
7439 | @findex atanh |
7440 | @findex atanhf | |
7441 | @findex atanhl | |
29f523be | 7442 | @findex atanl |
01702459 JM |
7443 | @findex bcmp |
7444 | @findex bzero | |
075ec276 RS |
7445 | @findex cabs |
7446 | @findex cabsf | |
7447 | @findex cabsl | |
11bf0eb0 KG |
7448 | @findex cacos |
7449 | @findex cacosf | |
7450 | @findex cacosh | |
7451 | @findex cacoshf | |
7452 | @findex cacoshl | |
7453 | @findex cacosl | |
1331d16f | 7454 | @findex calloc |
11bf0eb0 KG |
7455 | @findex carg |
7456 | @findex cargf | |
7457 | @findex cargl | |
7458 | @findex casin | |
7459 | @findex casinf | |
7460 | @findex casinh | |
7461 | @findex casinhf | |
7462 | @findex casinhl | |
7463 | @findex casinl | |
7464 | @findex catan | |
7465 | @findex catanf | |
7466 | @findex catanh | |
7467 | @findex catanhf | |
7468 | @findex catanhl | |
7469 | @findex catanl | |
98ff7c4d KG |
7470 | @findex cbrt |
7471 | @findex cbrtf | |
7472 | @findex cbrtl | |
11bf0eb0 KG |
7473 | @findex ccos |
7474 | @findex ccosf | |
7475 | @findex ccosh | |
7476 | @findex ccoshf | |
7477 | @findex ccoshl | |
7478 | @findex ccosl | |
b052d8ee RS |
7479 | @findex ceil |
7480 | @findex ceilf | |
7481 | @findex ceill | |
11bf0eb0 KG |
7482 | @findex cexp |
7483 | @findex cexpf | |
7484 | @findex cexpl | |
341e3d11 JM |
7485 | @findex cimag |
7486 | @findex cimagf | |
7487 | @findex cimagl | |
c3887ef2 PC |
7488 | @findex clog |
7489 | @findex clogf | |
7490 | @findex clogl | |
341e3d11 JM |
7491 | @findex conj |
7492 | @findex conjf | |
7493 | @findex conjl | |
98ff7c4d KG |
7494 | @findex copysign |
7495 | @findex copysignf | |
7496 | @findex copysignl | |
01702459 JM |
7497 | @findex cos |
7498 | @findex cosf | |
98ff7c4d KG |
7499 | @findex cosh |
7500 | @findex coshf | |
7501 | @findex coshl | |
01702459 | 7502 | @findex cosl |
11bf0eb0 KG |
7503 | @findex cpow |
7504 | @findex cpowf | |
7505 | @findex cpowl | |
7506 | @findex cproj | |
7507 | @findex cprojf | |
7508 | @findex cprojl | |
341e3d11 JM |
7509 | @findex creal |
7510 | @findex crealf | |
7511 | @findex creall | |
11bf0eb0 KG |
7512 | @findex csin |
7513 | @findex csinf | |
7514 | @findex csinh | |
7515 | @findex csinhf | |
7516 | @findex csinhl | |
7517 | @findex csinl | |
7518 | @findex csqrt | |
7519 | @findex csqrtf | |
7520 | @findex csqrtl | |
7521 | @findex ctan | |
7522 | @findex ctanf | |
7523 | @findex ctanh | |
7524 | @findex ctanhf | |
7525 | @findex ctanhl | |
7526 | @findex ctanl | |
178b2b9f RS |
7527 | @findex dcgettext |
7528 | @findex dgettext | |
98ff7c4d KG |
7529 | @findex drem |
7530 | @findex dremf | |
7531 | @findex dreml | |
488f17e1 KG |
7532 | @findex erf |
7533 | @findex erfc | |
7534 | @findex erfcf | |
7535 | @findex erfcl | |
7536 | @findex erff | |
7537 | @findex erfl | |
01702459 | 7538 | @findex exit |
e7b489c8 | 7539 | @findex exp |
98ff7c4d KG |
7540 | @findex exp10 |
7541 | @findex exp10f | |
7542 | @findex exp10l | |
7543 | @findex exp2 | |
7544 | @findex exp2f | |
7545 | @findex exp2l | |
e7b489c8 RS |
7546 | @findex expf |
7547 | @findex expl | |
98ff7c4d KG |
7548 | @findex expm1 |
7549 | @findex expm1f | |
7550 | @findex expm1l | |
01702459 JM |
7551 | @findex fabs |
7552 | @findex fabsf | |
7553 | @findex fabsl | |
98ff7c4d KG |
7554 | @findex fdim |
7555 | @findex fdimf | |
7556 | @findex fdiml | |
01702459 | 7557 | @findex ffs |
b052d8ee RS |
7558 | @findex floor |
7559 | @findex floorf | |
7560 | @findex floorl | |
98ff7c4d KG |
7561 | @findex fma |
7562 | @findex fmaf | |
7563 | @findex fmal | |
7564 | @findex fmax | |
7565 | @findex fmaxf | |
7566 | @findex fmaxl | |
7567 | @findex fmin | |
7568 | @findex fminf | |
7569 | @findex fminl | |
b052d8ee RS |
7570 | @findex fmod |
7571 | @findex fmodf | |
7572 | @findex fmodl | |
18f988a0 | 7573 | @findex fprintf |
b4c984fb | 7574 | @findex fprintf_unlocked |
01702459 | 7575 | @findex fputs |
b4c984fb | 7576 | @findex fputs_unlocked |
a2a919aa KG |
7577 | @findex frexp |
7578 | @findex frexpf | |
7579 | @findex frexpl | |
178b2b9f | 7580 | @findex fscanf |
488f17e1 KG |
7581 | @findex gamma |
7582 | @findex gammaf | |
7583 | @findex gammal | |
bf460eec KG |
7584 | @findex gamma_r |
7585 | @findex gammaf_r | |
7586 | @findex gammal_r | |
178b2b9f | 7587 | @findex gettext |
98ff7c4d KG |
7588 | @findex hypot |
7589 | @findex hypotf | |
7590 | @findex hypotl | |
7591 | @findex ilogb | |
7592 | @findex ilogbf | |
7593 | @findex ilogbl | |
e78f4a97 | 7594 | @findex imaxabs |
c7b6c6cd | 7595 | @findex index |
740e5b6f KG |
7596 | @findex isalnum |
7597 | @findex isalpha | |
7598 | @findex isascii | |
7599 | @findex isblank | |
7600 | @findex iscntrl | |
7601 | @findex isdigit | |
7602 | @findex isgraph | |
7603 | @findex islower | |
7604 | @findex isprint | |
7605 | @findex ispunct | |
7606 | @findex isspace | |
7607 | @findex isupper | |
ca4944e1 KG |
7608 | @findex iswalnum |
7609 | @findex iswalpha | |
7610 | @findex iswblank | |
7611 | @findex iswcntrl | |
7612 | @findex iswdigit | |
7613 | @findex iswgraph | |
7614 | @findex iswlower | |
7615 | @findex iswprint | |
7616 | @findex iswpunct | |
7617 | @findex iswspace | |
7618 | @findex iswupper | |
7619 | @findex iswxdigit | |
740e5b6f | 7620 | @findex isxdigit |
488f17e1 KG |
7621 | @findex j0 |
7622 | @findex j0f | |
7623 | @findex j0l | |
7624 | @findex j1 | |
7625 | @findex j1f | |
7626 | @findex j1l | |
7627 | @findex jn | |
7628 | @findex jnf | |
7629 | @findex jnl | |
01702459 | 7630 | @findex labs |
98ff7c4d KG |
7631 | @findex ldexp |
7632 | @findex ldexpf | |
7633 | @findex ldexpl | |
488f17e1 KG |
7634 | @findex lgamma |
7635 | @findex lgammaf | |
7636 | @findex lgammal | |
bf460eec KG |
7637 | @findex lgamma_r |
7638 | @findex lgammaf_r | |
7639 | @findex lgammal_r | |
01702459 | 7640 | @findex llabs |
98ff7c4d KG |
7641 | @findex llrint |
7642 | @findex llrintf | |
7643 | @findex llrintl | |
7644 | @findex llround | |
7645 | @findex llroundf | |
7646 | @findex llroundl | |
e7b489c8 | 7647 | @findex log |
98ff7c4d KG |
7648 | @findex log10 |
7649 | @findex log10f | |
7650 | @findex log10l | |
7651 | @findex log1p | |
7652 | @findex log1pf | |
7653 | @findex log1pl | |
7654 | @findex log2 | |
7655 | @findex log2f | |
7656 | @findex log2l | |
7657 | @findex logb | |
7658 | @findex logbf | |
7659 | @findex logbl | |
e7b489c8 RS |
7660 | @findex logf |
7661 | @findex logl | |
98ff7c4d KG |
7662 | @findex lrint |
7663 | @findex lrintf | |
7664 | @findex lrintl | |
7665 | @findex lround | |
7666 | @findex lroundf | |
7667 | @findex lroundl | |
1331d16f | 7668 | @findex malloc |
2a5fce6d | 7669 | @findex memchr |
01702459 JM |
7670 | @findex memcmp |
7671 | @findex memcpy | |
9cb65f92 | 7672 | @findex mempcpy |
01702459 | 7673 | @findex memset |
a2a919aa KG |
7674 | @findex modf |
7675 | @findex modff | |
7676 | @findex modfl | |
b052d8ee RS |
7677 | @findex nearbyint |
7678 | @findex nearbyintf | |
7679 | @findex nearbyintl | |
98ff7c4d KG |
7680 | @findex nextafter |
7681 | @findex nextafterf | |
7682 | @findex nextafterl | |
7683 | @findex nexttoward | |
7684 | @findex nexttowardf | |
7685 | @findex nexttowardl | |
46847aa6 | 7686 | @findex pow |
98ff7c4d KG |
7687 | @findex pow10 |
7688 | @findex pow10f | |
7689 | @findex pow10l | |
46847aa6 RS |
7690 | @findex powf |
7691 | @findex powl | |
01702459 | 7692 | @findex printf |
b4c984fb | 7693 | @findex printf_unlocked |
08291658 RS |
7694 | @findex putchar |
7695 | @findex puts | |
98ff7c4d KG |
7696 | @findex remainder |
7697 | @findex remainderf | |
7698 | @findex remainderl | |
a2a919aa KG |
7699 | @findex remquo |
7700 | @findex remquof | |
7701 | @findex remquol | |
c7b6c6cd | 7702 | @findex rindex |
98ff7c4d KG |
7703 | @findex rint |
7704 | @findex rintf | |
7705 | @findex rintl | |
b052d8ee RS |
7706 | @findex round |
7707 | @findex roundf | |
7708 | @findex roundl | |
98ff7c4d KG |
7709 | @findex scalb |
7710 | @findex scalbf | |
7711 | @findex scalbl | |
7712 | @findex scalbln | |
7713 | @findex scalblnf | |
7714 | @findex scalblnf | |
7715 | @findex scalbn | |
7716 | @findex scalbnf | |
7717 | @findex scanfnl | |
ef79730c RS |
7718 | @findex signbit |
7719 | @findex signbitf | |
7720 | @findex signbitl | |
44aea9ac JJ |
7721 | @findex signbitd32 |
7722 | @findex signbitd64 | |
7723 | @findex signbitd128 | |
488f17e1 KG |
7724 | @findex significand |
7725 | @findex significandf | |
7726 | @findex significandl | |
01702459 | 7727 | @findex sin |
a2a919aa KG |
7728 | @findex sincos |
7729 | @findex sincosf | |
7730 | @findex sincosl | |
01702459 | 7731 | @findex sinf |
98ff7c4d KG |
7732 | @findex sinh |
7733 | @findex sinhf | |
7734 | @findex sinhl | |
01702459 | 7735 | @findex sinl |
08291658 RS |
7736 | @findex snprintf |
7737 | @findex sprintf | |
01702459 JM |
7738 | @findex sqrt |
7739 | @findex sqrtf | |
7740 | @findex sqrtl | |
08291658 | 7741 | @findex sscanf |
9cb65f92 | 7742 | @findex stpcpy |
e905ac64 KG |
7743 | @findex stpncpy |
7744 | @findex strcasecmp | |
d118937d | 7745 | @findex strcat |
01702459 JM |
7746 | @findex strchr |
7747 | @findex strcmp | |
7748 | @findex strcpy | |
d118937d | 7749 | @findex strcspn |
1331d16f | 7750 | @findex strdup |
178b2b9f RS |
7751 | @findex strfmon |
7752 | @findex strftime | |
01702459 | 7753 | @findex strlen |
e905ac64 | 7754 | @findex strncasecmp |
d118937d | 7755 | @findex strncat |
da9e9f08 KG |
7756 | @findex strncmp |
7757 | @findex strncpy | |
e905ac64 | 7758 | @findex strndup |
01702459 JM |
7759 | @findex strpbrk |
7760 | @findex strrchr | |
d118937d | 7761 | @findex strspn |
01702459 | 7762 | @findex strstr |
29f523be RS |
7763 | @findex tan |
7764 | @findex tanf | |
98ff7c4d KG |
7765 | @findex tanh |
7766 | @findex tanhf | |
7767 | @findex tanhl | |
29f523be | 7768 | @findex tanl |
488f17e1 KG |
7769 | @findex tgamma |
7770 | @findex tgammaf | |
7771 | @findex tgammal | |
740e5b6f KG |
7772 | @findex toascii |
7773 | @findex tolower | |
7774 | @findex toupper | |
ca4944e1 KG |
7775 | @findex towlower |
7776 | @findex towupper | |
4977bab6 ZW |
7777 | @findex trunc |
7778 | @findex truncf | |
7779 | @findex truncl | |
178b2b9f RS |
7780 | @findex vfprintf |
7781 | @findex vfscanf | |
08291658 RS |
7782 | @findex vprintf |
7783 | @findex vscanf | |
7784 | @findex vsnprintf | |
7785 | @findex vsprintf | |
7786 | @findex vsscanf | |
488f17e1 KG |
7787 | @findex y0 |
7788 | @findex y0f | |
7789 | @findex y0l | |
7790 | @findex y1 | |
7791 | @findex y1f | |
7792 | @findex y1l | |
7793 | @findex yn | |
7794 | @findex ynf | |
7795 | @findex ynl | |
185ebd6c | 7796 | |
f0523f02 | 7797 | GCC provides a large number of built-in functions other than the ones |
185ebd6c RH |
7798 | mentioned above. Some of these are for internal use in the processing |
7799 | of exceptions or variable-length argument lists and will not be | |
7800 | documented here because they may change from time to time; we do not | |
7801 | recommend general use of these functions. | |
7802 | ||
7803 | The remaining functions are provided for optimization purposes. | |
7804 | ||
84330467 | 7805 | @opindex fno-builtin |
9c34dbbf ZW |
7806 | GCC includes built-in versions of many of the functions in the standard |
7807 | C library. The versions prefixed with @code{__builtin_} will always be | |
7808 | treated as having the same meaning as the C library function even if you | |
8a36672b | 7809 | specify the @option{-fno-builtin} option. (@pxref{C Dialect Options}) |
9c34dbbf | 7810 | Many of these functions are only optimized in certain cases; if they are |
01702459 JM |
7811 | not optimized in a particular case, a call to the library function will |
7812 | be emitted. | |
7813 | ||
84330467 JM |
7814 | @opindex ansi |
7815 | @opindex std | |
2778d766 | 7816 | Outside strict ISO C mode (@option{-ansi}, @option{-std=c90}, |
48b0b196 | 7817 | @option{-std=c99} or @option{-std=c11}), the functions |
98ff7c4d KG |
7818 | @code{_exit}, @code{alloca}, @code{bcmp}, @code{bzero}, |
7819 | @code{dcgettext}, @code{dgettext}, @code{dremf}, @code{dreml}, | |
7820 | @code{drem}, @code{exp10f}, @code{exp10l}, @code{exp10}, @code{ffsll}, | |
bf460eec KG |
7821 | @code{ffsl}, @code{ffs}, @code{fprintf_unlocked}, |
7822 | @code{fputs_unlocked}, @code{gammaf}, @code{gammal}, @code{gamma}, | |
7823 | @code{gammaf_r}, @code{gammal_r}, @code{gamma_r}, @code{gettext}, | |
740e5b6f KG |
7824 | @code{index}, @code{isascii}, @code{j0f}, @code{j0l}, @code{j0}, |
7825 | @code{j1f}, @code{j1l}, @code{j1}, @code{jnf}, @code{jnl}, @code{jn}, | |
bf460eec KG |
7826 | @code{lgammaf_r}, @code{lgammal_r}, @code{lgamma_r}, @code{mempcpy}, |
7827 | @code{pow10f}, @code{pow10l}, @code{pow10}, @code{printf_unlocked}, | |
7828 | @code{rindex}, @code{scalbf}, @code{scalbl}, @code{scalb}, | |
7829 | @code{signbit}, @code{signbitf}, @code{signbitl}, @code{signbitd32}, | |
7830 | @code{signbitd64}, @code{signbitd128}, @code{significandf}, | |
7831 | @code{significandl}, @code{significand}, @code{sincosf}, | |
7832 | @code{sincosl}, @code{sincos}, @code{stpcpy}, @code{stpncpy}, | |
7833 | @code{strcasecmp}, @code{strdup}, @code{strfmon}, @code{strncasecmp}, | |
7834 | @code{strndup}, @code{toascii}, @code{y0f}, @code{y0l}, @code{y0}, | |
7835 | @code{y1f}, @code{y1l}, @code{y1}, @code{ynf}, @code{ynl} and | |
7836 | @code{yn} | |
1331d16f | 7837 | may be handled as built-in functions. |
b052d8ee | 7838 | All these functions have corresponding versions |
7e1542b9 | 7839 | prefixed with @code{__builtin_}, which may be used even in strict C90 |
9c34dbbf | 7840 | mode. |
01702459 | 7841 | |
075ec276 | 7842 | The ISO C99 functions |
98ff7c4d KG |
7843 | @code{_Exit}, @code{acoshf}, @code{acoshl}, @code{acosh}, @code{asinhf}, |
7844 | @code{asinhl}, @code{asinh}, @code{atanhf}, @code{atanhl}, @code{atanh}, | |
11bf0eb0 KG |
7845 | @code{cabsf}, @code{cabsl}, @code{cabs}, @code{cacosf}, @code{cacoshf}, |
7846 | @code{cacoshl}, @code{cacosh}, @code{cacosl}, @code{cacos}, | |
7847 | @code{cargf}, @code{cargl}, @code{carg}, @code{casinf}, @code{casinhf}, | |
7848 | @code{casinhl}, @code{casinh}, @code{casinl}, @code{casin}, | |
7849 | @code{catanf}, @code{catanhf}, @code{catanhl}, @code{catanh}, | |
7850 | @code{catanl}, @code{catan}, @code{cbrtf}, @code{cbrtl}, @code{cbrt}, | |
7851 | @code{ccosf}, @code{ccoshf}, @code{ccoshl}, @code{ccosh}, @code{ccosl}, | |
7852 | @code{ccos}, @code{cexpf}, @code{cexpl}, @code{cexp}, @code{cimagf}, | |
c3887ef2 PC |
7853 | @code{cimagl}, @code{cimag}, @code{clogf}, @code{clogl}, @code{clog}, |
7854 | @code{conjf}, @code{conjl}, @code{conj}, @code{copysignf}, @code{copysignl}, | |
7855 | @code{copysign}, @code{cpowf}, @code{cpowl}, @code{cpow}, @code{cprojf}, | |
7856 | @code{cprojl}, @code{cproj}, @code{crealf}, @code{creall}, @code{creal}, | |
7857 | @code{csinf}, @code{csinhf}, @code{csinhl}, @code{csinh}, @code{csinl}, | |
7858 | @code{csin}, @code{csqrtf}, @code{csqrtl}, @code{csqrt}, @code{ctanf}, | |
7859 | @code{ctanhf}, @code{ctanhl}, @code{ctanh}, @code{ctanl}, @code{ctan}, | |
7860 | @code{erfcf}, @code{erfcl}, @code{erfc}, @code{erff}, @code{erfl}, | |
7861 | @code{erf}, @code{exp2f}, @code{exp2l}, @code{exp2}, @code{expm1f}, | |
7862 | @code{expm1l}, @code{expm1}, @code{fdimf}, @code{fdiml}, @code{fdim}, | |
7863 | @code{fmaf}, @code{fmal}, @code{fmaxf}, @code{fmaxl}, @code{fmax}, | |
7864 | @code{fma}, @code{fminf}, @code{fminl}, @code{fmin}, @code{hypotf}, | |
7865 | @code{hypotl}, @code{hypot}, @code{ilogbf}, @code{ilogbl}, @code{ilogb}, | |
7866 | @code{imaxabs}, @code{isblank}, @code{iswblank}, @code{lgammaf}, | |
7867 | @code{lgammal}, @code{lgamma}, @code{llabs}, @code{llrintf}, @code{llrintl}, | |
ca4944e1 KG |
7868 | @code{llrint}, @code{llroundf}, @code{llroundl}, @code{llround}, |
7869 | @code{log1pf}, @code{log1pl}, @code{log1p}, @code{log2f}, @code{log2l}, | |
7870 | @code{log2}, @code{logbf}, @code{logbl}, @code{logb}, @code{lrintf}, | |
7871 | @code{lrintl}, @code{lrint}, @code{lroundf}, @code{lroundl}, | |
7872 | @code{lround}, @code{nearbyintf}, @code{nearbyintl}, @code{nearbyint}, | |
740e5b6f KG |
7873 | @code{nextafterf}, @code{nextafterl}, @code{nextafter}, |
7874 | @code{nexttowardf}, @code{nexttowardl}, @code{nexttoward}, | |
7875 | @code{remainderf}, @code{remainderl}, @code{remainder}, @code{remquof}, | |
7876 | @code{remquol}, @code{remquo}, @code{rintf}, @code{rintl}, @code{rint}, | |
7877 | @code{roundf}, @code{roundl}, @code{round}, @code{scalblnf}, | |
7878 | @code{scalblnl}, @code{scalbln}, @code{scalbnf}, @code{scalbnl}, | |
7879 | @code{scalbn}, @code{snprintf}, @code{tgammaf}, @code{tgammal}, | |
7880 | @code{tgamma}, @code{truncf}, @code{truncl}, @code{trunc}, | |
7881 | @code{vfscanf}, @code{vscanf}, @code{vsnprintf} and @code{vsscanf} | |
08291658 | 7882 | are handled as built-in functions |
7e1542b9 | 7883 | except in strict ISO C90 mode (@option{-ansi} or @option{-std=c90}). |
46847aa6 | 7884 | |
98ff7c4d KG |
7885 | There are also built-in versions of the ISO C99 functions |
7886 | @code{acosf}, @code{acosl}, @code{asinf}, @code{asinl}, @code{atan2f}, | |
29f523be | 7887 | @code{atan2l}, @code{atanf}, @code{atanl}, @code{ceilf}, @code{ceill}, |
98ff7c4d KG |
7888 | @code{cosf}, @code{coshf}, @code{coshl}, @code{cosl}, @code{expf}, |
7889 | @code{expl}, @code{fabsf}, @code{fabsl}, @code{floorf}, @code{floorl}, | |
a2a919aa KG |
7890 | @code{fmodf}, @code{fmodl}, @code{frexpf}, @code{frexpl}, @code{ldexpf}, |
7891 | @code{ldexpl}, @code{log10f}, @code{log10l}, @code{logf}, @code{logl}, | |
7892 | @code{modfl}, @code{modf}, @code{powf}, @code{powl}, @code{sinf}, | |
7893 | @code{sinhf}, @code{sinhl}, @code{sinl}, @code{sqrtf}, @code{sqrtl}, | |
7894 | @code{tanf}, @code{tanhf}, @code{tanhl} and @code{tanl} | |
46847aa6 RS |
7895 | that are recognized in any mode since ISO C90 reserves these names for |
7896 | the purpose to which ISO C99 puts them. All these functions have | |
7897 | corresponding versions prefixed with @code{__builtin_}. | |
7898 | ||
ca4944e1 KG |
7899 | The ISO C94 functions |
7900 | @code{iswalnum}, @code{iswalpha}, @code{iswcntrl}, @code{iswdigit}, | |
7901 | @code{iswgraph}, @code{iswlower}, @code{iswprint}, @code{iswpunct}, | |
7902 | @code{iswspace}, @code{iswupper}, @code{iswxdigit}, @code{towlower} and | |
7903 | @code{towupper} | |
7904 | are handled as built-in functions | |
7e1542b9 | 7905 | except in strict ISO C90 mode (@option{-ansi} or @option{-std=c90}). |
ca4944e1 | 7906 | |
98ff7c4d KG |
7907 | The ISO C90 functions |
7908 | @code{abort}, @code{abs}, @code{acos}, @code{asin}, @code{atan2}, | |
7909 | @code{atan}, @code{calloc}, @code{ceil}, @code{cosh}, @code{cos}, | |
7910 | @code{exit}, @code{exp}, @code{fabs}, @code{floor}, @code{fmod}, | |
740e5b6f KG |
7911 | @code{fprintf}, @code{fputs}, @code{frexp}, @code{fscanf}, |
7912 | @code{isalnum}, @code{isalpha}, @code{iscntrl}, @code{isdigit}, | |
7913 | @code{isgraph}, @code{islower}, @code{isprint}, @code{ispunct}, | |
7914 | @code{isspace}, @code{isupper}, @code{isxdigit}, @code{tolower}, | |
7915 | @code{toupper}, @code{labs}, @code{ldexp}, @code{log10}, @code{log}, | |
2a5fce6d PC |
7916 | @code{malloc}, @code{memchr}, @code{memcmp}, @code{memcpy}, |
7917 | @code{memset}, @code{modf}, @code{pow}, @code{printf}, @code{putchar}, | |
7918 | @code{puts}, @code{scanf}, @code{sinh}, @code{sin}, @code{snprintf}, | |
7919 | @code{sprintf}, @code{sqrt}, @code{sscanf}, @code{strcat}, | |
7920 | @code{strchr}, @code{strcmp}, @code{strcpy}, @code{strcspn}, | |
7921 | @code{strlen}, @code{strncat}, @code{strncmp}, @code{strncpy}, | |
7922 | @code{strpbrk}, @code{strrchr}, @code{strspn}, @code{strstr}, | |
7923 | @code{tanh}, @code{tan}, @code{vfprintf}, @code{vprintf} and @code{vsprintf} | |
08291658 | 7924 | are all recognized as built-in functions unless |
46847aa6 RS |
7925 | @option{-fno-builtin} is specified (or @option{-fno-builtin-@var{function}} |
7926 | is specified for an individual function). All of these functions have | |
4977bab6 | 7927 | corresponding versions prefixed with @code{__builtin_}. |
9c34dbbf ZW |
7928 | |
7929 | GCC provides built-in versions of the ISO C99 floating point comparison | |
7930 | macros that avoid raising exceptions for unordered operands. They have | |
7931 | the same names as the standard macros ( @code{isgreater}, | |
7932 | @code{isgreaterequal}, @code{isless}, @code{islessequal}, | |
7933 | @code{islessgreater}, and @code{isunordered}) , with @code{__builtin_} | |
7934 | prefixed. We intend for a library implementor to be able to simply | |
7935 | @code{#define} each standard macro to its built-in equivalent. | |
3bf5906b KG |
7936 | In the same fashion, GCC provides @code{fpclassify}, @code{isfinite}, |
7937 | @code{isinf_sign} and @code{isnormal} built-ins used with | |
7938 | @code{__builtin_} prefixed. The @code{isinf} and @code{isnan} | |
7939 | builtins appear both with and without the @code{__builtin_} prefix. | |
185ebd6c | 7940 | |
ecbcf7b3 AH |
7941 | @deftypefn {Built-in Function} int __builtin_types_compatible_p (@var{type1}, @var{type2}) |
7942 | ||
7943 | You can use the built-in function @code{__builtin_types_compatible_p} to | |
7944 | determine whether two types are the same. | |
7945 | ||
7946 | This built-in function returns 1 if the unqualified versions of the | |
7947 | types @var{type1} and @var{type2} (which are types, not expressions) are | |
7948 | compatible, 0 otherwise. The result of this built-in function can be | |
7949 | used in integer constant expressions. | |
7950 | ||
7951 | This built-in function ignores top level qualifiers (e.g., @code{const}, | |
7952 | @code{volatile}). For example, @code{int} is equivalent to @code{const | |
7953 | int}. | |
7954 | ||
7955 | The type @code{int[]} and @code{int[5]} are compatible. On the other | |
7956 | hand, @code{int} and @code{char *} are not compatible, even if the size | |
7957 | of their types, on the particular architecture are the same. Also, the | |
7958 | amount of pointer indirection is taken into account when determining | |
7959 | similarity. Consequently, @code{short *} is not similar to | |
7960 | @code{short **}. Furthermore, two types that are typedefed are | |
7961 | considered compatible if their underlying types are compatible. | |
7962 | ||
bca63328 JM |
7963 | An @code{enum} type is not considered to be compatible with another |
7964 | @code{enum} type even if both are compatible with the same integer | |
7965 | type; this is what the C standard specifies. | |
7966 | For example, @code{enum @{foo, bar@}} is not similar to | |
ecbcf7b3 AH |
7967 | @code{enum @{hot, dog@}}. |
7968 | ||
7969 | You would typically use this function in code whose execution varies | |
7970 | depending on the arguments' types. For example: | |
7971 | ||
7972 | @smallexample | |
6e5bb5ad JM |
7973 | #define foo(x) \ |
7974 | (@{ \ | |
b7886f14 | 7975 | typeof (x) tmp = (x); \ |
6e5bb5ad JM |
7976 | if (__builtin_types_compatible_p (typeof (x), long double)) \ |
7977 | tmp = foo_long_double (tmp); \ | |
7978 | else if (__builtin_types_compatible_p (typeof (x), double)) \ | |
7979 | tmp = foo_double (tmp); \ | |
7980 | else if (__builtin_types_compatible_p (typeof (x), float)) \ | |
7981 | tmp = foo_float (tmp); \ | |
7982 | else \ | |
7983 | abort (); \ | |
7984 | tmp; \ | |
ecbcf7b3 AH |
7985 | @}) |
7986 | @end smallexample | |
7987 | ||
8a36672b | 7988 | @emph{Note:} This construct is only available for C@. |
ecbcf7b3 AH |
7989 | |
7990 | @end deftypefn | |
7991 | ||
7992 | @deftypefn {Built-in Function} @var{type} __builtin_choose_expr (@var{const_exp}, @var{exp1}, @var{exp2}) | |
7993 | ||
7994 | You can use the built-in function @code{__builtin_choose_expr} to | |
7995 | evaluate code depending on the value of a constant expression. This | |
928c19bb | 7996 | built-in function returns @var{exp1} if @var{const_exp}, which is an |
6cea734d | 7997 | integer constant expression, is nonzero. Otherwise it returns @var{exp2}. |
ecbcf7b3 AH |
7998 | |
7999 | This built-in function is analogous to the @samp{? :} operator in C, | |
8000 | except that the expression returned has its type unaltered by promotion | |
8001 | rules. Also, the built-in function does not evaluate the expression | |
8002 | that was not chosen. For example, if @var{const_exp} evaluates to true, | |
8003 | @var{exp2} is not evaluated even if it has side-effects. | |
8004 | ||
8005 | This built-in function can return an lvalue if the chosen argument is an | |
8006 | lvalue. | |
8007 | ||
8008 | If @var{exp1} is returned, the return type is the same as @var{exp1}'s | |
8009 | type. Similarly, if @var{exp2} is returned, its return type is the same | |
8010 | as @var{exp2}. | |
8011 | ||
8012 | Example: | |
8013 | ||
8014 | @smallexample | |
478c9e72 JJ |
8015 | #define foo(x) \ |
8016 | __builtin_choose_expr ( \ | |
8017 | __builtin_types_compatible_p (typeof (x), double), \ | |
8018 | foo_double (x), \ | |
8019 | __builtin_choose_expr ( \ | |
8020 | __builtin_types_compatible_p (typeof (x), float), \ | |
8021 | foo_float (x), \ | |
8022 | /* @r{The void expression results in a compile-time error} \ | |
8023 | @r{when assigning the result to something.} */ \ | |
ecbcf7b3 AH |
8024 | (void)0)) |
8025 | @end smallexample | |
8026 | ||
8a36672b | 8027 | @emph{Note:} This construct is only available for C@. Furthermore, the |
ecbcf7b3 AH |
8028 | unused expression (@var{exp1} or @var{exp2} depending on the value of |
8029 | @var{const_exp}) may still generate syntax errors. This may change in | |
8030 | future revisions. | |
8031 | ||
8032 | @end deftypefn | |
8033 | ||
d4a83c10 JM |
8034 | @deftypefn {Built-in Function} @var{type} __builtin_complex (@var{real}, @var{imag}) |
8035 | ||
8036 | The built-in function @code{__builtin_complex} is provided for use in | |
48b0b196 | 8037 | implementing the ISO C11 macros @code{CMPLXF}, @code{CMPLX} and |
d4a83c10 JM |
8038 | @code{CMPLXL}. @var{real} and @var{imag} must have the same type, a |
8039 | real binary floating-point type, and the result has the corresponding | |
8040 | complex type with real and imaginary parts @var{real} and @var{imag}. | |
8041 | Unlike @samp{@var{real} + I * @var{imag}}, this works even when | |
8042 | infinities, NaNs and negative zeros are involved. | |
8043 | ||
8044 | @end deftypefn | |
8045 | ||
84330467 JM |
8046 | @deftypefn {Built-in Function} int __builtin_constant_p (@var{exp}) |
8047 | You can use the built-in function @code{__builtin_constant_p} to | |
185ebd6c | 8048 | determine if a value is known to be constant at compile-time and hence |
f0523f02 | 8049 | that GCC can perform constant-folding on expressions involving that |
185ebd6c RH |
8050 | value. The argument of the function is the value to test. The function |
8051 | returns the integer 1 if the argument is known to be a compile-time | |
8052 | constant and 0 if it is not known to be a compile-time constant. A | |
8053 | return of 0 does not indicate that the value is @emph{not} a constant, | |
f0523f02 | 8054 | but merely that GCC cannot prove it is a constant with the specified |
84330467 | 8055 | value of the @option{-O} option. |
185ebd6c RH |
8056 | |
8057 | You would typically use this function in an embedded application where | |
8058 | memory was a critical resource. If you have some complex calculation, | |
8059 | you may want it to be folded if it involves constants, but need to call | |
8060 | a function if it does not. For example: | |
8061 | ||
4d390518 | 8062 | @smallexample |
310668e8 JM |
8063 | #define Scale_Value(X) \ |
8064 | (__builtin_constant_p (X) \ | |
8065 | ? ((X) * SCALE + OFFSET) : Scale (X)) | |
185ebd6c RH |
8066 | @end smallexample |
8067 | ||
84330467 | 8068 | You may use this built-in function in either a macro or an inline |
185ebd6c | 8069 | function. However, if you use it in an inlined function and pass an |
f0523f02 | 8070 | argument of the function as the argument to the built-in, GCC will |
185ebd6c | 8071 | never return 1 when you call the inline function with a string constant |
4b404517 | 8072 | or compound literal (@pxref{Compound Literals}) and will not return 1 |
185ebd6c | 8073 | when you pass a constant numeric value to the inline function unless you |
84330467 | 8074 | specify the @option{-O} option. |
13104975 ZW |
8075 | |
8076 | You may also use @code{__builtin_constant_p} in initializers for static | |
8077 | data. For instance, you can write | |
8078 | ||
8079 | @smallexample | |
79323c50 | 8080 | static const int table[] = @{ |
13104975 | 8081 | __builtin_constant_p (EXPRESSION) ? (EXPRESSION) : -1, |
0d893a63 | 8082 | /* @r{@dots{}} */ |
79323c50 | 8083 | @}; |
13104975 ZW |
8084 | @end smallexample |
8085 | ||
8086 | @noindent | |
8087 | This is an acceptable initializer even if @var{EXPRESSION} is not a | |
928c19bb JM |
8088 | constant expression, including the case where |
8089 | @code{__builtin_constant_p} returns 1 because @var{EXPRESSION} can be | |
8090 | folded to a constant but @var{EXPRESSION} contains operands that would | |
c782f1dd | 8091 | not otherwise be permitted in a static initializer (for example, |
928c19bb | 8092 | @code{0 && foo ()}). GCC must be more conservative about evaluating the |
13104975 ZW |
8093 | built-in in this case, because it has no opportunity to perform |
8094 | optimization. | |
8095 | ||
8096 | Previous versions of GCC did not accept this built-in in data | |
8097 | initializers. The earliest version where it is completely safe is | |
8098 | 3.0.1. | |
84330467 | 8099 | @end deftypefn |
185ebd6c | 8100 | |
84330467 JM |
8101 | @deftypefn {Built-in Function} long __builtin_expect (long @var{exp}, long @var{c}) |
8102 | @opindex fprofile-arcs | |
02f52e19 | 8103 | You may use @code{__builtin_expect} to provide the compiler with |
994a57cd | 8104 | branch prediction information. In general, you should prefer to |
84330467 | 8105 | use actual profile feedback for this (@option{-fprofile-arcs}), as |
994a57cd | 8106 | programmers are notoriously bad at predicting how their programs |
60b6e1f5 | 8107 | actually perform. However, there are applications in which this |
994a57cd RH |
8108 | data is hard to collect. |
8109 | ||
ef950eba JH |
8110 | The return value is the value of @var{exp}, which should be an integral |
8111 | expression. The semantics of the built-in are that it is expected that | |
8112 | @var{exp} == @var{c}. For example: | |
994a57cd RH |
8113 | |
8114 | @smallexample | |
8115 | if (__builtin_expect (x, 0)) | |
8116 | foo (); | |
8117 | @end smallexample | |
8118 | ||
8119 | @noindent | |
8120 | would indicate that we do not expect to call @code{foo}, since | |
8121 | we expect @code{x} to be zero. Since you are limited to integral | |
8122 | expressions for @var{exp}, you should use constructions such as | |
8123 | ||
8124 | @smallexample | |
8125 | if (__builtin_expect (ptr != NULL, 1)) | |
e2724fd2 | 8126 | foo (*ptr); |
994a57cd RH |
8127 | @end smallexample |
8128 | ||
8129 | @noindent | |
8130 | when testing pointer or floating-point values. | |
84330467 | 8131 | @end deftypefn |
994a57cd | 8132 | |
a18c20ec AP |
8133 | @deftypefn {Built-in Function} void __builtin_trap (void) |
8134 | This function causes the program to exit abnormally. GCC implements | |
8135 | this function by using a target-dependent mechanism (such as | |
8136 | intentionally executing an illegal instruction) or by calling | |
8137 | @code{abort}. The mechanism used may vary from release to release so | |
8138 | you should not rely on any particular implementation. | |
8139 | @end deftypefn | |
8140 | ||
468059bc DD |
8141 | @deftypefn {Built-in Function} void __builtin_unreachable (void) |
8142 | If control flow reaches the point of the @code{__builtin_unreachable}, | |
8143 | the program is undefined. It is useful in situations where the | |
8144 | compiler cannot deduce the unreachability of the code. | |
8145 | ||
8146 | One such case is immediately following an @code{asm} statement that | |
8147 | will either never terminate, or one that transfers control elsewhere | |
8148 | and never returns. In this example, without the | |
8149 | @code{__builtin_unreachable}, GCC would issue a warning that control | |
8150 | reaches the end of a non-void function. It would also generate code | |
8151 | to return after the @code{asm}. | |
8152 | ||
8153 | @smallexample | |
8154 | int f (int c, int v) | |
8155 | @{ | |
8156 | if (c) | |
8157 | @{ | |
8158 | return v; | |
8159 | @} | |
8160 | else | |
8161 | @{ | |
8162 | asm("jmp error_handler"); | |
8163 | __builtin_unreachable (); | |
8164 | @} | |
8165 | @} | |
8166 | @end smallexample | |
8167 | ||
8168 | Because the @code{asm} statement unconditionally transfers control out | |
8169 | of the function, control will never reach the end of the function | |
8170 | body. The @code{__builtin_unreachable} is in fact unreachable and | |
8171 | communicates this fact to the compiler. | |
8172 | ||
8173 | Another use for @code{__builtin_unreachable} is following a call a | |
8174 | function that never returns but that is not declared | |
8175 | @code{__attribute__((noreturn))}, as in this example: | |
8176 | ||
8177 | @smallexample | |
8178 | void function_that_never_returns (void); | |
8179 | ||
8180 | int g (int c) | |
8181 | @{ | |
8182 | if (c) | |
8183 | @{ | |
8184 | return 1; | |
8185 | @} | |
8186 | else | |
8187 | @{ | |
8188 | function_that_never_returns (); | |
8189 | __builtin_unreachable (); | |
8190 | @} | |
8191 | @} | |
8192 | @end smallexample | |
8193 | ||
8194 | @end deftypefn | |
8195 | ||
45d439ac JJ |
8196 | @deftypefn {Built-in Function} void *__builtin_assume_aligned (const void *@var{exp}, size_t @var{align}, ...) |
8197 | This function returns its first argument, and allows the compiler | |
8198 | to assume that the returned pointer is at least @var{align} bytes | |
8199 | aligned. This built-in can have either two or three arguments, | |
8200 | if it has three, the third argument should have integer type, and | |
8201 | if it is non-zero means misalignment offset. For example: | |
8202 | ||
8203 | @smallexample | |
8204 | void *x = __builtin_assume_aligned (arg, 16); | |
8205 | @end smallexample | |
8206 | ||
8207 | means that the compiler can assume x, set to arg, is at least | |
8208 | 16 byte aligned, while: | |
8209 | ||
8210 | @smallexample | |
8211 | void *x = __builtin_assume_aligned (arg, 32, 8); | |
8212 | @end smallexample | |
8213 | ||
8214 | means that the compiler can assume for x, set to arg, that | |
8215 | (char *) x - 8 is 32 byte aligned. | |
8216 | @end deftypefn | |
8217 | ||
677feb77 DD |
8218 | @deftypefn {Built-in Function} void __builtin___clear_cache (char *@var{begin}, char *@var{end}) |
8219 | This function is used to flush the processor's instruction cache for | |
8220 | the region of memory between @var{begin} inclusive and @var{end} | |
8221 | exclusive. Some targets require that the instruction cache be | |
8222 | flushed, after modifying memory containing code, in order to obtain | |
8223 | deterministic behavior. | |
8224 | ||
8225 | If the target does not require instruction cache flushes, | |
8226 | @code{__builtin___clear_cache} has no effect. Otherwise either | |
8227 | instructions are emitted in-line to clear the instruction cache or a | |
8228 | call to the @code{__clear_cache} function in libgcc is made. | |
8229 | @end deftypefn | |
8230 | ||
3bca17dd | 8231 | @deftypefn {Built-in Function} void __builtin_prefetch (const void *@var{addr}, ...) |
a9ccbb60 JJ |
8232 | This function is used to minimize cache-miss latency by moving data into |
8233 | a cache before it is accessed. | |
8234 | You can insert calls to @code{__builtin_prefetch} into code for which | |
8235 | you know addresses of data in memory that is likely to be accessed soon. | |
8236 | If the target supports them, data prefetch instructions will be generated. | |
8237 | If the prefetch is done early enough before the access then the data will | |
8238 | be in the cache by the time it is accessed. | |
8239 | ||
8240 | The value of @var{addr} is the address of the memory to prefetch. | |
e83d297b | 8241 | There are two optional arguments, @var{rw} and @var{locality}. |
a9ccbb60 | 8242 | The value of @var{rw} is a compile-time constant one or zero; one |
e83d297b JJ |
8243 | means that the prefetch is preparing for a write to the memory address |
8244 | and zero, the default, means that the prefetch is preparing for a read. | |
a9ccbb60 JJ |
8245 | The value @var{locality} must be a compile-time constant integer between |
8246 | zero and three. A value of zero means that the data has no temporal | |
8247 | locality, so it need not be left in the cache after the access. A value | |
8248 | of three means that the data has a high degree of temporal locality and | |
8249 | should be left in all levels of cache possible. Values of one and two | |
e83d297b JJ |
8250 | mean, respectively, a low or moderate degree of temporal locality. The |
8251 | default is three. | |
a9ccbb60 JJ |
8252 | |
8253 | @smallexample | |
8254 | for (i = 0; i < n; i++) | |
8255 | @{ | |
8256 | a[i] = a[i] + b[i]; | |
8257 | __builtin_prefetch (&a[i+j], 1, 1); | |
8258 | __builtin_prefetch (&b[i+j], 0, 1); | |
0d893a63 | 8259 | /* @r{@dots{}} */ |
a9ccbb60 JJ |
8260 | @} |
8261 | @end smallexample | |
8262 | ||
f282ffb3 | 8263 | Data prefetch does not generate faults if @var{addr} is invalid, but |
a9ccbb60 JJ |
8264 | the address expression itself must be valid. For example, a prefetch |
8265 | of @code{p->next} will not fault if @code{p->next} is not a valid | |
8266 | address, but evaluation will fault if @code{p} is not a valid address. | |
8267 | ||
8268 | If the target does not support data prefetch, the address expression | |
8269 | is evaluated if it includes side effects but no other code is generated | |
8270 | and GCC does not issue a warning. | |
8271 | @end deftypefn | |
8272 | ||
ab5e2615 RH |
8273 | @deftypefn {Built-in Function} double __builtin_huge_val (void) |
8274 | Returns a positive infinity, if supported by the floating-point format, | |
8275 | else @code{DBL_MAX}. This function is suitable for implementing the | |
8276 | ISO C macro @code{HUGE_VAL}. | |
8277 | @end deftypefn | |
8278 | ||
8279 | @deftypefn {Built-in Function} float __builtin_huge_valf (void) | |
8280 | Similar to @code{__builtin_huge_val}, except the return type is @code{float}. | |
8281 | @end deftypefn | |
8282 | ||
dad78426 | 8283 | @deftypefn {Built-in Function} {long double} __builtin_huge_vall (void) |
ab5e2615 RH |
8284 | Similar to @code{__builtin_huge_val}, except the return |
8285 | type is @code{long double}. | |
8286 | @end deftypefn | |
8287 | ||
3bf5906b KG |
8288 | @deftypefn {Built-in Function} int __builtin_fpclassify (int, int, int, int, int, ...) |
8289 | This built-in implements the C99 fpclassify functionality. The first | |
8290 | five int arguments should be the target library's notion of the | |
8291 | possible FP classes and are used for return values. They must be | |
8292 | constant values and they must appear in this order: @code{FP_NAN}, | |
32101f99 | 8293 | @code{FP_INFINITE}, @code{FP_NORMAL}, @code{FP_SUBNORMAL} and |
3bf5906b KG |
8294 | @code{FP_ZERO}. The ellipsis is for exactly one floating point value |
8295 | to classify. GCC treats the last argument as type-generic, which | |
8296 | means it does not do default promotion from float to double. | |
8297 | @end deftypefn | |
8298 | ||
ab5e2615 RH |
8299 | @deftypefn {Built-in Function} double __builtin_inf (void) |
8300 | Similar to @code{__builtin_huge_val}, except a warning is generated | |
8301 | if the target floating-point format does not support infinities. | |
ab5e2615 RH |
8302 | @end deftypefn |
8303 | ||
9a8ce21f JG |
8304 | @deftypefn {Built-in Function} _Decimal32 __builtin_infd32 (void) |
8305 | Similar to @code{__builtin_inf}, except the return type is @code{_Decimal32}. | |
8306 | @end deftypefn | |
8307 | ||
8308 | @deftypefn {Built-in Function} _Decimal64 __builtin_infd64 (void) | |
8309 | Similar to @code{__builtin_inf}, except the return type is @code{_Decimal64}. | |
8310 | @end deftypefn | |
8311 | ||
8312 | @deftypefn {Built-in Function} _Decimal128 __builtin_infd128 (void) | |
8313 | Similar to @code{__builtin_inf}, except the return type is @code{_Decimal128}. | |
8314 | @end deftypefn | |
8315 | ||
ab5e2615 RH |
8316 | @deftypefn {Built-in Function} float __builtin_inff (void) |
8317 | Similar to @code{__builtin_inf}, except the return type is @code{float}. | |
9c86fc0b | 8318 | This function is suitable for implementing the ISO C99 macro @code{INFINITY}. |
ab5e2615 RH |
8319 | @end deftypefn |
8320 | ||
dad78426 | 8321 | @deftypefn {Built-in Function} {long double} __builtin_infl (void) |
ab5e2615 RH |
8322 | Similar to @code{__builtin_inf}, except the return |
8323 | type is @code{long double}. | |
8324 | @end deftypefn | |
8325 | ||
05f41289 KG |
8326 | @deftypefn {Built-in Function} int __builtin_isinf_sign (...) |
8327 | Similar to @code{isinf}, except the return value will be negative for | |
8328 | an argument of @code{-Inf}. Note while the parameter list is an | |
8329 | ellipsis, this function only accepts exactly one floating point | |
8330 | argument. GCC treats this parameter as type-generic, which means it | |
8331 | does not do default promotion from float to double. | |
8332 | @end deftypefn | |
8333 | ||
1472e41c RH |
8334 | @deftypefn {Built-in Function} double __builtin_nan (const char *str) |
8335 | This is an implementation of the ISO C99 function @code{nan}. | |
8336 | ||
8337 | Since ISO C99 defines this function in terms of @code{strtod}, which we | |
c0478a66 | 8338 | do not implement, a description of the parsing is in order. The string |
1472e41c RH |
8339 | is parsed as by @code{strtol}; that is, the base is recognized by |
8340 | leading @samp{0} or @samp{0x} prefixes. The number parsed is placed | |
8341 | in the significand such that the least significant bit of the number | |
daf2f129 | 8342 | is at the least significant bit of the significand. The number is |
1472e41c | 8343 | truncated to fit the significand field provided. The significand is |
8a36672b | 8344 | forced to be a quiet NaN@. |
1472e41c | 8345 | |
a7d37464 GK |
8346 | This function, if given a string literal all of which would have been |
8347 | consumed by strtol, is evaluated early enough that it is considered a | |
8348 | compile-time constant. | |
1472e41c RH |
8349 | @end deftypefn |
8350 | ||
9a8ce21f JG |
8351 | @deftypefn {Built-in Function} _Decimal32 __builtin_nand32 (const char *str) |
8352 | Similar to @code{__builtin_nan}, except the return type is @code{_Decimal32}. | |
8353 | @end deftypefn | |
8354 | ||
8355 | @deftypefn {Built-in Function} _Decimal64 __builtin_nand64 (const char *str) | |
8356 | Similar to @code{__builtin_nan}, except the return type is @code{_Decimal64}. | |
8357 | @end deftypefn | |
8358 | ||
8359 | @deftypefn {Built-in Function} _Decimal128 __builtin_nand128 (const char *str) | |
8360 | Similar to @code{__builtin_nan}, except the return type is @code{_Decimal128}. | |
8361 | @end deftypefn | |
8362 | ||
1472e41c RH |
8363 | @deftypefn {Built-in Function} float __builtin_nanf (const char *str) |
8364 | Similar to @code{__builtin_nan}, except the return type is @code{float}. | |
8365 | @end deftypefn | |
8366 | ||
dad78426 | 8367 | @deftypefn {Built-in Function} {long double} __builtin_nanl (const char *str) |
1472e41c RH |
8368 | Similar to @code{__builtin_nan}, except the return type is @code{long double}. |
8369 | @end deftypefn | |
8370 | ||
8371 | @deftypefn {Built-in Function} double __builtin_nans (const char *str) | |
daf2f129 | 8372 | Similar to @code{__builtin_nan}, except the significand is forced |
8a36672b | 8373 | to be a signaling NaN@. The @code{nans} function is proposed by |
aaa67502 | 8374 | @uref{http://www.open-std.org/jtc1/sc22/wg14/www/docs/n965.htm,,WG14 N965}. |
1472e41c RH |
8375 | @end deftypefn |
8376 | ||
8377 | @deftypefn {Built-in Function} float __builtin_nansf (const char *str) | |
8378 | Similar to @code{__builtin_nans}, except the return type is @code{float}. | |
8379 | @end deftypefn | |
8380 | ||
dad78426 | 8381 | @deftypefn {Built-in Function} {long double} __builtin_nansl (const char *str) |
1472e41c RH |
8382 | Similar to @code{__builtin_nans}, except the return type is @code{long double}. |
8383 | @end deftypefn | |
8384 | ||
2928cd7a RH |
8385 | @deftypefn {Built-in Function} int __builtin_ffs (unsigned int x) |
8386 | Returns one plus the index of the least significant 1-bit of @var{x}, or | |
8387 | if @var{x} is zero, returns zero. | |
8388 | @end deftypefn | |
8389 | ||
8390 | @deftypefn {Built-in Function} int __builtin_clz (unsigned int x) | |
8391 | Returns the number of leading 0-bits in @var{x}, starting at the most | |
8392 | significant bit position. If @var{x} is 0, the result is undefined. | |
8393 | @end deftypefn | |
8394 | ||
8395 | @deftypefn {Built-in Function} int __builtin_ctz (unsigned int x) | |
8396 | Returns the number of trailing 0-bits in @var{x}, starting at the least | |
8397 | significant bit position. If @var{x} is 0, the result is undefined. | |
8398 | @end deftypefn | |
8399 | ||
3801c801 BS |
8400 | @deftypefn {Built-in Function} int __builtin_clrsb (int x) |
8401 | Returns the number of leading redundant sign bits in @var{x}, i.e. the | |
8402 | number of bits following the most significant bit which are identical | |
8403 | to it. There are no special cases for 0 or other values. | |
8404 | @end deftypefn | |
8405 | ||
2928cd7a RH |
8406 | @deftypefn {Built-in Function} int __builtin_popcount (unsigned int x) |
8407 | Returns the number of 1-bits in @var{x}. | |
8408 | @end deftypefn | |
8409 | ||
8410 | @deftypefn {Built-in Function} int __builtin_parity (unsigned int x) | |
8a36672b | 8411 | Returns the parity of @var{x}, i.e.@: the number of 1-bits in @var{x} |
2928cd7a RH |
8412 | modulo 2. |
8413 | @end deftypefn | |
8414 | ||
8415 | @deftypefn {Built-in Function} int __builtin_ffsl (unsigned long) | |
8416 | Similar to @code{__builtin_ffs}, except the argument type is | |
8417 | @code{unsigned long}. | |
8418 | @end deftypefn | |
8419 | ||
8420 | @deftypefn {Built-in Function} int __builtin_clzl (unsigned long) | |
8421 | Similar to @code{__builtin_clz}, except the argument type is | |
8422 | @code{unsigned long}. | |
8423 | @end deftypefn | |
8424 | ||
8425 | @deftypefn {Built-in Function} int __builtin_ctzl (unsigned long) | |
8426 | Similar to @code{__builtin_ctz}, except the argument type is | |
8427 | @code{unsigned long}. | |
8428 | @end deftypefn | |
8429 | ||
3801c801 BS |
8430 | @deftypefn {Built-in Function} int __builtin_clrsbl (long) |
8431 | Similar to @code{__builtin_clrsb}, except the argument type is | |
8432 | @code{long}. | |
8433 | @end deftypefn | |
8434 | ||
2928cd7a RH |
8435 | @deftypefn {Built-in Function} int __builtin_popcountl (unsigned long) |
8436 | Similar to @code{__builtin_popcount}, except the argument type is | |
8437 | @code{unsigned long}. | |
8438 | @end deftypefn | |
8439 | ||
8440 | @deftypefn {Built-in Function} int __builtin_parityl (unsigned long) | |
8441 | Similar to @code{__builtin_parity}, except the argument type is | |
8442 | @code{unsigned long}. | |
8443 | @end deftypefn | |
8444 | ||
8445 | @deftypefn {Built-in Function} int __builtin_ffsll (unsigned long long) | |
8446 | Similar to @code{__builtin_ffs}, except the argument type is | |
8447 | @code{unsigned long long}. | |
8448 | @end deftypefn | |
8449 | ||
8450 | @deftypefn {Built-in Function} int __builtin_clzll (unsigned long long) | |
8451 | Similar to @code{__builtin_clz}, except the argument type is | |
8452 | @code{unsigned long long}. | |
8453 | @end deftypefn | |
8454 | ||
8455 | @deftypefn {Built-in Function} int __builtin_ctzll (unsigned long long) | |
8456 | Similar to @code{__builtin_ctz}, except the argument type is | |
8457 | @code{unsigned long long}. | |
8458 | @end deftypefn | |
8459 | ||
3801c801 BS |
8460 | @deftypefn {Built-in Function} int __builtin_clrsbll (long long) |
8461 | Similar to @code{__builtin_clrsb}, except the argument type is | |
8462 | @code{long long}. | |
8463 | @end deftypefn | |
8464 | ||
2928cd7a RH |
8465 | @deftypefn {Built-in Function} int __builtin_popcountll (unsigned long long) |
8466 | Similar to @code{__builtin_popcount}, except the argument type is | |
8467 | @code{unsigned long long}. | |
8468 | @end deftypefn | |
8469 | ||
8470 | @deftypefn {Built-in Function} int __builtin_parityll (unsigned long long) | |
8471 | Similar to @code{__builtin_parity}, except the argument type is | |
8472 | @code{unsigned long long}. | |
8473 | @end deftypefn | |
8474 | ||
17684d46 RG |
8475 | @deftypefn {Built-in Function} double __builtin_powi (double, int) |
8476 | Returns the first argument raised to the power of the second. Unlike the | |
8477 | @code{pow} function no guarantees about precision and rounding are made. | |
8478 | @end deftypefn | |
8479 | ||
8480 | @deftypefn {Built-in Function} float __builtin_powif (float, int) | |
8481 | Similar to @code{__builtin_powi}, except the argument and return types | |
8482 | are @code{float}. | |
8483 | @end deftypefn | |
8484 | ||
8485 | @deftypefn {Built-in Function} {long double} __builtin_powil (long double, int) | |
8486 | Similar to @code{__builtin_powi}, except the argument and return types | |
8487 | are @code{long double}. | |
8488 | @end deftypefn | |
8489 | ||
167fa32c EC |
8490 | @deftypefn {Built-in Function} int32_t __builtin_bswap32 (int32_t x) |
8491 | Returns @var{x} with the order of the bytes reversed; for example, | |
8492 | @code{0xaabbccdd} becomes @code{0xddccbbaa}. Byte here always means | |
8493 | exactly 8 bits. | |
8494 | @end deftypefn | |
8495 | ||
8496 | @deftypefn {Built-in Function} int64_t __builtin_bswap64 (int64_t x) | |
8497 | Similar to @code{__builtin_bswap32}, except the argument and return types | |
8498 | are 64-bit. | |
8499 | @end deftypefn | |
2928cd7a | 8500 | |
0975678f JM |
8501 | @node Target Builtins |
8502 | @section Built-in Functions Specific to Particular Target Machines | |
8503 | ||
8504 | On some target machines, GCC supports many built-in functions specific | |
8505 | to those machines. Generally these generate calls to specific machine | |
8506 | instructions, but allow the compiler to schedule those calls. | |
8507 | ||
8508 | @menu | |
6d8fd7bb | 8509 | * Alpha Built-in Functions:: |
88f77cba JB |
8510 | * ARM iWMMXt Built-in Functions:: |
8511 | * ARM NEON Intrinsics:: | |
43ea6502 | 8512 | * AVR Built-in Functions:: |
161c21b6 | 8513 | * Blackfin Built-in Functions:: |
c3ee0579 | 8514 | * FR-V Built-in Functions:: |
0975678f | 8515 | * X86 Built-in Functions:: |
118ea793 | 8516 | * MIPS DSP Built-in Functions:: |
d840bfd3 | 8517 | * MIPS Paired-Single Support:: |
93581857 | 8518 | * MIPS Loongson Built-in Functions:: |
4d210b07 | 8519 | * Other MIPS Built-in Functions:: |
358da97e | 8520 | * picoChip Built-in Functions:: |
29e6733c | 8521 | * PowerPC AltiVec/VSX Built-in Functions:: |
65a324b4 | 8522 | * RX Built-in Functions:: |
c5145ceb | 8523 | * SPARC VIS Built-in Functions:: |
85d9c13c | 8524 | * SPU Built-in Functions:: |
bcead286 | 8525 | * TI C6X Built-in Functions:: |
0975678f JM |
8526 | @end menu |
8527 | ||
6d8fd7bb RH |
8528 | @node Alpha Built-in Functions |
8529 | @subsection Alpha Built-in Functions | |
8530 | ||
8531 | These built-in functions are available for the Alpha family of | |
8532 | processors, depending on the command-line switches used. | |
8533 | ||
95b1627e | 8534 | The following built-in functions are always available. They |
6d8fd7bb RH |
8535 | all generate the machine instruction that is part of the name. |
8536 | ||
3ab51846 | 8537 | @smallexample |
6d8fd7bb RH |
8538 | long __builtin_alpha_implver (void) |
8539 | long __builtin_alpha_rpcc (void) | |
8540 | long __builtin_alpha_amask (long) | |
8541 | long __builtin_alpha_cmpbge (long, long) | |
c4b50f1a RH |
8542 | long __builtin_alpha_extbl (long, long) |
8543 | long __builtin_alpha_extwl (long, long) | |
8544 | long __builtin_alpha_extll (long, long) | |
6d8fd7bb | 8545 | long __builtin_alpha_extql (long, long) |
c4b50f1a RH |
8546 | long __builtin_alpha_extwh (long, long) |
8547 | long __builtin_alpha_extlh (long, long) | |
6d8fd7bb | 8548 | long __builtin_alpha_extqh (long, long) |
c4b50f1a RH |
8549 | long __builtin_alpha_insbl (long, long) |
8550 | long __builtin_alpha_inswl (long, long) | |
8551 | long __builtin_alpha_insll (long, long) | |
8552 | long __builtin_alpha_insql (long, long) | |
8553 | long __builtin_alpha_inswh (long, long) | |
8554 | long __builtin_alpha_inslh (long, long) | |
8555 | long __builtin_alpha_insqh (long, long) | |
8556 | long __builtin_alpha_mskbl (long, long) | |
8557 | long __builtin_alpha_mskwl (long, long) | |
8558 | long __builtin_alpha_mskll (long, long) | |
8559 | long __builtin_alpha_mskql (long, long) | |
8560 | long __builtin_alpha_mskwh (long, long) | |
8561 | long __builtin_alpha_msklh (long, long) | |
8562 | long __builtin_alpha_mskqh (long, long) | |
8563 | long __builtin_alpha_umulh (long, long) | |
6d8fd7bb RH |
8564 | long __builtin_alpha_zap (long, long) |
8565 | long __builtin_alpha_zapnot (long, long) | |
3ab51846 | 8566 | @end smallexample |
6d8fd7bb RH |
8567 | |
8568 | The following built-in functions are always with @option{-mmax} | |
8569 | or @option{-mcpu=@var{cpu}} where @var{cpu} is @code{pca56} or | |
8570 | later. They all generate the machine instruction that is part | |
8571 | of the name. | |
8572 | ||
3ab51846 | 8573 | @smallexample |
6d8fd7bb RH |
8574 | long __builtin_alpha_pklb (long) |
8575 | long __builtin_alpha_pkwb (long) | |
8576 | long __builtin_alpha_unpkbl (long) | |
8577 | long __builtin_alpha_unpkbw (long) | |
8578 | long __builtin_alpha_minub8 (long, long) | |
8579 | long __builtin_alpha_minsb8 (long, long) | |
8580 | long __builtin_alpha_minuw4 (long, long) | |
8581 | long __builtin_alpha_minsw4 (long, long) | |
8582 | long __builtin_alpha_maxub8 (long, long) | |
8583 | long __builtin_alpha_maxsb8 (long, long) | |
8584 | long __builtin_alpha_maxuw4 (long, long) | |
8585 | long __builtin_alpha_maxsw4 (long, long) | |
8586 | long __builtin_alpha_perr (long, long) | |
3ab51846 | 8587 | @end smallexample |
6d8fd7bb | 8588 | |
c4b50f1a RH |
8589 | The following built-in functions are always with @option{-mcix} |
8590 | or @option{-mcpu=@var{cpu}} where @var{cpu} is @code{ev67} or | |
8591 | later. They all generate the machine instruction that is part | |
8592 | of the name. | |
8593 | ||
3ab51846 | 8594 | @smallexample |
c4b50f1a RH |
8595 | long __builtin_alpha_cttz (long) |
8596 | long __builtin_alpha_ctlz (long) | |
8597 | long __builtin_alpha_ctpop (long) | |
3ab51846 | 8598 | @end smallexample |
c4b50f1a | 8599 | |
116b7a5e RH |
8600 | The following builtins are available on systems that use the OSF/1 |
8601 | PALcode. Normally they invoke the @code{rduniq} and @code{wruniq} | |
8602 | PAL calls, but when invoked with @option{-mtls-kernel}, they invoke | |
8603 | @code{rdval} and @code{wrval}. | |
8604 | ||
3ab51846 | 8605 | @smallexample |
116b7a5e RH |
8606 | void *__builtin_thread_pointer (void) |
8607 | void __builtin_set_thread_pointer (void *) | |
3ab51846 | 8608 | @end smallexample |
116b7a5e | 8609 | |
88f77cba JB |
8610 | @node ARM iWMMXt Built-in Functions |
8611 | @subsection ARM iWMMXt Built-in Functions | |
4bc73018 NC |
8612 | |
8613 | These built-in functions are available for the ARM family of | |
88f77cba | 8614 | processors when the @option{-mcpu=iwmmxt} switch is used: |
4bc73018 | 8615 | |
3ab51846 | 8616 | @smallexample |
d63851eb ILT |
8617 | typedef int v2si __attribute__ ((vector_size (8))); |
8618 | typedef short v4hi __attribute__ ((vector_size (8))); | |
8619 | typedef char v8qi __attribute__ ((vector_size (8))); | |
8620 | ||
8621 | int __builtin_arm_getwcx (int) | |
8622 | void __builtin_arm_setwcx (int, int) | |
8623 | int __builtin_arm_textrmsb (v8qi, int) | |
8624 | int __builtin_arm_textrmsh (v4hi, int) | |
8625 | int __builtin_arm_textrmsw (v2si, int) | |
8626 | int __builtin_arm_textrmub (v8qi, int) | |
8627 | int __builtin_arm_textrmuh (v4hi, int) | |
8628 | int __builtin_arm_textrmuw (v2si, int) | |
8629 | v8qi __builtin_arm_tinsrb (v8qi, int) | |
8630 | v4hi __builtin_arm_tinsrh (v4hi, int) | |
8631 | v2si __builtin_arm_tinsrw (v2si, int) | |
8632 | long long __builtin_arm_tmia (long long, int, int) | |
8633 | long long __builtin_arm_tmiabb (long long, int, int) | |
8634 | long long __builtin_arm_tmiabt (long long, int, int) | |
8635 | long long __builtin_arm_tmiaph (long long, int, int) | |
8636 | long long __builtin_arm_tmiatb (long long, int, int) | |
8637 | long long __builtin_arm_tmiatt (long long, int, int) | |
8638 | int __builtin_arm_tmovmskb (v8qi) | |
8639 | int __builtin_arm_tmovmskh (v4hi) | |
8640 | int __builtin_arm_tmovmskw (v2si) | |
8641 | long long __builtin_arm_waccb (v8qi) | |
8642 | long long __builtin_arm_wacch (v4hi) | |
8643 | long long __builtin_arm_waccw (v2si) | |
8644 | v8qi __builtin_arm_waddb (v8qi, v8qi) | |
8645 | v8qi __builtin_arm_waddbss (v8qi, v8qi) | |
8646 | v8qi __builtin_arm_waddbus (v8qi, v8qi) | |
8647 | v4hi __builtin_arm_waddh (v4hi, v4hi) | |
8648 | v4hi __builtin_arm_waddhss (v4hi, v4hi) | |
8649 | v4hi __builtin_arm_waddhus (v4hi, v4hi) | |
4bc73018 | 8650 | v2si __builtin_arm_waddw (v2si, v2si) |
4bc73018 | 8651 | v2si __builtin_arm_waddwss (v2si, v2si) |
4bc73018 | 8652 | v2si __builtin_arm_waddwus (v2si, v2si) |
d63851eb ILT |
8653 | v8qi __builtin_arm_walign (v8qi, v8qi, int) |
8654 | long long __builtin_arm_wand(long long, long long) | |
8655 | long long __builtin_arm_wandn (long long, long long) | |
8656 | v8qi __builtin_arm_wavg2b (v8qi, v8qi) | |
8657 | v8qi __builtin_arm_wavg2br (v8qi, v8qi) | |
8658 | v4hi __builtin_arm_wavg2h (v4hi, v4hi) | |
8659 | v4hi __builtin_arm_wavg2hr (v4hi, v4hi) | |
8660 | v8qi __builtin_arm_wcmpeqb (v8qi, v8qi) | |
8661 | v4hi __builtin_arm_wcmpeqh (v4hi, v4hi) | |
4bc73018 | 8662 | v2si __builtin_arm_wcmpeqw (v2si, v2si) |
d63851eb ILT |
8663 | v8qi __builtin_arm_wcmpgtsb (v8qi, v8qi) |
8664 | v4hi __builtin_arm_wcmpgtsh (v4hi, v4hi) | |
4bc73018 | 8665 | v2si __builtin_arm_wcmpgtsw (v2si, v2si) |
d63851eb ILT |
8666 | v8qi __builtin_arm_wcmpgtub (v8qi, v8qi) |
8667 | v4hi __builtin_arm_wcmpgtuh (v4hi, v4hi) | |
8668 | v2si __builtin_arm_wcmpgtuw (v2si, v2si) | |
8669 | long long __builtin_arm_wmacs (long long, v4hi, v4hi) | |
8670 | long long __builtin_arm_wmacsz (v4hi, v4hi) | |
8671 | long long __builtin_arm_wmacu (long long, v4hi, v4hi) | |
8672 | long long __builtin_arm_wmacuz (v4hi, v4hi) | |
8673 | v4hi __builtin_arm_wmadds (v4hi, v4hi) | |
8674 | v4hi __builtin_arm_wmaddu (v4hi, v4hi) | |
8675 | v8qi __builtin_arm_wmaxsb (v8qi, v8qi) | |
8676 | v4hi __builtin_arm_wmaxsh (v4hi, v4hi) | |
4bc73018 | 8677 | v2si __builtin_arm_wmaxsw (v2si, v2si) |
d63851eb ILT |
8678 | v8qi __builtin_arm_wmaxub (v8qi, v8qi) |
8679 | v4hi __builtin_arm_wmaxuh (v4hi, v4hi) | |
4bc73018 | 8680 | v2si __builtin_arm_wmaxuw (v2si, v2si) |
d63851eb ILT |
8681 | v8qi __builtin_arm_wminsb (v8qi, v8qi) |
8682 | v4hi __builtin_arm_wminsh (v4hi, v4hi) | |
4bc73018 | 8683 | v2si __builtin_arm_wminsw (v2si, v2si) |
d63851eb ILT |
8684 | v8qi __builtin_arm_wminub (v8qi, v8qi) |
8685 | v4hi __builtin_arm_wminuh (v4hi, v4hi) | |
4bc73018 | 8686 | v2si __builtin_arm_wminuw (v2si, v2si) |
d63851eb ILT |
8687 | v4hi __builtin_arm_wmulsm (v4hi, v4hi) |
8688 | v4hi __builtin_arm_wmulul (v4hi, v4hi) | |
8689 | v4hi __builtin_arm_wmulum (v4hi, v4hi) | |
8690 | long long __builtin_arm_wor (long long, long long) | |
8691 | v2si __builtin_arm_wpackdss (long long, long long) | |
8692 | v2si __builtin_arm_wpackdus (long long, long long) | |
8693 | v8qi __builtin_arm_wpackhss (v4hi, v4hi) | |
8694 | v8qi __builtin_arm_wpackhus (v4hi, v4hi) | |
8695 | v4hi __builtin_arm_wpackwss (v2si, v2si) | |
8696 | v4hi __builtin_arm_wpackwus (v2si, v2si) | |
8697 | long long __builtin_arm_wrord (long long, long long) | |
8698 | long long __builtin_arm_wrordi (long long, int) | |
8699 | v4hi __builtin_arm_wrorh (v4hi, long long) | |
8700 | v4hi __builtin_arm_wrorhi (v4hi, int) | |
8701 | v2si __builtin_arm_wrorw (v2si, long long) | |
8702 | v2si __builtin_arm_wrorwi (v2si, int) | |
8703 | v2si __builtin_arm_wsadb (v8qi, v8qi) | |
8704 | v2si __builtin_arm_wsadbz (v8qi, v8qi) | |
8705 | v2si __builtin_arm_wsadh (v4hi, v4hi) | |
8706 | v2si __builtin_arm_wsadhz (v4hi, v4hi) | |
8707 | v4hi __builtin_arm_wshufh (v4hi, int) | |
8708 | long long __builtin_arm_wslld (long long, long long) | |
8709 | long long __builtin_arm_wslldi (long long, int) | |
8710 | v4hi __builtin_arm_wsllh (v4hi, long long) | |
8711 | v4hi __builtin_arm_wsllhi (v4hi, int) | |
8712 | v2si __builtin_arm_wsllw (v2si, long long) | |
4bc73018 | 8713 | v2si __builtin_arm_wsllwi (v2si, int) |
d63851eb ILT |
8714 | long long __builtin_arm_wsrad (long long, long long) |
8715 | long long __builtin_arm_wsradi (long long, int) | |
8716 | v4hi __builtin_arm_wsrah (v4hi, long long) | |
8717 | v4hi __builtin_arm_wsrahi (v4hi, int) | |
8718 | v2si __builtin_arm_wsraw (v2si, long long) | |
4bc73018 | 8719 | v2si __builtin_arm_wsrawi (v2si, int) |
d63851eb ILT |
8720 | long long __builtin_arm_wsrld (long long, long long) |
8721 | long long __builtin_arm_wsrldi (long long, int) | |
8722 | v4hi __builtin_arm_wsrlh (v4hi, long long) | |
8723 | v4hi __builtin_arm_wsrlhi (v4hi, int) | |
8724 | v2si __builtin_arm_wsrlw (v2si, long long) | |
4bc73018 | 8725 | v2si __builtin_arm_wsrlwi (v2si, int) |
d63851eb ILT |
8726 | v8qi __builtin_arm_wsubb (v8qi, v8qi) |
8727 | v8qi __builtin_arm_wsubbss (v8qi, v8qi) | |
8728 | v8qi __builtin_arm_wsubbus (v8qi, v8qi) | |
8729 | v4hi __builtin_arm_wsubh (v4hi, v4hi) | |
8730 | v4hi __builtin_arm_wsubhss (v4hi, v4hi) | |
8731 | v4hi __builtin_arm_wsubhus (v4hi, v4hi) | |
8732 | v2si __builtin_arm_wsubw (v2si, v2si) | |
8733 | v2si __builtin_arm_wsubwss (v2si, v2si) | |
8734 | v2si __builtin_arm_wsubwus (v2si, v2si) | |
8735 | v4hi __builtin_arm_wunpckehsb (v8qi) | |
8736 | v2si __builtin_arm_wunpckehsh (v4hi) | |
8737 | long long __builtin_arm_wunpckehsw (v2si) | |
8738 | v4hi __builtin_arm_wunpckehub (v8qi) | |
8739 | v2si __builtin_arm_wunpckehuh (v4hi) | |
8740 | long long __builtin_arm_wunpckehuw (v2si) | |
8741 | v4hi __builtin_arm_wunpckelsb (v8qi) | |
8742 | v2si __builtin_arm_wunpckelsh (v4hi) | |
8743 | long long __builtin_arm_wunpckelsw (v2si) | |
8744 | v4hi __builtin_arm_wunpckelub (v8qi) | |
8745 | v2si __builtin_arm_wunpckeluh (v4hi) | |
8746 | long long __builtin_arm_wunpckeluw (v2si) | |
8747 | v8qi __builtin_arm_wunpckihb (v8qi, v8qi) | |
8748 | v4hi __builtin_arm_wunpckihh (v4hi, v4hi) | |
4bc73018 | 8749 | v2si __builtin_arm_wunpckihw (v2si, v2si) |
d63851eb ILT |
8750 | v8qi __builtin_arm_wunpckilb (v8qi, v8qi) |
8751 | v4hi __builtin_arm_wunpckilh (v4hi, v4hi) | |
4bc73018 | 8752 | v2si __builtin_arm_wunpckilw (v2si, v2si) |
d63851eb ILT |
8753 | long long __builtin_arm_wxor (long long, long long) |
8754 | long long __builtin_arm_wzero () | |
3ab51846 | 8755 | @end smallexample |
4bc73018 | 8756 | |
88f77cba JB |
8757 | @node ARM NEON Intrinsics |
8758 | @subsection ARM NEON Intrinsics | |
8759 | ||
8760 | These built-in intrinsics for the ARM Advanced SIMD extension are available | |
8761 | when the @option{-mfpu=neon} switch is used: | |
8762 | ||
8763 | @include arm-neon-intrinsics.texi | |
8764 | ||
43ea6502 AS |
8765 | @node AVR Built-in Functions |
8766 | @subsection AVR Built-in Functions | |
8767 | ||
8768 | For each built-in function for AVR, there is an equally named, | |
8769 | uppercase built-in macro defined. That way users can easily query if | |
8770 | or if not a specific built-in is implemented or not. For example, if | |
8771 | @code{__builtin_avr_nop} is available the macro | |
8772 | @code{__BUILTIN_AVR_NOP} is defined to @code{1} and undefined otherwise. | |
8773 | ||
8774 | The following built-in functions map to the respective machine | |
8775 | instruction, i.e. @code{nop}, @code{sei}, @code{cli}, @code{sleep}, | |
8776 | @code{wdr}, @code{swap}, @code{fmul}, @code{fmuls} | |
f451d14d GJL |
8777 | resp. @code{fmulsu}. The three @code{fmul*} built-ins are implemented |
8778 | as library call if no hardware multiplier is available. | |
43ea6502 AS |
8779 | |
8780 | @smallexample | |
8781 | void __builtin_avr_nop (void) | |
8782 | void __builtin_avr_sei (void) | |
8783 | void __builtin_avr_cli (void) | |
8784 | void __builtin_avr_sleep (void) | |
8785 | void __builtin_avr_wdr (void) | |
8786 | unsigned char __builtin_avr_swap (unsigned char) | |
8787 | unsigned int __builtin_avr_fmul (unsigned char, unsigned char) | |
8788 | int __builtin_avr_fmuls (char, char) | |
8789 | int __builtin_avr_fmulsu (char, unsigned char) | |
8790 | @end smallexample | |
8791 | ||
8792 | In order to delay execution for a specific number of cycles, GCC | |
8793 | implements | |
8794 | @smallexample | |
8795 | void __builtin_avr_delay_cycles (unsigned long ticks) | |
8796 | @end smallexample | |
8797 | ||
49b2772e | 8798 | @noindent |
43ea6502 AS |
8799 | @code{ticks} is the number of ticks to delay execution. Note that this |
8800 | built-in does not take into account the effect of interrupts which | |
8801 | might increase delay time. @code{ticks} must be a compile time | |
8802 | integer constant; delays with a variable number of cycles are not supported. | |
8803 | ||
49b2772e GJL |
8804 | @smallexample |
8805 | unsigned char __builtin_avr_map8 (unsigned long map, unsigned char val) | |
8806 | @end smallexample | |
8807 | ||
8808 | @noindent | |
8809 | Each bit of the result is copied from a specific bit of @code{val}. | |
8810 | @code{map} is a compile time constant that represents a map composed | |
8811 | of 8 nibbles (4-bit groups): | |
8812 | The @var{n}-th nibble of @code{map} specifies which bit of @code{val} | |
8813 | is to be moved to the @var{n}-th bit of the result. | |
8814 | For example, @code{map = 0x76543210} represents identity: The MSB of | |
8815 | the result is read from the 7-th bit of @code{val}, the LSB is | |
8816 | read from the 0-th bit to @code{val}, etc. | |
8817 | Two more examples: @code{0x01234567} reverses the bit order and | |
8818 | @code{0x32107654} is equivalent to a @code{swap} instruction. | |
8819 | ||
8820 | @noindent | |
8821 | One typical use case for this and the following built-in is adjusting input and | |
8822 | output values to non-contiguous port layouts. | |
8823 | ||
8824 | @smallexample | |
8825 | unsigned int __builtin_avr_map16 (unsigned long long map, unsigned int val) | |
8826 | @end smallexample | |
8827 | ||
8828 | @noindent | |
8829 | Similar to the previous built-in except that it operates on @code{int} | |
8830 | and thus 16 bits are involved. Again, @code{map} must be a compile | |
8831 | time constant. | |
8832 | ||
161c21b6 BS |
8833 | @node Blackfin Built-in Functions |
8834 | @subsection Blackfin Built-in Functions | |
8835 | ||
8836 | Currently, there are two Blackfin-specific built-in functions. These are | |
8837 | used for generating @code{CSYNC} and @code{SSYNC} machine insns without | |
8838 | using inline assembly; by using these built-in functions the compiler can | |
8839 | automatically add workarounds for hardware errata involving these | |
8840 | instructions. These functions are named as follows: | |
8841 | ||
8842 | @smallexample | |
8843 | void __builtin_bfin_csync (void) | |
8844 | void __builtin_bfin_ssync (void) | |
8845 | @end smallexample | |
8846 | ||
c3ee0579 RS |
8847 | @node FR-V Built-in Functions |
8848 | @subsection FR-V Built-in Functions | |
8849 | ||
8850 | GCC provides many FR-V-specific built-in functions. In general, | |
8851 | these functions are intended to be compatible with those described | |
8852 | by @cite{FR-V Family, Softune C/C++ Compiler Manual (V6), Fujitsu | |
8853 | Semiconductor}. The two exceptions are @code{__MDUNPACKH} and | |
8854 | @code{__MBTOHE}, the gcc forms of which pass 128-bit values by | |
8855 | pointer rather than by value. | |
8856 | ||
8857 | Most of the functions are named after specific FR-V instructions. | |
27ef2cdd | 8858 | Such functions are said to be ``directly mapped'' and are summarized |
c3ee0579 RS |
8859 | here in tabular form. |
8860 | ||
8861 | @menu | |
8862 | * Argument Types:: | |
8863 | * Directly-mapped Integer Functions:: | |
8864 | * Directly-mapped Media Functions:: | |
c14ff86e | 8865 | * Raw read/write Functions:: |
c3ee0579 RS |
8866 | * Other Built-in Functions:: |
8867 | @end menu | |
8868 | ||
8869 | @node Argument Types | |
8870 | @subsubsection Argument Types | |
8871 | ||
8872 | The arguments to the built-in functions can be divided into three groups: | |
8873 | register numbers, compile-time constants and run-time values. In order | |
8874 | to make this classification clear at a glance, the arguments and return | |
8875 | values are given the following pseudo types: | |
8876 | ||
8877 | @multitable @columnfractions .20 .30 .15 .35 | |
8878 | @item Pseudo type @tab Real C type @tab Constant? @tab Description | |
8879 | @item @code{uh} @tab @code{unsigned short} @tab No @tab an unsigned halfword | |
8880 | @item @code{uw1} @tab @code{unsigned int} @tab No @tab an unsigned word | |
8881 | @item @code{sw1} @tab @code{int} @tab No @tab a signed word | |
8882 | @item @code{uw2} @tab @code{unsigned long long} @tab No | |
8883 | @tab an unsigned doubleword | |
8884 | @item @code{sw2} @tab @code{long long} @tab No @tab a signed doubleword | |
8885 | @item @code{const} @tab @code{int} @tab Yes @tab an integer constant | |
8886 | @item @code{acc} @tab @code{int} @tab Yes @tab an ACC register number | |
8887 | @item @code{iacc} @tab @code{int} @tab Yes @tab an IACC register number | |
8888 | @end multitable | |
8889 | ||
8890 | These pseudo types are not defined by GCC, they are simply a notational | |
8891 | convenience used in this manual. | |
8892 | ||
8893 | Arguments of type @code{uh}, @code{uw1}, @code{sw1}, @code{uw2} | |
8894 | and @code{sw2} are evaluated at run time. They correspond to | |
8895 | register operands in the underlying FR-V instructions. | |
8896 | ||
8897 | @code{const} arguments represent immediate operands in the underlying | |
8898 | FR-V instructions. They must be compile-time constants. | |
8899 | ||
8900 | @code{acc} arguments are evaluated at compile time and specify the number | |
8901 | of an accumulator register. For example, an @code{acc} argument of 2 | |
8902 | will select the ACC2 register. | |
8903 | ||
8904 | @code{iacc} arguments are similar to @code{acc} arguments but specify the | |
8905 | number of an IACC register. See @pxref{Other Built-in Functions} | |
8906 | for more details. | |
8907 | ||
8908 | @node Directly-mapped Integer Functions | |
8909 | @subsubsection Directly-mapped Integer Functions | |
8910 | ||
8911 | The functions listed below map directly to FR-V I-type instructions. | |
8912 | ||
8913 | @multitable @columnfractions .45 .32 .23 | |
8914 | @item Function prototype @tab Example usage @tab Assembly output | |
8915 | @item @code{sw1 __ADDSS (sw1, sw1)} | |
8916 | @tab @code{@var{c} = __ADDSS (@var{a}, @var{b})} | |
8917 | @tab @code{ADDSS @var{a},@var{b},@var{c}} | |
8918 | @item @code{sw1 __SCAN (sw1, sw1)} | |
8919 | @tab @code{@var{c} = __SCAN (@var{a}, @var{b})} | |
8920 | @tab @code{SCAN @var{a},@var{b},@var{c}} | |
8921 | @item @code{sw1 __SCUTSS (sw1)} | |
8922 | @tab @code{@var{b} = __SCUTSS (@var{a})} | |
8923 | @tab @code{SCUTSS @var{a},@var{b}} | |
8924 | @item @code{sw1 __SLASS (sw1, sw1)} | |
8925 | @tab @code{@var{c} = __SLASS (@var{a}, @var{b})} | |
8926 | @tab @code{SLASS @var{a},@var{b},@var{c}} | |
8927 | @item @code{void __SMASS (sw1, sw1)} | |
8928 | @tab @code{__SMASS (@var{a}, @var{b})} | |
8929 | @tab @code{SMASS @var{a},@var{b}} | |
8930 | @item @code{void __SMSSS (sw1, sw1)} | |
8931 | @tab @code{__SMSSS (@var{a}, @var{b})} | |
8932 | @tab @code{SMSSS @var{a},@var{b}} | |
8933 | @item @code{void __SMU (sw1, sw1)} | |
8934 | @tab @code{__SMU (@var{a}, @var{b})} | |
8935 | @tab @code{SMU @var{a},@var{b}} | |
8936 | @item @code{sw2 __SMUL (sw1, sw1)} | |
8937 | @tab @code{@var{c} = __SMUL (@var{a}, @var{b})} | |
8938 | @tab @code{SMUL @var{a},@var{b},@var{c}} | |
8939 | @item @code{sw1 __SUBSS (sw1, sw1)} | |
8940 | @tab @code{@var{c} = __SUBSS (@var{a}, @var{b})} | |
8941 | @tab @code{SUBSS @var{a},@var{b},@var{c}} | |
8942 | @item @code{uw2 __UMUL (uw1, uw1)} | |
8943 | @tab @code{@var{c} = __UMUL (@var{a}, @var{b})} | |
8944 | @tab @code{UMUL @var{a},@var{b},@var{c}} | |
8945 | @end multitable | |
8946 | ||
8947 | @node Directly-mapped Media Functions | |
8948 | @subsubsection Directly-mapped Media Functions | |
8949 | ||
8950 | The functions listed below map directly to FR-V M-type instructions. | |
8951 | ||
8952 | @multitable @columnfractions .45 .32 .23 | |
8953 | @item Function prototype @tab Example usage @tab Assembly output | |
8954 | @item @code{uw1 __MABSHS (sw1)} | |
8955 | @tab @code{@var{b} = __MABSHS (@var{a})} | |
8956 | @tab @code{MABSHS @var{a},@var{b}} | |
8957 | @item @code{void __MADDACCS (acc, acc)} | |
8958 | @tab @code{__MADDACCS (@var{b}, @var{a})} | |
8959 | @tab @code{MADDACCS @var{a},@var{b}} | |
8960 | @item @code{sw1 __MADDHSS (sw1, sw1)} | |
8961 | @tab @code{@var{c} = __MADDHSS (@var{a}, @var{b})} | |
8962 | @tab @code{MADDHSS @var{a},@var{b},@var{c}} | |
8963 | @item @code{uw1 __MADDHUS (uw1, uw1)} | |
8964 | @tab @code{@var{c} = __MADDHUS (@var{a}, @var{b})} | |
8965 | @tab @code{MADDHUS @var{a},@var{b},@var{c}} | |
8966 | @item @code{uw1 __MAND (uw1, uw1)} | |
8967 | @tab @code{@var{c} = __MAND (@var{a}, @var{b})} | |
8968 | @tab @code{MAND @var{a},@var{b},@var{c}} | |
8969 | @item @code{void __MASACCS (acc, acc)} | |
8970 | @tab @code{__MASACCS (@var{b}, @var{a})} | |
8971 | @tab @code{MASACCS @var{a},@var{b}} | |
8972 | @item @code{uw1 __MAVEH (uw1, uw1)} | |
8973 | @tab @code{@var{c} = __MAVEH (@var{a}, @var{b})} | |
8974 | @tab @code{MAVEH @var{a},@var{b},@var{c}} | |
8975 | @item @code{uw2 __MBTOH (uw1)} | |
8976 | @tab @code{@var{b} = __MBTOH (@var{a})} | |
8977 | @tab @code{MBTOH @var{a},@var{b}} | |
8978 | @item @code{void __MBTOHE (uw1 *, uw1)} | |
8979 | @tab @code{__MBTOHE (&@var{b}, @var{a})} | |
8980 | @tab @code{MBTOHE @var{a},@var{b}} | |
8981 | @item @code{void __MCLRACC (acc)} | |
8982 | @tab @code{__MCLRACC (@var{a})} | |
8983 | @tab @code{MCLRACC @var{a}} | |
8984 | @item @code{void __MCLRACCA (void)} | |
8985 | @tab @code{__MCLRACCA ()} | |
8986 | @tab @code{MCLRACCA} | |
8987 | @item @code{uw1 __Mcop1 (uw1, uw1)} | |
8988 | @tab @code{@var{c} = __Mcop1 (@var{a}, @var{b})} | |
8989 | @tab @code{Mcop1 @var{a},@var{b},@var{c}} | |
8990 | @item @code{uw1 __Mcop2 (uw1, uw1)} | |
8991 | @tab @code{@var{c} = __Mcop2 (@var{a}, @var{b})} | |
8992 | @tab @code{Mcop2 @var{a},@var{b},@var{c}} | |
8993 | @item @code{uw1 __MCPLHI (uw2, const)} | |
8994 | @tab @code{@var{c} = __MCPLHI (@var{a}, @var{b})} | |
8995 | @tab @code{MCPLHI @var{a},#@var{b},@var{c}} | |
8996 | @item @code{uw1 __MCPLI (uw2, const)} | |
8997 | @tab @code{@var{c} = __MCPLI (@var{a}, @var{b})} | |
8998 | @tab @code{MCPLI @var{a},#@var{b},@var{c}} | |
8999 | @item @code{void __MCPXIS (acc, sw1, sw1)} | |
9000 | @tab @code{__MCPXIS (@var{c}, @var{a}, @var{b})} | |
9001 | @tab @code{MCPXIS @var{a},@var{b},@var{c}} | |
9002 | @item @code{void __MCPXIU (acc, uw1, uw1)} | |
9003 | @tab @code{__MCPXIU (@var{c}, @var{a}, @var{b})} | |
9004 | @tab @code{MCPXIU @var{a},@var{b},@var{c}} | |
9005 | @item @code{void __MCPXRS (acc, sw1, sw1)} | |
9006 | @tab @code{__MCPXRS (@var{c}, @var{a}, @var{b})} | |
9007 | @tab @code{MCPXRS @var{a},@var{b},@var{c}} | |
9008 | @item @code{void __MCPXRU (acc, uw1, uw1)} | |
9009 | @tab @code{__MCPXRU (@var{c}, @var{a}, @var{b})} | |
9010 | @tab @code{MCPXRU @var{a},@var{b},@var{c}} | |
9011 | @item @code{uw1 __MCUT (acc, uw1)} | |
9012 | @tab @code{@var{c} = __MCUT (@var{a}, @var{b})} | |
9013 | @tab @code{MCUT @var{a},@var{b},@var{c}} | |
9014 | @item @code{uw1 __MCUTSS (acc, sw1)} | |
9015 | @tab @code{@var{c} = __MCUTSS (@var{a}, @var{b})} | |
9016 | @tab @code{MCUTSS @var{a},@var{b},@var{c}} | |
9017 | @item @code{void __MDADDACCS (acc, acc)} | |
9018 | @tab @code{__MDADDACCS (@var{b}, @var{a})} | |
9019 | @tab @code{MDADDACCS @var{a},@var{b}} | |
9020 | @item @code{void __MDASACCS (acc, acc)} | |
9021 | @tab @code{__MDASACCS (@var{b}, @var{a})} | |
9022 | @tab @code{MDASACCS @var{a},@var{b}} | |
9023 | @item @code{uw2 __MDCUTSSI (acc, const)} | |
9024 | @tab @code{@var{c} = __MDCUTSSI (@var{a}, @var{b})} | |
9025 | @tab @code{MDCUTSSI @var{a},#@var{b},@var{c}} | |
9026 | @item @code{uw2 __MDPACKH (uw2, uw2)} | |
9027 | @tab @code{@var{c} = __MDPACKH (@var{a}, @var{b})} | |
9028 | @tab @code{MDPACKH @var{a},@var{b},@var{c}} | |
9029 | @item @code{uw2 __MDROTLI (uw2, const)} | |
9030 | @tab @code{@var{c} = __MDROTLI (@var{a}, @var{b})} | |
9031 | @tab @code{MDROTLI @var{a},#@var{b},@var{c}} | |
9032 | @item @code{void __MDSUBACCS (acc, acc)} | |
9033 | @tab @code{__MDSUBACCS (@var{b}, @var{a})} | |
9034 | @tab @code{MDSUBACCS @var{a},@var{b}} | |
9035 | @item @code{void __MDUNPACKH (uw1 *, uw2)} | |
9036 | @tab @code{__MDUNPACKH (&@var{b}, @var{a})} | |
9037 | @tab @code{MDUNPACKH @var{a},@var{b}} | |
9038 | @item @code{uw2 __MEXPDHD (uw1, const)} | |
9039 | @tab @code{@var{c} = __MEXPDHD (@var{a}, @var{b})} | |
9040 | @tab @code{MEXPDHD @var{a},#@var{b},@var{c}} | |
9041 | @item @code{uw1 __MEXPDHW (uw1, const)} | |
9042 | @tab @code{@var{c} = __MEXPDHW (@var{a}, @var{b})} | |
9043 | @tab @code{MEXPDHW @var{a},#@var{b},@var{c}} | |
9044 | @item @code{uw1 __MHDSETH (uw1, const)} | |
9045 | @tab @code{@var{c} = __MHDSETH (@var{a}, @var{b})} | |
9046 | @tab @code{MHDSETH @var{a},#@var{b},@var{c}} | |
9047 | @item @code{sw1 __MHDSETS (const)} | |
9048 | @tab @code{@var{b} = __MHDSETS (@var{a})} | |
9049 | @tab @code{MHDSETS #@var{a},@var{b}} | |
9050 | @item @code{uw1 __MHSETHIH (uw1, const)} | |
9051 | @tab @code{@var{b} = __MHSETHIH (@var{b}, @var{a})} | |
9052 | @tab @code{MHSETHIH #@var{a},@var{b}} | |
9053 | @item @code{sw1 __MHSETHIS (sw1, const)} | |
9054 | @tab @code{@var{b} = __MHSETHIS (@var{b}, @var{a})} | |
9055 | @tab @code{MHSETHIS #@var{a},@var{b}} | |
9056 | @item @code{uw1 __MHSETLOH (uw1, const)} | |
9057 | @tab @code{@var{b} = __MHSETLOH (@var{b}, @var{a})} | |
9058 | @tab @code{MHSETLOH #@var{a},@var{b}} | |
9059 | @item @code{sw1 __MHSETLOS (sw1, const)} | |
9060 | @tab @code{@var{b} = __MHSETLOS (@var{b}, @var{a})} | |
9061 | @tab @code{MHSETLOS #@var{a},@var{b}} | |
9062 | @item @code{uw1 __MHTOB (uw2)} | |
9063 | @tab @code{@var{b} = __MHTOB (@var{a})} | |
9064 | @tab @code{MHTOB @var{a},@var{b}} | |
9065 | @item @code{void __MMACHS (acc, sw1, sw1)} | |
9066 | @tab @code{__MMACHS (@var{c}, @var{a}, @var{b})} | |
9067 | @tab @code{MMACHS @var{a},@var{b},@var{c}} | |
9068 | @item @code{void __MMACHU (acc, uw1, uw1)} | |
9069 | @tab @code{__MMACHU (@var{c}, @var{a}, @var{b})} | |
9070 | @tab @code{MMACHU @var{a},@var{b},@var{c}} | |
9071 | @item @code{void __MMRDHS (acc, sw1, sw1)} | |
9072 | @tab @code{__MMRDHS (@var{c}, @var{a}, @var{b})} | |
9073 | @tab @code{MMRDHS @var{a},@var{b},@var{c}} | |
9074 | @item @code{void __MMRDHU (acc, uw1, uw1)} | |
9075 | @tab @code{__MMRDHU (@var{c}, @var{a}, @var{b})} | |
9076 | @tab @code{MMRDHU @var{a},@var{b},@var{c}} | |
9077 | @item @code{void __MMULHS (acc, sw1, sw1)} | |
9078 | @tab @code{__MMULHS (@var{c}, @var{a}, @var{b})} | |
9079 | @tab @code{MMULHS @var{a},@var{b},@var{c}} | |
9080 | @item @code{void __MMULHU (acc, uw1, uw1)} | |
9081 | @tab @code{__MMULHU (@var{c}, @var{a}, @var{b})} | |
9082 | @tab @code{MMULHU @var{a},@var{b},@var{c}} | |
9083 | @item @code{void __MMULXHS (acc, sw1, sw1)} | |
9084 | @tab @code{__MMULXHS (@var{c}, @var{a}, @var{b})} | |
9085 | @tab @code{MMULXHS @var{a},@var{b},@var{c}} | |
9086 | @item @code{void __MMULXHU (acc, uw1, uw1)} | |
9087 | @tab @code{__MMULXHU (@var{c}, @var{a}, @var{b})} | |
9088 | @tab @code{MMULXHU @var{a},@var{b},@var{c}} | |
9089 | @item @code{uw1 __MNOT (uw1)} | |
9090 | @tab @code{@var{b} = __MNOT (@var{a})} | |
9091 | @tab @code{MNOT @var{a},@var{b}} | |
9092 | @item @code{uw1 __MOR (uw1, uw1)} | |
9093 | @tab @code{@var{c} = __MOR (@var{a}, @var{b})} | |
9094 | @tab @code{MOR @var{a},@var{b},@var{c}} | |
9095 | @item @code{uw1 __MPACKH (uh, uh)} | |
9096 | @tab @code{@var{c} = __MPACKH (@var{a}, @var{b})} | |
9097 | @tab @code{MPACKH @var{a},@var{b},@var{c}} | |
9098 | @item @code{sw2 __MQADDHSS (sw2, sw2)} | |
9099 | @tab @code{@var{c} = __MQADDHSS (@var{a}, @var{b})} | |
9100 | @tab @code{MQADDHSS @var{a},@var{b},@var{c}} | |
9101 | @item @code{uw2 __MQADDHUS (uw2, uw2)} | |
9102 | @tab @code{@var{c} = __MQADDHUS (@var{a}, @var{b})} | |
9103 | @tab @code{MQADDHUS @var{a},@var{b},@var{c}} | |
9104 | @item @code{void __MQCPXIS (acc, sw2, sw2)} | |
9105 | @tab @code{__MQCPXIS (@var{c}, @var{a}, @var{b})} | |
9106 | @tab @code{MQCPXIS @var{a},@var{b},@var{c}} | |
9107 | @item @code{void __MQCPXIU (acc, uw2, uw2)} | |
9108 | @tab @code{__MQCPXIU (@var{c}, @var{a}, @var{b})} | |
9109 | @tab @code{MQCPXIU @var{a},@var{b},@var{c}} | |
9110 | @item @code{void __MQCPXRS (acc, sw2, sw2)} | |
9111 | @tab @code{__MQCPXRS (@var{c}, @var{a}, @var{b})} | |
9112 | @tab @code{MQCPXRS @var{a},@var{b},@var{c}} | |
9113 | @item @code{void __MQCPXRU (acc, uw2, uw2)} | |
9114 | @tab @code{__MQCPXRU (@var{c}, @var{a}, @var{b})} | |
9115 | @tab @code{MQCPXRU @var{a},@var{b},@var{c}} | |
9116 | @item @code{sw2 __MQLCLRHS (sw2, sw2)} | |
9117 | @tab @code{@var{c} = __MQLCLRHS (@var{a}, @var{b})} | |
9118 | @tab @code{MQLCLRHS @var{a},@var{b},@var{c}} | |
9119 | @item @code{sw2 __MQLMTHS (sw2, sw2)} | |
9120 | @tab @code{@var{c} = __MQLMTHS (@var{a}, @var{b})} | |
9121 | @tab @code{MQLMTHS @var{a},@var{b},@var{c}} | |
9122 | @item @code{void __MQMACHS (acc, sw2, sw2)} | |
9123 | @tab @code{__MQMACHS (@var{c}, @var{a}, @var{b})} | |
9124 | @tab @code{MQMACHS @var{a},@var{b},@var{c}} | |
9125 | @item @code{void __MQMACHU (acc, uw2, uw2)} | |
9126 | @tab @code{__MQMACHU (@var{c}, @var{a}, @var{b})} | |
9127 | @tab @code{MQMACHU @var{a},@var{b},@var{c}} | |
9128 | @item @code{void __MQMACXHS (acc, sw2, sw2)} | |
9129 | @tab @code{__MQMACXHS (@var{c}, @var{a}, @var{b})} | |
9130 | @tab @code{MQMACXHS @var{a},@var{b},@var{c}} | |
9131 | @item @code{void __MQMULHS (acc, sw2, sw2)} | |
9132 | @tab @code{__MQMULHS (@var{c}, @var{a}, @var{b})} | |
9133 | @tab @code{MQMULHS @var{a},@var{b},@var{c}} | |
9134 | @item @code{void __MQMULHU (acc, uw2, uw2)} | |
9135 | @tab @code{__MQMULHU (@var{c}, @var{a}, @var{b})} | |
9136 | @tab @code{MQMULHU @var{a},@var{b},@var{c}} | |
9137 | @item @code{void __MQMULXHS (acc, sw2, sw2)} | |
9138 | @tab @code{__MQMULXHS (@var{c}, @var{a}, @var{b})} | |
9139 | @tab @code{MQMULXHS @var{a},@var{b},@var{c}} | |
9140 | @item @code{void __MQMULXHU (acc, uw2, uw2)} | |
9141 | @tab @code{__MQMULXHU (@var{c}, @var{a}, @var{b})} | |
9142 | @tab @code{MQMULXHU @var{a},@var{b},@var{c}} | |
9143 | @item @code{sw2 __MQSATHS (sw2, sw2)} | |
9144 | @tab @code{@var{c} = __MQSATHS (@var{a}, @var{b})} | |
9145 | @tab @code{MQSATHS @var{a},@var{b},@var{c}} | |
9146 | @item @code{uw2 __MQSLLHI (uw2, int)} | |
9147 | @tab @code{@var{c} = __MQSLLHI (@var{a}, @var{b})} | |
9148 | @tab @code{MQSLLHI @var{a},@var{b},@var{c}} | |
9149 | @item @code{sw2 __MQSRAHI (sw2, int)} | |
9150 | @tab @code{@var{c} = __MQSRAHI (@var{a}, @var{b})} | |
9151 | @tab @code{MQSRAHI @var{a},@var{b},@var{c}} | |
9152 | @item @code{sw2 __MQSUBHSS (sw2, sw2)} | |
9153 | @tab @code{@var{c} = __MQSUBHSS (@var{a}, @var{b})} | |
9154 | @tab @code{MQSUBHSS @var{a},@var{b},@var{c}} | |
9155 | @item @code{uw2 __MQSUBHUS (uw2, uw2)} | |
9156 | @tab @code{@var{c} = __MQSUBHUS (@var{a}, @var{b})} | |
9157 | @tab @code{MQSUBHUS @var{a},@var{b},@var{c}} | |
9158 | @item @code{void __MQXMACHS (acc, sw2, sw2)} | |
9159 | @tab @code{__MQXMACHS (@var{c}, @var{a}, @var{b})} | |
9160 | @tab @code{MQXMACHS @var{a},@var{b},@var{c}} | |
9161 | @item @code{void __MQXMACXHS (acc, sw2, sw2)} | |
9162 | @tab @code{__MQXMACXHS (@var{c}, @var{a}, @var{b})} | |
9163 | @tab @code{MQXMACXHS @var{a},@var{b},@var{c}} | |
9164 | @item @code{uw1 __MRDACC (acc)} | |
9165 | @tab @code{@var{b} = __MRDACC (@var{a})} | |
9166 | @tab @code{MRDACC @var{a},@var{b}} | |
9167 | @item @code{uw1 __MRDACCG (acc)} | |
9168 | @tab @code{@var{b} = __MRDACCG (@var{a})} | |
9169 | @tab @code{MRDACCG @var{a},@var{b}} | |
9170 | @item @code{uw1 __MROTLI (uw1, const)} | |
9171 | @tab @code{@var{c} = __MROTLI (@var{a}, @var{b})} | |
9172 | @tab @code{MROTLI @var{a},#@var{b},@var{c}} | |
9173 | @item @code{uw1 __MROTRI (uw1, const)} | |
9174 | @tab @code{@var{c} = __MROTRI (@var{a}, @var{b})} | |
9175 | @tab @code{MROTRI @var{a},#@var{b},@var{c}} | |
9176 | @item @code{sw1 __MSATHS (sw1, sw1)} | |
9177 | @tab @code{@var{c} = __MSATHS (@var{a}, @var{b})} | |
9178 | @tab @code{MSATHS @var{a},@var{b},@var{c}} | |
9179 | @item @code{uw1 __MSATHU (uw1, uw1)} | |
9180 | @tab @code{@var{c} = __MSATHU (@var{a}, @var{b})} | |
9181 | @tab @code{MSATHU @var{a},@var{b},@var{c}} | |
9182 | @item @code{uw1 __MSLLHI (uw1, const)} | |
9183 | @tab @code{@var{c} = __MSLLHI (@var{a}, @var{b})} | |
9184 | @tab @code{MSLLHI @var{a},#@var{b},@var{c}} | |
9185 | @item @code{sw1 __MSRAHI (sw1, const)} | |
9186 | @tab @code{@var{c} = __MSRAHI (@var{a}, @var{b})} | |
9187 | @tab @code{MSRAHI @var{a},#@var{b},@var{c}} | |
9188 | @item @code{uw1 __MSRLHI (uw1, const)} | |
9189 | @tab @code{@var{c} = __MSRLHI (@var{a}, @var{b})} | |
9190 | @tab @code{MSRLHI @var{a},#@var{b},@var{c}} | |
9191 | @item @code{void __MSUBACCS (acc, acc)} | |
9192 | @tab @code{__MSUBACCS (@var{b}, @var{a})} | |
9193 | @tab @code{MSUBACCS @var{a},@var{b}} | |
9194 | @item @code{sw1 __MSUBHSS (sw1, sw1)} | |
9195 | @tab @code{@var{c} = __MSUBHSS (@var{a}, @var{b})} | |
9196 | @tab @code{MSUBHSS @var{a},@var{b},@var{c}} | |
9197 | @item @code{uw1 __MSUBHUS (uw1, uw1)} | |
9198 | @tab @code{@var{c} = __MSUBHUS (@var{a}, @var{b})} | |
9199 | @tab @code{MSUBHUS @var{a},@var{b},@var{c}} | |
9200 | @item @code{void __MTRAP (void)} | |
9201 | @tab @code{__MTRAP ()} | |
9202 | @tab @code{MTRAP} | |
9203 | @item @code{uw2 __MUNPACKH (uw1)} | |
9204 | @tab @code{@var{b} = __MUNPACKH (@var{a})} | |
9205 | @tab @code{MUNPACKH @var{a},@var{b}} | |
9206 | @item @code{uw1 __MWCUT (uw2, uw1)} | |
9207 | @tab @code{@var{c} = __MWCUT (@var{a}, @var{b})} | |
9208 | @tab @code{MWCUT @var{a},@var{b},@var{c}} | |
9209 | @item @code{void __MWTACC (acc, uw1)} | |
9210 | @tab @code{__MWTACC (@var{b}, @var{a})} | |
9211 | @tab @code{MWTACC @var{a},@var{b}} | |
9212 | @item @code{void __MWTACCG (acc, uw1)} | |
9213 | @tab @code{__MWTACCG (@var{b}, @var{a})} | |
9214 | @tab @code{MWTACCG @var{a},@var{b}} | |
9215 | @item @code{uw1 __MXOR (uw1, uw1)} | |
9216 | @tab @code{@var{c} = __MXOR (@var{a}, @var{b})} | |
9217 | @tab @code{MXOR @var{a},@var{b},@var{c}} | |
9218 | @end multitable | |
9219 | ||
c14ff86e AH |
9220 | @node Raw read/write Functions |
9221 | @subsubsection Raw read/write Functions | |
9222 | ||
9223 | This sections describes built-in functions related to read and write | |
9224 | instructions to access memory. These functions generate | |
9225 | @code{membar} instructions to flush the I/O load and stores where | |
9226 | appropriate, as described in Fujitsu's manual described above. | |
9227 | ||
9228 | @table @code | |
9229 | ||
9230 | @item unsigned char __builtin_read8 (void *@var{data}) | |
9231 | @item unsigned short __builtin_read16 (void *@var{data}) | |
9232 | @item unsigned long __builtin_read32 (void *@var{data}) | |
9233 | @item unsigned long long __builtin_read64 (void *@var{data}) | |
9234 | ||
9235 | @item void __builtin_write8 (void *@var{data}, unsigned char @var{datum}) | |
9236 | @item void __builtin_write16 (void *@var{data}, unsigned short @var{datum}) | |
9237 | @item void __builtin_write32 (void *@var{data}, unsigned long @var{datum}) | |
9238 | @item void __builtin_write64 (void *@var{data}, unsigned long long @var{datum}) | |
9239 | @end table | |
9240 | ||
c3ee0579 RS |
9241 | @node Other Built-in Functions |
9242 | @subsubsection Other Built-in Functions | |
9243 | ||
9244 | This section describes built-in functions that are not named after | |
9245 | a specific FR-V instruction. | |
9246 | ||
9247 | @table @code | |
9248 | @item sw2 __IACCreadll (iacc @var{reg}) | |
9249 | Return the full 64-bit value of IACC0@. The @var{reg} argument is reserved | |
9250 | for future expansion and must be 0. | |
9251 | ||
9252 | @item sw1 __IACCreadl (iacc @var{reg}) | |
9253 | Return the value of IACC0H if @var{reg} is 0 and IACC0L if @var{reg} is 1. | |
9254 | Other values of @var{reg} are rejected as invalid. | |
9255 | ||
9256 | @item void __IACCsetll (iacc @var{reg}, sw2 @var{x}) | |
9257 | Set the full 64-bit value of IACC0 to @var{x}. The @var{reg} argument | |
9258 | is reserved for future expansion and must be 0. | |
9259 | ||
9260 | @item void __IACCsetl (iacc @var{reg}, sw1 @var{x}) | |
9261 | Set IACC0H to @var{x} if @var{reg} is 0 and IACC0L to @var{x} if @var{reg} | |
9262 | is 1. Other values of @var{reg} are rejected as invalid. | |
9263 | ||
9264 | @item void __data_prefetch0 (const void *@var{x}) | |
9265 | Use the @code{dcpl} instruction to load the contents of address @var{x} | |
9266 | into the data cache. | |
9267 | ||
9268 | @item void __data_prefetch (const void *@var{x}) | |
9269 | Use the @code{nldub} instruction to load the contents of address @var{x} | |
9270 | into the data cache. The instruction will be issued in slot I1@. | |
9271 | @end table | |
9272 | ||
0975678f JM |
9273 | @node X86 Built-in Functions |
9274 | @subsection X86 Built-in Functions | |
9275 | ||
9276 | These built-in functions are available for the i386 and x86-64 family | |
9277 | of computers, depending on the command-line switches used. | |
9278 | ||
75576871 BB |
9279 | Note that, if you specify command-line switches such as @option{-msse}, |
9280 | the compiler could use the extended instruction sets even if the built-ins | |
9281 | are not used explicitly in the program. For this reason, applications | |
9282 | which perform runtime CPU detection must compile separate files for each | |
9283 | supported architecture, using the appropriate flags. In particular, | |
9284 | the file containing the CPU detection code should be compiled without | |
9285 | these options. | |
9286 | ||
0975678f | 9287 | The following machine modes are available for use with MMX built-in functions |
333c8841 AH |
9288 | (@pxref{Vector Extensions}): @code{V2SI} for a vector of two 32-bit integers, |
9289 | @code{V4HI} for a vector of four 16-bit integers, and @code{V8QI} for a | |
9290 | vector of eight 8-bit integers. Some of the built-in functions operate on | |
75d8b30e | 9291 | MMX registers as a whole 64-bit entity, these use @code{V1DI} as their mode. |
0975678f | 9292 | |
f8723eb6 | 9293 | If 3DNow!@: extensions are enabled, @code{V2SF} is used as a mode for a vector |
333c8841 | 9294 | of two 32-bit floating point values. |
0975678f | 9295 | |
333c8841 AH |
9296 | If SSE extensions are enabled, @code{V4SF} is used for a vector of four 32-bit |
9297 | floating point values. Some instructions use a vector of four 32-bit | |
0975678f | 9298 | integers, these use @code{V4SI}. Finally, some instructions operate on an |
333c8841 | 9299 | entire vector register, interpreting it as a 128-bit integer, these use mode |
0975678f JM |
9300 | @code{TI}. |
9301 | ||
27f56cb1 | 9302 | In 64-bit mode, the x86-64 family of processors uses additional built-in |
5513e239 UB |
9303 | functions for efficient use of @code{TF} (@code{__float128}) 128-bit |
9304 | floating point and @code{TC} 128-bit complex floating point values. | |
9305 | ||
27f56cb1 GP |
9306 | The following floating point built-in functions are available in 64-bit |
9307 | mode. All of them implement the function that is part of the name. | |
5513e239 UB |
9308 | |
9309 | @smallexample | |
9310 | __float128 __builtin_fabsq (__float128) | |
9311 | __float128 __builtin_copysignq (__float128, __float128) | |
9312 | @end smallexample | |
9313 | ||
74838de3 L |
9314 | The following built-in function is always available. |
9315 | ||
9316 | @table @code | |
9317 | @item void __builtin_ia32_pause (void) | |
6c81b2bc L |
9318 | Generates the @code{pause} machine instruction with a compiler memory |
9319 | barrier. | |
74838de3 L |
9320 | @end table |
9321 | ||
5513e239 UB |
9322 | The following floating point built-in functions are made available in the |
9323 | 64-bit mode. | |
9324 | ||
9325 | @table @code | |
9326 | @item __float128 __builtin_infq (void) | |
9327 | Similar to @code{__builtin_inf}, except the return type is @code{__float128}. | |
593812b6 BE |
9328 | @findex __builtin_infq |
9329 | ||
9330 | @item __float128 __builtin_huge_valq (void) | |
9331 | Similar to @code{__builtin_huge_val}, except the return type is @code{__float128}. | |
9332 | @findex __builtin_huge_valq | |
5513e239 UB |
9333 | @end table |
9334 | ||
0975678f JM |
9335 | The following built-in functions are made available by @option{-mmmx}. |
9336 | All of them generate the machine instruction that is part of the name. | |
9337 | ||
3ab51846 | 9338 | @smallexample |
0975678f JM |
9339 | v8qi __builtin_ia32_paddb (v8qi, v8qi) |
9340 | v4hi __builtin_ia32_paddw (v4hi, v4hi) | |
9341 | v2si __builtin_ia32_paddd (v2si, v2si) | |
9342 | v8qi __builtin_ia32_psubb (v8qi, v8qi) | |
9343 | v4hi __builtin_ia32_psubw (v4hi, v4hi) | |
9344 | v2si __builtin_ia32_psubd (v2si, v2si) | |
9345 | v8qi __builtin_ia32_paddsb (v8qi, v8qi) | |
9346 | v4hi __builtin_ia32_paddsw (v4hi, v4hi) | |
9347 | v8qi __builtin_ia32_psubsb (v8qi, v8qi) | |
9348 | v4hi __builtin_ia32_psubsw (v4hi, v4hi) | |
9349 | v8qi __builtin_ia32_paddusb (v8qi, v8qi) | |
9350 | v4hi __builtin_ia32_paddusw (v4hi, v4hi) | |
9351 | v8qi __builtin_ia32_psubusb (v8qi, v8qi) | |
9352 | v4hi __builtin_ia32_psubusw (v4hi, v4hi) | |
9353 | v4hi __builtin_ia32_pmullw (v4hi, v4hi) | |
9354 | v4hi __builtin_ia32_pmulhw (v4hi, v4hi) | |
9355 | di __builtin_ia32_pand (di, di) | |
9356 | di __builtin_ia32_pandn (di,di) | |
9357 | di __builtin_ia32_por (di, di) | |
9358 | di __builtin_ia32_pxor (di, di) | |
9359 | v8qi __builtin_ia32_pcmpeqb (v8qi, v8qi) | |
9360 | v4hi __builtin_ia32_pcmpeqw (v4hi, v4hi) | |
9361 | v2si __builtin_ia32_pcmpeqd (v2si, v2si) | |
9362 | v8qi __builtin_ia32_pcmpgtb (v8qi, v8qi) | |
9363 | v4hi __builtin_ia32_pcmpgtw (v4hi, v4hi) | |
9364 | v2si __builtin_ia32_pcmpgtd (v2si, v2si) | |
9365 | v8qi __builtin_ia32_punpckhbw (v8qi, v8qi) | |
9366 | v4hi __builtin_ia32_punpckhwd (v4hi, v4hi) | |
9367 | v2si __builtin_ia32_punpckhdq (v2si, v2si) | |
9368 | v8qi __builtin_ia32_punpcklbw (v8qi, v8qi) | |
9369 | v4hi __builtin_ia32_punpcklwd (v4hi, v4hi) | |
9370 | v2si __builtin_ia32_punpckldq (v2si, v2si) | |
9371 | v8qi __builtin_ia32_packsswb (v4hi, v4hi) | |
9372 | v4hi __builtin_ia32_packssdw (v2si, v2si) | |
9373 | v8qi __builtin_ia32_packuswb (v4hi, v4hi) | |
10a97ae6 | 9374 | |
52eaae97 UB |
9375 | v4hi __builtin_ia32_psllw (v4hi, v4hi) |
9376 | v2si __builtin_ia32_pslld (v2si, v2si) | |
9377 | v1di __builtin_ia32_psllq (v1di, v1di) | |
9378 | v4hi __builtin_ia32_psrlw (v4hi, v4hi) | |
9379 | v2si __builtin_ia32_psrld (v2si, v2si) | |
9380 | v1di __builtin_ia32_psrlq (v1di, v1di) | |
9381 | v4hi __builtin_ia32_psraw (v4hi, v4hi) | |
9382 | v2si __builtin_ia32_psrad (v2si, v2si) | |
9383 | v4hi __builtin_ia32_psllwi (v4hi, int) | |
9384 | v2si __builtin_ia32_pslldi (v2si, int) | |
9385 | v1di __builtin_ia32_psllqi (v1di, int) | |
9386 | v4hi __builtin_ia32_psrlwi (v4hi, int) | |
9387 | v2si __builtin_ia32_psrldi (v2si, int) | |
9388 | v1di __builtin_ia32_psrlqi (v1di, int) | |
9389 | v4hi __builtin_ia32_psrawi (v4hi, int) | |
9390 | v2si __builtin_ia32_psradi (v2si, int) | |
10a97ae6 | 9391 | |
3ab51846 | 9392 | @end smallexample |
0975678f JM |
9393 | |
9394 | The following built-in functions are made available either with | |
9395 | @option{-msse}, or with a combination of @option{-m3dnow} and | |
9396 | @option{-march=athlon}. All of them generate the machine | |
9397 | instruction that is part of the name. | |
9398 | ||
3ab51846 | 9399 | @smallexample |
0975678f JM |
9400 | v4hi __builtin_ia32_pmulhuw (v4hi, v4hi) |
9401 | v8qi __builtin_ia32_pavgb (v8qi, v8qi) | |
9402 | v4hi __builtin_ia32_pavgw (v4hi, v4hi) | |
ab555a5b | 9403 | v1di __builtin_ia32_psadbw (v8qi, v8qi) |
0975678f JM |
9404 | v8qi __builtin_ia32_pmaxub (v8qi, v8qi) |
9405 | v4hi __builtin_ia32_pmaxsw (v4hi, v4hi) | |
9406 | v8qi __builtin_ia32_pminub (v8qi, v8qi) | |
9407 | v4hi __builtin_ia32_pminsw (v4hi, v4hi) | |
9408 | int __builtin_ia32_pextrw (v4hi, int) | |
9409 | v4hi __builtin_ia32_pinsrw (v4hi, int, int) | |
9410 | int __builtin_ia32_pmovmskb (v8qi) | |
9411 | void __builtin_ia32_maskmovq (v8qi, v8qi, char *) | |
9412 | void __builtin_ia32_movntq (di *, di) | |
9413 | void __builtin_ia32_sfence (void) | |
3ab51846 | 9414 | @end smallexample |
0975678f JM |
9415 | |
9416 | The following built-in functions are available when @option{-msse} is used. | |
9417 | All of them generate the machine instruction that is part of the name. | |
9418 | ||
3ab51846 | 9419 | @smallexample |
0975678f JM |
9420 | int __builtin_ia32_comieq (v4sf, v4sf) |
9421 | int __builtin_ia32_comineq (v4sf, v4sf) | |
9422 | int __builtin_ia32_comilt (v4sf, v4sf) | |
9423 | int __builtin_ia32_comile (v4sf, v4sf) | |
9424 | int __builtin_ia32_comigt (v4sf, v4sf) | |
9425 | int __builtin_ia32_comige (v4sf, v4sf) | |
9426 | int __builtin_ia32_ucomieq (v4sf, v4sf) | |
9427 | int __builtin_ia32_ucomineq (v4sf, v4sf) | |
9428 | int __builtin_ia32_ucomilt (v4sf, v4sf) | |
9429 | int __builtin_ia32_ucomile (v4sf, v4sf) | |
9430 | int __builtin_ia32_ucomigt (v4sf, v4sf) | |
9431 | int __builtin_ia32_ucomige (v4sf, v4sf) | |
9432 | v4sf __builtin_ia32_addps (v4sf, v4sf) | |
9433 | v4sf __builtin_ia32_subps (v4sf, v4sf) | |
9434 | v4sf __builtin_ia32_mulps (v4sf, v4sf) | |
9435 | v4sf __builtin_ia32_divps (v4sf, v4sf) | |
9436 | v4sf __builtin_ia32_addss (v4sf, v4sf) | |
9437 | v4sf __builtin_ia32_subss (v4sf, v4sf) | |
9438 | v4sf __builtin_ia32_mulss (v4sf, v4sf) | |
9439 | v4sf __builtin_ia32_divss (v4sf, v4sf) | |
9440 | v4si __builtin_ia32_cmpeqps (v4sf, v4sf) | |
9441 | v4si __builtin_ia32_cmpltps (v4sf, v4sf) | |
9442 | v4si __builtin_ia32_cmpleps (v4sf, v4sf) | |
9443 | v4si __builtin_ia32_cmpgtps (v4sf, v4sf) | |
9444 | v4si __builtin_ia32_cmpgeps (v4sf, v4sf) | |
9445 | v4si __builtin_ia32_cmpunordps (v4sf, v4sf) | |
9446 | v4si __builtin_ia32_cmpneqps (v4sf, v4sf) | |
9447 | v4si __builtin_ia32_cmpnltps (v4sf, v4sf) | |
9448 | v4si __builtin_ia32_cmpnleps (v4sf, v4sf) | |
9449 | v4si __builtin_ia32_cmpngtps (v4sf, v4sf) | |
9450 | v4si __builtin_ia32_cmpngeps (v4sf, v4sf) | |
9451 | v4si __builtin_ia32_cmpordps (v4sf, v4sf) | |
9452 | v4si __builtin_ia32_cmpeqss (v4sf, v4sf) | |
9453 | v4si __builtin_ia32_cmpltss (v4sf, v4sf) | |
9454 | v4si __builtin_ia32_cmpless (v4sf, v4sf) | |
0975678f JM |
9455 | v4si __builtin_ia32_cmpunordss (v4sf, v4sf) |
9456 | v4si __builtin_ia32_cmpneqss (v4sf, v4sf) | |
9457 | v4si __builtin_ia32_cmpnlts (v4sf, v4sf) | |
9458 | v4si __builtin_ia32_cmpnless (v4sf, v4sf) | |
0975678f JM |
9459 | v4si __builtin_ia32_cmpordss (v4sf, v4sf) |
9460 | v4sf __builtin_ia32_maxps (v4sf, v4sf) | |
9461 | v4sf __builtin_ia32_maxss (v4sf, v4sf) | |
9462 | v4sf __builtin_ia32_minps (v4sf, v4sf) | |
9463 | v4sf __builtin_ia32_minss (v4sf, v4sf) | |
9464 | v4sf __builtin_ia32_andps (v4sf, v4sf) | |
9465 | v4sf __builtin_ia32_andnps (v4sf, v4sf) | |
9466 | v4sf __builtin_ia32_orps (v4sf, v4sf) | |
9467 | v4sf __builtin_ia32_xorps (v4sf, v4sf) | |
9468 | v4sf __builtin_ia32_movss (v4sf, v4sf) | |
9469 | v4sf __builtin_ia32_movhlps (v4sf, v4sf) | |
9470 | v4sf __builtin_ia32_movlhps (v4sf, v4sf) | |
9471 | v4sf __builtin_ia32_unpckhps (v4sf, v4sf) | |
9472 | v4sf __builtin_ia32_unpcklps (v4sf, v4sf) | |
9473 | v4sf __builtin_ia32_cvtpi2ps (v4sf, v2si) | |
9474 | v4sf __builtin_ia32_cvtsi2ss (v4sf, int) | |
9475 | v2si __builtin_ia32_cvtps2pi (v4sf) | |
9476 | int __builtin_ia32_cvtss2si (v4sf) | |
9477 | v2si __builtin_ia32_cvttps2pi (v4sf) | |
9478 | int __builtin_ia32_cvttss2si (v4sf) | |
9479 | v4sf __builtin_ia32_rcpps (v4sf) | |
9480 | v4sf __builtin_ia32_rsqrtps (v4sf) | |
9481 | v4sf __builtin_ia32_sqrtps (v4sf) | |
9482 | v4sf __builtin_ia32_rcpss (v4sf) | |
9483 | v4sf __builtin_ia32_rsqrtss (v4sf) | |
9484 | v4sf __builtin_ia32_sqrtss (v4sf) | |
9485 | v4sf __builtin_ia32_shufps (v4sf, v4sf, int) | |
9486 | void __builtin_ia32_movntps (float *, v4sf) | |
9487 | int __builtin_ia32_movmskps (v4sf) | |
3ab51846 | 9488 | @end smallexample |
0975678f JM |
9489 | |
9490 | The following built-in functions are available when @option{-msse} is used. | |
9491 | ||
9492 | @table @code | |
9493 | @item v4sf __builtin_ia32_loadaps (float *) | |
9494 | Generates the @code{movaps} machine instruction as a load from memory. | |
9495 | @item void __builtin_ia32_storeaps (float *, v4sf) | |
9496 | Generates the @code{movaps} machine instruction as a store to memory. | |
9497 | @item v4sf __builtin_ia32_loadups (float *) | |
9498 | Generates the @code{movups} machine instruction as a load from memory. | |
9499 | @item void __builtin_ia32_storeups (float *, v4sf) | |
9500 | Generates the @code{movups} machine instruction as a store to memory. | |
9501 | @item v4sf __builtin_ia32_loadsss (float *) | |
9502 | Generates the @code{movss} machine instruction as a load from memory. | |
9503 | @item void __builtin_ia32_storess (float *, v4sf) | |
9504 | Generates the @code{movss} machine instruction as a store to memory. | |
bb1418c1 | 9505 | @item v4sf __builtin_ia32_loadhps (v4sf, const v2sf *) |
0975678f | 9506 | Generates the @code{movhps} machine instruction as a load from memory. |
bb1418c1 | 9507 | @item v4sf __builtin_ia32_loadlps (v4sf, const v2sf *) |
0975678f | 9508 | Generates the @code{movlps} machine instruction as a load from memory |
bb1418c1 | 9509 | @item void __builtin_ia32_storehps (v2sf *, v4sf) |
0975678f | 9510 | Generates the @code{movhps} machine instruction as a store to memory. |
bb1418c1 | 9511 | @item void __builtin_ia32_storelps (v2sf *, v4sf) |
0975678f JM |
9512 | Generates the @code{movlps} machine instruction as a store to memory. |
9513 | @end table | |
9514 | ||
d7aa4788 RG |
9515 | The following built-in functions are available when @option{-msse2} is used. |
9516 | All of them generate the machine instruction that is part of the name. | |
9517 | ||
9518 | @smallexample | |
9519 | int __builtin_ia32_comisdeq (v2df, v2df) | |
9520 | int __builtin_ia32_comisdlt (v2df, v2df) | |
9521 | int __builtin_ia32_comisdle (v2df, v2df) | |
9522 | int __builtin_ia32_comisdgt (v2df, v2df) | |
9523 | int __builtin_ia32_comisdge (v2df, v2df) | |
9524 | int __builtin_ia32_comisdneq (v2df, v2df) | |
9525 | int __builtin_ia32_ucomisdeq (v2df, v2df) | |
9526 | int __builtin_ia32_ucomisdlt (v2df, v2df) | |
9527 | int __builtin_ia32_ucomisdle (v2df, v2df) | |
9528 | int __builtin_ia32_ucomisdgt (v2df, v2df) | |
9529 | int __builtin_ia32_ucomisdge (v2df, v2df) | |
9530 | int __builtin_ia32_ucomisdneq (v2df, v2df) | |
9531 | v2df __builtin_ia32_cmpeqpd (v2df, v2df) | |
9532 | v2df __builtin_ia32_cmpltpd (v2df, v2df) | |
9533 | v2df __builtin_ia32_cmplepd (v2df, v2df) | |
9534 | v2df __builtin_ia32_cmpgtpd (v2df, v2df) | |
9535 | v2df __builtin_ia32_cmpgepd (v2df, v2df) | |
9536 | v2df __builtin_ia32_cmpunordpd (v2df, v2df) | |
9537 | v2df __builtin_ia32_cmpneqpd (v2df, v2df) | |
9538 | v2df __builtin_ia32_cmpnltpd (v2df, v2df) | |
9539 | v2df __builtin_ia32_cmpnlepd (v2df, v2df) | |
9540 | v2df __builtin_ia32_cmpngtpd (v2df, v2df) | |
9541 | v2df __builtin_ia32_cmpngepd (v2df, v2df) | |
9542 | v2df __builtin_ia32_cmpordpd (v2df, v2df) | |
9543 | v2df __builtin_ia32_cmpeqsd (v2df, v2df) | |
9544 | v2df __builtin_ia32_cmpltsd (v2df, v2df) | |
9545 | v2df __builtin_ia32_cmplesd (v2df, v2df) | |
9546 | v2df __builtin_ia32_cmpunordsd (v2df, v2df) | |
9547 | v2df __builtin_ia32_cmpneqsd (v2df, v2df) | |
9548 | v2df __builtin_ia32_cmpnltsd (v2df, v2df) | |
9549 | v2df __builtin_ia32_cmpnlesd (v2df, v2df) | |
9550 | v2df __builtin_ia32_cmpordsd (v2df, v2df) | |
9551 | v2di __builtin_ia32_paddq (v2di, v2di) | |
9552 | v2di __builtin_ia32_psubq (v2di, v2di) | |
9553 | v2df __builtin_ia32_addpd (v2df, v2df) | |
9554 | v2df __builtin_ia32_subpd (v2df, v2df) | |
9555 | v2df __builtin_ia32_mulpd (v2df, v2df) | |
9556 | v2df __builtin_ia32_divpd (v2df, v2df) | |
9557 | v2df __builtin_ia32_addsd (v2df, v2df) | |
9558 | v2df __builtin_ia32_subsd (v2df, v2df) | |
9559 | v2df __builtin_ia32_mulsd (v2df, v2df) | |
9560 | v2df __builtin_ia32_divsd (v2df, v2df) | |
9561 | v2df __builtin_ia32_minpd (v2df, v2df) | |
9562 | v2df __builtin_ia32_maxpd (v2df, v2df) | |
9563 | v2df __builtin_ia32_minsd (v2df, v2df) | |
9564 | v2df __builtin_ia32_maxsd (v2df, v2df) | |
9565 | v2df __builtin_ia32_andpd (v2df, v2df) | |
9566 | v2df __builtin_ia32_andnpd (v2df, v2df) | |
9567 | v2df __builtin_ia32_orpd (v2df, v2df) | |
9568 | v2df __builtin_ia32_xorpd (v2df, v2df) | |
9569 | v2df __builtin_ia32_movsd (v2df, v2df) | |
9570 | v2df __builtin_ia32_unpckhpd (v2df, v2df) | |
9571 | v2df __builtin_ia32_unpcklpd (v2df, v2df) | |
9572 | v16qi __builtin_ia32_paddb128 (v16qi, v16qi) | |
9573 | v8hi __builtin_ia32_paddw128 (v8hi, v8hi) | |
9574 | v4si __builtin_ia32_paddd128 (v4si, v4si) | |
9575 | v2di __builtin_ia32_paddq128 (v2di, v2di) | |
9576 | v16qi __builtin_ia32_psubb128 (v16qi, v16qi) | |
9577 | v8hi __builtin_ia32_psubw128 (v8hi, v8hi) | |
9578 | v4si __builtin_ia32_psubd128 (v4si, v4si) | |
9579 | v2di __builtin_ia32_psubq128 (v2di, v2di) | |
9580 | v8hi __builtin_ia32_pmullw128 (v8hi, v8hi) | |
9581 | v8hi __builtin_ia32_pmulhw128 (v8hi, v8hi) | |
9582 | v2di __builtin_ia32_pand128 (v2di, v2di) | |
9583 | v2di __builtin_ia32_pandn128 (v2di, v2di) | |
9584 | v2di __builtin_ia32_por128 (v2di, v2di) | |
9585 | v2di __builtin_ia32_pxor128 (v2di, v2di) | |
9586 | v16qi __builtin_ia32_pavgb128 (v16qi, v16qi) | |
9587 | v8hi __builtin_ia32_pavgw128 (v8hi, v8hi) | |
9588 | v16qi __builtin_ia32_pcmpeqb128 (v16qi, v16qi) | |
9589 | v8hi __builtin_ia32_pcmpeqw128 (v8hi, v8hi) | |
9590 | v4si __builtin_ia32_pcmpeqd128 (v4si, v4si) | |
9591 | v16qi __builtin_ia32_pcmpgtb128 (v16qi, v16qi) | |
9592 | v8hi __builtin_ia32_pcmpgtw128 (v8hi, v8hi) | |
9593 | v4si __builtin_ia32_pcmpgtd128 (v4si, v4si) | |
9594 | v16qi __builtin_ia32_pmaxub128 (v16qi, v16qi) | |
9595 | v8hi __builtin_ia32_pmaxsw128 (v8hi, v8hi) | |
9596 | v16qi __builtin_ia32_pminub128 (v16qi, v16qi) | |
9597 | v8hi __builtin_ia32_pminsw128 (v8hi, v8hi) | |
9598 | v16qi __builtin_ia32_punpckhbw128 (v16qi, v16qi) | |
9599 | v8hi __builtin_ia32_punpckhwd128 (v8hi, v8hi) | |
9600 | v4si __builtin_ia32_punpckhdq128 (v4si, v4si) | |
9601 | v2di __builtin_ia32_punpckhqdq128 (v2di, v2di) | |
9602 | v16qi __builtin_ia32_punpcklbw128 (v16qi, v16qi) | |
9603 | v8hi __builtin_ia32_punpcklwd128 (v8hi, v8hi) | |
9604 | v4si __builtin_ia32_punpckldq128 (v4si, v4si) | |
9605 | v2di __builtin_ia32_punpcklqdq128 (v2di, v2di) | |
1b667c82 L |
9606 | v16qi __builtin_ia32_packsswb128 (v8hi, v8hi) |
9607 | v8hi __builtin_ia32_packssdw128 (v4si, v4si) | |
9608 | v16qi __builtin_ia32_packuswb128 (v8hi, v8hi) | |
d7aa4788 RG |
9609 | v8hi __builtin_ia32_pmulhuw128 (v8hi, v8hi) |
9610 | void __builtin_ia32_maskmovdqu (v16qi, v16qi) | |
9611 | v2df __builtin_ia32_loadupd (double *) | |
9612 | void __builtin_ia32_storeupd (double *, v2df) | |
bb1418c1 L |
9613 | v2df __builtin_ia32_loadhpd (v2df, double const *) |
9614 | v2df __builtin_ia32_loadlpd (v2df, double const *) | |
d7aa4788 RG |
9615 | int __builtin_ia32_movmskpd (v2df) |
9616 | int __builtin_ia32_pmovmskb128 (v16qi) | |
9617 | void __builtin_ia32_movnti (int *, int) | |
f32c951e | 9618 | void __builtin_ia32_movnti64 (long long int *, long long int) |
d7aa4788 RG |
9619 | void __builtin_ia32_movntpd (double *, v2df) |
9620 | void __builtin_ia32_movntdq (v2df *, v2df) | |
9621 | v4si __builtin_ia32_pshufd (v4si, int) | |
9622 | v8hi __builtin_ia32_pshuflw (v8hi, int) | |
9623 | v8hi __builtin_ia32_pshufhw (v8hi, int) | |
9624 | v2di __builtin_ia32_psadbw128 (v16qi, v16qi) | |
9625 | v2df __builtin_ia32_sqrtpd (v2df) | |
9626 | v2df __builtin_ia32_sqrtsd (v2df) | |
9627 | v2df __builtin_ia32_shufpd (v2df, v2df, int) | |
9628 | v2df __builtin_ia32_cvtdq2pd (v4si) | |
9629 | v4sf __builtin_ia32_cvtdq2ps (v4si) | |
9630 | v4si __builtin_ia32_cvtpd2dq (v2df) | |
9631 | v2si __builtin_ia32_cvtpd2pi (v2df) | |
9632 | v4sf __builtin_ia32_cvtpd2ps (v2df) | |
9633 | v4si __builtin_ia32_cvttpd2dq (v2df) | |
9634 | v2si __builtin_ia32_cvttpd2pi (v2df) | |
9635 | v2df __builtin_ia32_cvtpi2pd (v2si) | |
9636 | int __builtin_ia32_cvtsd2si (v2df) | |
9637 | int __builtin_ia32_cvttsd2si (v2df) | |
9638 | long long __builtin_ia32_cvtsd2si64 (v2df) | |
9639 | long long __builtin_ia32_cvttsd2si64 (v2df) | |
9640 | v4si __builtin_ia32_cvtps2dq (v4sf) | |
9641 | v2df __builtin_ia32_cvtps2pd (v4sf) | |
9642 | v4si __builtin_ia32_cvttps2dq (v4sf) | |
9643 | v2df __builtin_ia32_cvtsi2sd (v2df, int) | |
9644 | v2df __builtin_ia32_cvtsi642sd (v2df, long long) | |
9645 | v4sf __builtin_ia32_cvtsd2ss (v4sf, v2df) | |
9646 | v2df __builtin_ia32_cvtss2sd (v2df, v4sf) | |
9647 | void __builtin_ia32_clflush (const void *) | |
9648 | void __builtin_ia32_lfence (void) | |
9649 | void __builtin_ia32_mfence (void) | |
9650 | v16qi __builtin_ia32_loaddqu (const char *) | |
9651 | void __builtin_ia32_storedqu (char *, v16qi) | |
ab555a5b | 9652 | v1di __builtin_ia32_pmuludq (v2si, v2si) |
d7aa4788 | 9653 | v2di __builtin_ia32_pmuludq128 (v4si, v4si) |
52eaae97 UB |
9654 | v8hi __builtin_ia32_psllw128 (v8hi, v8hi) |
9655 | v4si __builtin_ia32_pslld128 (v4si, v4si) | |
9656 | v2di __builtin_ia32_psllq128 (v2di, v2di) | |
9657 | v8hi __builtin_ia32_psrlw128 (v8hi, v8hi) | |
9658 | v4si __builtin_ia32_psrld128 (v4si, v4si) | |
d7aa4788 | 9659 | v2di __builtin_ia32_psrlq128 (v2di, v2di) |
52eaae97 UB |
9660 | v8hi __builtin_ia32_psraw128 (v8hi, v8hi) |
9661 | v4si __builtin_ia32_psrad128 (v4si, v4si) | |
d7aa4788 RG |
9662 | v2di __builtin_ia32_pslldqi128 (v2di, int) |
9663 | v8hi __builtin_ia32_psllwi128 (v8hi, int) | |
9664 | v4si __builtin_ia32_pslldi128 (v4si, int) | |
9665 | v2di __builtin_ia32_psllqi128 (v2di, int) | |
9666 | v2di __builtin_ia32_psrldqi128 (v2di, int) | |
9667 | v8hi __builtin_ia32_psrlwi128 (v8hi, int) | |
9668 | v4si __builtin_ia32_psrldi128 (v4si, int) | |
9669 | v2di __builtin_ia32_psrlqi128 (v2di, int) | |
9670 | v8hi __builtin_ia32_psrawi128 (v8hi, int) | |
9671 | v4si __builtin_ia32_psradi128 (v4si, int) | |
9672 | v4si __builtin_ia32_pmaddwd128 (v8hi, v8hi) | |
b53b23dc | 9673 | v2di __builtin_ia32_movq128 (v2di) |
d7aa4788 RG |
9674 | @end smallexample |
9675 | ||
9e200aaf | 9676 | The following built-in functions are available when @option{-msse3} is used. |
22c7c85e L |
9677 | All of them generate the machine instruction that is part of the name. |
9678 | ||
3ab51846 | 9679 | @smallexample |
22c7c85e | 9680 | v2df __builtin_ia32_addsubpd (v2df, v2df) |
d7aa4788 | 9681 | v4sf __builtin_ia32_addsubps (v4sf, v4sf) |
22c7c85e | 9682 | v2df __builtin_ia32_haddpd (v2df, v2df) |
d7aa4788 | 9683 | v4sf __builtin_ia32_haddps (v4sf, v4sf) |
22c7c85e | 9684 | v2df __builtin_ia32_hsubpd (v2df, v2df) |
d7aa4788 | 9685 | v4sf __builtin_ia32_hsubps (v4sf, v4sf) |
22c7c85e L |
9686 | v16qi __builtin_ia32_lddqu (char const *) |
9687 | void __builtin_ia32_monitor (void *, unsigned int, unsigned int) | |
9688 | v2df __builtin_ia32_movddup (v2df) | |
9689 | v4sf __builtin_ia32_movshdup (v4sf) | |
9690 | v4sf __builtin_ia32_movsldup (v4sf) | |
9691 | void __builtin_ia32_mwait (unsigned int, unsigned int) | |
3ab51846 | 9692 | @end smallexample |
22c7c85e | 9693 | |
9e200aaf | 9694 | The following built-in functions are available when @option{-msse3} is used. |
22c7c85e L |
9695 | |
9696 | @table @code | |
9697 | @item v2df __builtin_ia32_loadddup (double const *) | |
9698 | Generates the @code{movddup} machine instruction as a load from memory. | |
9699 | @end table | |
9700 | ||
b1875f52 L |
9701 | The following built-in functions are available when @option{-mssse3} is used. |
9702 | All of them generate the machine instruction that is part of the name | |
9703 | with MMX registers. | |
9704 | ||
9705 | @smallexample | |
9706 | v2si __builtin_ia32_phaddd (v2si, v2si) | |
9707 | v4hi __builtin_ia32_phaddw (v4hi, v4hi) | |
9708 | v4hi __builtin_ia32_phaddsw (v4hi, v4hi) | |
9709 | v2si __builtin_ia32_phsubd (v2si, v2si) | |
9710 | v4hi __builtin_ia32_phsubw (v4hi, v4hi) | |
9711 | v4hi __builtin_ia32_phsubsw (v4hi, v4hi) | |
1b667c82 | 9712 | v4hi __builtin_ia32_pmaddubsw (v8qi, v8qi) |
b1875f52 L |
9713 | v4hi __builtin_ia32_pmulhrsw (v4hi, v4hi) |
9714 | v8qi __builtin_ia32_pshufb (v8qi, v8qi) | |
9715 | v8qi __builtin_ia32_psignb (v8qi, v8qi) | |
9716 | v2si __builtin_ia32_psignd (v2si, v2si) | |
9717 | v4hi __builtin_ia32_psignw (v4hi, v4hi) | |
99c25ac1 | 9718 | v1di __builtin_ia32_palignr (v1di, v1di, int) |
b1875f52 L |
9719 | v8qi __builtin_ia32_pabsb (v8qi) |
9720 | v2si __builtin_ia32_pabsd (v2si) | |
9721 | v4hi __builtin_ia32_pabsw (v4hi) | |
9722 | @end smallexample | |
9723 | ||
9724 | The following built-in functions are available when @option{-mssse3} is used. | |
9725 | All of them generate the machine instruction that is part of the name | |
9726 | with SSE registers. | |
9727 | ||
9728 | @smallexample | |
9729 | v4si __builtin_ia32_phaddd128 (v4si, v4si) | |
9730 | v8hi __builtin_ia32_phaddw128 (v8hi, v8hi) | |
9731 | v8hi __builtin_ia32_phaddsw128 (v8hi, v8hi) | |
9732 | v4si __builtin_ia32_phsubd128 (v4si, v4si) | |
9733 | v8hi __builtin_ia32_phsubw128 (v8hi, v8hi) | |
9734 | v8hi __builtin_ia32_phsubsw128 (v8hi, v8hi) | |
1b667c82 | 9735 | v8hi __builtin_ia32_pmaddubsw128 (v16qi, v16qi) |
b1875f52 L |
9736 | v8hi __builtin_ia32_pmulhrsw128 (v8hi, v8hi) |
9737 | v16qi __builtin_ia32_pshufb128 (v16qi, v16qi) | |
9738 | v16qi __builtin_ia32_psignb128 (v16qi, v16qi) | |
9739 | v4si __builtin_ia32_psignd128 (v4si, v4si) | |
9740 | v8hi __builtin_ia32_psignw128 (v8hi, v8hi) | |
858e5e79 | 9741 | v2di __builtin_ia32_palignr128 (v2di, v2di, int) |
b1875f52 L |
9742 | v16qi __builtin_ia32_pabsb128 (v16qi) |
9743 | v4si __builtin_ia32_pabsd128 (v4si) | |
9744 | v8hi __builtin_ia32_pabsw128 (v8hi) | |
9745 | @end smallexample | |
9746 | ||
9a5cee02 L |
9747 | The following built-in functions are available when @option{-msse4.1} is |
9748 | used. All of them generate the machine instruction that is part of the | |
9749 | name. | |
9750 | ||
9751 | @smallexample | |
9752 | v2df __builtin_ia32_blendpd (v2df, v2df, const int) | |
9753 | v4sf __builtin_ia32_blendps (v4sf, v4sf, const int) | |
9754 | v2df __builtin_ia32_blendvpd (v2df, v2df, v2df) | |
9755 | v4sf __builtin_ia32_blendvps (v4sf, v4sf, v4sf) | |
291d9a2d | 9756 | v2df __builtin_ia32_dppd (v2df, v2df, const int) |
9a5cee02 L |
9757 | v4sf __builtin_ia32_dpps (v4sf, v4sf, const int) |
9758 | v4sf __builtin_ia32_insertps128 (v4sf, v4sf, const int) | |
9759 | v2di __builtin_ia32_movntdqa (v2di *); | |
9760 | v16qi __builtin_ia32_mpsadbw128 (v16qi, v16qi, const int) | |
9761 | v8hi __builtin_ia32_packusdw128 (v4si, v4si) | |
9762 | v16qi __builtin_ia32_pblendvb128 (v16qi, v16qi, v16qi) | |
9763 | v8hi __builtin_ia32_pblendw128 (v8hi, v8hi, const int) | |
9764 | v2di __builtin_ia32_pcmpeqq (v2di, v2di) | |
9765 | v8hi __builtin_ia32_phminposuw128 (v8hi) | |
9766 | v16qi __builtin_ia32_pmaxsb128 (v16qi, v16qi) | |
9767 | v4si __builtin_ia32_pmaxsd128 (v4si, v4si) | |
9768 | v4si __builtin_ia32_pmaxud128 (v4si, v4si) | |
9769 | v8hi __builtin_ia32_pmaxuw128 (v8hi, v8hi) | |
9770 | v16qi __builtin_ia32_pminsb128 (v16qi, v16qi) | |
9771 | v4si __builtin_ia32_pminsd128 (v4si, v4si) | |
9772 | v4si __builtin_ia32_pminud128 (v4si, v4si) | |
9773 | v8hi __builtin_ia32_pminuw128 (v8hi, v8hi) | |
9774 | v4si __builtin_ia32_pmovsxbd128 (v16qi) | |
9775 | v2di __builtin_ia32_pmovsxbq128 (v16qi) | |
9776 | v8hi __builtin_ia32_pmovsxbw128 (v16qi) | |
9777 | v2di __builtin_ia32_pmovsxdq128 (v4si) | |
9778 | v4si __builtin_ia32_pmovsxwd128 (v8hi) | |
9779 | v2di __builtin_ia32_pmovsxwq128 (v8hi) | |
9780 | v4si __builtin_ia32_pmovzxbd128 (v16qi) | |
9781 | v2di __builtin_ia32_pmovzxbq128 (v16qi) | |
9782 | v8hi __builtin_ia32_pmovzxbw128 (v16qi) | |
9783 | v2di __builtin_ia32_pmovzxdq128 (v4si) | |
9784 | v4si __builtin_ia32_pmovzxwd128 (v8hi) | |
9785 | v2di __builtin_ia32_pmovzxwq128 (v8hi) | |
9786 | v2di __builtin_ia32_pmuldq128 (v4si, v4si) | |
9787 | v4si __builtin_ia32_pmulld128 (v4si, v4si) | |
9788 | int __builtin_ia32_ptestc128 (v2di, v2di) | |
9789 | int __builtin_ia32_ptestnzc128 (v2di, v2di) | |
9790 | int __builtin_ia32_ptestz128 (v2di, v2di) | |
9791 | v2df __builtin_ia32_roundpd (v2df, const int) | |
9792 | v4sf __builtin_ia32_roundps (v4sf, const int) | |
9793 | v2df __builtin_ia32_roundsd (v2df, v2df, const int) | |
9794 | v4sf __builtin_ia32_roundss (v4sf, v4sf, const int) | |
9795 | @end smallexample | |
9796 | ||
9797 | The following built-in functions are available when @option{-msse4.1} is | |
9798 | used. | |
9799 | ||
9800 | @table @code | |
9801 | @item v4sf __builtin_ia32_vec_set_v4sf (v4sf, float, const int) | |
9802 | Generates the @code{insertps} machine instruction. | |
9803 | @item int __builtin_ia32_vec_ext_v16qi (v16qi, const int) | |
9804 | Generates the @code{pextrb} machine instruction. | |
9805 | @item v16qi __builtin_ia32_vec_set_v16qi (v16qi, int, const int) | |
9806 | Generates the @code{pinsrb} machine instruction. | |
9807 | @item v4si __builtin_ia32_vec_set_v4si (v4si, int, const int) | |
9808 | Generates the @code{pinsrd} machine instruction. | |
9809 | @item v2di __builtin_ia32_vec_set_v2di (v2di, long long, const int) | |
9810 | Generates the @code{pinsrq} machine instruction in 64bit mode. | |
9811 | @end table | |
9812 | ||
9813 | The following built-in functions are changed to generate new SSE4.1 | |
9814 | instructions when @option{-msse4.1} is used. | |
9815 | ||
9816 | @table @code | |
9817 | @item float __builtin_ia32_vec_ext_v4sf (v4sf, const int) | |
9818 | Generates the @code{extractps} machine instruction. | |
9819 | @item int __builtin_ia32_vec_ext_v4si (v4si, const int) | |
9820 | Generates the @code{pextrd} machine instruction. | |
9821 | @item long long __builtin_ia32_vec_ext_v2di (v2di, const int) | |
9822 | Generates the @code{pextrq} machine instruction in 64bit mode. | |
9823 | @end table | |
9824 | ||
3b8dd071 L |
9825 | The following built-in functions are available when @option{-msse4.2} is |
9826 | used. All of them generate the machine instruction that is part of the | |
9827 | name. | |
9828 | ||
9829 | @smallexample | |
9830 | v16qi __builtin_ia32_pcmpestrm128 (v16qi, int, v16qi, int, const int) | |
9831 | int __builtin_ia32_pcmpestri128 (v16qi, int, v16qi, int, const int) | |
9832 | int __builtin_ia32_pcmpestria128 (v16qi, int, v16qi, int, const int) | |
9833 | int __builtin_ia32_pcmpestric128 (v16qi, int, v16qi, int, const int) | |
9834 | int __builtin_ia32_pcmpestrio128 (v16qi, int, v16qi, int, const int) | |
9835 | int __builtin_ia32_pcmpestris128 (v16qi, int, v16qi, int, const int) | |
9836 | int __builtin_ia32_pcmpestriz128 (v16qi, int, v16qi, int, const int) | |
9837 | v16qi __builtin_ia32_pcmpistrm128 (v16qi, v16qi, const int) | |
9838 | int __builtin_ia32_pcmpistri128 (v16qi, v16qi, const int) | |
9839 | int __builtin_ia32_pcmpistria128 (v16qi, v16qi, const int) | |
9840 | int __builtin_ia32_pcmpistric128 (v16qi, v16qi, const int) | |
9841 | int __builtin_ia32_pcmpistrio128 (v16qi, v16qi, const int) | |
9842 | int __builtin_ia32_pcmpistris128 (v16qi, v16qi, const int) | |
9843 | int __builtin_ia32_pcmpistriz128 (v16qi, v16qi, const int) | |
291d9a2d | 9844 | v2di __builtin_ia32_pcmpgtq (v2di, v2di) |
3b8dd071 L |
9845 | @end smallexample |
9846 | ||
9847 | The following built-in functions are available when @option{-msse4.2} is | |
9848 | used. | |
9849 | ||
9850 | @table @code | |
291d9a2d | 9851 | @item unsigned int __builtin_ia32_crc32qi (unsigned int, unsigned char) |
3b8dd071 | 9852 | Generates the @code{crc32b} machine instruction. |
291d9a2d | 9853 | @item unsigned int __builtin_ia32_crc32hi (unsigned int, unsigned short) |
3b8dd071 | 9854 | Generates the @code{crc32w} machine instruction. |
291d9a2d | 9855 | @item unsigned int __builtin_ia32_crc32si (unsigned int, unsigned int) |
3b8dd071 | 9856 | Generates the @code{crc32l} machine instruction. |
a44acfb9 | 9857 | @item unsigned long long __builtin_ia32_crc32di (unsigned long long, unsigned long long) |
412ac8d5 | 9858 | Generates the @code{crc32q} machine instruction. |
3b8dd071 L |
9859 | @end table |
9860 | ||
9861 | The following built-in functions are changed to generate new SSE4.2 | |
9862 | instructions when @option{-msse4.2} is used. | |
9863 | ||
9864 | @table @code | |
291d9a2d | 9865 | @item int __builtin_popcount (unsigned int) |
3b8dd071 | 9866 | Generates the @code{popcntl} machine instruction. |
291d9a2d | 9867 | @item int __builtin_popcountl (unsigned long) |
3b8dd071 L |
9868 | Generates the @code{popcntl} or @code{popcntq} machine instruction, |
9869 | depending on the size of @code{unsigned long}. | |
291d9a2d | 9870 | @item int __builtin_popcountll (unsigned long long) |
3b8dd071 L |
9871 | Generates the @code{popcntq} machine instruction. |
9872 | @end table | |
9873 | ||
31cb596a JY |
9874 | The following built-in functions are available when @option{-mavx} is |
9875 | used. All of them generate the machine instruction that is part of the | |
9876 | name. | |
9877 | ||
9878 | @smallexample | |
9879 | v4df __builtin_ia32_addpd256 (v4df,v4df) | |
9880 | v8sf __builtin_ia32_addps256 (v8sf,v8sf) | |
9881 | v4df __builtin_ia32_addsubpd256 (v4df,v4df) | |
9882 | v8sf __builtin_ia32_addsubps256 (v8sf,v8sf) | |
9883 | v4df __builtin_ia32_andnpd256 (v4df,v4df) | |
9884 | v8sf __builtin_ia32_andnps256 (v8sf,v8sf) | |
9885 | v4df __builtin_ia32_andpd256 (v4df,v4df) | |
9886 | v8sf __builtin_ia32_andps256 (v8sf,v8sf) | |
9887 | v4df __builtin_ia32_blendpd256 (v4df,v4df,int) | |
9888 | v8sf __builtin_ia32_blendps256 (v8sf,v8sf,int) | |
9889 | v4df __builtin_ia32_blendvpd256 (v4df,v4df,v4df) | |
9890 | v8sf __builtin_ia32_blendvps256 (v8sf,v8sf,v8sf) | |
9891 | v2df __builtin_ia32_cmppd (v2df,v2df,int) | |
9892 | v4df __builtin_ia32_cmppd256 (v4df,v4df,int) | |
9893 | v4sf __builtin_ia32_cmpps (v4sf,v4sf,int) | |
9894 | v8sf __builtin_ia32_cmpps256 (v8sf,v8sf,int) | |
9895 | v2df __builtin_ia32_cmpsd (v2df,v2df,int) | |
9896 | v4sf __builtin_ia32_cmpss (v4sf,v4sf,int) | |
9897 | v4df __builtin_ia32_cvtdq2pd256 (v4si) | |
9898 | v8sf __builtin_ia32_cvtdq2ps256 (v8si) | |
9899 | v4si __builtin_ia32_cvtpd2dq256 (v4df) | |
9900 | v4sf __builtin_ia32_cvtpd2ps256 (v4df) | |
9901 | v8si __builtin_ia32_cvtps2dq256 (v8sf) | |
9902 | v4df __builtin_ia32_cvtps2pd256 (v4sf) | |
9903 | v4si __builtin_ia32_cvttpd2dq256 (v4df) | |
9904 | v8si __builtin_ia32_cvttps2dq256 (v8sf) | |
9905 | v4df __builtin_ia32_divpd256 (v4df,v4df) | |
9906 | v8sf __builtin_ia32_divps256 (v8sf,v8sf) | |
9907 | v8sf __builtin_ia32_dpps256 (v8sf,v8sf,int) | |
9908 | v4df __builtin_ia32_haddpd256 (v4df,v4df) | |
9909 | v8sf __builtin_ia32_haddps256 (v8sf,v8sf) | |
9910 | v4df __builtin_ia32_hsubpd256 (v4df,v4df) | |
9911 | v8sf __builtin_ia32_hsubps256 (v8sf,v8sf) | |
9912 | v32qi __builtin_ia32_lddqu256 (pcchar) | |
9913 | v32qi __builtin_ia32_loaddqu256 (pcchar) | |
9914 | v4df __builtin_ia32_loadupd256 (pcdouble) | |
9915 | v8sf __builtin_ia32_loadups256 (pcfloat) | |
9916 | v2df __builtin_ia32_maskloadpd (pcv2df,v2df) | |
9917 | v4df __builtin_ia32_maskloadpd256 (pcv4df,v4df) | |
9918 | v4sf __builtin_ia32_maskloadps (pcv4sf,v4sf) | |
9919 | v8sf __builtin_ia32_maskloadps256 (pcv8sf,v8sf) | |
9920 | void __builtin_ia32_maskstorepd (pv2df,v2df,v2df) | |
9921 | void __builtin_ia32_maskstorepd256 (pv4df,v4df,v4df) | |
9922 | void __builtin_ia32_maskstoreps (pv4sf,v4sf,v4sf) | |
9923 | void __builtin_ia32_maskstoreps256 (pv8sf,v8sf,v8sf) | |
9924 | v4df __builtin_ia32_maxpd256 (v4df,v4df) | |
9925 | v8sf __builtin_ia32_maxps256 (v8sf,v8sf) | |
9926 | v4df __builtin_ia32_minpd256 (v4df,v4df) | |
9927 | v8sf __builtin_ia32_minps256 (v8sf,v8sf) | |
9928 | v4df __builtin_ia32_movddup256 (v4df) | |
9929 | int __builtin_ia32_movmskpd256 (v4df) | |
9930 | int __builtin_ia32_movmskps256 (v8sf) | |
9931 | v8sf __builtin_ia32_movshdup256 (v8sf) | |
9932 | v8sf __builtin_ia32_movsldup256 (v8sf) | |
9933 | v4df __builtin_ia32_mulpd256 (v4df,v4df) | |
9934 | v8sf __builtin_ia32_mulps256 (v8sf,v8sf) | |
9935 | v4df __builtin_ia32_orpd256 (v4df,v4df) | |
9936 | v8sf __builtin_ia32_orps256 (v8sf,v8sf) | |
9937 | v2df __builtin_ia32_pd_pd256 (v4df) | |
9938 | v4df __builtin_ia32_pd256_pd (v2df) | |
9939 | v4sf __builtin_ia32_ps_ps256 (v8sf) | |
9940 | v8sf __builtin_ia32_ps256_ps (v4sf) | |
9941 | int __builtin_ia32_ptestc256 (v4di,v4di,ptest) | |
9942 | int __builtin_ia32_ptestnzc256 (v4di,v4di,ptest) | |
9943 | int __builtin_ia32_ptestz256 (v4di,v4di,ptest) | |
9944 | v8sf __builtin_ia32_rcpps256 (v8sf) | |
9945 | v4df __builtin_ia32_roundpd256 (v4df,int) | |
9946 | v8sf __builtin_ia32_roundps256 (v8sf,int) | |
9947 | v8sf __builtin_ia32_rsqrtps_nr256 (v8sf) | |
9948 | v8sf __builtin_ia32_rsqrtps256 (v8sf) | |
9949 | v4df __builtin_ia32_shufpd256 (v4df,v4df,int) | |
9950 | v8sf __builtin_ia32_shufps256 (v8sf,v8sf,int) | |
9951 | v4si __builtin_ia32_si_si256 (v8si) | |
9952 | v8si __builtin_ia32_si256_si (v4si) | |
9953 | v4df __builtin_ia32_sqrtpd256 (v4df) | |
9954 | v8sf __builtin_ia32_sqrtps_nr256 (v8sf) | |
9955 | v8sf __builtin_ia32_sqrtps256 (v8sf) | |
9956 | void __builtin_ia32_storedqu256 (pchar,v32qi) | |
9957 | void __builtin_ia32_storeupd256 (pdouble,v4df) | |
9958 | void __builtin_ia32_storeups256 (pfloat,v8sf) | |
9959 | v4df __builtin_ia32_subpd256 (v4df,v4df) | |
9960 | v8sf __builtin_ia32_subps256 (v8sf,v8sf) | |
9961 | v4df __builtin_ia32_unpckhpd256 (v4df,v4df) | |
9962 | v8sf __builtin_ia32_unpckhps256 (v8sf,v8sf) | |
9963 | v4df __builtin_ia32_unpcklpd256 (v4df,v4df) | |
9964 | v8sf __builtin_ia32_unpcklps256 (v8sf,v8sf) | |
9965 | v4df __builtin_ia32_vbroadcastf128_pd256 (pcv2df) | |
9966 | v8sf __builtin_ia32_vbroadcastf128_ps256 (pcv4sf) | |
9967 | v4df __builtin_ia32_vbroadcastsd256 (pcdouble) | |
9968 | v4sf __builtin_ia32_vbroadcastss (pcfloat) | |
9969 | v8sf __builtin_ia32_vbroadcastss256 (pcfloat) | |
9970 | v2df __builtin_ia32_vextractf128_pd256 (v4df,int) | |
9971 | v4sf __builtin_ia32_vextractf128_ps256 (v8sf,int) | |
9972 | v4si __builtin_ia32_vextractf128_si256 (v8si,int) | |
9973 | v4df __builtin_ia32_vinsertf128_pd256 (v4df,v2df,int) | |
9974 | v8sf __builtin_ia32_vinsertf128_ps256 (v8sf,v4sf,int) | |
9975 | v8si __builtin_ia32_vinsertf128_si256 (v8si,v4si,int) | |
9976 | v4df __builtin_ia32_vperm2f128_pd256 (v4df,v4df,int) | |
9977 | v8sf __builtin_ia32_vperm2f128_ps256 (v8sf,v8sf,int) | |
9978 | v8si __builtin_ia32_vperm2f128_si256 (v8si,v8si,int) | |
9979 | v2df __builtin_ia32_vpermil2pd (v2df,v2df,v2di,int) | |
9980 | v4df __builtin_ia32_vpermil2pd256 (v4df,v4df,v4di,int) | |
9981 | v4sf __builtin_ia32_vpermil2ps (v4sf,v4sf,v4si,int) | |
9982 | v8sf __builtin_ia32_vpermil2ps256 (v8sf,v8sf,v8si,int) | |
9983 | v2df __builtin_ia32_vpermilpd (v2df,int) | |
9984 | v4df __builtin_ia32_vpermilpd256 (v4df,int) | |
9985 | v4sf __builtin_ia32_vpermilps (v4sf,int) | |
9986 | v8sf __builtin_ia32_vpermilps256 (v8sf,int) | |
9987 | v2df __builtin_ia32_vpermilvarpd (v2df,v2di) | |
9988 | v4df __builtin_ia32_vpermilvarpd256 (v4df,v4di) | |
9989 | v4sf __builtin_ia32_vpermilvarps (v4sf,v4si) | |
9990 | v8sf __builtin_ia32_vpermilvarps256 (v8sf,v8si) | |
9991 | int __builtin_ia32_vtestcpd (v2df,v2df,ptest) | |
9992 | int __builtin_ia32_vtestcpd256 (v4df,v4df,ptest) | |
9993 | int __builtin_ia32_vtestcps (v4sf,v4sf,ptest) | |
9994 | int __builtin_ia32_vtestcps256 (v8sf,v8sf,ptest) | |
9995 | int __builtin_ia32_vtestnzcpd (v2df,v2df,ptest) | |
9996 | int __builtin_ia32_vtestnzcpd256 (v4df,v4df,ptest) | |
9997 | int __builtin_ia32_vtestnzcps (v4sf,v4sf,ptest) | |
9998 | int __builtin_ia32_vtestnzcps256 (v8sf,v8sf,ptest) | |
9999 | int __builtin_ia32_vtestzpd (v2df,v2df,ptest) | |
10000 | int __builtin_ia32_vtestzpd256 (v4df,v4df,ptest) | |
10001 | int __builtin_ia32_vtestzps (v4sf,v4sf,ptest) | |
10002 | int __builtin_ia32_vtestzps256 (v8sf,v8sf,ptest) | |
10003 | void __builtin_ia32_vzeroall (void) | |
10004 | void __builtin_ia32_vzeroupper (void) | |
10005 | v4df __builtin_ia32_xorpd256 (v4df,v4df) | |
10006 | v8sf __builtin_ia32_xorps256 (v8sf,v8sf) | |
10007 | @end smallexample | |
10008 | ||
977e83a3 KY |
10009 | The following built-in functions are available when @option{-mavx2} is |
10010 | used. All of them generate the machine instruction that is part of the | |
10011 | name. | |
10012 | ||
10013 | @smallexample | |
10014 | v32qi __builtin_ia32_mpsadbw256 (v32qi,v32qi,v32qi,int) | |
10015 | v32qi __builtin_ia32_pabsb256 (v32qi) | |
10016 | v16hi __builtin_ia32_pabsw256 (v16hi) | |
10017 | v8si __builtin_ia32_pabsd256 (v8si) | |
10018 | v16hi builtin_ia32_packssdw256 (v8si,v8si) | |
10019 | v32qi __builtin_ia32_packsswb256 (v16hi,v16hi) | |
10020 | v16hi __builtin_ia32_packusdw256 (v8si,v8si) | |
10021 | v32qi __builtin_ia32_packuswb256 (v16hi,v16hi) | |
10022 | v32qi__builtin_ia32_paddb256 (v32qi,v32qi) | |
10023 | v16hi __builtin_ia32_paddw256 (v16hi,v16hi) | |
10024 | v8si __builtin_ia32_paddd256 (v8si,v8si) | |
10025 | v4di __builtin_ia32_paddq256 (v4di,v4di) | |
10026 | v32qi __builtin_ia32_paddsb256 (v32qi,v32qi) | |
10027 | v16hi __builtin_ia32_paddsw256 (v16hi,v16hi) | |
10028 | v32qi __builtin_ia32_paddusb256 (v32qi,v32qi) | |
10029 | v16hi __builtin_ia32_paddusw256 (v16hi,v16hi) | |
10030 | v4di __builtin_ia32_palignr256 (v4di,v4di,int) | |
10031 | v4di __builtin_ia32_andsi256 (v4di,v4di) | |
10032 | v4di __builtin_ia32_andnotsi256 (v4di,v4di) | |
10033 | v32qi__builtin_ia32_pavgb256 (v32qi,v32qi) | |
10034 | v16hi __builtin_ia32_pavgw256 (v16hi,v16hi) | |
10035 | v32qi __builtin_ia32_pblendvb256 (v32qi,v32qi,v32qi) | |
10036 | v16hi __builtin_ia32_pblendw256 (v16hi,v16hi,int) | |
10037 | v32qi __builtin_ia32_pcmpeqb256 (v32qi,v32qi) | |
10038 | v16hi __builtin_ia32_pcmpeqw256 (v16hi,v16hi) | |
10039 | v8si __builtin_ia32_pcmpeqd256 (c8si,v8si) | |
10040 | v4di __builtin_ia32_pcmpeqq256 (v4di,v4di) | |
10041 | v32qi __builtin_ia32_pcmpgtb256 (v32qi,v32qi) | |
10042 | v16hi __builtin_ia32_pcmpgtw256 (16hi,v16hi) | |
10043 | v8si __builtin_ia32_pcmpgtd256 (v8si,v8si) | |
10044 | v4di __builtin_ia32_pcmpgtq256 (v4di,v4di) | |
10045 | v16hi __builtin_ia32_phaddw256 (v16hi,v16hi) | |
10046 | v8si __builtin_ia32_phaddd256 (v8si,v8si) | |
10047 | v16hi __builtin_ia32_phaddsw256 (v16hi,v16hi) | |
10048 | v16hi __builtin_ia32_phsubw256 (v16hi,v16hi) | |
10049 | v8si __builtin_ia32_phsubd256 (v8si,v8si) | |
10050 | v16hi __builtin_ia32_phsubsw256 (v16hi,v16hi) | |
10051 | v32qi __builtin_ia32_pmaddubsw256 (v32qi,v32qi) | |
10052 | v16hi __builtin_ia32_pmaddwd256 (v16hi,v16hi) | |
10053 | v32qi __builtin_ia32_pmaxsb256 (v32qi,v32qi) | |
10054 | v16hi __builtin_ia32_pmaxsw256 (v16hi,v16hi) | |
10055 | v8si __builtin_ia32_pmaxsd256 (v8si,v8si) | |
10056 | v32qi __builtin_ia32_pmaxub256 (v32qi,v32qi) | |
10057 | v16hi __builtin_ia32_pmaxuw256 (v16hi,v16hi) | |
10058 | v8si __builtin_ia32_pmaxud256 (v8si,v8si) | |
10059 | v32qi __builtin_ia32_pminsb256 (v32qi,v32qi) | |
10060 | v16hi __builtin_ia32_pminsw256 (v16hi,v16hi) | |
10061 | v8si __builtin_ia32_pminsd256 (v8si,v8si) | |
10062 | v32qi __builtin_ia32_pminub256 (v32qi,v32qi) | |
10063 | v16hi __builtin_ia32_pminuw256 (v16hi,v16hi) | |
10064 | v8si __builtin_ia32_pminud256 (v8si,v8si) | |
10065 | int __builtin_ia32_pmovmskb256 (v32qi) | |
10066 | v16hi __builtin_ia32_pmovsxbw256 (v16qi) | |
10067 | v8si __builtin_ia32_pmovsxbd256 (v16qi) | |
10068 | v4di __builtin_ia32_pmovsxbq256 (v16qi) | |
10069 | v8si __builtin_ia32_pmovsxwd256 (v8hi) | |
10070 | v4di __builtin_ia32_pmovsxwq256 (v8hi) | |
10071 | v4di __builtin_ia32_pmovsxdq256 (v4si) | |
10072 | v16hi __builtin_ia32_pmovzxbw256 (v16qi) | |
10073 | v8si __builtin_ia32_pmovzxbd256 (v16qi) | |
10074 | v4di __builtin_ia32_pmovzxbq256 (v16qi) | |
10075 | v8si __builtin_ia32_pmovzxwd256 (v8hi) | |
10076 | v4di __builtin_ia32_pmovzxwq256 (v8hi) | |
10077 | v4di __builtin_ia32_pmovzxdq256 (v4si) | |
10078 | v4di __builtin_ia32_pmuldq256 (v8si,v8si) | |
10079 | v16hi __builtin_ia32_pmulhrsw256 (v16hi, v16hi) | |
10080 | v16hi __builtin_ia32_pmulhuw256 (v16hi,v16hi) | |
10081 | v16hi __builtin_ia32_pmulhw256 (v16hi,v16hi) | |
10082 | v16hi __builtin_ia32_pmullw256 (v16hi,v16hi) | |
10083 | v8si __builtin_ia32_pmulld256 (v8si,v8si) | |
10084 | v4di __builtin_ia32_pmuludq256 (v8si,v8si) | |
10085 | v4di __builtin_ia32_por256 (v4di,v4di) | |
10086 | v16hi __builtin_ia32_psadbw256 (v32qi,v32qi) | |
10087 | v32qi __builtin_ia32_pshufb256 (v32qi,v32qi) | |
10088 | v8si __builtin_ia32_pshufd256 (v8si,int) | |
10089 | v16hi __builtin_ia32_pshufhw256 (v16hi,int) | |
10090 | v16hi __builtin_ia32_pshuflw256 (v16hi,int) | |
10091 | v32qi __builtin_ia32_psignb256 (v32qi,v32qi) | |
10092 | v16hi __builtin_ia32_psignw256 (v16hi,v16hi) | |
10093 | v8si __builtin_ia32_psignd256 (v8si,v8si) | |
10094 | v4di __builtin_ia32_pslldqi256 (v4di,int) | |
10095 | v16hi __builtin_ia32_psllwi256 (16hi,int) | |
10096 | v16hi __builtin_ia32_psllw256(v16hi,v8hi) | |
10097 | v8si __builtin_ia32_pslldi256 (v8si,int) | |
10098 | v8si __builtin_ia32_pslld256(v8si,v4si) | |
10099 | v4di __builtin_ia32_psllqi256 (v4di,int) | |
10100 | v4di __builtin_ia32_psllq256(v4di,v2di) | |
10101 | v16hi __builtin_ia32_psrawi256 (v16hi,int) | |
10102 | v16hi __builtin_ia32_psraw256 (v16hi,v8hi) | |
10103 | v8si __builtin_ia32_psradi256 (v8si,int) | |
10104 | v8si __builtin_ia32_psrad256 (v8si,v4si) | |
10105 | v4di __builtin_ia32_psrldqi256 (v4di, int) | |
10106 | v16hi __builtin_ia32_psrlwi256 (v16hi,int) | |
10107 | v16hi __builtin_ia32_psrlw256 (v16hi,v8hi) | |
10108 | v8si __builtin_ia32_psrldi256 (v8si,int) | |
10109 | v8si __builtin_ia32_psrld256 (v8si,v4si) | |
10110 | v4di __builtin_ia32_psrlqi256 (v4di,int) | |
10111 | v4di __builtin_ia32_psrlq256(v4di,v2di) | |
10112 | v32qi __builtin_ia32_psubb256 (v32qi,v32qi) | |
10113 | v32hi __builtin_ia32_psubw256 (v16hi,v16hi) | |
10114 | v8si __builtin_ia32_psubd256 (v8si,v8si) | |
10115 | v4di __builtin_ia32_psubq256 (v4di,v4di) | |
10116 | v32qi __builtin_ia32_psubsb256 (v32qi,v32qi) | |
10117 | v16hi __builtin_ia32_psubsw256 (v16hi,v16hi) | |
10118 | v32qi __builtin_ia32_psubusb256 (v32qi,v32qi) | |
10119 | v16hi __builtin_ia32_psubusw256 (v16hi,v16hi) | |
10120 | v32qi __builtin_ia32_punpckhbw256 (v32qi,v32qi) | |
10121 | v16hi __builtin_ia32_punpckhwd256 (v16hi,v16hi) | |
10122 | v8si __builtin_ia32_punpckhdq256 (v8si,v8si) | |
10123 | v4di __builtin_ia32_punpckhqdq256 (v4di,v4di) | |
10124 | v32qi __builtin_ia32_punpcklbw256 (v32qi,v32qi) | |
10125 | v16hi __builtin_ia32_punpcklwd256 (v16hi,v16hi) | |
10126 | v8si __builtin_ia32_punpckldq256 (v8si,v8si) | |
10127 | v4di __builtin_ia32_punpcklqdq256 (v4di,v4di) | |
10128 | v4di __builtin_ia32_pxor256 (v4di,v4di) | |
10129 | v4di __builtin_ia32_movntdqa256 (pv4di) | |
10130 | v4sf __builtin_ia32_vbroadcastss_ps (v4sf) | |
10131 | v8sf __builtin_ia32_vbroadcastss_ps256 (v4sf) | |
10132 | v4df __builtin_ia32_vbroadcastsd_pd256 (v2df) | |
10133 | v4di __builtin_ia32_vbroadcastsi256 (v2di) | |
10134 | v4si __builtin_ia32_pblendd128 (v4si,v4si) | |
10135 | v8si __builtin_ia32_pblendd256 (v8si,v8si) | |
10136 | v32qi __builtin_ia32_pbroadcastb256 (v16qi) | |
10137 | v16hi __builtin_ia32_pbroadcastw256 (v8hi) | |
10138 | v8si __builtin_ia32_pbroadcastd256 (v4si) | |
10139 | v4di __builtin_ia32_pbroadcastq256 (v2di) | |
10140 | v16qi __builtin_ia32_pbroadcastb128 (v16qi) | |
10141 | v8hi __builtin_ia32_pbroadcastw128 (v8hi) | |
10142 | v4si __builtin_ia32_pbroadcastd128 (v4si) | |
10143 | v2di __builtin_ia32_pbroadcastq128 (v2di) | |
10144 | v8si __builtin_ia32_permvarsi256 (v8si,v8si) | |
10145 | v4df __builtin_ia32_permdf256 (v4df,int) | |
10146 | v8sf __builtin_ia32_permvarsf256 (v8sf,v8sf) | |
10147 | v4di __builtin_ia32_permdi256 (v4di,int) | |
10148 | v4di __builtin_ia32_permti256 (v4di,v4di,int) | |
10149 | v4di __builtin_ia32_extract128i256 (v4di,int) | |
10150 | v4di __builtin_ia32_insert128i256 (v4di,v2di,int) | |
10151 | v8si __builtin_ia32_maskloadd256 (pcv8si,v8si) | |
10152 | v4di __builtin_ia32_maskloadq256 (pcv4di,v4di) | |
10153 | v4si __builtin_ia32_maskloadd (pcv4si,v4si) | |
10154 | v2di __builtin_ia32_maskloadq (pcv2di,v2di) | |
10155 | void __builtin_ia32_maskstored256 (pv8si,v8si,v8si) | |
10156 | void __builtin_ia32_maskstoreq256 (pv4di,v4di,v4di) | |
10157 | void __builtin_ia32_maskstored (pv4si,v4si,v4si) | |
10158 | void __builtin_ia32_maskstoreq (pv2di,v2di,v2di) | |
10159 | v8si __builtin_ia32_psllv8si (v8si,v8si) | |
10160 | v4si __builtin_ia32_psllv4si (v4si,v4si) | |
10161 | v4di __builtin_ia32_psllv4di (v4di,v4di) | |
10162 | v2di __builtin_ia32_psllv2di (v2di,v2di) | |
10163 | v8si __builtin_ia32_psrav8si (v8si,v8si) | |
10164 | v4si __builtin_ia32_psrav4si (v4si,v4si) | |
10165 | v8si __builtin_ia32_psrlv8si (v8si,v8si) | |
10166 | v4si __builtin_ia32_psrlv4si (v4si,v4si) | |
10167 | v4di __builtin_ia32_psrlv4di (v4di,v4di) | |
10168 | v2di __builtin_ia32_psrlv2di (v2di,v2di) | |
10169 | v2df __builtin_ia32_gathersiv2df (v2df, pcdouble,v4si,v2df,int) | |
10170 | v4df __builtin_ia32_gathersiv4df (v4df, pcdouble,v4si,v4df,int) | |
10171 | v2df __builtin_ia32_gatherdiv2df (v2df, pcdouble,v2di,v2df,int) | |
10172 | v4df __builtin_ia32_gatherdiv4df (v4df, pcdouble,v4di,v4df,int) | |
10173 | v4sf __builtin_ia32_gathersiv4sf (v4sf, pcfloat,v4si,v4sf,int) | |
10174 | v8sf __builtin_ia32_gathersiv8sf (v8sf, pcfloat,v8si,v8sf,int) | |
10175 | v4sf __builtin_ia32_gatherdiv4sf (v4sf, pcfloat,v2di,v4sf,int) | |
10176 | v4sf __builtin_ia32_gatherdiv4sf256 (v4sf, pcfloat,v4di,v4sf,int) | |
10177 | v2di __builtin_ia32_gathersiv2di (v2di, pcint64,v4si,v2di,int) | |
10178 | v4di __builtin_ia32_gathersiv4di (v4di, pcint64,v4si,v4di,int) | |
10179 | v2di __builtin_ia32_gatherdiv2di (v2di, pcint64,v2di,v2di,int) | |
10180 | v4di __builtin_ia32_gatherdiv4di (v4di, pcint64,v4di,v4di,int) | |
10181 | v4si __builtin_ia32_gathersiv4si (v4si, pcint,v4si,v4si,int) | |
10182 | v8si __builtin_ia32_gathersiv8si (v8si, pcint,v8si,v8si,int) | |
10183 | v4si __builtin_ia32_gatherdiv4si (v4si, pcint,v2di,v4si,int) | |
10184 | v4si __builtin_ia32_gatherdiv4si256 (v4si, pcint,v4di,v4si,int) | |
10185 | @end smallexample | |
10186 | ||
8b96a312 L |
10187 | The following built-in functions are available when @option{-maes} is |
10188 | used. All of them generate the machine instruction that is part of the | |
10189 | name. | |
10190 | ||
10191 | @smallexample | |
10192 | v2di __builtin_ia32_aesenc128 (v2di, v2di) | |
10193 | v2di __builtin_ia32_aesenclast128 (v2di, v2di) | |
10194 | v2di __builtin_ia32_aesdec128 (v2di, v2di) | |
10195 | v2di __builtin_ia32_aesdeclast128 (v2di, v2di) | |
10196 | v2di __builtin_ia32_aeskeygenassist128 (v2di, const int) | |
10197 | v2di __builtin_ia32_aesimc128 (v2di) | |
10198 | @end smallexample | |
10199 | ||
10200 | The following built-in function is available when @option{-mpclmul} is | |
10201 | used. | |
10202 | ||
10203 | @table @code | |
10204 | @item v2di __builtin_ia32_pclmulqdq128 (v2di, v2di, const int) | |
10205 | Generates the @code{pclmulqdq} machine instruction. | |
10206 | @end table | |
10207 | ||
4ee89d5f L |
10208 | The following built-in function is available when @option{-mfsgsbase} is |
10209 | used. All of them generate the machine instruction that is part of the | |
10210 | name. | |
10211 | ||
10212 | @smallexample | |
10213 | unsigned int __builtin_ia32_rdfsbase32 (void) | |
10214 | unsigned long long __builtin_ia32_rdfsbase64 (void) | |
10215 | unsigned int __builtin_ia32_rdgsbase32 (void) | |
10216 | unsigned long long __builtin_ia32_rdgsbase64 (void) | |
10217 | void _writefsbase_u32 (unsigned int) | |
10218 | void _writefsbase_u64 (unsigned long long) | |
10219 | void _writegsbase_u32 (unsigned int) | |
10220 | void _writegsbase_u64 (unsigned long long) | |
10221 | @end smallexample | |
10222 | ||
10223 | The following built-in function is available when @option{-mrdrnd} is | |
10224 | used. All of them generate the machine instruction that is part of the | |
10225 | name. | |
10226 | ||
10227 | @smallexample | |
11c4a1c0 L |
10228 | unsigned int __builtin_ia32_rdrand16_step (unsigned short *) |
10229 | unsigned int __builtin_ia32_rdrand32_step (unsigned int *) | |
10230 | unsigned int __builtin_ia32_rdrand64_step (unsigned long long *) | |
4ee89d5f L |
10231 | @end smallexample |
10232 | ||
21efb4d4 | 10233 | The following built-in functions are available when @option{-msse4a} is used. |
291d9a2d | 10234 | All of them generate the machine instruction that is part of the name. |
21efb4d4 HJ |
10235 | |
10236 | @smallexample | |
291d9a2d UB |
10237 | void __builtin_ia32_movntsd (double *, v2df) |
10238 | void __builtin_ia32_movntss (float *, v4sf) | |
10239 | v2di __builtin_ia32_extrq (v2di, v16qi) | |
10240 | v2di __builtin_ia32_extrqi (v2di, const unsigned int, const unsigned int) | |
10241 | v2di __builtin_ia32_insertq (v2di, v2di) | |
10242 | v2di __builtin_ia32_insertqi (v2di, v2di, const unsigned int, const unsigned int) | |
21efb4d4 HJ |
10243 | @end smallexample |
10244 | ||
43a8b705 HJ |
10245 | The following built-in functions are available when @option{-mxop} is used. |
10246 | @smallexample | |
10247 | v2df __builtin_ia32_vfrczpd (v2df) | |
10248 | v4sf __builtin_ia32_vfrczps (v4sf) | |
10249 | v2df __builtin_ia32_vfrczsd (v2df, v2df) | |
10250 | v4sf __builtin_ia32_vfrczss (v4sf, v4sf) | |
10251 | v4df __builtin_ia32_vfrczpd256 (v4df) | |
10252 | v8sf __builtin_ia32_vfrczps256 (v8sf) | |
10253 | v2di __builtin_ia32_vpcmov (v2di, v2di, v2di) | |
10254 | v2di __builtin_ia32_vpcmov_v2di (v2di, v2di, v2di) | |
10255 | v4si __builtin_ia32_vpcmov_v4si (v4si, v4si, v4si) | |
10256 | v8hi __builtin_ia32_vpcmov_v8hi (v8hi, v8hi, v8hi) | |
10257 | v16qi __builtin_ia32_vpcmov_v16qi (v16qi, v16qi, v16qi) | |
10258 | v2df __builtin_ia32_vpcmov_v2df (v2df, v2df, v2df) | |
10259 | v4sf __builtin_ia32_vpcmov_v4sf (v4sf, v4sf, v4sf) | |
10260 | v4di __builtin_ia32_vpcmov_v4di256 (v4di, v4di, v4di) | |
10261 | v8si __builtin_ia32_vpcmov_v8si256 (v8si, v8si, v8si) | |
10262 | v16hi __builtin_ia32_vpcmov_v16hi256 (v16hi, v16hi, v16hi) | |
10263 | v32qi __builtin_ia32_vpcmov_v32qi256 (v32qi, v32qi, v32qi) | |
10264 | v4df __builtin_ia32_vpcmov_v4df256 (v4df, v4df, v4df) | |
10265 | v8sf __builtin_ia32_vpcmov_v8sf256 (v8sf, v8sf, v8sf) | |
10266 | v16qi __builtin_ia32_vpcomeqb (v16qi, v16qi) | |
10267 | v8hi __builtin_ia32_vpcomeqw (v8hi, v8hi) | |
10268 | v4si __builtin_ia32_vpcomeqd (v4si, v4si) | |
10269 | v2di __builtin_ia32_vpcomeqq (v2di, v2di) | |
10270 | v16qi __builtin_ia32_vpcomequb (v16qi, v16qi) | |
10271 | v4si __builtin_ia32_vpcomequd (v4si, v4si) | |
10272 | v2di __builtin_ia32_vpcomequq (v2di, v2di) | |
10273 | v8hi __builtin_ia32_vpcomequw (v8hi, v8hi) | |
10274 | v8hi __builtin_ia32_vpcomeqw (v8hi, v8hi) | |
10275 | v16qi __builtin_ia32_vpcomfalseb (v16qi, v16qi) | |
10276 | v4si __builtin_ia32_vpcomfalsed (v4si, v4si) | |
10277 | v2di __builtin_ia32_vpcomfalseq (v2di, v2di) | |
10278 | v16qi __builtin_ia32_vpcomfalseub (v16qi, v16qi) | |
10279 | v4si __builtin_ia32_vpcomfalseud (v4si, v4si) | |
10280 | v2di __builtin_ia32_vpcomfalseuq (v2di, v2di) | |
10281 | v8hi __builtin_ia32_vpcomfalseuw (v8hi, v8hi) | |
10282 | v8hi __builtin_ia32_vpcomfalsew (v8hi, v8hi) | |
10283 | v16qi __builtin_ia32_vpcomgeb (v16qi, v16qi) | |
10284 | v4si __builtin_ia32_vpcomged (v4si, v4si) | |
10285 | v2di __builtin_ia32_vpcomgeq (v2di, v2di) | |
10286 | v16qi __builtin_ia32_vpcomgeub (v16qi, v16qi) | |
10287 | v4si __builtin_ia32_vpcomgeud (v4si, v4si) | |
10288 | v2di __builtin_ia32_vpcomgeuq (v2di, v2di) | |
10289 | v8hi __builtin_ia32_vpcomgeuw (v8hi, v8hi) | |
10290 | v8hi __builtin_ia32_vpcomgew (v8hi, v8hi) | |
10291 | v16qi __builtin_ia32_vpcomgtb (v16qi, v16qi) | |
10292 | v4si __builtin_ia32_vpcomgtd (v4si, v4si) | |
10293 | v2di __builtin_ia32_vpcomgtq (v2di, v2di) | |
10294 | v16qi __builtin_ia32_vpcomgtub (v16qi, v16qi) | |
10295 | v4si __builtin_ia32_vpcomgtud (v4si, v4si) | |
10296 | v2di __builtin_ia32_vpcomgtuq (v2di, v2di) | |
10297 | v8hi __builtin_ia32_vpcomgtuw (v8hi, v8hi) | |
10298 | v8hi __builtin_ia32_vpcomgtw (v8hi, v8hi) | |
10299 | v16qi __builtin_ia32_vpcomleb (v16qi, v16qi) | |
10300 | v4si __builtin_ia32_vpcomled (v4si, v4si) | |
10301 | v2di __builtin_ia32_vpcomleq (v2di, v2di) | |
10302 | v16qi __builtin_ia32_vpcomleub (v16qi, v16qi) | |
10303 | v4si __builtin_ia32_vpcomleud (v4si, v4si) | |
10304 | v2di __builtin_ia32_vpcomleuq (v2di, v2di) | |
10305 | v8hi __builtin_ia32_vpcomleuw (v8hi, v8hi) | |
10306 | v8hi __builtin_ia32_vpcomlew (v8hi, v8hi) | |
10307 | v16qi __builtin_ia32_vpcomltb (v16qi, v16qi) | |
10308 | v4si __builtin_ia32_vpcomltd (v4si, v4si) | |
10309 | v2di __builtin_ia32_vpcomltq (v2di, v2di) | |
10310 | v16qi __builtin_ia32_vpcomltub (v16qi, v16qi) | |
10311 | v4si __builtin_ia32_vpcomltud (v4si, v4si) | |
10312 | v2di __builtin_ia32_vpcomltuq (v2di, v2di) | |
10313 | v8hi __builtin_ia32_vpcomltuw (v8hi, v8hi) | |
10314 | v8hi __builtin_ia32_vpcomltw (v8hi, v8hi) | |
10315 | v16qi __builtin_ia32_vpcomneb (v16qi, v16qi) | |
10316 | v4si __builtin_ia32_vpcomned (v4si, v4si) | |
10317 | v2di __builtin_ia32_vpcomneq (v2di, v2di) | |
10318 | v16qi __builtin_ia32_vpcomneub (v16qi, v16qi) | |
10319 | v4si __builtin_ia32_vpcomneud (v4si, v4si) | |
10320 | v2di __builtin_ia32_vpcomneuq (v2di, v2di) | |
10321 | v8hi __builtin_ia32_vpcomneuw (v8hi, v8hi) | |
10322 | v8hi __builtin_ia32_vpcomnew (v8hi, v8hi) | |
10323 | v16qi __builtin_ia32_vpcomtrueb (v16qi, v16qi) | |
10324 | v4si __builtin_ia32_vpcomtrued (v4si, v4si) | |
10325 | v2di __builtin_ia32_vpcomtrueq (v2di, v2di) | |
10326 | v16qi __builtin_ia32_vpcomtrueub (v16qi, v16qi) | |
10327 | v4si __builtin_ia32_vpcomtrueud (v4si, v4si) | |
10328 | v2di __builtin_ia32_vpcomtrueuq (v2di, v2di) | |
10329 | v8hi __builtin_ia32_vpcomtrueuw (v8hi, v8hi) | |
10330 | v8hi __builtin_ia32_vpcomtruew (v8hi, v8hi) | |
10331 | v4si __builtin_ia32_vphaddbd (v16qi) | |
10332 | v2di __builtin_ia32_vphaddbq (v16qi) | |
10333 | v8hi __builtin_ia32_vphaddbw (v16qi) | |
10334 | v2di __builtin_ia32_vphadddq (v4si) | |
10335 | v4si __builtin_ia32_vphaddubd (v16qi) | |
10336 | v2di __builtin_ia32_vphaddubq (v16qi) | |
10337 | v8hi __builtin_ia32_vphaddubw (v16qi) | |
10338 | v2di __builtin_ia32_vphaddudq (v4si) | |
10339 | v4si __builtin_ia32_vphadduwd (v8hi) | |
10340 | v2di __builtin_ia32_vphadduwq (v8hi) | |
10341 | v4si __builtin_ia32_vphaddwd (v8hi) | |
10342 | v2di __builtin_ia32_vphaddwq (v8hi) | |
10343 | v8hi __builtin_ia32_vphsubbw (v16qi) | |
10344 | v2di __builtin_ia32_vphsubdq (v4si) | |
10345 | v4si __builtin_ia32_vphsubwd (v8hi) | |
10346 | v4si __builtin_ia32_vpmacsdd (v4si, v4si, v4si) | |
10347 | v2di __builtin_ia32_vpmacsdqh (v4si, v4si, v2di) | |
10348 | v2di __builtin_ia32_vpmacsdql (v4si, v4si, v2di) | |
10349 | v4si __builtin_ia32_vpmacssdd (v4si, v4si, v4si) | |
10350 | v2di __builtin_ia32_vpmacssdqh (v4si, v4si, v2di) | |
10351 | v2di __builtin_ia32_vpmacssdql (v4si, v4si, v2di) | |
10352 | v4si __builtin_ia32_vpmacsswd (v8hi, v8hi, v4si) | |
10353 | v8hi __builtin_ia32_vpmacssww (v8hi, v8hi, v8hi) | |
10354 | v4si __builtin_ia32_vpmacswd (v8hi, v8hi, v4si) | |
10355 | v8hi __builtin_ia32_vpmacsww (v8hi, v8hi, v8hi) | |
10356 | v4si __builtin_ia32_vpmadcsswd (v8hi, v8hi, v4si) | |
10357 | v4si __builtin_ia32_vpmadcswd (v8hi, v8hi, v4si) | |
10358 | v16qi __builtin_ia32_vpperm (v16qi, v16qi, v16qi) | |
10359 | v16qi __builtin_ia32_vprotb (v16qi, v16qi) | |
10360 | v4si __builtin_ia32_vprotd (v4si, v4si) | |
10361 | v2di __builtin_ia32_vprotq (v2di, v2di) | |
10362 | v8hi __builtin_ia32_vprotw (v8hi, v8hi) | |
10363 | v16qi __builtin_ia32_vpshab (v16qi, v16qi) | |
10364 | v4si __builtin_ia32_vpshad (v4si, v4si) | |
10365 | v2di __builtin_ia32_vpshaq (v2di, v2di) | |
10366 | v8hi __builtin_ia32_vpshaw (v8hi, v8hi) | |
10367 | v16qi __builtin_ia32_vpshlb (v16qi, v16qi) | |
10368 | v4si __builtin_ia32_vpshld (v4si, v4si) | |
10369 | v2di __builtin_ia32_vpshlq (v2di, v2di) | |
10370 | v8hi __builtin_ia32_vpshlw (v8hi, v8hi) | |
10371 | @end smallexample | |
10372 | ||
cbf2e4d4 HJ |
10373 | The following built-in functions are available when @option{-mfma4} is used. |
10374 | All of them generate the machine instruction that is part of the name | |
10375 | with MMX registers. | |
10376 | ||
10377 | @smallexample | |
10378 | v2df __builtin_ia32_fmaddpd (v2df, v2df, v2df) | |
10379 | v4sf __builtin_ia32_fmaddps (v4sf, v4sf, v4sf) | |
10380 | v2df __builtin_ia32_fmaddsd (v2df, v2df, v2df) | |
10381 | v4sf __builtin_ia32_fmaddss (v4sf, v4sf, v4sf) | |
10382 | v2df __builtin_ia32_fmsubpd (v2df, v2df, v2df) | |
10383 | v4sf __builtin_ia32_fmsubps (v4sf, v4sf, v4sf) | |
10384 | v2df __builtin_ia32_fmsubsd (v2df, v2df, v2df) | |
10385 | v4sf __builtin_ia32_fmsubss (v4sf, v4sf, v4sf) | |
10386 | v2df __builtin_ia32_fnmaddpd (v2df, v2df, v2df) | |
10387 | v4sf __builtin_ia32_fnmaddps (v4sf, v4sf, v4sf) | |
10388 | v2df __builtin_ia32_fnmaddsd (v2df, v2df, v2df) | |
10389 | v4sf __builtin_ia32_fnmaddss (v4sf, v4sf, v4sf) | |
10390 | v2df __builtin_ia32_fnmsubpd (v2df, v2df, v2df) | |
10391 | v4sf __builtin_ia32_fnmsubps (v4sf, v4sf, v4sf) | |
10392 | v2df __builtin_ia32_fnmsubsd (v2df, v2df, v2df) | |
10393 | v4sf __builtin_ia32_fnmsubss (v4sf, v4sf, v4sf) | |
10394 | v2df __builtin_ia32_fmaddsubpd (v2df, v2df, v2df) | |
10395 | v4sf __builtin_ia32_fmaddsubps (v4sf, v4sf, v4sf) | |
10396 | v2df __builtin_ia32_fmsubaddpd (v2df, v2df, v2df) | |
10397 | v4sf __builtin_ia32_fmsubaddps (v4sf, v4sf, v4sf) | |
10398 | v4df __builtin_ia32_fmaddpd256 (v4df, v4df, v4df) | |
10399 | v8sf __builtin_ia32_fmaddps256 (v8sf, v8sf, v8sf) | |
10400 | v4df __builtin_ia32_fmsubpd256 (v4df, v4df, v4df) | |
10401 | v8sf __builtin_ia32_fmsubps256 (v8sf, v8sf, v8sf) | |
10402 | v4df __builtin_ia32_fnmaddpd256 (v4df, v4df, v4df) | |
10403 | v8sf __builtin_ia32_fnmaddps256 (v8sf, v8sf, v8sf) | |
10404 | v4df __builtin_ia32_fnmsubpd256 (v4df, v4df, v4df) | |
10405 | v8sf __builtin_ia32_fnmsubps256 (v8sf, v8sf, v8sf) | |
10406 | v4df __builtin_ia32_fmaddsubpd256 (v4df, v4df, v4df) | |
10407 | v8sf __builtin_ia32_fmaddsubps256 (v8sf, v8sf, v8sf) | |
10408 | v4df __builtin_ia32_fmsubaddpd256 (v4df, v4df, v4df) | |
10409 | v8sf __builtin_ia32_fmsubaddps256 (v8sf, v8sf, v8sf) | |
10410 | ||
10411 | @end smallexample | |
3e901069 HJ |
10412 | |
10413 | The following built-in functions are available when @option{-mlwp} is used. | |
10414 | ||
10415 | @smallexample | |
10416 | void __builtin_ia32_llwpcb16 (void *); | |
10417 | void __builtin_ia32_llwpcb32 (void *); | |
10418 | void __builtin_ia32_llwpcb64 (void *); | |
10419 | void * __builtin_ia32_llwpcb16 (void); | |
10420 | void * __builtin_ia32_llwpcb32 (void); | |
10421 | void * __builtin_ia32_llwpcb64 (void); | |
10422 | void __builtin_ia32_lwpval16 (unsigned short, unsigned int, unsigned short) | |
10423 | void __builtin_ia32_lwpval32 (unsigned int, unsigned int, unsigned int) | |
10424 | void __builtin_ia32_lwpval64 (unsigned __int64, unsigned int, unsigned int) | |
10425 | unsigned char __builtin_ia32_lwpins16 (unsigned short, unsigned int, unsigned short) | |
10426 | unsigned char __builtin_ia32_lwpins32 (unsigned int, unsigned int, unsigned int) | |
10427 | unsigned char __builtin_ia32_lwpins64 (unsigned __int64, unsigned int, unsigned int) | |
10428 | @end smallexample | |
cbf2e4d4 | 10429 | |
91afcfa3 QN |
10430 | The following built-in functions are available when @option{-mbmi} is used. |
10431 | All of them generate the machine instruction that is part of the name. | |
10432 | @smallexample | |
10433 | unsigned int __builtin_ia32_bextr_u32(unsigned int, unsigned int); | |
10434 | unsigned long long __builtin_ia32_bextr_u64 (unsigned long long, unsigned long long); | |
5fcafa60 KY |
10435 | @end smallexample |
10436 | ||
82feeb8d L |
10437 | The following built-in functions are available when @option{-mbmi2} is used. |
10438 | All of them generate the machine instruction that is part of the name. | |
10439 | @smallexample | |
10440 | unsigned int _bzhi_u32 (unsigned int, unsigned int) | |
10441 | unsigned int _pdep_u32 (unsigned int, unsigned int) | |
10442 | unsigned int _pext_u32 (unsigned int, unsigned int) | |
10443 | unsigned long long _bzhi_u64 (unsigned long long, unsigned long long) | |
10444 | unsigned long long _pdep_u64 (unsigned long long, unsigned long long) | |
10445 | unsigned long long _pext_u64 (unsigned long long, unsigned long long) | |
10446 | @end smallexample | |
10447 | ||
5fcafa60 KY |
10448 | The following built-in functions are available when @option{-mlzcnt} is used. |
10449 | All of them generate the machine instruction that is part of the name. | |
10450 | @smallexample | |
91afcfa3 QN |
10451 | unsigned short __builtin_ia32_lzcnt_16(unsigned short); |
10452 | unsigned int __builtin_ia32_lzcnt_u32(unsigned int); | |
10453 | unsigned long long __builtin_ia32_lzcnt_u64 (unsigned long long); | |
10454 | @end smallexample | |
10455 | ||
94d13ad1 QN |
10456 | The following built-in functions are available when @option{-mtbm} is used. |
10457 | Both of them generate the immediate form of the bextr machine instruction. | |
10458 | @smallexample | |
10459 | unsigned int __builtin_ia32_bextri_u32 (unsigned int, const unsigned int); | |
10460 | unsigned long long __builtin_ia32_bextri_u64 (unsigned long long, const unsigned long long); | |
10461 | @end smallexample | |
10462 | ||
10463 | ||
0975678f JM |
10464 | The following built-in functions are available when @option{-m3dnow} is used. |
10465 | All of them generate the machine instruction that is part of the name. | |
10466 | ||
3ab51846 | 10467 | @smallexample |
0975678f JM |
10468 | void __builtin_ia32_femms (void) |
10469 | v8qi __builtin_ia32_pavgusb (v8qi, v8qi) | |
10470 | v2si __builtin_ia32_pf2id (v2sf) | |
10471 | v2sf __builtin_ia32_pfacc (v2sf, v2sf) | |
10472 | v2sf __builtin_ia32_pfadd (v2sf, v2sf) | |
10473 | v2si __builtin_ia32_pfcmpeq (v2sf, v2sf) | |
10474 | v2si __builtin_ia32_pfcmpge (v2sf, v2sf) | |
10475 | v2si __builtin_ia32_pfcmpgt (v2sf, v2sf) | |
10476 | v2sf __builtin_ia32_pfmax (v2sf, v2sf) | |
10477 | v2sf __builtin_ia32_pfmin (v2sf, v2sf) | |
10478 | v2sf __builtin_ia32_pfmul (v2sf, v2sf) | |
10479 | v2sf __builtin_ia32_pfrcp (v2sf) | |
10480 | v2sf __builtin_ia32_pfrcpit1 (v2sf, v2sf) | |
10481 | v2sf __builtin_ia32_pfrcpit2 (v2sf, v2sf) | |
10482 | v2sf __builtin_ia32_pfrsqrt (v2sf) | |
10483 | v2sf __builtin_ia32_pfrsqrtit1 (v2sf, v2sf) | |
10484 | v2sf __builtin_ia32_pfsub (v2sf, v2sf) | |
10485 | v2sf __builtin_ia32_pfsubr (v2sf, v2sf) | |
10486 | v2sf __builtin_ia32_pi2fd (v2si) | |
10487 | v4hi __builtin_ia32_pmulhrw (v4hi, v4hi) | |
3ab51846 | 10488 | @end smallexample |
0975678f JM |
10489 | |
10490 | The following built-in functions are available when both @option{-m3dnow} | |
10491 | and @option{-march=athlon} are used. All of them generate the machine | |
10492 | instruction that is part of the name. | |
10493 | ||
3ab51846 | 10494 | @smallexample |
0975678f JM |
10495 | v2si __builtin_ia32_pf2iw (v2sf) |
10496 | v2sf __builtin_ia32_pfnacc (v2sf, v2sf) | |
10497 | v2sf __builtin_ia32_pfpnacc (v2sf, v2sf) | |
10498 | v2sf __builtin_ia32_pi2fw (v2si) | |
10499 | v2sf __builtin_ia32_pswapdsf (v2sf) | |
10500 | v2si __builtin_ia32_pswapdsi (v2si) | |
3ab51846 | 10501 | @end smallexample |
0975678f | 10502 | |
118ea793 CF |
10503 | @node MIPS DSP Built-in Functions |
10504 | @subsection MIPS DSP Built-in Functions | |
10505 | ||
10506 | The MIPS DSP Application-Specific Extension (ASE) includes new | |
10507 | instructions that are designed to improve the performance of DSP and | |
10508 | media applications. It provides instructions that operate on packed | |
32041385 | 10509 | 8-bit/16-bit integer data, Q7, Q15 and Q31 fractional data. |
118ea793 CF |
10510 | |
10511 | GCC supports MIPS DSP operations using both the generic | |
10512 | vector extensions (@pxref{Vector Extensions}) and a collection of | |
10513 | MIPS-specific built-in functions. Both kinds of support are | |
10514 | enabled by the @option{-mdsp} command-line option. | |
10515 | ||
32041385 CF |
10516 | Revision 2 of the ASE was introduced in the second half of 2006. |
10517 | This revision adds extra instructions to the original ASE, but is | |
10518 | otherwise backwards-compatible with it. You can select revision 2 | |
10519 | using the command-line option @option{-mdspr2}; this option implies | |
10520 | @option{-mdsp}. | |
10521 | ||
1e27273f CM |
10522 | The SCOUNT and POS bits of the DSP control register are global. The |
10523 | WRDSP, EXTPDP, EXTPDPV and MTHLIP instructions modify the SCOUNT and | |
10524 | POS bits. During optimization, the compiler will not delete these | |
10525 | instructions and it will not delete calls to functions containing | |
10526 | these instructions. | |
10527 | ||
118ea793 CF |
10528 | At present, GCC only provides support for operations on 32-bit |
10529 | vectors. The vector type associated with 8-bit integer data is | |
32041385 CF |
10530 | usually called @code{v4i8}, the vector type associated with Q7 |
10531 | is usually called @code{v4q7}, the vector type associated with 16-bit | |
10532 | integer data is usually called @code{v2i16}, and the vector type | |
10533 | associated with Q15 is usually called @code{v2q15}. They can be | |
10534 | defined in C as follows: | |
118ea793 CF |
10535 | |
10536 | @smallexample | |
32041385 CF |
10537 | typedef signed char v4i8 __attribute__ ((vector_size(4))); |
10538 | typedef signed char v4q7 __attribute__ ((vector_size(4))); | |
10539 | typedef short v2i16 __attribute__ ((vector_size(4))); | |
118ea793 CF |
10540 | typedef short v2q15 __attribute__ ((vector_size(4))); |
10541 | @end smallexample | |
10542 | ||
32041385 CF |
10543 | @code{v4i8}, @code{v4q7}, @code{v2i16} and @code{v2q15} values are |
10544 | initialized in the same way as aggregates. For example: | |
118ea793 CF |
10545 | |
10546 | @smallexample | |
10547 | v4i8 a = @{1, 2, 3, 4@}; | |
10548 | v4i8 b; | |
10549 | b = (v4i8) @{5, 6, 7, 8@}; | |
10550 | ||
10551 | v2q15 c = @{0x0fcb, 0x3a75@}; | |
10552 | v2q15 d; | |
10553 | d = (v2q15) @{0.1234 * 0x1.0p15, 0.4567 * 0x1.0p15@}; | |
10554 | @end smallexample | |
10555 | ||
10556 | @emph{Note:} The CPU's endianness determines the order in which values | |
10557 | are packed. On little-endian targets, the first value is the least | |
10558 | significant and the last value is the most significant. The opposite | |
10559 | order applies to big-endian targets. For example, the code above will | |
10560 | set the lowest byte of @code{a} to @code{1} on little-endian targets | |
10561 | and @code{4} on big-endian targets. | |
10562 | ||
32041385 | 10563 | @emph{Note:} Q7, Q15 and Q31 values must be initialized with their integer |
118ea793 | 10564 | representation. As shown in this example, the integer representation |
32041385 CF |
10565 | of a Q7 value can be obtained by multiplying the fractional value by |
10566 | @code{0x1.0p7}. The equivalent for Q15 values is to multiply by | |
118ea793 CF |
10567 | @code{0x1.0p15}. The equivalent for Q31 values is to multiply by |
10568 | @code{0x1.0p31}. | |
10569 | ||
10570 | The table below lists the @code{v4i8} and @code{v2q15} operations for which | |
10571 | hardware support exists. @code{a} and @code{b} are @code{v4i8} values, | |
10572 | and @code{c} and @code{d} are @code{v2q15} values. | |
10573 | ||
10574 | @multitable @columnfractions .50 .50 | |
10575 | @item C code @tab MIPS instruction | |
10576 | @item @code{a + b} @tab @code{addu.qb} | |
10577 | @item @code{c + d} @tab @code{addq.ph} | |
10578 | @item @code{a - b} @tab @code{subu.qb} | |
10579 | @item @code{c - d} @tab @code{subq.ph} | |
10580 | @end multitable | |
10581 | ||
32041385 CF |
10582 | The table below lists the @code{v2i16} operation for which |
10583 | hardware support exists for the DSP ASE REV 2. @code{e} and @code{f} are | |
10584 | @code{v2i16} values. | |
10585 | ||
10586 | @multitable @columnfractions .50 .50 | |
10587 | @item C code @tab MIPS instruction | |
10588 | @item @code{e * f} @tab @code{mul.ph} | |
10589 | @end multitable | |
10590 | ||
118ea793 CF |
10591 | It is easier to describe the DSP built-in functions if we first define |
10592 | the following types: | |
10593 | ||
10594 | @smallexample | |
10595 | typedef int q31; | |
10596 | typedef int i32; | |
32041385 | 10597 | typedef unsigned int ui32; |
118ea793 CF |
10598 | typedef long long a64; |
10599 | @end smallexample | |
10600 | ||
10601 | @code{q31} and @code{i32} are actually the same as @code{int}, but we | |
10602 | use @code{q31} to indicate a Q31 fractional value and @code{i32} to | |
10603 | indicate a 32-bit integer value. Similarly, @code{a64} is the same as | |
10604 | @code{long long}, but we use @code{a64} to indicate values that will | |
10605 | be placed in one of the four DSP accumulators (@code{$ac0}, | |
10606 | @code{$ac1}, @code{$ac2} or @code{$ac3}). | |
10607 | ||
10608 | Also, some built-in functions prefer or require immediate numbers as | |
10609 | parameters, because the corresponding DSP instructions accept both immediate | |
10610 | numbers and register operands, or accept immediate numbers only. The | |
10611 | immediate parameters are listed as follows. | |
10612 | ||
10613 | @smallexample | |
32041385 | 10614 | imm0_3: 0 to 3. |
118ea793 CF |
10615 | imm0_7: 0 to 7. |
10616 | imm0_15: 0 to 15. | |
10617 | imm0_31: 0 to 31. | |
10618 | imm0_63: 0 to 63. | |
10619 | imm0_255: 0 to 255. | |
10620 | imm_n32_31: -32 to 31. | |
10621 | imm_n512_511: -512 to 511. | |
10622 | @end smallexample | |
10623 | ||
10624 | The following built-in functions map directly to a particular MIPS DSP | |
10625 | instruction. Please refer to the architecture specification | |
10626 | for details on what each instruction does. | |
10627 | ||
10628 | @smallexample | |
10629 | v2q15 __builtin_mips_addq_ph (v2q15, v2q15) | |
10630 | v2q15 __builtin_mips_addq_s_ph (v2q15, v2q15) | |
10631 | q31 __builtin_mips_addq_s_w (q31, q31) | |
10632 | v4i8 __builtin_mips_addu_qb (v4i8, v4i8) | |
10633 | v4i8 __builtin_mips_addu_s_qb (v4i8, v4i8) | |
10634 | v2q15 __builtin_mips_subq_ph (v2q15, v2q15) | |
10635 | v2q15 __builtin_mips_subq_s_ph (v2q15, v2q15) | |
10636 | q31 __builtin_mips_subq_s_w (q31, q31) | |
10637 | v4i8 __builtin_mips_subu_qb (v4i8, v4i8) | |
10638 | v4i8 __builtin_mips_subu_s_qb (v4i8, v4i8) | |
10639 | i32 __builtin_mips_addsc (i32, i32) | |
10640 | i32 __builtin_mips_addwc (i32, i32) | |
10641 | i32 __builtin_mips_modsub (i32, i32) | |
10642 | i32 __builtin_mips_raddu_w_qb (v4i8) | |
10643 | v2q15 __builtin_mips_absq_s_ph (v2q15) | |
10644 | q31 __builtin_mips_absq_s_w (q31) | |
10645 | v4i8 __builtin_mips_precrq_qb_ph (v2q15, v2q15) | |
10646 | v2q15 __builtin_mips_precrq_ph_w (q31, q31) | |
10647 | v2q15 __builtin_mips_precrq_rs_ph_w (q31, q31) | |
10648 | v4i8 __builtin_mips_precrqu_s_qb_ph (v2q15, v2q15) | |
10649 | q31 __builtin_mips_preceq_w_phl (v2q15) | |
10650 | q31 __builtin_mips_preceq_w_phr (v2q15) | |
10651 | v2q15 __builtin_mips_precequ_ph_qbl (v4i8) | |
10652 | v2q15 __builtin_mips_precequ_ph_qbr (v4i8) | |
10653 | v2q15 __builtin_mips_precequ_ph_qbla (v4i8) | |
10654 | v2q15 __builtin_mips_precequ_ph_qbra (v4i8) | |
10655 | v2q15 __builtin_mips_preceu_ph_qbl (v4i8) | |
10656 | v2q15 __builtin_mips_preceu_ph_qbr (v4i8) | |
10657 | v2q15 __builtin_mips_preceu_ph_qbla (v4i8) | |
10658 | v2q15 __builtin_mips_preceu_ph_qbra (v4i8) | |
10659 | v4i8 __builtin_mips_shll_qb (v4i8, imm0_7) | |
10660 | v4i8 __builtin_mips_shll_qb (v4i8, i32) | |
10661 | v2q15 __builtin_mips_shll_ph (v2q15, imm0_15) | |
10662 | v2q15 __builtin_mips_shll_ph (v2q15, i32) | |
10663 | v2q15 __builtin_mips_shll_s_ph (v2q15, imm0_15) | |
10664 | v2q15 __builtin_mips_shll_s_ph (v2q15, i32) | |
10665 | q31 __builtin_mips_shll_s_w (q31, imm0_31) | |
10666 | q31 __builtin_mips_shll_s_w (q31, i32) | |
10667 | v4i8 __builtin_mips_shrl_qb (v4i8, imm0_7) | |
10668 | v4i8 __builtin_mips_shrl_qb (v4i8, i32) | |
10669 | v2q15 __builtin_mips_shra_ph (v2q15, imm0_15) | |
10670 | v2q15 __builtin_mips_shra_ph (v2q15, i32) | |
10671 | v2q15 __builtin_mips_shra_r_ph (v2q15, imm0_15) | |
10672 | v2q15 __builtin_mips_shra_r_ph (v2q15, i32) | |
10673 | q31 __builtin_mips_shra_r_w (q31, imm0_31) | |
10674 | q31 __builtin_mips_shra_r_w (q31, i32) | |
10675 | v2q15 __builtin_mips_muleu_s_ph_qbl (v4i8, v2q15) | |
10676 | v2q15 __builtin_mips_muleu_s_ph_qbr (v4i8, v2q15) | |
10677 | v2q15 __builtin_mips_mulq_rs_ph (v2q15, v2q15) | |
10678 | q31 __builtin_mips_muleq_s_w_phl (v2q15, v2q15) | |
10679 | q31 __builtin_mips_muleq_s_w_phr (v2q15, v2q15) | |
10680 | a64 __builtin_mips_dpau_h_qbl (a64, v4i8, v4i8) | |
10681 | a64 __builtin_mips_dpau_h_qbr (a64, v4i8, v4i8) | |
10682 | a64 __builtin_mips_dpsu_h_qbl (a64, v4i8, v4i8) | |
10683 | a64 __builtin_mips_dpsu_h_qbr (a64, v4i8, v4i8) | |
10684 | a64 __builtin_mips_dpaq_s_w_ph (a64, v2q15, v2q15) | |
10685 | a64 __builtin_mips_dpaq_sa_l_w (a64, q31, q31) | |
10686 | a64 __builtin_mips_dpsq_s_w_ph (a64, v2q15, v2q15) | |
10687 | a64 __builtin_mips_dpsq_sa_l_w (a64, q31, q31) | |
10688 | a64 __builtin_mips_mulsaq_s_w_ph (a64, v2q15, v2q15) | |
10689 | a64 __builtin_mips_maq_s_w_phl (a64, v2q15, v2q15) | |
10690 | a64 __builtin_mips_maq_s_w_phr (a64, v2q15, v2q15) | |
10691 | a64 __builtin_mips_maq_sa_w_phl (a64, v2q15, v2q15) | |
10692 | a64 __builtin_mips_maq_sa_w_phr (a64, v2q15, v2q15) | |
10693 | i32 __builtin_mips_bitrev (i32) | |
10694 | i32 __builtin_mips_insv (i32, i32) | |
10695 | v4i8 __builtin_mips_repl_qb (imm0_255) | |
10696 | v4i8 __builtin_mips_repl_qb (i32) | |
10697 | v2q15 __builtin_mips_repl_ph (imm_n512_511) | |
10698 | v2q15 __builtin_mips_repl_ph (i32) | |
10699 | void __builtin_mips_cmpu_eq_qb (v4i8, v4i8) | |
10700 | void __builtin_mips_cmpu_lt_qb (v4i8, v4i8) | |
10701 | void __builtin_mips_cmpu_le_qb (v4i8, v4i8) | |
10702 | i32 __builtin_mips_cmpgu_eq_qb (v4i8, v4i8) | |
10703 | i32 __builtin_mips_cmpgu_lt_qb (v4i8, v4i8) | |
10704 | i32 __builtin_mips_cmpgu_le_qb (v4i8, v4i8) | |
10705 | void __builtin_mips_cmp_eq_ph (v2q15, v2q15) | |
10706 | void __builtin_mips_cmp_lt_ph (v2q15, v2q15) | |
10707 | void __builtin_mips_cmp_le_ph (v2q15, v2q15) | |
10708 | v4i8 __builtin_mips_pick_qb (v4i8, v4i8) | |
10709 | v2q15 __builtin_mips_pick_ph (v2q15, v2q15) | |
10710 | v2q15 __builtin_mips_packrl_ph (v2q15, v2q15) | |
10711 | i32 __builtin_mips_extr_w (a64, imm0_31) | |
10712 | i32 __builtin_mips_extr_w (a64, i32) | |
10713 | i32 __builtin_mips_extr_r_w (a64, imm0_31) | |
10714 | i32 __builtin_mips_extr_s_h (a64, i32) | |
10715 | i32 __builtin_mips_extr_rs_w (a64, imm0_31) | |
10716 | i32 __builtin_mips_extr_rs_w (a64, i32) | |
10717 | i32 __builtin_mips_extr_s_h (a64, imm0_31) | |
10718 | i32 __builtin_mips_extr_r_w (a64, i32) | |
10719 | i32 __builtin_mips_extp (a64, imm0_31) | |
10720 | i32 __builtin_mips_extp (a64, i32) | |
10721 | i32 __builtin_mips_extpdp (a64, imm0_31) | |
10722 | i32 __builtin_mips_extpdp (a64, i32) | |
10723 | a64 __builtin_mips_shilo (a64, imm_n32_31) | |
10724 | a64 __builtin_mips_shilo (a64, i32) | |
10725 | a64 __builtin_mips_mthlip (a64, i32) | |
10726 | void __builtin_mips_wrdsp (i32, imm0_63) | |
10727 | i32 __builtin_mips_rddsp (imm0_63) | |
10728 | i32 __builtin_mips_lbux (void *, i32) | |
10729 | i32 __builtin_mips_lhx (void *, i32) | |
10730 | i32 __builtin_mips_lwx (void *, i32) | |
770da00a | 10731 | a64 __builtin_mips_ldx (void *, i32) [MIPS64 only] |
118ea793 | 10732 | i32 __builtin_mips_bposge32 (void) |
293b77b0 CF |
10733 | a64 __builtin_mips_madd (a64, i32, i32); |
10734 | a64 __builtin_mips_maddu (a64, ui32, ui32); | |
10735 | a64 __builtin_mips_msub (a64, i32, i32); | |
10736 | a64 __builtin_mips_msubu (a64, ui32, ui32); | |
10737 | a64 __builtin_mips_mult (i32, i32); | |
10738 | a64 __builtin_mips_multu (ui32, ui32); | |
118ea793 CF |
10739 | @end smallexample |
10740 | ||
32041385 CF |
10741 | The following built-in functions map directly to a particular MIPS DSP REV 2 |
10742 | instruction. Please refer to the architecture specification | |
10743 | for details on what each instruction does. | |
10744 | ||
10745 | @smallexample | |
10746 | v4q7 __builtin_mips_absq_s_qb (v4q7); | |
10747 | v2i16 __builtin_mips_addu_ph (v2i16, v2i16); | |
10748 | v2i16 __builtin_mips_addu_s_ph (v2i16, v2i16); | |
10749 | v4i8 __builtin_mips_adduh_qb (v4i8, v4i8); | |
10750 | v4i8 __builtin_mips_adduh_r_qb (v4i8, v4i8); | |
10751 | i32 __builtin_mips_append (i32, i32, imm0_31); | |
10752 | i32 __builtin_mips_balign (i32, i32, imm0_3); | |
10753 | i32 __builtin_mips_cmpgdu_eq_qb (v4i8, v4i8); | |
10754 | i32 __builtin_mips_cmpgdu_lt_qb (v4i8, v4i8); | |
10755 | i32 __builtin_mips_cmpgdu_le_qb (v4i8, v4i8); | |
10756 | a64 __builtin_mips_dpa_w_ph (a64, v2i16, v2i16); | |
10757 | a64 __builtin_mips_dps_w_ph (a64, v2i16, v2i16); | |
32041385 CF |
10758 | v2i16 __builtin_mips_mul_ph (v2i16, v2i16); |
10759 | v2i16 __builtin_mips_mul_s_ph (v2i16, v2i16); | |
10760 | q31 __builtin_mips_mulq_rs_w (q31, q31); | |
10761 | v2q15 __builtin_mips_mulq_s_ph (v2q15, v2q15); | |
10762 | q31 __builtin_mips_mulq_s_w (q31, q31); | |
10763 | a64 __builtin_mips_mulsa_w_ph (a64, v2i16, v2i16); | |
32041385 CF |
10764 | v4i8 __builtin_mips_precr_qb_ph (v2i16, v2i16); |
10765 | v2i16 __builtin_mips_precr_sra_ph_w (i32, i32, imm0_31); | |
10766 | v2i16 __builtin_mips_precr_sra_r_ph_w (i32, i32, imm0_31); | |
10767 | i32 __builtin_mips_prepend (i32, i32, imm0_31); | |
10768 | v4i8 __builtin_mips_shra_qb (v4i8, imm0_7); | |
10769 | v4i8 __builtin_mips_shra_r_qb (v4i8, imm0_7); | |
10770 | v4i8 __builtin_mips_shra_qb (v4i8, i32); | |
10771 | v4i8 __builtin_mips_shra_r_qb (v4i8, i32); | |
10772 | v2i16 __builtin_mips_shrl_ph (v2i16, imm0_15); | |
10773 | v2i16 __builtin_mips_shrl_ph (v2i16, i32); | |
10774 | v2i16 __builtin_mips_subu_ph (v2i16, v2i16); | |
10775 | v2i16 __builtin_mips_subu_s_ph (v2i16, v2i16); | |
10776 | v4i8 __builtin_mips_subuh_qb (v4i8, v4i8); | |
10777 | v4i8 __builtin_mips_subuh_r_qb (v4i8, v4i8); | |
10778 | v2q15 __builtin_mips_addqh_ph (v2q15, v2q15); | |
10779 | v2q15 __builtin_mips_addqh_r_ph (v2q15, v2q15); | |
10780 | q31 __builtin_mips_addqh_w (q31, q31); | |
10781 | q31 __builtin_mips_addqh_r_w (q31, q31); | |
10782 | v2q15 __builtin_mips_subqh_ph (v2q15, v2q15); | |
10783 | v2q15 __builtin_mips_subqh_r_ph (v2q15, v2q15); | |
10784 | q31 __builtin_mips_subqh_w (q31, q31); | |
10785 | q31 __builtin_mips_subqh_r_w (q31, q31); | |
10786 | a64 __builtin_mips_dpax_w_ph (a64, v2i16, v2i16); | |
10787 | a64 __builtin_mips_dpsx_w_ph (a64, v2i16, v2i16); | |
10788 | a64 __builtin_mips_dpaqx_s_w_ph (a64, v2q15, v2q15); | |
10789 | a64 __builtin_mips_dpaqx_sa_w_ph (a64, v2q15, v2q15); | |
10790 | a64 __builtin_mips_dpsqx_s_w_ph (a64, v2q15, v2q15); | |
10791 | a64 __builtin_mips_dpsqx_sa_w_ph (a64, v2q15, v2q15); | |
10792 | @end smallexample | |
10793 | ||
10794 | ||
d840bfd3 CF |
10795 | @node MIPS Paired-Single Support |
10796 | @subsection MIPS Paired-Single Support | |
10797 | ||
10798 | The MIPS64 architecture includes a number of instructions that | |
10799 | operate on pairs of single-precision floating-point values. | |
10800 | Each pair is packed into a 64-bit floating-point register, | |
10801 | with one element being designated the ``upper half'' and | |
10802 | the other being designated the ``lower half''. | |
10803 | ||
10804 | GCC supports paired-single operations using both the generic | |
10805 | vector extensions (@pxref{Vector Extensions}) and a collection of | |
10806 | MIPS-specific built-in functions. Both kinds of support are | |
10807 | enabled by the @option{-mpaired-single} command-line option. | |
10808 | ||
10809 | The vector type associated with paired-single values is usually | |
10810 | called @code{v2sf}. It can be defined in C as follows: | |
10811 | ||
10812 | @smallexample | |
10813 | typedef float v2sf __attribute__ ((vector_size (8))); | |
10814 | @end smallexample | |
10815 | ||
10816 | @code{v2sf} values are initialized in the same way as aggregates. | |
10817 | For example: | |
10818 | ||
10819 | @smallexample | |
10820 | v2sf a = @{1.5, 9.1@}; | |
10821 | v2sf b; | |
10822 | float e, f; | |
10823 | b = (v2sf) @{e, f@}; | |
10824 | @end smallexample | |
10825 | ||
10826 | @emph{Note:} The CPU's endianness determines which value is stored in | |
10827 | the upper half of a register and which value is stored in the lower half. | |
10828 | On little-endian targets, the first value is the lower one and the second | |
10829 | value is the upper one. The opposite order applies to big-endian targets. | |
10830 | For example, the code above will set the lower half of @code{a} to | |
10831 | @code{1.5} on little-endian targets and @code{9.1} on big-endian targets. | |
10832 | ||
93581857 MS |
10833 | @node MIPS Loongson Built-in Functions |
10834 | @subsection MIPS Loongson Built-in Functions | |
10835 | ||
10836 | GCC provides intrinsics to access the SIMD instructions provided by the | |
10837 | ST Microelectronics Loongson-2E and -2F processors. These intrinsics, | |
10838 | available after inclusion of the @code{loongson.h} header file, | |
10839 | operate on the following 64-bit vector types: | |
10840 | ||
10841 | @itemize | |
10842 | @item @code{uint8x8_t}, a vector of eight unsigned 8-bit integers; | |
10843 | @item @code{uint16x4_t}, a vector of four unsigned 16-bit integers; | |
10844 | @item @code{uint32x2_t}, a vector of two unsigned 32-bit integers; | |
10845 | @item @code{int8x8_t}, a vector of eight signed 8-bit integers; | |
10846 | @item @code{int16x4_t}, a vector of four signed 16-bit integers; | |
10847 | @item @code{int32x2_t}, a vector of two signed 32-bit integers. | |
10848 | @end itemize | |
10849 | ||
10850 | The intrinsics provided are listed below; each is named after the | |
10851 | machine instruction to which it corresponds, with suffixes added as | |
10852 | appropriate to distinguish intrinsics that expand to the same machine | |
10853 | instruction yet have different argument types. Refer to the architecture | |
10854 | documentation for a description of the functionality of each | |
10855 | instruction. | |
10856 | ||
10857 | @smallexample | |
10858 | int16x4_t packsswh (int32x2_t s, int32x2_t t); | |
10859 | int8x8_t packsshb (int16x4_t s, int16x4_t t); | |
10860 | uint8x8_t packushb (uint16x4_t s, uint16x4_t t); | |
10861 | uint32x2_t paddw_u (uint32x2_t s, uint32x2_t t); | |
10862 | uint16x4_t paddh_u (uint16x4_t s, uint16x4_t t); | |
10863 | uint8x8_t paddb_u (uint8x8_t s, uint8x8_t t); | |
10864 | int32x2_t paddw_s (int32x2_t s, int32x2_t t); | |
10865 | int16x4_t paddh_s (int16x4_t s, int16x4_t t); | |
10866 | int8x8_t paddb_s (int8x8_t s, int8x8_t t); | |
10867 | uint64_t paddd_u (uint64_t s, uint64_t t); | |
10868 | int64_t paddd_s (int64_t s, int64_t t); | |
10869 | int16x4_t paddsh (int16x4_t s, int16x4_t t); | |
10870 | int8x8_t paddsb (int8x8_t s, int8x8_t t); | |
10871 | uint16x4_t paddush (uint16x4_t s, uint16x4_t t); | |
10872 | uint8x8_t paddusb (uint8x8_t s, uint8x8_t t); | |
10873 | uint64_t pandn_ud (uint64_t s, uint64_t t); | |
10874 | uint32x2_t pandn_uw (uint32x2_t s, uint32x2_t t); | |
10875 | uint16x4_t pandn_uh (uint16x4_t s, uint16x4_t t); | |
10876 | uint8x8_t pandn_ub (uint8x8_t s, uint8x8_t t); | |
10877 | int64_t pandn_sd (int64_t s, int64_t t); | |
10878 | int32x2_t pandn_sw (int32x2_t s, int32x2_t t); | |
10879 | int16x4_t pandn_sh (int16x4_t s, int16x4_t t); | |
10880 | int8x8_t pandn_sb (int8x8_t s, int8x8_t t); | |
10881 | uint16x4_t pavgh (uint16x4_t s, uint16x4_t t); | |
10882 | uint8x8_t pavgb (uint8x8_t s, uint8x8_t t); | |
10883 | uint32x2_t pcmpeqw_u (uint32x2_t s, uint32x2_t t); | |
10884 | uint16x4_t pcmpeqh_u (uint16x4_t s, uint16x4_t t); | |
10885 | uint8x8_t pcmpeqb_u (uint8x8_t s, uint8x8_t t); | |
10886 | int32x2_t pcmpeqw_s (int32x2_t s, int32x2_t t); | |
10887 | int16x4_t pcmpeqh_s (int16x4_t s, int16x4_t t); | |
10888 | int8x8_t pcmpeqb_s (int8x8_t s, int8x8_t t); | |
10889 | uint32x2_t pcmpgtw_u (uint32x2_t s, uint32x2_t t); | |
10890 | uint16x4_t pcmpgth_u (uint16x4_t s, uint16x4_t t); | |
10891 | uint8x8_t pcmpgtb_u (uint8x8_t s, uint8x8_t t); | |
10892 | int32x2_t pcmpgtw_s (int32x2_t s, int32x2_t t); | |
10893 | int16x4_t pcmpgth_s (int16x4_t s, int16x4_t t); | |
10894 | int8x8_t pcmpgtb_s (int8x8_t s, int8x8_t t); | |
10895 | uint16x4_t pextrh_u (uint16x4_t s, int field); | |
10896 | int16x4_t pextrh_s (int16x4_t s, int field); | |
10897 | uint16x4_t pinsrh_0_u (uint16x4_t s, uint16x4_t t); | |
10898 | uint16x4_t pinsrh_1_u (uint16x4_t s, uint16x4_t t); | |
10899 | uint16x4_t pinsrh_2_u (uint16x4_t s, uint16x4_t t); | |
10900 | uint16x4_t pinsrh_3_u (uint16x4_t s, uint16x4_t t); | |
10901 | int16x4_t pinsrh_0_s (int16x4_t s, int16x4_t t); | |
10902 | int16x4_t pinsrh_1_s (int16x4_t s, int16x4_t t); | |
10903 | int16x4_t pinsrh_2_s (int16x4_t s, int16x4_t t); | |
10904 | int16x4_t pinsrh_3_s (int16x4_t s, int16x4_t t); | |
10905 | int32x2_t pmaddhw (int16x4_t s, int16x4_t t); | |
10906 | int16x4_t pmaxsh (int16x4_t s, int16x4_t t); | |
10907 | uint8x8_t pmaxub (uint8x8_t s, uint8x8_t t); | |
10908 | int16x4_t pminsh (int16x4_t s, int16x4_t t); | |
10909 | uint8x8_t pminub (uint8x8_t s, uint8x8_t t); | |
10910 | uint8x8_t pmovmskb_u (uint8x8_t s); | |
10911 | int8x8_t pmovmskb_s (int8x8_t s); | |
10912 | uint16x4_t pmulhuh (uint16x4_t s, uint16x4_t t); | |
10913 | int16x4_t pmulhh (int16x4_t s, int16x4_t t); | |
10914 | int16x4_t pmullh (int16x4_t s, int16x4_t t); | |
10915 | int64_t pmuluw (uint32x2_t s, uint32x2_t t); | |
10916 | uint8x8_t pasubub (uint8x8_t s, uint8x8_t t); | |
10917 | uint16x4_t biadd (uint8x8_t s); | |
10918 | uint16x4_t psadbh (uint8x8_t s, uint8x8_t t); | |
10919 | uint16x4_t pshufh_u (uint16x4_t dest, uint16x4_t s, uint8_t order); | |
10920 | int16x4_t pshufh_s (int16x4_t dest, int16x4_t s, uint8_t order); | |
10921 | uint16x4_t psllh_u (uint16x4_t s, uint8_t amount); | |
10922 | int16x4_t psllh_s (int16x4_t s, uint8_t amount); | |
10923 | uint32x2_t psllw_u (uint32x2_t s, uint8_t amount); | |
10924 | int32x2_t psllw_s (int32x2_t s, uint8_t amount); | |
10925 | uint16x4_t psrlh_u (uint16x4_t s, uint8_t amount); | |
10926 | int16x4_t psrlh_s (int16x4_t s, uint8_t amount); | |
10927 | uint32x2_t psrlw_u (uint32x2_t s, uint8_t amount); | |
10928 | int32x2_t psrlw_s (int32x2_t s, uint8_t amount); | |
10929 | uint16x4_t psrah_u (uint16x4_t s, uint8_t amount); | |
10930 | int16x4_t psrah_s (int16x4_t s, uint8_t amount); | |
10931 | uint32x2_t psraw_u (uint32x2_t s, uint8_t amount); | |
10932 | int32x2_t psraw_s (int32x2_t s, uint8_t amount); | |
10933 | uint32x2_t psubw_u (uint32x2_t s, uint32x2_t t); | |
10934 | uint16x4_t psubh_u (uint16x4_t s, uint16x4_t t); | |
10935 | uint8x8_t psubb_u (uint8x8_t s, uint8x8_t t); | |
10936 | int32x2_t psubw_s (int32x2_t s, int32x2_t t); | |
10937 | int16x4_t psubh_s (int16x4_t s, int16x4_t t); | |
10938 | int8x8_t psubb_s (int8x8_t s, int8x8_t t); | |
10939 | uint64_t psubd_u (uint64_t s, uint64_t t); | |
10940 | int64_t psubd_s (int64_t s, int64_t t); | |
10941 | int16x4_t psubsh (int16x4_t s, int16x4_t t); | |
10942 | int8x8_t psubsb (int8x8_t s, int8x8_t t); | |
10943 | uint16x4_t psubush (uint16x4_t s, uint16x4_t t); | |
10944 | uint8x8_t psubusb (uint8x8_t s, uint8x8_t t); | |
10945 | uint32x2_t punpckhwd_u (uint32x2_t s, uint32x2_t t); | |
10946 | uint16x4_t punpckhhw_u (uint16x4_t s, uint16x4_t t); | |
10947 | uint8x8_t punpckhbh_u (uint8x8_t s, uint8x8_t t); | |
10948 | int32x2_t punpckhwd_s (int32x2_t s, int32x2_t t); | |
10949 | int16x4_t punpckhhw_s (int16x4_t s, int16x4_t t); | |
10950 | int8x8_t punpckhbh_s (int8x8_t s, int8x8_t t); | |
10951 | uint32x2_t punpcklwd_u (uint32x2_t s, uint32x2_t t); | |
10952 | uint16x4_t punpcklhw_u (uint16x4_t s, uint16x4_t t); | |
10953 | uint8x8_t punpcklbh_u (uint8x8_t s, uint8x8_t t); | |
10954 | int32x2_t punpcklwd_s (int32x2_t s, int32x2_t t); | |
10955 | int16x4_t punpcklhw_s (int16x4_t s, int16x4_t t); | |
10956 | int8x8_t punpcklbh_s (int8x8_t s, int8x8_t t); | |
10957 | @end smallexample | |
10958 | ||
d840bfd3 CF |
10959 | @menu |
10960 | * Paired-Single Arithmetic:: | |
10961 | * Paired-Single Built-in Functions:: | |
10962 | * MIPS-3D Built-in Functions:: | |
10963 | @end menu | |
10964 | ||
10965 | @node Paired-Single Arithmetic | |
10966 | @subsubsection Paired-Single Arithmetic | |
10967 | ||
10968 | The table below lists the @code{v2sf} operations for which hardware | |
10969 | support exists. @code{a}, @code{b} and @code{c} are @code{v2sf} | |
10970 | values and @code{x} is an integral value. | |
10971 | ||
10972 | @multitable @columnfractions .50 .50 | |
10973 | @item C code @tab MIPS instruction | |
10974 | @item @code{a + b} @tab @code{add.ps} | |
10975 | @item @code{a - b} @tab @code{sub.ps} | |
10976 | @item @code{-a} @tab @code{neg.ps} | |
10977 | @item @code{a * b} @tab @code{mul.ps} | |
10978 | @item @code{a * b + c} @tab @code{madd.ps} | |
10979 | @item @code{a * b - c} @tab @code{msub.ps} | |
10980 | @item @code{-(a * b + c)} @tab @code{nmadd.ps} | |
10981 | @item @code{-(a * b - c)} @tab @code{nmsub.ps} | |
10982 | @item @code{x ? a : b} @tab @code{movn.ps}/@code{movz.ps} | |
10983 | @end multitable | |
10984 | ||
10985 | Note that the multiply-accumulate instructions can be disabled | |
10986 | using the command-line option @code{-mno-fused-madd}. | |
10987 | ||
10988 | @node Paired-Single Built-in Functions | |
10989 | @subsubsection Paired-Single Built-in Functions | |
10990 | ||
10991 | The following paired-single functions map directly to a particular | |
10992 | MIPS instruction. Please refer to the architecture specification | |
10993 | for details on what each instruction does. | |
10994 | ||
10995 | @table @code | |
10996 | @item v2sf __builtin_mips_pll_ps (v2sf, v2sf) | |
10997 | Pair lower lower (@code{pll.ps}). | |
10998 | ||
10999 | @item v2sf __builtin_mips_pul_ps (v2sf, v2sf) | |
11000 | Pair upper lower (@code{pul.ps}). | |
11001 | ||
11002 | @item v2sf __builtin_mips_plu_ps (v2sf, v2sf) | |
11003 | Pair lower upper (@code{plu.ps}). | |
11004 | ||
11005 | @item v2sf __builtin_mips_puu_ps (v2sf, v2sf) | |
11006 | Pair upper upper (@code{puu.ps}). | |
11007 | ||
11008 | @item v2sf __builtin_mips_cvt_ps_s (float, float) | |
11009 | Convert pair to paired single (@code{cvt.ps.s}). | |
11010 | ||
11011 | @item float __builtin_mips_cvt_s_pl (v2sf) | |
11012 | Convert pair lower to single (@code{cvt.s.pl}). | |
11013 | ||
11014 | @item float __builtin_mips_cvt_s_pu (v2sf) | |
11015 | Convert pair upper to single (@code{cvt.s.pu}). | |
11016 | ||
11017 | @item v2sf __builtin_mips_abs_ps (v2sf) | |
11018 | Absolute value (@code{abs.ps}). | |
11019 | ||
11020 | @item v2sf __builtin_mips_alnv_ps (v2sf, v2sf, int) | |
11021 | Align variable (@code{alnv.ps}). | |
11022 | ||
11023 | @emph{Note:} The value of the third parameter must be 0 or 4 | |
11024 | modulo 8, otherwise the result will be unpredictable. Please read the | |
11025 | instruction description for details. | |
11026 | @end table | |
11027 | ||
11028 | The following multi-instruction functions are also available. | |
11029 | In each case, @var{cond} can be any of the 16 floating-point conditions: | |
11030 | @code{f}, @code{un}, @code{eq}, @code{ueq}, @code{olt}, @code{ult}, | |
11031 | @code{ole}, @code{ule}, @code{sf}, @code{ngle}, @code{seq}, @code{ngl}, | |
11032 | @code{lt}, @code{nge}, @code{le} or @code{ngt}. | |
11033 | ||
11034 | @table @code | |
11035 | @item v2sf __builtin_mips_movt_c_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) | |
11036 | @itemx v2sf __builtin_mips_movf_c_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) | |
11037 | Conditional move based on floating point comparison (@code{c.@var{cond}.ps}, | |
11038 | @code{movt.ps}/@code{movf.ps}). | |
11039 | ||
11040 | The @code{movt} functions return the value @var{x} computed by: | |
11041 | ||
11042 | @smallexample | |
11043 | c.@var{cond}.ps @var{cc},@var{a},@var{b} | |
11044 | mov.ps @var{x},@var{c} | |
11045 | movt.ps @var{x},@var{d},@var{cc} | |
11046 | @end smallexample | |
11047 | ||
11048 | The @code{movf} functions are similar but use @code{movf.ps} instead | |
11049 | of @code{movt.ps}. | |
11050 | ||
11051 | @item int __builtin_mips_upper_c_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) | |
11052 | @itemx int __builtin_mips_lower_c_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) | |
11053 | Comparison of two paired-single values (@code{c.@var{cond}.ps}, | |
11054 | @code{bc1t}/@code{bc1f}). | |
11055 | ||
11056 | These functions compare @var{a} and @var{b} using @code{c.@var{cond}.ps} | |
11057 | and return either the upper or lower half of the result. For example: | |
11058 | ||
11059 | @smallexample | |
11060 | v2sf a, b; | |
11061 | if (__builtin_mips_upper_c_eq_ps (a, b)) | |
11062 | upper_halves_are_equal (); | |
11063 | else | |
11064 | upper_halves_are_unequal (); | |
11065 | ||
11066 | if (__builtin_mips_lower_c_eq_ps (a, b)) | |
11067 | lower_halves_are_equal (); | |
11068 | else | |
11069 | lower_halves_are_unequal (); | |
11070 | @end smallexample | |
11071 | @end table | |
11072 | ||
11073 | @node MIPS-3D Built-in Functions | |
11074 | @subsubsection MIPS-3D Built-in Functions | |
11075 | ||
11076 | The MIPS-3D Application-Specific Extension (ASE) includes additional | |
11077 | paired-single instructions that are designed to improve the performance | |
11078 | of 3D graphics operations. Support for these instructions is controlled | |
11079 | by the @option{-mips3d} command-line option. | |
11080 | ||
11081 | The functions listed below map directly to a particular MIPS-3D | |
11082 | instruction. Please refer to the architecture specification for | |
11083 | more details on what each instruction does. | |
11084 | ||
11085 | @table @code | |
11086 | @item v2sf __builtin_mips_addr_ps (v2sf, v2sf) | |
11087 | Reduction add (@code{addr.ps}). | |
11088 | ||
11089 | @item v2sf __builtin_mips_mulr_ps (v2sf, v2sf) | |
11090 | Reduction multiply (@code{mulr.ps}). | |
11091 | ||
11092 | @item v2sf __builtin_mips_cvt_pw_ps (v2sf) | |
11093 | Convert paired single to paired word (@code{cvt.pw.ps}). | |
11094 | ||
11095 | @item v2sf __builtin_mips_cvt_ps_pw (v2sf) | |
11096 | Convert paired word to paired single (@code{cvt.ps.pw}). | |
11097 | ||
11098 | @item float __builtin_mips_recip1_s (float) | |
11099 | @itemx double __builtin_mips_recip1_d (double) | |
11100 | @itemx v2sf __builtin_mips_recip1_ps (v2sf) | |
11101 | Reduced precision reciprocal (sequence step 1) (@code{recip1.@var{fmt}}). | |
11102 | ||
11103 | @item float __builtin_mips_recip2_s (float, float) | |
11104 | @itemx double __builtin_mips_recip2_d (double, double) | |
11105 | @itemx v2sf __builtin_mips_recip2_ps (v2sf, v2sf) | |
11106 | Reduced precision reciprocal (sequence step 2) (@code{recip2.@var{fmt}}). | |
11107 | ||
11108 | @item float __builtin_mips_rsqrt1_s (float) | |
11109 | @itemx double __builtin_mips_rsqrt1_d (double) | |
11110 | @itemx v2sf __builtin_mips_rsqrt1_ps (v2sf) | |
11111 | Reduced precision reciprocal square root (sequence step 1) | |
11112 | (@code{rsqrt1.@var{fmt}}). | |
11113 | ||
11114 | @item float __builtin_mips_rsqrt2_s (float, float) | |
11115 | @itemx double __builtin_mips_rsqrt2_d (double, double) | |
11116 | @itemx v2sf __builtin_mips_rsqrt2_ps (v2sf, v2sf) | |
11117 | Reduced precision reciprocal square root (sequence step 2) | |
11118 | (@code{rsqrt2.@var{fmt}}). | |
11119 | @end table | |
11120 | ||
11121 | The following multi-instruction functions are also available. | |
11122 | In each case, @var{cond} can be any of the 16 floating-point conditions: | |
11123 | @code{f}, @code{un}, @code{eq}, @code{ueq}, @code{olt}, @code{ult}, | |
11124 | @code{ole}, @code{ule}, @code{sf}, @code{ngle}, @code{seq}, | |
11125 | @code{ngl}, @code{lt}, @code{nge}, @code{le} or @code{ngt}. | |
11126 | ||
11127 | @table @code | |
11128 | @item int __builtin_mips_cabs_@var{cond}_s (float @var{a}, float @var{b}) | |
11129 | @itemx int __builtin_mips_cabs_@var{cond}_d (double @var{a}, double @var{b}) | |
11130 | Absolute comparison of two scalar values (@code{cabs.@var{cond}.@var{fmt}}, | |
11131 | @code{bc1t}/@code{bc1f}). | |
11132 | ||
11133 | These functions compare @var{a} and @var{b} using @code{cabs.@var{cond}.s} | |
11134 | or @code{cabs.@var{cond}.d} and return the result as a boolean value. | |
11135 | For example: | |
11136 | ||
11137 | @smallexample | |
11138 | float a, b; | |
11139 | if (__builtin_mips_cabs_eq_s (a, b)) | |
11140 | true (); | |
11141 | else | |
11142 | false (); | |
11143 | @end smallexample | |
11144 | ||
11145 | @item int __builtin_mips_upper_cabs_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) | |
11146 | @itemx int __builtin_mips_lower_cabs_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) | |
11147 | Absolute comparison of two paired-single values (@code{cabs.@var{cond}.ps}, | |
11148 | @code{bc1t}/@code{bc1f}). | |
11149 | ||
11150 | These functions compare @var{a} and @var{b} using @code{cabs.@var{cond}.ps} | |
11151 | and return either the upper or lower half of the result. For example: | |
11152 | ||
11153 | @smallexample | |
11154 | v2sf a, b; | |
11155 | if (__builtin_mips_upper_cabs_eq_ps (a, b)) | |
11156 | upper_halves_are_equal (); | |
11157 | else | |
11158 | upper_halves_are_unequal (); | |
11159 | ||
11160 | if (__builtin_mips_lower_cabs_eq_ps (a, b)) | |
11161 | lower_halves_are_equal (); | |
11162 | else | |
11163 | lower_halves_are_unequal (); | |
11164 | @end smallexample | |
11165 | ||
11166 | @item v2sf __builtin_mips_movt_cabs_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) | |
11167 | @itemx v2sf __builtin_mips_movf_cabs_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) | |
11168 | Conditional move based on absolute comparison (@code{cabs.@var{cond}.ps}, | |
11169 | @code{movt.ps}/@code{movf.ps}). | |
11170 | ||
11171 | The @code{movt} functions return the value @var{x} computed by: | |
11172 | ||
11173 | @smallexample | |
11174 | cabs.@var{cond}.ps @var{cc},@var{a},@var{b} | |
11175 | mov.ps @var{x},@var{c} | |
11176 | movt.ps @var{x},@var{d},@var{cc} | |
11177 | @end smallexample | |
11178 | ||
11179 | The @code{movf} functions are similar but use @code{movf.ps} instead | |
11180 | of @code{movt.ps}. | |
11181 | ||
11182 | @item int __builtin_mips_any_c_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) | |
11183 | @itemx int __builtin_mips_all_c_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) | |
11184 | @itemx int __builtin_mips_any_cabs_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) | |
11185 | @itemx int __builtin_mips_all_cabs_@var{cond}_ps (v2sf @var{a}, v2sf @var{b}) | |
11186 | Comparison of two paired-single values | |
11187 | (@code{c.@var{cond}.ps}/@code{cabs.@var{cond}.ps}, | |
11188 | @code{bc1any2t}/@code{bc1any2f}). | |
11189 | ||
11190 | These functions compare @var{a} and @var{b} using @code{c.@var{cond}.ps} | |
11191 | or @code{cabs.@var{cond}.ps}. The @code{any} forms return true if either | |
11192 | result is true and the @code{all} forms return true if both results are true. | |
11193 | For example: | |
11194 | ||
11195 | @smallexample | |
11196 | v2sf a, b; | |
11197 | if (__builtin_mips_any_c_eq_ps (a, b)) | |
11198 | one_is_true (); | |
11199 | else | |
11200 | both_are_false (); | |
11201 | ||
11202 | if (__builtin_mips_all_c_eq_ps (a, b)) | |
11203 | both_are_true (); | |
11204 | else | |
11205 | one_is_false (); | |
11206 | @end smallexample | |
11207 | ||
11208 | @item int __builtin_mips_any_c_@var{cond}_4s (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) | |
11209 | @itemx int __builtin_mips_all_c_@var{cond}_4s (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) | |
11210 | @itemx int __builtin_mips_any_cabs_@var{cond}_4s (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) | |
11211 | @itemx int __builtin_mips_all_cabs_@var{cond}_4s (v2sf @var{a}, v2sf @var{b}, v2sf @var{c}, v2sf @var{d}) | |
11212 | Comparison of four paired-single values | |
11213 | (@code{c.@var{cond}.ps}/@code{cabs.@var{cond}.ps}, | |
11214 | @code{bc1any4t}/@code{bc1any4f}). | |
11215 | ||
11216 | These functions use @code{c.@var{cond}.ps} or @code{cabs.@var{cond}.ps} | |
11217 | to compare @var{a} with @var{b} and to compare @var{c} with @var{d}. | |
11218 | The @code{any} forms return true if any of the four results are true | |
11219 | and the @code{all} forms return true if all four results are true. | |
11220 | For example: | |
11221 | ||
11222 | @smallexample | |
11223 | v2sf a, b, c, d; | |
11224 | if (__builtin_mips_any_c_eq_4s (a, b, c, d)) | |
11225 | some_are_true (); | |
11226 | else | |
11227 | all_are_false (); | |
11228 | ||
11229 | if (__builtin_mips_all_c_eq_4s (a, b, c, d)) | |
11230 | all_are_true (); | |
11231 | else | |
11232 | some_are_false (); | |
11233 | @end smallexample | |
11234 | @end table | |
11235 | ||
358da97e HS |
11236 | @node picoChip Built-in Functions |
11237 | @subsection picoChip Built-in Functions | |
11238 | ||
11239 | GCC provides an interface to selected machine instructions from the | |
11240 | picoChip instruction set. | |
11241 | ||
11242 | @table @code | |
11243 | @item int __builtin_sbc (int @var{value}) | |
11244 | Sign bit count. Return the number of consecutive bits in @var{value} | |
11245 | which have the same value as the sign-bit. The result is the number of | |
11246 | leading sign bits minus one, giving the number of redundant sign bits in | |
11247 | @var{value}. | |
11248 | ||
11249 | @item int __builtin_byteswap (int @var{value}) | |
11250 | Byte swap. Return the result of swapping the upper and lower bytes of | |
11251 | @var{value}. | |
11252 | ||
11253 | @item int __builtin_brev (int @var{value}) | |
11254 | Bit reversal. Return the result of reversing the bits in | |
11255 | @var{value}. Bit 15 is swapped with bit 0, bit 14 is swapped with bit 1, | |
11256 | and so on. | |
11257 | ||
11258 | @item int __builtin_adds (int @var{x}, int @var{y}) | |
11259 | Saturating addition. Return the result of adding @var{x} and @var{y}, | |
11260 | storing the value 32767 if the result overflows. | |
11261 | ||
11262 | @item int __builtin_subs (int @var{x}, int @var{y}) | |
11263 | Saturating subtraction. Return the result of subtracting @var{y} from | |
8ad1dde7 | 11264 | @var{x}, storing the value @minus{}32768 if the result overflows. |
358da97e HS |
11265 | |
11266 | @item void __builtin_halt (void) | |
11267 | Halt. The processor will stop execution. This built-in is useful for | |
11268 | implementing assertions. | |
11269 | ||
11270 | @end table | |
11271 | ||
4d210b07 RS |
11272 | @node Other MIPS Built-in Functions |
11273 | @subsection Other MIPS Built-in Functions | |
11274 | ||
11275 | GCC provides other MIPS-specific built-in functions: | |
11276 | ||
11277 | @table @code | |
11278 | @item void __builtin_mips_cache (int @var{op}, const volatile void *@var{addr}) | |
11279 | Insert a @samp{cache} instruction with operands @var{op} and @var{addr}. | |
11280 | GCC defines the preprocessor macro @code{___GCC_HAVE_BUILTIN_MIPS_CACHE} | |
11281 | when this function is available. | |
11282 | @end table | |
11283 | ||
29e6733c | 11284 | @node PowerPC AltiVec/VSX Built-in Functions |
333c8841 AH |
11285 | @subsection PowerPC AltiVec Built-in Functions |
11286 | ||
b0b343db JJ |
11287 | GCC provides an interface for the PowerPC family of processors to access |
11288 | the AltiVec operations described in Motorola's AltiVec Programming | |
11289 | Interface Manual. The interface is made available by including | |
11290 | @code{<altivec.h>} and using @option{-maltivec} and | |
11291 | @option{-mabi=altivec}. The interface supports the following vector | |
11292 | types. | |
333c8841 | 11293 | |
b0b343db JJ |
11294 | @smallexample |
11295 | vector unsigned char | |
11296 | vector signed char | |
11297 | vector bool char | |
333c8841 | 11298 | |
b0b343db JJ |
11299 | vector unsigned short |
11300 | vector signed short | |
11301 | vector bool short | |
11302 | vector pixel | |
11303 | ||
11304 | vector unsigned int | |
11305 | vector signed int | |
11306 | vector bool int | |
11307 | vector float | |
11308 | @end smallexample | |
11309 | ||
29e6733c MM |
11310 | If @option{-mvsx} is used the following additional vector types are |
11311 | implemented. | |
11312 | ||
11313 | @smallexample | |
11314 | vector unsigned long | |
11315 | vector signed long | |
11316 | vector double | |
11317 | @end smallexample | |
11318 | ||
11319 | The long types are only implemented for 64-bit code generation, and | |
11320 | the long type is only used in the floating point/integer conversion | |
11321 | instructions. | |
11322 | ||
b0b343db JJ |
11323 | GCC's implementation of the high-level language interface available from |
11324 | C and C++ code differs from Motorola's documentation in several ways. | |
11325 | ||
11326 | @itemize @bullet | |
11327 | ||
11328 | @item | |
11329 | A vector constant is a list of constant expressions within curly braces. | |
11330 | ||
11331 | @item | |
11332 | A vector initializer requires no cast if the vector constant is of the | |
11333 | same type as the variable it is initializing. | |
333c8841 | 11334 | |
b0b343db | 11335 | @item |
5edea4c6 JJ |
11336 | If @code{signed} or @code{unsigned} is omitted, the signedness of the |
11337 | vector type is the default signedness of the base type. The default | |
11338 | varies depending on the operating system, so a portable program should | |
11339 | always specify the signedness. | |
4e6e4e4c JJ |
11340 | |
11341 | @item | |
11342 | Compiling with @option{-maltivec} adds keywords @code{__vector}, | |
5950c3c9 BE |
11343 | @code{vector}, @code{__pixel}, @code{pixel}, @code{__bool} and |
11344 | @code{bool}. When compiling ISO C, the context-sensitive substitution | |
11345 | of the keywords @code{vector}, @code{pixel} and @code{bool} is | |
11346 | disabled. To use them, you must include @code{<altivec.h>} instead. | |
4e6e4e4c JJ |
11347 | |
11348 | @item | |
11349 | GCC allows using a @code{typedef} name as the type specifier for a | |
11350 | vector type. | |
b0b343db JJ |
11351 | |
11352 | @item | |
11353 | For C, overloaded functions are implemented with macros so the following | |
11354 | does not work: | |
90989b26 AH |
11355 | |
11356 | @smallexample | |
8254cb45 | 11357 | vec_add ((vector signed int)@{1, 2, 3, 4@}, foo); |
90989b26 AH |
11358 | @end smallexample |
11359 | ||
b0b343db JJ |
11360 | Since @code{vec_add} is a macro, the vector constant in the example |
11361 | is treated as four separate arguments. Wrap the entire argument in | |
11362 | parentheses for this to work. | |
11363 | @end itemize | |
90989b26 | 11364 | |
ae4b4a02 AH |
11365 | @emph{Note:} Only the @code{<altivec.h>} interface is supported. |
11366 | Internally, GCC uses built-in functions to achieve the functionality in | |
11367 | the aforementioned header file, but they are not supported and are | |
11368 | subject to change without notice. | |
11369 | ||
b0b343db JJ |
11370 | The following interfaces are supported for the generic and specific |
11371 | AltiVec operations and the AltiVec predicates. In cases where there | |
11372 | is a direct mapping between generic and specific operations, only the | |
11373 | generic names are shown here, although the specific operations can also | |
11374 | be used. | |
333c8841 | 11375 | |
b0b343db JJ |
11376 | Arguments that are documented as @code{const int} require literal |
11377 | integral values within the range required for that operation. | |
333c8841 | 11378 | |
b0b343db JJ |
11379 | @smallexample |
11380 | vector signed char vec_abs (vector signed char); | |
11381 | vector signed short vec_abs (vector signed short); | |
11382 | vector signed int vec_abs (vector signed int); | |
11383 | vector float vec_abs (vector float); | |
333c8841 | 11384 | |
b0b343db JJ |
11385 | vector signed char vec_abss (vector signed char); |
11386 | vector signed short vec_abss (vector signed short); | |
11387 | vector signed int vec_abss (vector signed int); | |
333c8841 | 11388 | |
b0b343db JJ |
11389 | vector signed char vec_add (vector bool char, vector signed char); |
11390 | vector signed char vec_add (vector signed char, vector bool char); | |
11391 | vector signed char vec_add (vector signed char, vector signed char); | |
11392 | vector unsigned char vec_add (vector bool char, vector unsigned char); | |
11393 | vector unsigned char vec_add (vector unsigned char, vector bool char); | |
924fcc4e JM |
11394 | vector unsigned char vec_add (vector unsigned char, |
11395 | vector unsigned char); | |
b0b343db JJ |
11396 | vector signed short vec_add (vector bool short, vector signed short); |
11397 | vector signed short vec_add (vector signed short, vector bool short); | |
333c8841 | 11398 | vector signed short vec_add (vector signed short, vector signed short); |
b0b343db | 11399 | vector unsigned short vec_add (vector bool short, |
924fcc4e JM |
11400 | vector unsigned short); |
11401 | vector unsigned short vec_add (vector unsigned short, | |
b0b343db | 11402 | vector bool short); |
6e5bb5ad JM |
11403 | vector unsigned short vec_add (vector unsigned short, |
11404 | vector unsigned short); | |
b0b343db JJ |
11405 | vector signed int vec_add (vector bool int, vector signed int); |
11406 | vector signed int vec_add (vector signed int, vector bool int); | |
333c8841 | 11407 | vector signed int vec_add (vector signed int, vector signed int); |
b0b343db JJ |
11408 | vector unsigned int vec_add (vector bool int, vector unsigned int); |
11409 | vector unsigned int vec_add (vector unsigned int, vector bool int); | |
333c8841 AH |
11410 | vector unsigned int vec_add (vector unsigned int, vector unsigned int); |
11411 | vector float vec_add (vector float, vector float); | |
11412 | ||
b0b343db JJ |
11413 | vector float vec_vaddfp (vector float, vector float); |
11414 | ||
11415 | vector signed int vec_vadduwm (vector bool int, vector signed int); | |
11416 | vector signed int vec_vadduwm (vector signed int, vector bool int); | |
11417 | vector signed int vec_vadduwm (vector signed int, vector signed int); | |
11418 | vector unsigned int vec_vadduwm (vector bool int, vector unsigned int); | |
11419 | vector unsigned int vec_vadduwm (vector unsigned int, vector bool int); | |
11420 | vector unsigned int vec_vadduwm (vector unsigned int, | |
11421 | vector unsigned int); | |
11422 | ||
11423 | vector signed short vec_vadduhm (vector bool short, | |
11424 | vector signed short); | |
11425 | vector signed short vec_vadduhm (vector signed short, | |
11426 | vector bool short); | |
11427 | vector signed short vec_vadduhm (vector signed short, | |
11428 | vector signed short); | |
11429 | vector unsigned short vec_vadduhm (vector bool short, | |
11430 | vector unsigned short); | |
11431 | vector unsigned short vec_vadduhm (vector unsigned short, | |
11432 | vector bool short); | |
11433 | vector unsigned short vec_vadduhm (vector unsigned short, | |
11434 | vector unsigned short); | |
11435 | ||
11436 | vector signed char vec_vaddubm (vector bool char, vector signed char); | |
11437 | vector signed char vec_vaddubm (vector signed char, vector bool char); | |
11438 | vector signed char vec_vaddubm (vector signed char, vector signed char); | |
11439 | vector unsigned char vec_vaddubm (vector bool char, | |
11440 | vector unsigned char); | |
11441 | vector unsigned char vec_vaddubm (vector unsigned char, | |
11442 | vector bool char); | |
11443 | vector unsigned char vec_vaddubm (vector unsigned char, | |
11444 | vector unsigned char); | |
11445 | ||
333c8841 AH |
11446 | vector unsigned int vec_addc (vector unsigned int, vector unsigned int); |
11447 | ||
b0b343db JJ |
11448 | vector unsigned char vec_adds (vector bool char, vector unsigned char); |
11449 | vector unsigned char vec_adds (vector unsigned char, vector bool char); | |
924fcc4e JM |
11450 | vector unsigned char vec_adds (vector unsigned char, |
11451 | vector unsigned char); | |
b0b343db JJ |
11452 | vector signed char vec_adds (vector bool char, vector signed char); |
11453 | vector signed char vec_adds (vector signed char, vector bool char); | |
333c8841 | 11454 | vector signed char vec_adds (vector signed char, vector signed char); |
b0b343db | 11455 | vector unsigned short vec_adds (vector bool short, |
924fcc4e JM |
11456 | vector unsigned short); |
11457 | vector unsigned short vec_adds (vector unsigned short, | |
b0b343db | 11458 | vector bool short); |
6e5bb5ad JM |
11459 | vector unsigned short vec_adds (vector unsigned short, |
11460 | vector unsigned short); | |
b0b343db JJ |
11461 | vector signed short vec_adds (vector bool short, vector signed short); |
11462 | vector signed short vec_adds (vector signed short, vector bool short); | |
333c8841 | 11463 | vector signed short vec_adds (vector signed short, vector signed short); |
b0b343db JJ |
11464 | vector unsigned int vec_adds (vector bool int, vector unsigned int); |
11465 | vector unsigned int vec_adds (vector unsigned int, vector bool int); | |
333c8841 | 11466 | vector unsigned int vec_adds (vector unsigned int, vector unsigned int); |
b0b343db JJ |
11467 | vector signed int vec_adds (vector bool int, vector signed int); |
11468 | vector signed int vec_adds (vector signed int, vector bool int); | |
333c8841 AH |
11469 | vector signed int vec_adds (vector signed int, vector signed int); |
11470 | ||
b0b343db JJ |
11471 | vector signed int vec_vaddsws (vector bool int, vector signed int); |
11472 | vector signed int vec_vaddsws (vector signed int, vector bool int); | |
11473 | vector signed int vec_vaddsws (vector signed int, vector signed int); | |
11474 | ||
11475 | vector unsigned int vec_vadduws (vector bool int, vector unsigned int); | |
11476 | vector unsigned int vec_vadduws (vector unsigned int, vector bool int); | |
11477 | vector unsigned int vec_vadduws (vector unsigned int, | |
11478 | vector unsigned int); | |
11479 | ||
11480 | vector signed short vec_vaddshs (vector bool short, | |
11481 | vector signed short); | |
11482 | vector signed short vec_vaddshs (vector signed short, | |
11483 | vector bool short); | |
11484 | vector signed short vec_vaddshs (vector signed short, | |
11485 | vector signed short); | |
11486 | ||
11487 | vector unsigned short vec_vadduhs (vector bool short, | |
11488 | vector unsigned short); | |
11489 | vector unsigned short vec_vadduhs (vector unsigned short, | |
11490 | vector bool short); | |
11491 | vector unsigned short vec_vadduhs (vector unsigned short, | |
11492 | vector unsigned short); | |
11493 | ||
11494 | vector signed char vec_vaddsbs (vector bool char, vector signed char); | |
11495 | vector signed char vec_vaddsbs (vector signed char, vector bool char); | |
11496 | vector signed char vec_vaddsbs (vector signed char, vector signed char); | |
11497 | ||
11498 | vector unsigned char vec_vaddubs (vector bool char, | |
11499 | vector unsigned char); | |
11500 | vector unsigned char vec_vaddubs (vector unsigned char, | |
11501 | vector bool char); | |
11502 | vector unsigned char vec_vaddubs (vector unsigned char, | |
11503 | vector unsigned char); | |
11504 | ||
333c8841 | 11505 | vector float vec_and (vector float, vector float); |
b0b343db JJ |
11506 | vector float vec_and (vector float, vector bool int); |
11507 | vector float vec_and (vector bool int, vector float); | |
11508 | vector bool int vec_and (vector bool int, vector bool int); | |
11509 | vector signed int vec_and (vector bool int, vector signed int); | |
11510 | vector signed int vec_and (vector signed int, vector bool int); | |
333c8841 | 11511 | vector signed int vec_and (vector signed int, vector signed int); |
b0b343db JJ |
11512 | vector unsigned int vec_and (vector bool int, vector unsigned int); |
11513 | vector unsigned int vec_and (vector unsigned int, vector bool int); | |
333c8841 | 11514 | vector unsigned int vec_and (vector unsigned int, vector unsigned int); |
b0b343db JJ |
11515 | vector bool short vec_and (vector bool short, vector bool short); |
11516 | vector signed short vec_and (vector bool short, vector signed short); | |
11517 | vector signed short vec_and (vector signed short, vector bool short); | |
333c8841 | 11518 | vector signed short vec_and (vector signed short, vector signed short); |
b0b343db | 11519 | vector unsigned short vec_and (vector bool short, |
924fcc4e JM |
11520 | vector unsigned short); |
11521 | vector unsigned short vec_and (vector unsigned short, | |
b0b343db | 11522 | vector bool short); |
6e5bb5ad JM |
11523 | vector unsigned short vec_and (vector unsigned short, |
11524 | vector unsigned short); | |
b0b343db JJ |
11525 | vector signed char vec_and (vector bool char, vector signed char); |
11526 | vector bool char vec_and (vector bool char, vector bool char); | |
11527 | vector signed char vec_and (vector signed char, vector bool char); | |
333c8841 | 11528 | vector signed char vec_and (vector signed char, vector signed char); |
b0b343db JJ |
11529 | vector unsigned char vec_and (vector bool char, vector unsigned char); |
11530 | vector unsigned char vec_and (vector unsigned char, vector bool char); | |
924fcc4e JM |
11531 | vector unsigned char vec_and (vector unsigned char, |
11532 | vector unsigned char); | |
333c8841 AH |
11533 | |
11534 | vector float vec_andc (vector float, vector float); | |
b0b343db JJ |
11535 | vector float vec_andc (vector float, vector bool int); |
11536 | vector float vec_andc (vector bool int, vector float); | |
11537 | vector bool int vec_andc (vector bool int, vector bool int); | |
11538 | vector signed int vec_andc (vector bool int, vector signed int); | |
11539 | vector signed int vec_andc (vector signed int, vector bool int); | |
333c8841 | 11540 | vector signed int vec_andc (vector signed int, vector signed int); |
b0b343db JJ |
11541 | vector unsigned int vec_andc (vector bool int, vector unsigned int); |
11542 | vector unsigned int vec_andc (vector unsigned int, vector bool int); | |
333c8841 | 11543 | vector unsigned int vec_andc (vector unsigned int, vector unsigned int); |
b0b343db JJ |
11544 | vector bool short vec_andc (vector bool short, vector bool short); |
11545 | vector signed short vec_andc (vector bool short, vector signed short); | |
11546 | vector signed short vec_andc (vector signed short, vector bool short); | |
333c8841 | 11547 | vector signed short vec_andc (vector signed short, vector signed short); |
b0b343db | 11548 | vector unsigned short vec_andc (vector bool short, |
924fcc4e JM |
11549 | vector unsigned short); |
11550 | vector unsigned short vec_andc (vector unsigned short, | |
b0b343db | 11551 | vector bool short); |
6e5bb5ad JM |
11552 | vector unsigned short vec_andc (vector unsigned short, |
11553 | vector unsigned short); | |
b0b343db JJ |
11554 | vector signed char vec_andc (vector bool char, vector signed char); |
11555 | vector bool char vec_andc (vector bool char, vector bool char); | |
11556 | vector signed char vec_andc (vector signed char, vector bool char); | |
333c8841 | 11557 | vector signed char vec_andc (vector signed char, vector signed char); |
b0b343db JJ |
11558 | vector unsigned char vec_andc (vector bool char, vector unsigned char); |
11559 | vector unsigned char vec_andc (vector unsigned char, vector bool char); | |
924fcc4e JM |
11560 | vector unsigned char vec_andc (vector unsigned char, |
11561 | vector unsigned char); | |
333c8841 | 11562 | |
924fcc4e JM |
11563 | vector unsigned char vec_avg (vector unsigned char, |
11564 | vector unsigned char); | |
333c8841 | 11565 | vector signed char vec_avg (vector signed char, vector signed char); |
6e5bb5ad JM |
11566 | vector unsigned short vec_avg (vector unsigned short, |
11567 | vector unsigned short); | |
333c8841 AH |
11568 | vector signed short vec_avg (vector signed short, vector signed short); |
11569 | vector unsigned int vec_avg (vector unsigned int, vector unsigned int); | |
11570 | vector signed int vec_avg (vector signed int, vector signed int); | |
11571 | ||
b0b343db JJ |
11572 | vector signed int vec_vavgsw (vector signed int, vector signed int); |
11573 | ||
11574 | vector unsigned int vec_vavguw (vector unsigned int, | |
11575 | vector unsigned int); | |
11576 | ||
11577 | vector signed short vec_vavgsh (vector signed short, | |
11578 | vector signed short); | |
11579 | ||
11580 | vector unsigned short vec_vavguh (vector unsigned short, | |
11581 | vector unsigned short); | |
11582 | ||
11583 | vector signed char vec_vavgsb (vector signed char, vector signed char); | |
11584 | ||
11585 | vector unsigned char vec_vavgub (vector unsigned char, | |
11586 | vector unsigned char); | |
11587 | ||
29e6733c MM |
11588 | vector float vec_copysign (vector float); |
11589 | ||
333c8841 AH |
11590 | vector float vec_ceil (vector float); |
11591 | ||
11592 | vector signed int vec_cmpb (vector float, vector float); | |
11593 | ||
b0b343db JJ |
11594 | vector bool char vec_cmpeq (vector signed char, vector signed char); |
11595 | vector bool char vec_cmpeq (vector unsigned char, vector unsigned char); | |
11596 | vector bool short vec_cmpeq (vector signed short, vector signed short); | |
11597 | vector bool short vec_cmpeq (vector unsigned short, | |
11598 | vector unsigned short); | |
11599 | vector bool int vec_cmpeq (vector signed int, vector signed int); | |
11600 | vector bool int vec_cmpeq (vector unsigned int, vector unsigned int); | |
11601 | vector bool int vec_cmpeq (vector float, vector float); | |
333c8841 | 11602 | |
b0b343db | 11603 | vector bool int vec_vcmpeqfp (vector float, vector float); |
333c8841 | 11604 | |
b0b343db JJ |
11605 | vector bool int vec_vcmpequw (vector signed int, vector signed int); |
11606 | vector bool int vec_vcmpequw (vector unsigned int, vector unsigned int); | |
11607 | ||
11608 | vector bool short vec_vcmpequh (vector signed short, | |
11609 | vector signed short); | |
11610 | vector bool short vec_vcmpequh (vector unsigned short, | |
11611 | vector unsigned short); | |
333c8841 | 11612 | |
b0b343db JJ |
11613 | vector bool char vec_vcmpequb (vector signed char, vector signed char); |
11614 | vector bool char vec_vcmpequb (vector unsigned char, | |
11615 | vector unsigned char); | |
333c8841 | 11616 | |
b0b343db | 11617 | vector bool int vec_cmpge (vector float, vector float); |
333c8841 | 11618 | |
b0b343db JJ |
11619 | vector bool char vec_cmpgt (vector unsigned char, vector unsigned char); |
11620 | vector bool char vec_cmpgt (vector signed char, vector signed char); | |
11621 | vector bool short vec_cmpgt (vector unsigned short, | |
11622 | vector unsigned short); | |
11623 | vector bool short vec_cmpgt (vector signed short, vector signed short); | |
11624 | vector bool int vec_cmpgt (vector unsigned int, vector unsigned int); | |
11625 | vector bool int vec_cmpgt (vector signed int, vector signed int); | |
11626 | vector bool int vec_cmpgt (vector float, vector float); | |
11627 | ||
11628 | vector bool int vec_vcmpgtfp (vector float, vector float); | |
11629 | ||
11630 | vector bool int vec_vcmpgtsw (vector signed int, vector signed int); | |
11631 | ||
11632 | vector bool int vec_vcmpgtuw (vector unsigned int, vector unsigned int); | |
333c8841 | 11633 | |
b0b343db JJ |
11634 | vector bool short vec_vcmpgtsh (vector signed short, |
11635 | vector signed short); | |
11636 | ||
11637 | vector bool short vec_vcmpgtuh (vector unsigned short, | |
11638 | vector unsigned short); | |
11639 | ||
11640 | vector bool char vec_vcmpgtsb (vector signed char, vector signed char); | |
11641 | ||
11642 | vector bool char vec_vcmpgtub (vector unsigned char, | |
11643 | vector unsigned char); | |
11644 | ||
11645 | vector bool int vec_cmple (vector float, vector float); | |
11646 | ||
11647 | vector bool char vec_cmplt (vector unsigned char, vector unsigned char); | |
11648 | vector bool char vec_cmplt (vector signed char, vector signed char); | |
11649 | vector bool short vec_cmplt (vector unsigned short, | |
11650 | vector unsigned short); | |
11651 | vector bool short vec_cmplt (vector signed short, vector signed short); | |
11652 | vector bool int vec_cmplt (vector unsigned int, vector unsigned int); | |
11653 | vector bool int vec_cmplt (vector signed int, vector signed int); | |
11654 | vector bool int vec_cmplt (vector float, vector float); | |
333c8841 | 11655 | |
b0b343db JJ |
11656 | vector float vec_ctf (vector unsigned int, const int); |
11657 | vector float vec_ctf (vector signed int, const int); | |
333c8841 | 11658 | |
b0b343db JJ |
11659 | vector float vec_vcfsx (vector signed int, const int); |
11660 | ||
11661 | vector float vec_vcfux (vector unsigned int, const int); | |
11662 | ||
11663 | vector signed int vec_cts (vector float, const int); | |
11664 | ||
11665 | vector unsigned int vec_ctu (vector float, const int); | |
11666 | ||
11667 | void vec_dss (const int); | |
333c8841 AH |
11668 | |
11669 | void vec_dssall (void); | |
11670 | ||
b0b343db JJ |
11671 | void vec_dst (const vector unsigned char *, int, const int); |
11672 | void vec_dst (const vector signed char *, int, const int); | |
11673 | void vec_dst (const vector bool char *, int, const int); | |
11674 | void vec_dst (const vector unsigned short *, int, const int); | |
11675 | void vec_dst (const vector signed short *, int, const int); | |
11676 | void vec_dst (const vector bool short *, int, const int); | |
11677 | void vec_dst (const vector pixel *, int, const int); | |
11678 | void vec_dst (const vector unsigned int *, int, const int); | |
11679 | void vec_dst (const vector signed int *, int, const int); | |
11680 | void vec_dst (const vector bool int *, int, const int); | |
11681 | void vec_dst (const vector float *, int, const int); | |
11682 | void vec_dst (const unsigned char *, int, const int); | |
11683 | void vec_dst (const signed char *, int, const int); | |
11684 | void vec_dst (const unsigned short *, int, const int); | |
11685 | void vec_dst (const short *, int, const int); | |
11686 | void vec_dst (const unsigned int *, int, const int); | |
11687 | void vec_dst (const int *, int, const int); | |
11688 | void vec_dst (const unsigned long *, int, const int); | |
11689 | void vec_dst (const long *, int, const int); | |
11690 | void vec_dst (const float *, int, const int); | |
11691 | ||
11692 | void vec_dstst (const vector unsigned char *, int, const int); | |
11693 | void vec_dstst (const vector signed char *, int, const int); | |
11694 | void vec_dstst (const vector bool char *, int, const int); | |
11695 | void vec_dstst (const vector unsigned short *, int, const int); | |
11696 | void vec_dstst (const vector signed short *, int, const int); | |
11697 | void vec_dstst (const vector bool short *, int, const int); | |
11698 | void vec_dstst (const vector pixel *, int, const int); | |
11699 | void vec_dstst (const vector unsigned int *, int, const int); | |
11700 | void vec_dstst (const vector signed int *, int, const int); | |
11701 | void vec_dstst (const vector bool int *, int, const int); | |
11702 | void vec_dstst (const vector float *, int, const int); | |
11703 | void vec_dstst (const unsigned char *, int, const int); | |
11704 | void vec_dstst (const signed char *, int, const int); | |
11705 | void vec_dstst (const unsigned short *, int, const int); | |
11706 | void vec_dstst (const short *, int, const int); | |
11707 | void vec_dstst (const unsigned int *, int, const int); | |
11708 | void vec_dstst (const int *, int, const int); | |
11709 | void vec_dstst (const unsigned long *, int, const int); | |
11710 | void vec_dstst (const long *, int, const int); | |
11711 | void vec_dstst (const float *, int, const int); | |
11712 | ||
11713 | void vec_dststt (const vector unsigned char *, int, const int); | |
11714 | void vec_dststt (const vector signed char *, int, const int); | |
11715 | void vec_dststt (const vector bool char *, int, const int); | |
11716 | void vec_dststt (const vector unsigned short *, int, const int); | |
11717 | void vec_dststt (const vector signed short *, int, const int); | |
11718 | void vec_dststt (const vector bool short *, int, const int); | |
11719 | void vec_dststt (const vector pixel *, int, const int); | |
11720 | void vec_dststt (const vector unsigned int *, int, const int); | |
11721 | void vec_dststt (const vector signed int *, int, const int); | |
11722 | void vec_dststt (const vector bool int *, int, const int); | |
11723 | void vec_dststt (const vector float *, int, const int); | |
11724 | void vec_dststt (const unsigned char *, int, const int); | |
11725 | void vec_dststt (const signed char *, int, const int); | |
11726 | void vec_dststt (const unsigned short *, int, const int); | |
11727 | void vec_dststt (const short *, int, const int); | |
11728 | void vec_dststt (const unsigned int *, int, const int); | |
11729 | void vec_dststt (const int *, int, const int); | |
11730 | void vec_dststt (const unsigned long *, int, const int); | |
11731 | void vec_dststt (const long *, int, const int); | |
11732 | void vec_dststt (const float *, int, const int); | |
11733 | ||
11734 | void vec_dstt (const vector unsigned char *, int, const int); | |
11735 | void vec_dstt (const vector signed char *, int, const int); | |
11736 | void vec_dstt (const vector bool char *, int, const int); | |
11737 | void vec_dstt (const vector unsigned short *, int, const int); | |
11738 | void vec_dstt (const vector signed short *, int, const int); | |
11739 | void vec_dstt (const vector bool short *, int, const int); | |
11740 | void vec_dstt (const vector pixel *, int, const int); | |
11741 | void vec_dstt (const vector unsigned int *, int, const int); | |
11742 | void vec_dstt (const vector signed int *, int, const int); | |
11743 | void vec_dstt (const vector bool int *, int, const int); | |
11744 | void vec_dstt (const vector float *, int, const int); | |
11745 | void vec_dstt (const unsigned char *, int, const int); | |
11746 | void vec_dstt (const signed char *, int, const int); | |
11747 | void vec_dstt (const unsigned short *, int, const int); | |
11748 | void vec_dstt (const short *, int, const int); | |
11749 | void vec_dstt (const unsigned int *, int, const int); | |
11750 | void vec_dstt (const int *, int, const int); | |
11751 | void vec_dstt (const unsigned long *, int, const int); | |
11752 | void vec_dstt (const long *, int, const int); | |
11753 | void vec_dstt (const float *, int, const int); | |
11754 | ||
11755 | vector float vec_expte (vector float); | |
11756 | ||
11757 | vector float vec_floor (vector float); | |
11758 | ||
11759 | vector float vec_ld (int, const vector float *); | |
11760 | vector float vec_ld (int, const float *); | |
11761 | vector bool int vec_ld (int, const vector bool int *); | |
11762 | vector signed int vec_ld (int, const vector signed int *); | |
11763 | vector signed int vec_ld (int, const int *); | |
11764 | vector signed int vec_ld (int, const long *); | |
11765 | vector unsigned int vec_ld (int, const vector unsigned int *); | |
11766 | vector unsigned int vec_ld (int, const unsigned int *); | |
11767 | vector unsigned int vec_ld (int, const unsigned long *); | |
11768 | vector bool short vec_ld (int, const vector bool short *); | |
11769 | vector pixel vec_ld (int, const vector pixel *); | |
11770 | vector signed short vec_ld (int, const vector signed short *); | |
11771 | vector signed short vec_ld (int, const short *); | |
11772 | vector unsigned short vec_ld (int, const vector unsigned short *); | |
11773 | vector unsigned short vec_ld (int, const unsigned short *); | |
11774 | vector bool char vec_ld (int, const vector bool char *); | |
11775 | vector signed char vec_ld (int, const vector signed char *); | |
11776 | vector signed char vec_ld (int, const signed char *); | |
11777 | vector unsigned char vec_ld (int, const vector unsigned char *); | |
11778 | vector unsigned char vec_ld (int, const unsigned char *); | |
11779 | ||
11780 | vector signed char vec_lde (int, const signed char *); | |
11781 | vector unsigned char vec_lde (int, const unsigned char *); | |
11782 | vector signed short vec_lde (int, const short *); | |
11783 | vector unsigned short vec_lde (int, const unsigned short *); | |
11784 | vector float vec_lde (int, const float *); | |
11785 | vector signed int vec_lde (int, const int *); | |
11786 | vector unsigned int vec_lde (int, const unsigned int *); | |
11787 | vector signed int vec_lde (int, const long *); | |
11788 | vector unsigned int vec_lde (int, const unsigned long *); | |
11789 | ||
11790 | vector float vec_lvewx (int, float *); | |
11791 | vector signed int vec_lvewx (int, int *); | |
11792 | vector unsigned int vec_lvewx (int, unsigned int *); | |
11793 | vector signed int vec_lvewx (int, long *); | |
11794 | vector unsigned int vec_lvewx (int, unsigned long *); | |
11795 | ||
11796 | vector signed short vec_lvehx (int, short *); | |
11797 | vector unsigned short vec_lvehx (int, unsigned short *); | |
11798 | ||
11799 | vector signed char vec_lvebx (int, char *); | |
11800 | vector unsigned char vec_lvebx (int, unsigned char *); | |
11801 | ||
11802 | vector float vec_ldl (int, const vector float *); | |
11803 | vector float vec_ldl (int, const float *); | |
11804 | vector bool int vec_ldl (int, const vector bool int *); | |
11805 | vector signed int vec_ldl (int, const vector signed int *); | |
11806 | vector signed int vec_ldl (int, const int *); | |
11807 | vector signed int vec_ldl (int, const long *); | |
11808 | vector unsigned int vec_ldl (int, const vector unsigned int *); | |
11809 | vector unsigned int vec_ldl (int, const unsigned int *); | |
11810 | vector unsigned int vec_ldl (int, const unsigned long *); | |
11811 | vector bool short vec_ldl (int, const vector bool short *); | |
11812 | vector pixel vec_ldl (int, const vector pixel *); | |
11813 | vector signed short vec_ldl (int, const vector signed short *); | |
11814 | vector signed short vec_ldl (int, const short *); | |
11815 | vector unsigned short vec_ldl (int, const vector unsigned short *); | |
11816 | vector unsigned short vec_ldl (int, const unsigned short *); | |
11817 | vector bool char vec_ldl (int, const vector bool char *); | |
11818 | vector signed char vec_ldl (int, const vector signed char *); | |
11819 | vector signed char vec_ldl (int, const signed char *); | |
11820 | vector unsigned char vec_ldl (int, const vector unsigned char *); | |
11821 | vector unsigned char vec_ldl (int, const unsigned char *); | |
333c8841 AH |
11822 | |
11823 | vector float vec_loge (vector float); | |
11824 | ||
b0b343db JJ |
11825 | vector unsigned char vec_lvsl (int, const volatile unsigned char *); |
11826 | vector unsigned char vec_lvsl (int, const volatile signed char *); | |
11827 | vector unsigned char vec_lvsl (int, const volatile unsigned short *); | |
11828 | vector unsigned char vec_lvsl (int, const volatile short *); | |
11829 | vector unsigned char vec_lvsl (int, const volatile unsigned int *); | |
11830 | vector unsigned char vec_lvsl (int, const volatile int *); | |
11831 | vector unsigned char vec_lvsl (int, const volatile unsigned long *); | |
11832 | vector unsigned char vec_lvsl (int, const volatile long *); | |
11833 | vector unsigned char vec_lvsl (int, const volatile float *); | |
11834 | ||
11835 | vector unsigned char vec_lvsr (int, const volatile unsigned char *); | |
11836 | vector unsigned char vec_lvsr (int, const volatile signed char *); | |
11837 | vector unsigned char vec_lvsr (int, const volatile unsigned short *); | |
11838 | vector unsigned char vec_lvsr (int, const volatile short *); | |
11839 | vector unsigned char vec_lvsr (int, const volatile unsigned int *); | |
11840 | vector unsigned char vec_lvsr (int, const volatile int *); | |
11841 | vector unsigned char vec_lvsr (int, const volatile unsigned long *); | |
11842 | vector unsigned char vec_lvsr (int, const volatile long *); | |
11843 | vector unsigned char vec_lvsr (int, const volatile float *); | |
333c8841 AH |
11844 | |
11845 | vector float vec_madd (vector float, vector float, vector float); | |
11846 | ||
b0b343db JJ |
11847 | vector signed short vec_madds (vector signed short, |
11848 | vector signed short, | |
6e5bb5ad | 11849 | vector signed short); |
333c8841 | 11850 | |
b0b343db JJ |
11851 | vector unsigned char vec_max (vector bool char, vector unsigned char); |
11852 | vector unsigned char vec_max (vector unsigned char, vector bool char); | |
924fcc4e JM |
11853 | vector unsigned char vec_max (vector unsigned char, |
11854 | vector unsigned char); | |
b0b343db JJ |
11855 | vector signed char vec_max (vector bool char, vector signed char); |
11856 | vector signed char vec_max (vector signed char, vector bool char); | |
333c8841 | 11857 | vector signed char vec_max (vector signed char, vector signed char); |
b0b343db | 11858 | vector unsigned short vec_max (vector bool short, |
924fcc4e JM |
11859 | vector unsigned short); |
11860 | vector unsigned short vec_max (vector unsigned short, | |
b0b343db | 11861 | vector bool short); |
6e5bb5ad JM |
11862 | vector unsigned short vec_max (vector unsigned short, |
11863 | vector unsigned short); | |
b0b343db JJ |
11864 | vector signed short vec_max (vector bool short, vector signed short); |
11865 | vector signed short vec_max (vector signed short, vector bool short); | |
333c8841 | 11866 | vector signed short vec_max (vector signed short, vector signed short); |
b0b343db JJ |
11867 | vector unsigned int vec_max (vector bool int, vector unsigned int); |
11868 | vector unsigned int vec_max (vector unsigned int, vector bool int); | |
333c8841 | 11869 | vector unsigned int vec_max (vector unsigned int, vector unsigned int); |
b0b343db JJ |
11870 | vector signed int vec_max (vector bool int, vector signed int); |
11871 | vector signed int vec_max (vector signed int, vector bool int); | |
333c8841 AH |
11872 | vector signed int vec_max (vector signed int, vector signed int); |
11873 | vector float vec_max (vector float, vector float); | |
11874 | ||
b0b343db JJ |
11875 | vector float vec_vmaxfp (vector float, vector float); |
11876 | ||
11877 | vector signed int vec_vmaxsw (vector bool int, vector signed int); | |
11878 | vector signed int vec_vmaxsw (vector signed int, vector bool int); | |
11879 | vector signed int vec_vmaxsw (vector signed int, vector signed int); | |
11880 | ||
11881 | vector unsigned int vec_vmaxuw (vector bool int, vector unsigned int); | |
11882 | vector unsigned int vec_vmaxuw (vector unsigned int, vector bool int); | |
11883 | vector unsigned int vec_vmaxuw (vector unsigned int, | |
11884 | vector unsigned int); | |
11885 | ||
11886 | vector signed short vec_vmaxsh (vector bool short, vector signed short); | |
11887 | vector signed short vec_vmaxsh (vector signed short, vector bool short); | |
11888 | vector signed short vec_vmaxsh (vector signed short, | |
11889 | vector signed short); | |
11890 | ||
11891 | vector unsigned short vec_vmaxuh (vector bool short, | |
11892 | vector unsigned short); | |
11893 | vector unsigned short vec_vmaxuh (vector unsigned short, | |
11894 | vector bool short); | |
11895 | vector unsigned short vec_vmaxuh (vector unsigned short, | |
11896 | vector unsigned short); | |
11897 | ||
11898 | vector signed char vec_vmaxsb (vector bool char, vector signed char); | |
11899 | vector signed char vec_vmaxsb (vector signed char, vector bool char); | |
11900 | vector signed char vec_vmaxsb (vector signed char, vector signed char); | |
11901 | ||
11902 | vector unsigned char vec_vmaxub (vector bool char, | |
11903 | vector unsigned char); | |
11904 | vector unsigned char vec_vmaxub (vector unsigned char, | |
11905 | vector bool char); | |
11906 | vector unsigned char vec_vmaxub (vector unsigned char, | |
11907 | vector unsigned char); | |
11908 | ||
11909 | vector bool char vec_mergeh (vector bool char, vector bool char); | |
333c8841 | 11910 | vector signed char vec_mergeh (vector signed char, vector signed char); |
6e5bb5ad JM |
11911 | vector unsigned char vec_mergeh (vector unsigned char, |
11912 | vector unsigned char); | |
b0b343db JJ |
11913 | vector bool short vec_mergeh (vector bool short, vector bool short); |
11914 | vector pixel vec_mergeh (vector pixel, vector pixel); | |
924fcc4e JM |
11915 | vector signed short vec_mergeh (vector signed short, |
11916 | vector signed short); | |
6e5bb5ad JM |
11917 | vector unsigned short vec_mergeh (vector unsigned short, |
11918 | vector unsigned short); | |
333c8841 | 11919 | vector float vec_mergeh (vector float, vector float); |
b0b343db | 11920 | vector bool int vec_mergeh (vector bool int, vector bool int); |
333c8841 | 11921 | vector signed int vec_mergeh (vector signed int, vector signed int); |
924fcc4e JM |
11922 | vector unsigned int vec_mergeh (vector unsigned int, |
11923 | vector unsigned int); | |
333c8841 | 11924 | |
b0b343db JJ |
11925 | vector float vec_vmrghw (vector float, vector float); |
11926 | vector bool int vec_vmrghw (vector bool int, vector bool int); | |
11927 | vector signed int vec_vmrghw (vector signed int, vector signed int); | |
11928 | vector unsigned int vec_vmrghw (vector unsigned int, | |
11929 | vector unsigned int); | |
11930 | ||
11931 | vector bool short vec_vmrghh (vector bool short, vector bool short); | |
11932 | vector signed short vec_vmrghh (vector signed short, | |
11933 | vector signed short); | |
11934 | vector unsigned short vec_vmrghh (vector unsigned short, | |
11935 | vector unsigned short); | |
11936 | vector pixel vec_vmrghh (vector pixel, vector pixel); | |
11937 | ||
11938 | vector bool char vec_vmrghb (vector bool char, vector bool char); | |
11939 | vector signed char vec_vmrghb (vector signed char, vector signed char); | |
11940 | vector unsigned char vec_vmrghb (vector unsigned char, | |
11941 | vector unsigned char); | |
11942 | ||
11943 | vector bool char vec_mergel (vector bool char, vector bool char); | |
333c8841 | 11944 | vector signed char vec_mergel (vector signed char, vector signed char); |
6e5bb5ad JM |
11945 | vector unsigned char vec_mergel (vector unsigned char, |
11946 | vector unsigned char); | |
b0b343db JJ |
11947 | vector bool short vec_mergel (vector bool short, vector bool short); |
11948 | vector pixel vec_mergel (vector pixel, vector pixel); | |
924fcc4e JM |
11949 | vector signed short vec_mergel (vector signed short, |
11950 | vector signed short); | |
6e5bb5ad JM |
11951 | vector unsigned short vec_mergel (vector unsigned short, |
11952 | vector unsigned short); | |
333c8841 | 11953 | vector float vec_mergel (vector float, vector float); |
b0b343db | 11954 | vector bool int vec_mergel (vector bool int, vector bool int); |
333c8841 | 11955 | vector signed int vec_mergel (vector signed int, vector signed int); |
924fcc4e JM |
11956 | vector unsigned int vec_mergel (vector unsigned int, |
11957 | vector unsigned int); | |
333c8841 | 11958 | |
b0b343db JJ |
11959 | vector float vec_vmrglw (vector float, vector float); |
11960 | vector signed int vec_vmrglw (vector signed int, vector signed int); | |
11961 | vector unsigned int vec_vmrglw (vector unsigned int, | |
11962 | vector unsigned int); | |
11963 | vector bool int vec_vmrglw (vector bool int, vector bool int); | |
333c8841 | 11964 | |
b0b343db JJ |
11965 | vector bool short vec_vmrglh (vector bool short, vector bool short); |
11966 | vector signed short vec_vmrglh (vector signed short, | |
11967 | vector signed short); | |
11968 | vector unsigned short vec_vmrglh (vector unsigned short, | |
11969 | vector unsigned short); | |
11970 | vector pixel vec_vmrglh (vector pixel, vector pixel); | |
11971 | ||
11972 | vector bool char vec_vmrglb (vector bool char, vector bool char); | |
11973 | vector signed char vec_vmrglb (vector signed char, vector signed char); | |
11974 | vector unsigned char vec_vmrglb (vector unsigned char, | |
11975 | vector unsigned char); | |
333c8841 | 11976 | |
b0b343db | 11977 | vector unsigned short vec_mfvscr (void); |
333c8841 | 11978 | |
b0b343db JJ |
11979 | vector unsigned char vec_min (vector bool char, vector unsigned char); |
11980 | vector unsigned char vec_min (vector unsigned char, vector bool char); | |
924fcc4e JM |
11981 | vector unsigned char vec_min (vector unsigned char, |
11982 | vector unsigned char); | |
b0b343db JJ |
11983 | vector signed char vec_min (vector bool char, vector signed char); |
11984 | vector signed char vec_min (vector signed char, vector bool char); | |
333c8841 | 11985 | vector signed char vec_min (vector signed char, vector signed char); |
b0b343db | 11986 | vector unsigned short vec_min (vector bool short, |
924fcc4e JM |
11987 | vector unsigned short); |
11988 | vector unsigned short vec_min (vector unsigned short, | |
b0b343db | 11989 | vector bool short); |
6e5bb5ad JM |
11990 | vector unsigned short vec_min (vector unsigned short, |
11991 | vector unsigned short); | |
b0b343db JJ |
11992 | vector signed short vec_min (vector bool short, vector signed short); |
11993 | vector signed short vec_min (vector signed short, vector bool short); | |
333c8841 | 11994 | vector signed short vec_min (vector signed short, vector signed short); |
b0b343db JJ |
11995 | vector unsigned int vec_min (vector bool int, vector unsigned int); |
11996 | vector unsigned int vec_min (vector unsigned int, vector bool int); | |
333c8841 | 11997 | vector unsigned int vec_min (vector unsigned int, vector unsigned int); |
b0b343db JJ |
11998 | vector signed int vec_min (vector bool int, vector signed int); |
11999 | vector signed int vec_min (vector signed int, vector bool int); | |
333c8841 AH |
12000 | vector signed int vec_min (vector signed int, vector signed int); |
12001 | vector float vec_min (vector float, vector float); | |
12002 | ||
b0b343db JJ |
12003 | vector float vec_vminfp (vector float, vector float); |
12004 | ||
12005 | vector signed int vec_vminsw (vector bool int, vector signed int); | |
12006 | vector signed int vec_vminsw (vector signed int, vector bool int); | |
12007 | vector signed int vec_vminsw (vector signed int, vector signed int); | |
12008 | ||
12009 | vector unsigned int vec_vminuw (vector bool int, vector unsigned int); | |
12010 | vector unsigned int vec_vminuw (vector unsigned int, vector bool int); | |
12011 | vector unsigned int vec_vminuw (vector unsigned int, | |
12012 | vector unsigned int); | |
12013 | ||
12014 | vector signed short vec_vminsh (vector bool short, vector signed short); | |
12015 | vector signed short vec_vminsh (vector signed short, vector bool short); | |
12016 | vector signed short vec_vminsh (vector signed short, | |
12017 | vector signed short); | |
12018 | ||
12019 | vector unsigned short vec_vminuh (vector bool short, | |
12020 | vector unsigned short); | |
12021 | vector unsigned short vec_vminuh (vector unsigned short, | |
12022 | vector bool short); | |
12023 | vector unsigned short vec_vminuh (vector unsigned short, | |
12024 | vector unsigned short); | |
12025 | ||
12026 | vector signed char vec_vminsb (vector bool char, vector signed char); | |
12027 | vector signed char vec_vminsb (vector signed char, vector bool char); | |
12028 | vector signed char vec_vminsb (vector signed char, vector signed char); | |
12029 | ||
12030 | vector unsigned char vec_vminub (vector bool char, | |
12031 | vector unsigned char); | |
12032 | vector unsigned char vec_vminub (vector unsigned char, | |
12033 | vector bool char); | |
12034 | vector unsigned char vec_vminub (vector unsigned char, | |
12035 | vector unsigned char); | |
12036 | ||
12037 | vector signed short vec_mladd (vector signed short, | |
12038 | vector signed short, | |
6e5bb5ad | 12039 | vector signed short); |
924fcc4e JM |
12040 | vector signed short vec_mladd (vector signed short, |
12041 | vector unsigned short, | |
6e5bb5ad | 12042 | vector unsigned short); |
924fcc4e JM |
12043 | vector signed short vec_mladd (vector unsigned short, |
12044 | vector signed short, | |
6e5bb5ad JM |
12045 | vector signed short); |
12046 | vector unsigned short vec_mladd (vector unsigned short, | |
12047 | vector unsigned short, | |
12048 | vector unsigned short); | |
12049 | ||
924fcc4e JM |
12050 | vector signed short vec_mradds (vector signed short, |
12051 | vector signed short, | |
6e5bb5ad JM |
12052 | vector signed short); |
12053 | ||
924fcc4e JM |
12054 | vector unsigned int vec_msum (vector unsigned char, |
12055 | vector unsigned char, | |
6e5bb5ad | 12056 | vector unsigned int); |
b0b343db JJ |
12057 | vector signed int vec_msum (vector signed char, |
12058 | vector unsigned char, | |
6e5bb5ad | 12059 | vector signed int); |
924fcc4e JM |
12060 | vector unsigned int vec_msum (vector unsigned short, |
12061 | vector unsigned short, | |
6e5bb5ad | 12062 | vector unsigned int); |
b0b343db JJ |
12063 | vector signed int vec_msum (vector signed short, |
12064 | vector signed short, | |
6e5bb5ad JM |
12065 | vector signed int); |
12066 | ||
b0b343db JJ |
12067 | vector signed int vec_vmsumshm (vector signed short, |
12068 | vector signed short, | |
12069 | vector signed int); | |
12070 | ||
12071 | vector unsigned int vec_vmsumuhm (vector unsigned short, | |
12072 | vector unsigned short, | |
12073 | vector unsigned int); | |
12074 | ||
12075 | vector signed int vec_vmsummbm (vector signed char, | |
12076 | vector unsigned char, | |
12077 | vector signed int); | |
12078 | ||
12079 | vector unsigned int vec_vmsumubm (vector unsigned char, | |
12080 | vector unsigned char, | |
12081 | vector unsigned int); | |
12082 | ||
6e5bb5ad | 12083 | vector unsigned int vec_msums (vector unsigned short, |
924fcc4e JM |
12084 | vector unsigned short, |
12085 | vector unsigned int); | |
b0b343db JJ |
12086 | vector signed int vec_msums (vector signed short, |
12087 | vector signed short, | |
6e5bb5ad | 12088 | vector signed int); |
333c8841 | 12089 | |
b0b343db JJ |
12090 | vector signed int vec_vmsumshs (vector signed short, |
12091 | vector signed short, | |
12092 | vector signed int); | |
12093 | ||
12094 | vector unsigned int vec_vmsumuhs (vector unsigned short, | |
12095 | vector unsigned short, | |
12096 | vector unsigned int); | |
12097 | ||
333c8841 AH |
12098 | void vec_mtvscr (vector signed int); |
12099 | void vec_mtvscr (vector unsigned int); | |
b0b343db | 12100 | void vec_mtvscr (vector bool int); |
333c8841 AH |
12101 | void vec_mtvscr (vector signed short); |
12102 | void vec_mtvscr (vector unsigned short); | |
b0b343db JJ |
12103 | void vec_mtvscr (vector bool short); |
12104 | void vec_mtvscr (vector pixel); | |
333c8841 AH |
12105 | void vec_mtvscr (vector signed char); |
12106 | void vec_mtvscr (vector unsigned char); | |
b0b343db | 12107 | void vec_mtvscr (vector bool char); |
333c8841 | 12108 | |
924fcc4e JM |
12109 | vector unsigned short vec_mule (vector unsigned char, |
12110 | vector unsigned char); | |
b0b343db JJ |
12111 | vector signed short vec_mule (vector signed char, |
12112 | vector signed char); | |
924fcc4e JM |
12113 | vector unsigned int vec_mule (vector unsigned short, |
12114 | vector unsigned short); | |
333c8841 AH |
12115 | vector signed int vec_mule (vector signed short, vector signed short); |
12116 | ||
b0b343db JJ |
12117 | vector signed int vec_vmulesh (vector signed short, |
12118 | vector signed short); | |
12119 | ||
12120 | vector unsigned int vec_vmuleuh (vector unsigned short, | |
12121 | vector unsigned short); | |
12122 | ||
12123 | vector signed short vec_vmulesb (vector signed char, | |
12124 | vector signed char); | |
12125 | ||
12126 | vector unsigned short vec_vmuleub (vector unsigned char, | |
12127 | vector unsigned char); | |
12128 | ||
924fcc4e JM |
12129 | vector unsigned short vec_mulo (vector unsigned char, |
12130 | vector unsigned char); | |
333c8841 | 12131 | vector signed short vec_mulo (vector signed char, vector signed char); |
924fcc4e JM |
12132 | vector unsigned int vec_mulo (vector unsigned short, |
12133 | vector unsigned short); | |
333c8841 AH |
12134 | vector signed int vec_mulo (vector signed short, vector signed short); |
12135 | ||
b0b343db JJ |
12136 | vector signed int vec_vmulosh (vector signed short, |
12137 | vector signed short); | |
12138 | ||
12139 | vector unsigned int vec_vmulouh (vector unsigned short, | |
12140 | vector unsigned short); | |
12141 | ||
12142 | vector signed short vec_vmulosb (vector signed char, | |
12143 | vector signed char); | |
12144 | ||
12145 | vector unsigned short vec_vmuloub (vector unsigned char, | |
12146 | vector unsigned char); | |
12147 | ||
333c8841 AH |
12148 | vector float vec_nmsub (vector float, vector float, vector float); |
12149 | ||
12150 | vector float vec_nor (vector float, vector float); | |
12151 | vector signed int vec_nor (vector signed int, vector signed int); | |
12152 | vector unsigned int vec_nor (vector unsigned int, vector unsigned int); | |
b0b343db | 12153 | vector bool int vec_nor (vector bool int, vector bool int); |
333c8841 | 12154 | vector signed short vec_nor (vector signed short, vector signed short); |
6e5bb5ad JM |
12155 | vector unsigned short vec_nor (vector unsigned short, |
12156 | vector unsigned short); | |
b0b343db | 12157 | vector bool short vec_nor (vector bool short, vector bool short); |
333c8841 | 12158 | vector signed char vec_nor (vector signed char, vector signed char); |
924fcc4e JM |
12159 | vector unsigned char vec_nor (vector unsigned char, |
12160 | vector unsigned char); | |
b0b343db | 12161 | vector bool char vec_nor (vector bool char, vector bool char); |
333c8841 AH |
12162 | |
12163 | vector float vec_or (vector float, vector float); | |
b0b343db JJ |
12164 | vector float vec_or (vector float, vector bool int); |
12165 | vector float vec_or (vector bool int, vector float); | |
12166 | vector bool int vec_or (vector bool int, vector bool int); | |
12167 | vector signed int vec_or (vector bool int, vector signed int); | |
12168 | vector signed int vec_or (vector signed int, vector bool int); | |
333c8841 | 12169 | vector signed int vec_or (vector signed int, vector signed int); |
b0b343db JJ |
12170 | vector unsigned int vec_or (vector bool int, vector unsigned int); |
12171 | vector unsigned int vec_or (vector unsigned int, vector bool int); | |
333c8841 | 12172 | vector unsigned int vec_or (vector unsigned int, vector unsigned int); |
b0b343db JJ |
12173 | vector bool short vec_or (vector bool short, vector bool short); |
12174 | vector signed short vec_or (vector bool short, vector signed short); | |
12175 | vector signed short vec_or (vector signed short, vector bool short); | |
333c8841 | 12176 | vector signed short vec_or (vector signed short, vector signed short); |
b0b343db JJ |
12177 | vector unsigned short vec_or (vector bool short, vector unsigned short); |
12178 | vector unsigned short vec_or (vector unsigned short, vector bool short); | |
924fcc4e JM |
12179 | vector unsigned short vec_or (vector unsigned short, |
12180 | vector unsigned short); | |
b0b343db JJ |
12181 | vector signed char vec_or (vector bool char, vector signed char); |
12182 | vector bool char vec_or (vector bool char, vector bool char); | |
12183 | vector signed char vec_or (vector signed char, vector bool char); | |
333c8841 | 12184 | vector signed char vec_or (vector signed char, vector signed char); |
b0b343db JJ |
12185 | vector unsigned char vec_or (vector bool char, vector unsigned char); |
12186 | vector unsigned char vec_or (vector unsigned char, vector bool char); | |
924fcc4e JM |
12187 | vector unsigned char vec_or (vector unsigned char, |
12188 | vector unsigned char); | |
333c8841 AH |
12189 | |
12190 | vector signed char vec_pack (vector signed short, vector signed short); | |
6e5bb5ad JM |
12191 | vector unsigned char vec_pack (vector unsigned short, |
12192 | vector unsigned short); | |
b0b343db | 12193 | vector bool char vec_pack (vector bool short, vector bool short); |
333c8841 | 12194 | vector signed short vec_pack (vector signed int, vector signed int); |
924fcc4e JM |
12195 | vector unsigned short vec_pack (vector unsigned int, |
12196 | vector unsigned int); | |
b0b343db | 12197 | vector bool short vec_pack (vector bool int, vector bool int); |
333c8841 | 12198 | |
b0b343db JJ |
12199 | vector bool short vec_vpkuwum (vector bool int, vector bool int); |
12200 | vector signed short vec_vpkuwum (vector signed int, vector signed int); | |
12201 | vector unsigned short vec_vpkuwum (vector unsigned int, | |
12202 | vector unsigned int); | |
12203 | ||
12204 | vector bool char vec_vpkuhum (vector bool short, vector bool short); | |
12205 | vector signed char vec_vpkuhum (vector signed short, | |
12206 | vector signed short); | |
12207 | vector unsigned char vec_vpkuhum (vector unsigned short, | |
12208 | vector unsigned short); | |
12209 | ||
12210 | vector pixel vec_packpx (vector unsigned int, vector unsigned int); | |
333c8841 | 12211 | |
6e5bb5ad JM |
12212 | vector unsigned char vec_packs (vector unsigned short, |
12213 | vector unsigned short); | |
333c8841 | 12214 | vector signed char vec_packs (vector signed short, vector signed short); |
924fcc4e JM |
12215 | vector unsigned short vec_packs (vector unsigned int, |
12216 | vector unsigned int); | |
333c8841 AH |
12217 | vector signed short vec_packs (vector signed int, vector signed int); |
12218 | ||
b0b343db JJ |
12219 | vector signed short vec_vpkswss (vector signed int, vector signed int); |
12220 | ||
12221 | vector unsigned short vec_vpkuwus (vector unsigned int, | |
12222 | vector unsigned int); | |
12223 | ||
12224 | vector signed char vec_vpkshss (vector signed short, | |
12225 | vector signed short); | |
12226 | ||
12227 | vector unsigned char vec_vpkuhus (vector unsigned short, | |
12228 | vector unsigned short); | |
12229 | ||
6e5bb5ad JM |
12230 | vector unsigned char vec_packsu (vector unsigned short, |
12231 | vector unsigned short); | |
924fcc4e JM |
12232 | vector unsigned char vec_packsu (vector signed short, |
12233 | vector signed short); | |
12234 | vector unsigned short vec_packsu (vector unsigned int, | |
12235 | vector unsigned int); | |
333c8841 AH |
12236 | vector unsigned short vec_packsu (vector signed int, vector signed int); |
12237 | ||
b0b343db JJ |
12238 | vector unsigned short vec_vpkswus (vector signed int, |
12239 | vector signed int); | |
12240 | ||
12241 | vector unsigned char vec_vpkshus (vector signed short, | |
12242 | vector signed short); | |
12243 | ||
12244 | vector float vec_perm (vector float, | |
12245 | vector float, | |
924fcc4e | 12246 | vector unsigned char); |
b0b343db JJ |
12247 | vector signed int vec_perm (vector signed int, |
12248 | vector signed int, | |
6e5bb5ad | 12249 | vector unsigned char); |
b0b343db JJ |
12250 | vector unsigned int vec_perm (vector unsigned int, |
12251 | vector unsigned int, | |
6e5bb5ad | 12252 | vector unsigned char); |
b0b343db JJ |
12253 | vector bool int vec_perm (vector bool int, |
12254 | vector bool int, | |
12255 | vector unsigned char); | |
12256 | vector signed short vec_perm (vector signed short, | |
12257 | vector signed short, | |
6e5bb5ad JM |
12258 | vector unsigned char); |
12259 | vector unsigned short vec_perm (vector unsigned short, | |
12260 | vector unsigned short, | |
12261 | vector unsigned char); | |
b0b343db JJ |
12262 | vector bool short vec_perm (vector bool short, |
12263 | vector bool short, | |
12264 | vector unsigned char); | |
12265 | vector pixel vec_perm (vector pixel, | |
12266 | vector pixel, | |
12267 | vector unsigned char); | |
12268 | vector signed char vec_perm (vector signed char, | |
12269 | vector signed char, | |
6e5bb5ad | 12270 | vector unsigned char); |
924fcc4e JM |
12271 | vector unsigned char vec_perm (vector unsigned char, |
12272 | vector unsigned char, | |
6e5bb5ad | 12273 | vector unsigned char); |
b0b343db JJ |
12274 | vector bool char vec_perm (vector bool char, |
12275 | vector bool char, | |
12276 | vector unsigned char); | |
333c8841 AH |
12277 | |
12278 | vector float vec_re (vector float); | |
12279 | ||
b0b343db JJ |
12280 | vector signed char vec_rl (vector signed char, |
12281 | vector unsigned char); | |
924fcc4e JM |
12282 | vector unsigned char vec_rl (vector unsigned char, |
12283 | vector unsigned char); | |
333c8841 | 12284 | vector signed short vec_rl (vector signed short, vector unsigned short); |
924fcc4e JM |
12285 | vector unsigned short vec_rl (vector unsigned short, |
12286 | vector unsigned short); | |
333c8841 AH |
12287 | vector signed int vec_rl (vector signed int, vector unsigned int); |
12288 | vector unsigned int vec_rl (vector unsigned int, vector unsigned int); | |
12289 | ||
b0b343db JJ |
12290 | vector signed int vec_vrlw (vector signed int, vector unsigned int); |
12291 | vector unsigned int vec_vrlw (vector unsigned int, vector unsigned int); | |
12292 | ||
12293 | vector signed short vec_vrlh (vector signed short, | |
12294 | vector unsigned short); | |
12295 | vector unsigned short vec_vrlh (vector unsigned short, | |
12296 | vector unsigned short); | |
12297 | ||
12298 | vector signed char vec_vrlb (vector signed char, vector unsigned char); | |
12299 | vector unsigned char vec_vrlb (vector unsigned char, | |
12300 | vector unsigned char); | |
12301 | ||
333c8841 AH |
12302 | vector float vec_round (vector float); |
12303 | ||
92902797 MM |
12304 | vector float vec_recip (vector float, vector float); |
12305 | ||
12306 | vector float vec_rsqrt (vector float); | |
12307 | ||
333c8841 AH |
12308 | vector float vec_rsqrte (vector float); |
12309 | ||
b0b343db | 12310 | vector float vec_sel (vector float, vector float, vector bool int); |
333c8841 | 12311 | vector float vec_sel (vector float, vector float, vector unsigned int); |
b0b343db JJ |
12312 | vector signed int vec_sel (vector signed int, |
12313 | vector signed int, | |
12314 | vector bool int); | |
12315 | vector signed int vec_sel (vector signed int, | |
12316 | vector signed int, | |
6e5bb5ad | 12317 | vector unsigned int); |
b0b343db JJ |
12318 | vector unsigned int vec_sel (vector unsigned int, |
12319 | vector unsigned int, | |
12320 | vector bool int); | |
12321 | vector unsigned int vec_sel (vector unsigned int, | |
12322 | vector unsigned int, | |
6e5bb5ad | 12323 | vector unsigned int); |
b0b343db JJ |
12324 | vector bool int vec_sel (vector bool int, |
12325 | vector bool int, | |
12326 | vector bool int); | |
12327 | vector bool int vec_sel (vector bool int, | |
12328 | vector bool int, | |
12329 | vector unsigned int); | |
12330 | vector signed short vec_sel (vector signed short, | |
12331 | vector signed short, | |
12332 | vector bool short); | |
12333 | vector signed short vec_sel (vector signed short, | |
12334 | vector signed short, | |
6e5bb5ad JM |
12335 | vector unsigned short); |
12336 | vector unsigned short vec_sel (vector unsigned short, | |
924fcc4e | 12337 | vector unsigned short, |
b0b343db | 12338 | vector bool short); |
6e5bb5ad JM |
12339 | vector unsigned short vec_sel (vector unsigned short, |
12340 | vector unsigned short, | |
12341 | vector unsigned short); | |
b0b343db JJ |
12342 | vector bool short vec_sel (vector bool short, |
12343 | vector bool short, | |
12344 | vector bool short); | |
12345 | vector bool short vec_sel (vector bool short, | |
12346 | vector bool short, | |
12347 | vector unsigned short); | |
12348 | vector signed char vec_sel (vector signed char, | |
12349 | vector signed char, | |
12350 | vector bool char); | |
12351 | vector signed char vec_sel (vector signed char, | |
12352 | vector signed char, | |
6e5bb5ad | 12353 | vector unsigned char); |
924fcc4e JM |
12354 | vector unsigned char vec_sel (vector unsigned char, |
12355 | vector unsigned char, | |
b0b343db | 12356 | vector bool char); |
924fcc4e JM |
12357 | vector unsigned char vec_sel (vector unsigned char, |
12358 | vector unsigned char, | |
6e5bb5ad | 12359 | vector unsigned char); |
b0b343db JJ |
12360 | vector bool char vec_sel (vector bool char, |
12361 | vector bool char, | |
12362 | vector bool char); | |
12363 | vector bool char vec_sel (vector bool char, | |
12364 | vector bool char, | |
12365 | vector unsigned char); | |
12366 | ||
12367 | vector signed char vec_sl (vector signed char, | |
12368 | vector unsigned char); | |
924fcc4e JM |
12369 | vector unsigned char vec_sl (vector unsigned char, |
12370 | vector unsigned char); | |
333c8841 | 12371 | vector signed short vec_sl (vector signed short, vector unsigned short); |
924fcc4e JM |
12372 | vector unsigned short vec_sl (vector unsigned short, |
12373 | vector unsigned short); | |
333c8841 AH |
12374 | vector signed int vec_sl (vector signed int, vector unsigned int); |
12375 | vector unsigned int vec_sl (vector unsigned int, vector unsigned int); | |
12376 | ||
b0b343db JJ |
12377 | vector signed int vec_vslw (vector signed int, vector unsigned int); |
12378 | vector unsigned int vec_vslw (vector unsigned int, vector unsigned int); | |
12379 | ||
12380 | vector signed short vec_vslh (vector signed short, | |
12381 | vector unsigned short); | |
12382 | vector unsigned short vec_vslh (vector unsigned short, | |
12383 | vector unsigned short); | |
12384 | ||
12385 | vector signed char vec_vslb (vector signed char, vector unsigned char); | |
12386 | vector unsigned char vec_vslb (vector unsigned char, | |
12387 | vector unsigned char); | |
12388 | ||
12389 | vector float vec_sld (vector float, vector float, const int); | |
12390 | vector signed int vec_sld (vector signed int, | |
12391 | vector signed int, | |
12392 | const int); | |
12393 | vector unsigned int vec_sld (vector unsigned int, | |
12394 | vector unsigned int, | |
12395 | const int); | |
12396 | vector bool int vec_sld (vector bool int, | |
12397 | vector bool int, | |
12398 | const int); | |
12399 | vector signed short vec_sld (vector signed short, | |
12400 | vector signed short, | |
12401 | const int); | |
6e5bb5ad | 12402 | vector unsigned short vec_sld (vector unsigned short, |
b0b343db JJ |
12403 | vector unsigned short, |
12404 | const int); | |
12405 | vector bool short vec_sld (vector bool short, | |
12406 | vector bool short, | |
12407 | const int); | |
12408 | vector pixel vec_sld (vector pixel, | |
12409 | vector pixel, | |
12410 | const int); | |
12411 | vector signed char vec_sld (vector signed char, | |
12412 | vector signed char, | |
12413 | const int); | |
924fcc4e JM |
12414 | vector unsigned char vec_sld (vector unsigned char, |
12415 | vector unsigned char, | |
b0b343db JJ |
12416 | const int); |
12417 | vector bool char vec_sld (vector bool char, | |
12418 | vector bool char, | |
12419 | const int); | |
333c8841 | 12420 | |
b0b343db JJ |
12421 | vector signed int vec_sll (vector signed int, |
12422 | vector unsigned int); | |
12423 | vector signed int vec_sll (vector signed int, | |
12424 | vector unsigned short); | |
12425 | vector signed int vec_sll (vector signed int, | |
12426 | vector unsigned char); | |
12427 | vector unsigned int vec_sll (vector unsigned int, | |
12428 | vector unsigned int); | |
924fcc4e JM |
12429 | vector unsigned int vec_sll (vector unsigned int, |
12430 | vector unsigned short); | |
b0b343db JJ |
12431 | vector unsigned int vec_sll (vector unsigned int, |
12432 | vector unsigned char); | |
12433 | vector bool int vec_sll (vector bool int, | |
12434 | vector unsigned int); | |
12435 | vector bool int vec_sll (vector bool int, | |
12436 | vector unsigned short); | |
12437 | vector bool int vec_sll (vector bool int, | |
12438 | vector unsigned char); | |
12439 | vector signed short vec_sll (vector signed short, | |
12440 | vector unsigned int); | |
924fcc4e JM |
12441 | vector signed short vec_sll (vector signed short, |
12442 | vector unsigned short); | |
b0b343db JJ |
12443 | vector signed short vec_sll (vector signed short, |
12444 | vector unsigned char); | |
924fcc4e JM |
12445 | vector unsigned short vec_sll (vector unsigned short, |
12446 | vector unsigned int); | |
6e5bb5ad JM |
12447 | vector unsigned short vec_sll (vector unsigned short, |
12448 | vector unsigned short); | |
924fcc4e JM |
12449 | vector unsigned short vec_sll (vector unsigned short, |
12450 | vector unsigned char); | |
b0b343db JJ |
12451 | vector bool short vec_sll (vector bool short, vector unsigned int); |
12452 | vector bool short vec_sll (vector bool short, vector unsigned short); | |
12453 | vector bool short vec_sll (vector bool short, vector unsigned char); | |
12454 | vector pixel vec_sll (vector pixel, vector unsigned int); | |
12455 | vector pixel vec_sll (vector pixel, vector unsigned short); | |
12456 | vector pixel vec_sll (vector pixel, vector unsigned char); | |
333c8841 AH |
12457 | vector signed char vec_sll (vector signed char, vector unsigned int); |
12458 | vector signed char vec_sll (vector signed char, vector unsigned short); | |
12459 | vector signed char vec_sll (vector signed char, vector unsigned char); | |
924fcc4e JM |
12460 | vector unsigned char vec_sll (vector unsigned char, |
12461 | vector unsigned int); | |
12462 | vector unsigned char vec_sll (vector unsigned char, | |
12463 | vector unsigned short); | |
12464 | vector unsigned char vec_sll (vector unsigned char, | |
12465 | vector unsigned char); | |
b0b343db JJ |
12466 | vector bool char vec_sll (vector bool char, vector unsigned int); |
12467 | vector bool char vec_sll (vector bool char, vector unsigned short); | |
12468 | vector bool char vec_sll (vector bool char, vector unsigned char); | |
333c8841 AH |
12469 | |
12470 | vector float vec_slo (vector float, vector signed char); | |
12471 | vector float vec_slo (vector float, vector unsigned char); | |
12472 | vector signed int vec_slo (vector signed int, vector signed char); | |
12473 | vector signed int vec_slo (vector signed int, vector unsigned char); | |
12474 | vector unsigned int vec_slo (vector unsigned int, vector signed char); | |
12475 | vector unsigned int vec_slo (vector unsigned int, vector unsigned char); | |
333c8841 AH |
12476 | vector signed short vec_slo (vector signed short, vector signed char); |
12477 | vector signed short vec_slo (vector signed short, vector unsigned char); | |
924fcc4e JM |
12478 | vector unsigned short vec_slo (vector unsigned short, |
12479 | vector signed char); | |
12480 | vector unsigned short vec_slo (vector unsigned short, | |
12481 | vector unsigned char); | |
b0b343db JJ |
12482 | vector pixel vec_slo (vector pixel, vector signed char); |
12483 | vector pixel vec_slo (vector pixel, vector unsigned char); | |
333c8841 AH |
12484 | vector signed char vec_slo (vector signed char, vector signed char); |
12485 | vector signed char vec_slo (vector signed char, vector unsigned char); | |
12486 | vector unsigned char vec_slo (vector unsigned char, vector signed char); | |
924fcc4e JM |
12487 | vector unsigned char vec_slo (vector unsigned char, |
12488 | vector unsigned char); | |
333c8841 | 12489 | |
b0b343db JJ |
12490 | vector signed char vec_splat (vector signed char, const int); |
12491 | vector unsigned char vec_splat (vector unsigned char, const int); | |
12492 | vector bool char vec_splat (vector bool char, const int); | |
12493 | vector signed short vec_splat (vector signed short, const int); | |
12494 | vector unsigned short vec_splat (vector unsigned short, const int); | |
12495 | vector bool short vec_splat (vector bool short, const int); | |
12496 | vector pixel vec_splat (vector pixel, const int); | |
12497 | vector float vec_splat (vector float, const int); | |
12498 | vector signed int vec_splat (vector signed int, const int); | |
12499 | vector unsigned int vec_splat (vector unsigned int, const int); | |
12500 | vector bool int vec_splat (vector bool int, const int); | |
12501 | ||
12502 | vector float vec_vspltw (vector float, const int); | |
12503 | vector signed int vec_vspltw (vector signed int, const int); | |
12504 | vector unsigned int vec_vspltw (vector unsigned int, const int); | |
12505 | vector bool int vec_vspltw (vector bool int, const int); | |
12506 | ||
12507 | vector bool short vec_vsplth (vector bool short, const int); | |
12508 | vector signed short vec_vsplth (vector signed short, const int); | |
12509 | vector unsigned short vec_vsplth (vector unsigned short, const int); | |
12510 | vector pixel vec_vsplth (vector pixel, const int); | |
12511 | ||
12512 | vector signed char vec_vspltb (vector signed char, const int); | |
12513 | vector unsigned char vec_vspltb (vector unsigned char, const int); | |
12514 | vector bool char vec_vspltb (vector bool char, const int); | |
333c8841 | 12515 | |
b0b343db | 12516 | vector signed char vec_splat_s8 (const int); |
333c8841 | 12517 | |
b0b343db | 12518 | vector signed short vec_splat_s16 (const int); |
333c8841 | 12519 | |
b0b343db | 12520 | vector signed int vec_splat_s32 (const int); |
333c8841 | 12521 | |
b0b343db | 12522 | vector unsigned char vec_splat_u8 (const int); |
333c8841 | 12523 | |
b0b343db | 12524 | vector unsigned short vec_splat_u16 (const int); |
333c8841 | 12525 | |
b0b343db | 12526 | vector unsigned int vec_splat_u32 (const int); |
333c8841 AH |
12527 | |
12528 | vector signed char vec_sr (vector signed char, vector unsigned char); | |
924fcc4e JM |
12529 | vector unsigned char vec_sr (vector unsigned char, |
12530 | vector unsigned char); | |
b0b343db JJ |
12531 | vector signed short vec_sr (vector signed short, |
12532 | vector unsigned short); | |
924fcc4e JM |
12533 | vector unsigned short vec_sr (vector unsigned short, |
12534 | vector unsigned short); | |
333c8841 AH |
12535 | vector signed int vec_sr (vector signed int, vector unsigned int); |
12536 | vector unsigned int vec_sr (vector unsigned int, vector unsigned int); | |
12537 | ||
b0b343db JJ |
12538 | vector signed int vec_vsrw (vector signed int, vector unsigned int); |
12539 | vector unsigned int vec_vsrw (vector unsigned int, vector unsigned int); | |
12540 | ||
12541 | vector signed short vec_vsrh (vector signed short, | |
12542 | vector unsigned short); | |
12543 | vector unsigned short vec_vsrh (vector unsigned short, | |
12544 | vector unsigned short); | |
12545 | ||
12546 | vector signed char vec_vsrb (vector signed char, vector unsigned char); | |
12547 | vector unsigned char vec_vsrb (vector unsigned char, | |
12548 | vector unsigned char); | |
12549 | ||
333c8841 | 12550 | vector signed char vec_sra (vector signed char, vector unsigned char); |
924fcc4e JM |
12551 | vector unsigned char vec_sra (vector unsigned char, |
12552 | vector unsigned char); | |
12553 | vector signed short vec_sra (vector signed short, | |
12554 | vector unsigned short); | |
6e5bb5ad JM |
12555 | vector unsigned short vec_sra (vector unsigned short, |
12556 | vector unsigned short); | |
333c8841 AH |
12557 | vector signed int vec_sra (vector signed int, vector unsigned int); |
12558 | vector unsigned int vec_sra (vector unsigned int, vector unsigned int); | |
12559 | ||
b0b343db JJ |
12560 | vector signed int vec_vsraw (vector signed int, vector unsigned int); |
12561 | vector unsigned int vec_vsraw (vector unsigned int, | |
12562 | vector unsigned int); | |
12563 | ||
12564 | vector signed short vec_vsrah (vector signed short, | |
12565 | vector unsigned short); | |
12566 | vector unsigned short vec_vsrah (vector unsigned short, | |
12567 | vector unsigned short); | |
12568 | ||
12569 | vector signed char vec_vsrab (vector signed char, vector unsigned char); | |
12570 | vector unsigned char vec_vsrab (vector unsigned char, | |
12571 | vector unsigned char); | |
12572 | ||
333c8841 AH |
12573 | vector signed int vec_srl (vector signed int, vector unsigned int); |
12574 | vector signed int vec_srl (vector signed int, vector unsigned short); | |
12575 | vector signed int vec_srl (vector signed int, vector unsigned char); | |
12576 | vector unsigned int vec_srl (vector unsigned int, vector unsigned int); | |
924fcc4e JM |
12577 | vector unsigned int vec_srl (vector unsigned int, |
12578 | vector unsigned short); | |
333c8841 | 12579 | vector unsigned int vec_srl (vector unsigned int, vector unsigned char); |
b0b343db JJ |
12580 | vector bool int vec_srl (vector bool int, vector unsigned int); |
12581 | vector bool int vec_srl (vector bool int, vector unsigned short); | |
12582 | vector bool int vec_srl (vector bool int, vector unsigned char); | |
333c8841 | 12583 | vector signed short vec_srl (vector signed short, vector unsigned int); |
924fcc4e JM |
12584 | vector signed short vec_srl (vector signed short, |
12585 | vector unsigned short); | |
333c8841 | 12586 | vector signed short vec_srl (vector signed short, vector unsigned char); |
924fcc4e JM |
12587 | vector unsigned short vec_srl (vector unsigned short, |
12588 | vector unsigned int); | |
6e5bb5ad JM |
12589 | vector unsigned short vec_srl (vector unsigned short, |
12590 | vector unsigned short); | |
924fcc4e JM |
12591 | vector unsigned short vec_srl (vector unsigned short, |
12592 | vector unsigned char); | |
b0b343db JJ |
12593 | vector bool short vec_srl (vector bool short, vector unsigned int); |
12594 | vector bool short vec_srl (vector bool short, vector unsigned short); | |
12595 | vector bool short vec_srl (vector bool short, vector unsigned char); | |
12596 | vector pixel vec_srl (vector pixel, vector unsigned int); | |
12597 | vector pixel vec_srl (vector pixel, vector unsigned short); | |
12598 | vector pixel vec_srl (vector pixel, vector unsigned char); | |
333c8841 AH |
12599 | vector signed char vec_srl (vector signed char, vector unsigned int); |
12600 | vector signed char vec_srl (vector signed char, vector unsigned short); | |
12601 | vector signed char vec_srl (vector signed char, vector unsigned char); | |
924fcc4e JM |
12602 | vector unsigned char vec_srl (vector unsigned char, |
12603 | vector unsigned int); | |
12604 | vector unsigned char vec_srl (vector unsigned char, | |
12605 | vector unsigned short); | |
12606 | vector unsigned char vec_srl (vector unsigned char, | |
12607 | vector unsigned char); | |
b0b343db JJ |
12608 | vector bool char vec_srl (vector bool char, vector unsigned int); |
12609 | vector bool char vec_srl (vector bool char, vector unsigned short); | |
12610 | vector bool char vec_srl (vector bool char, vector unsigned char); | |
333c8841 AH |
12611 | |
12612 | vector float vec_sro (vector float, vector signed char); | |
12613 | vector float vec_sro (vector float, vector unsigned char); | |
12614 | vector signed int vec_sro (vector signed int, vector signed char); | |
12615 | vector signed int vec_sro (vector signed int, vector unsigned char); | |
12616 | vector unsigned int vec_sro (vector unsigned int, vector signed char); | |
12617 | vector unsigned int vec_sro (vector unsigned int, vector unsigned char); | |
333c8841 AH |
12618 | vector signed short vec_sro (vector signed short, vector signed char); |
12619 | vector signed short vec_sro (vector signed short, vector unsigned char); | |
924fcc4e JM |
12620 | vector unsigned short vec_sro (vector unsigned short, |
12621 | vector signed char); | |
12622 | vector unsigned short vec_sro (vector unsigned short, | |
12623 | vector unsigned char); | |
b0b343db JJ |
12624 | vector pixel vec_sro (vector pixel, vector signed char); |
12625 | vector pixel vec_sro (vector pixel, vector unsigned char); | |
333c8841 AH |
12626 | vector signed char vec_sro (vector signed char, vector signed char); |
12627 | vector signed char vec_sro (vector signed char, vector unsigned char); | |
12628 | vector unsigned char vec_sro (vector unsigned char, vector signed char); | |
924fcc4e JM |
12629 | vector unsigned char vec_sro (vector unsigned char, |
12630 | vector unsigned char); | |
333c8841 | 12631 | |
333c8841 | 12632 | void vec_st (vector float, int, vector float *); |
b0b343db JJ |
12633 | void vec_st (vector float, int, float *); |
12634 | void vec_st (vector signed int, int, vector signed int *); | |
333c8841 | 12635 | void vec_st (vector signed int, int, int *); |
333c8841 | 12636 | void vec_st (vector unsigned int, int, vector unsigned int *); |
b0b343db JJ |
12637 | void vec_st (vector unsigned int, int, unsigned int *); |
12638 | void vec_st (vector bool int, int, vector bool int *); | |
12639 | void vec_st (vector bool int, int, unsigned int *); | |
12640 | void vec_st (vector bool int, int, int *); | |
333c8841 | 12641 | void vec_st (vector signed short, int, vector signed short *); |
b0b343db | 12642 | void vec_st (vector signed short, int, short *); |
333c8841 | 12643 | void vec_st (vector unsigned short, int, vector unsigned short *); |
b0b343db JJ |
12644 | void vec_st (vector unsigned short, int, unsigned short *); |
12645 | void vec_st (vector bool short, int, vector bool short *); | |
12646 | void vec_st (vector bool short, int, unsigned short *); | |
12647 | void vec_st (vector pixel, int, vector pixel *); | |
12648 | void vec_st (vector pixel, int, unsigned short *); | |
12649 | void vec_st (vector pixel, int, short *); | |
12650 | void vec_st (vector bool short, int, short *); | |
333c8841 | 12651 | void vec_st (vector signed char, int, vector signed char *); |
b0b343db | 12652 | void vec_st (vector signed char, int, signed char *); |
333c8841 | 12653 | void vec_st (vector unsigned char, int, vector unsigned char *); |
b0b343db JJ |
12654 | void vec_st (vector unsigned char, int, unsigned char *); |
12655 | void vec_st (vector bool char, int, vector bool char *); | |
12656 | void vec_st (vector bool char, int, unsigned char *); | |
12657 | void vec_st (vector bool char, int, signed char *); | |
333c8841 | 12658 | |
333c8841 AH |
12659 | void vec_ste (vector signed char, int, signed char *); |
12660 | void vec_ste (vector unsigned char, int, unsigned char *); | |
b0b343db JJ |
12661 | void vec_ste (vector bool char, int, signed char *); |
12662 | void vec_ste (vector bool char, int, unsigned char *); | |
333c8841 | 12663 | void vec_ste (vector signed short, int, short *); |
b0b343db JJ |
12664 | void vec_ste (vector unsigned short, int, unsigned short *); |
12665 | void vec_ste (vector bool short, int, short *); | |
12666 | void vec_ste (vector bool short, int, unsigned short *); | |
12667 | void vec_ste (vector pixel, int, short *); | |
12668 | void vec_ste (vector pixel, int, unsigned short *); | |
12669 | void vec_ste (vector float, int, float *); | |
333c8841 AH |
12670 | void vec_ste (vector signed int, int, int *); |
12671 | void vec_ste (vector unsigned int, int, unsigned int *); | |
b0b343db JJ |
12672 | void vec_ste (vector bool int, int, int *); |
12673 | void vec_ste (vector bool int, int, unsigned int *); | |
12674 | ||
12675 | void vec_stvewx (vector float, int, float *); | |
12676 | void vec_stvewx (vector signed int, int, int *); | |
12677 | void vec_stvewx (vector unsigned int, int, unsigned int *); | |
12678 | void vec_stvewx (vector bool int, int, int *); | |
12679 | void vec_stvewx (vector bool int, int, unsigned int *); | |
12680 | ||
12681 | void vec_stvehx (vector signed short, int, short *); | |
12682 | void vec_stvehx (vector unsigned short, int, unsigned short *); | |
12683 | void vec_stvehx (vector bool short, int, short *); | |
12684 | void vec_stvehx (vector bool short, int, unsigned short *); | |
12685 | void vec_stvehx (vector pixel, int, short *); | |
12686 | void vec_stvehx (vector pixel, int, unsigned short *); | |
12687 | ||
12688 | void vec_stvebx (vector signed char, int, signed char *); | |
12689 | void vec_stvebx (vector unsigned char, int, unsigned char *); | |
12690 | void vec_stvebx (vector bool char, int, signed char *); | |
12691 | void vec_stvebx (vector bool char, int, unsigned char *); | |
333c8841 AH |
12692 | |
12693 | void vec_stl (vector float, int, vector float *); | |
12694 | void vec_stl (vector float, int, float *); | |
12695 | void vec_stl (vector signed int, int, vector signed int *); | |
12696 | void vec_stl (vector signed int, int, int *); | |
333c8841 AH |
12697 | void vec_stl (vector unsigned int, int, vector unsigned int *); |
12698 | void vec_stl (vector unsigned int, int, unsigned int *); | |
b0b343db JJ |
12699 | void vec_stl (vector bool int, int, vector bool int *); |
12700 | void vec_stl (vector bool int, int, unsigned int *); | |
12701 | void vec_stl (vector bool int, int, int *); | |
333c8841 | 12702 | void vec_stl (vector signed short, int, vector signed short *); |
b0b343db JJ |
12703 | void vec_stl (vector signed short, int, short *); |
12704 | void vec_stl (vector unsigned short, int, vector unsigned short *); | |
333c8841 | 12705 | void vec_stl (vector unsigned short, int, unsigned short *); |
b0b343db JJ |
12706 | void vec_stl (vector bool short, int, vector bool short *); |
12707 | void vec_stl (vector bool short, int, unsigned short *); | |
12708 | void vec_stl (vector bool short, int, short *); | |
12709 | void vec_stl (vector pixel, int, vector pixel *); | |
12710 | void vec_stl (vector pixel, int, unsigned short *); | |
12711 | void vec_stl (vector pixel, int, short *); | |
333c8841 | 12712 | void vec_stl (vector signed char, int, vector signed char *); |
b0b343db | 12713 | void vec_stl (vector signed char, int, signed char *); |
333c8841 | 12714 | void vec_stl (vector unsigned char, int, vector unsigned char *); |
b0b343db JJ |
12715 | void vec_stl (vector unsigned char, int, unsigned char *); |
12716 | void vec_stl (vector bool char, int, vector bool char *); | |
12717 | void vec_stl (vector bool char, int, unsigned char *); | |
12718 | void vec_stl (vector bool char, int, signed char *); | |
333c8841 | 12719 | |
b0b343db JJ |
12720 | vector signed char vec_sub (vector bool char, vector signed char); |
12721 | vector signed char vec_sub (vector signed char, vector bool char); | |
333c8841 | 12722 | vector signed char vec_sub (vector signed char, vector signed char); |
b0b343db JJ |
12723 | vector unsigned char vec_sub (vector bool char, vector unsigned char); |
12724 | vector unsigned char vec_sub (vector unsigned char, vector bool char); | |
924fcc4e JM |
12725 | vector unsigned char vec_sub (vector unsigned char, |
12726 | vector unsigned char); | |
b0b343db JJ |
12727 | vector signed short vec_sub (vector bool short, vector signed short); |
12728 | vector signed short vec_sub (vector signed short, vector bool short); | |
333c8841 | 12729 | vector signed short vec_sub (vector signed short, vector signed short); |
b0b343db | 12730 | vector unsigned short vec_sub (vector bool short, |
924fcc4e JM |
12731 | vector unsigned short); |
12732 | vector unsigned short vec_sub (vector unsigned short, | |
b0b343db | 12733 | vector bool short); |
6e5bb5ad JM |
12734 | vector unsigned short vec_sub (vector unsigned short, |
12735 | vector unsigned short); | |
b0b343db JJ |
12736 | vector signed int vec_sub (vector bool int, vector signed int); |
12737 | vector signed int vec_sub (vector signed int, vector bool int); | |
333c8841 | 12738 | vector signed int vec_sub (vector signed int, vector signed int); |
b0b343db JJ |
12739 | vector unsigned int vec_sub (vector bool int, vector unsigned int); |
12740 | vector unsigned int vec_sub (vector unsigned int, vector bool int); | |
333c8841 AH |
12741 | vector unsigned int vec_sub (vector unsigned int, vector unsigned int); |
12742 | vector float vec_sub (vector float, vector float); | |
12743 | ||
b0b343db JJ |
12744 | vector float vec_vsubfp (vector float, vector float); |
12745 | ||
12746 | vector signed int vec_vsubuwm (vector bool int, vector signed int); | |
12747 | vector signed int vec_vsubuwm (vector signed int, vector bool int); | |
12748 | vector signed int vec_vsubuwm (vector signed int, vector signed int); | |
12749 | vector unsigned int vec_vsubuwm (vector bool int, vector unsigned int); | |
12750 | vector unsigned int vec_vsubuwm (vector unsigned int, vector bool int); | |
12751 | vector unsigned int vec_vsubuwm (vector unsigned int, | |
12752 | vector unsigned int); | |
12753 | ||
12754 | vector signed short vec_vsubuhm (vector bool short, | |
12755 | vector signed short); | |
12756 | vector signed short vec_vsubuhm (vector signed short, | |
12757 | vector bool short); | |
12758 | vector signed short vec_vsubuhm (vector signed short, | |
12759 | vector signed short); | |
12760 | vector unsigned short vec_vsubuhm (vector bool short, | |
12761 | vector unsigned short); | |
12762 | vector unsigned short vec_vsubuhm (vector unsigned short, | |
12763 | vector bool short); | |
12764 | vector unsigned short vec_vsubuhm (vector unsigned short, | |
12765 | vector unsigned short); | |
12766 | ||
12767 | vector signed char vec_vsububm (vector bool char, vector signed char); | |
12768 | vector signed char vec_vsububm (vector signed char, vector bool char); | |
12769 | vector signed char vec_vsububm (vector signed char, vector signed char); | |
12770 | vector unsigned char vec_vsububm (vector bool char, | |
12771 | vector unsigned char); | |
12772 | vector unsigned char vec_vsububm (vector unsigned char, | |
12773 | vector bool char); | |
12774 | vector unsigned char vec_vsububm (vector unsigned char, | |
12775 | vector unsigned char); | |
12776 | ||
333c8841 AH |
12777 | vector unsigned int vec_subc (vector unsigned int, vector unsigned int); |
12778 | ||
b0b343db JJ |
12779 | vector unsigned char vec_subs (vector bool char, vector unsigned char); |
12780 | vector unsigned char vec_subs (vector unsigned char, vector bool char); | |
924fcc4e JM |
12781 | vector unsigned char vec_subs (vector unsigned char, |
12782 | vector unsigned char); | |
b0b343db JJ |
12783 | vector signed char vec_subs (vector bool char, vector signed char); |
12784 | vector signed char vec_subs (vector signed char, vector bool char); | |
333c8841 | 12785 | vector signed char vec_subs (vector signed char, vector signed char); |
b0b343db | 12786 | vector unsigned short vec_subs (vector bool short, |
924fcc4e JM |
12787 | vector unsigned short); |
12788 | vector unsigned short vec_subs (vector unsigned short, | |
b0b343db | 12789 | vector bool short); |
6e5bb5ad JM |
12790 | vector unsigned short vec_subs (vector unsigned short, |
12791 | vector unsigned short); | |
b0b343db JJ |
12792 | vector signed short vec_subs (vector bool short, vector signed short); |
12793 | vector signed short vec_subs (vector signed short, vector bool short); | |
333c8841 | 12794 | vector signed short vec_subs (vector signed short, vector signed short); |
b0b343db JJ |
12795 | vector unsigned int vec_subs (vector bool int, vector unsigned int); |
12796 | vector unsigned int vec_subs (vector unsigned int, vector bool int); | |
333c8841 | 12797 | vector unsigned int vec_subs (vector unsigned int, vector unsigned int); |
b0b343db JJ |
12798 | vector signed int vec_subs (vector bool int, vector signed int); |
12799 | vector signed int vec_subs (vector signed int, vector bool int); | |
333c8841 AH |
12800 | vector signed int vec_subs (vector signed int, vector signed int); |
12801 | ||
b0b343db JJ |
12802 | vector signed int vec_vsubsws (vector bool int, vector signed int); |
12803 | vector signed int vec_vsubsws (vector signed int, vector bool int); | |
12804 | vector signed int vec_vsubsws (vector signed int, vector signed int); | |
12805 | ||
12806 | vector unsigned int vec_vsubuws (vector bool int, vector unsigned int); | |
12807 | vector unsigned int vec_vsubuws (vector unsigned int, vector bool int); | |
12808 | vector unsigned int vec_vsubuws (vector unsigned int, | |
12809 | vector unsigned int); | |
12810 | ||
12811 | vector signed short vec_vsubshs (vector bool short, | |
12812 | vector signed short); | |
12813 | vector signed short vec_vsubshs (vector signed short, | |
12814 | vector bool short); | |
12815 | vector signed short vec_vsubshs (vector signed short, | |
12816 | vector signed short); | |
12817 | ||
12818 | vector unsigned short vec_vsubuhs (vector bool short, | |
12819 | vector unsigned short); | |
12820 | vector unsigned short vec_vsubuhs (vector unsigned short, | |
12821 | vector bool short); | |
12822 | vector unsigned short vec_vsubuhs (vector unsigned short, | |
12823 | vector unsigned short); | |
12824 | ||
12825 | vector signed char vec_vsubsbs (vector bool char, vector signed char); | |
12826 | vector signed char vec_vsubsbs (vector signed char, vector bool char); | |
12827 | vector signed char vec_vsubsbs (vector signed char, vector signed char); | |
12828 | ||
12829 | vector unsigned char vec_vsububs (vector bool char, | |
12830 | vector unsigned char); | |
12831 | vector unsigned char vec_vsububs (vector unsigned char, | |
12832 | vector bool char); | |
12833 | vector unsigned char vec_vsububs (vector unsigned char, | |
12834 | vector unsigned char); | |
12835 | ||
924fcc4e JM |
12836 | vector unsigned int vec_sum4s (vector unsigned char, |
12837 | vector unsigned int); | |
333c8841 AH |
12838 | vector signed int vec_sum4s (vector signed char, vector signed int); |
12839 | vector signed int vec_sum4s (vector signed short, vector signed int); | |
12840 | ||
b0b343db JJ |
12841 | vector signed int vec_vsum4shs (vector signed short, vector signed int); |
12842 | ||
12843 | vector signed int vec_vsum4sbs (vector signed char, vector signed int); | |
12844 | ||
12845 | vector unsigned int vec_vsum4ubs (vector unsigned char, | |
12846 | vector unsigned int); | |
12847 | ||
333c8841 AH |
12848 | vector signed int vec_sum2s (vector signed int, vector signed int); |
12849 | ||
12850 | vector signed int vec_sums (vector signed int, vector signed int); | |
12851 | ||
12852 | vector float vec_trunc (vector float); | |
12853 | ||
12854 | vector signed short vec_unpackh (vector signed char); | |
b0b343db | 12855 | vector bool short vec_unpackh (vector bool char); |
333c8841 | 12856 | vector signed int vec_unpackh (vector signed short); |
b0b343db JJ |
12857 | vector bool int vec_unpackh (vector bool short); |
12858 | vector unsigned int vec_unpackh (vector pixel); | |
12859 | ||
12860 | vector bool int vec_vupkhsh (vector bool short); | |
12861 | vector signed int vec_vupkhsh (vector signed short); | |
12862 | ||
12863 | vector unsigned int vec_vupkhpx (vector pixel); | |
12864 | ||
12865 | vector bool short vec_vupkhsb (vector bool char); | |
12866 | vector signed short vec_vupkhsb (vector signed char); | |
333c8841 AH |
12867 | |
12868 | vector signed short vec_unpackl (vector signed char); | |
b0b343db JJ |
12869 | vector bool short vec_unpackl (vector bool char); |
12870 | vector unsigned int vec_unpackl (vector pixel); | |
333c8841 | 12871 | vector signed int vec_unpackl (vector signed short); |
b0b343db JJ |
12872 | vector bool int vec_unpackl (vector bool short); |
12873 | ||
12874 | vector unsigned int vec_vupklpx (vector pixel); | |
12875 | ||
12876 | vector bool int vec_vupklsh (vector bool short); | |
12877 | vector signed int vec_vupklsh (vector signed short); | |
12878 | ||
12879 | vector bool short vec_vupklsb (vector bool char); | |
12880 | vector signed short vec_vupklsb (vector signed char); | |
333c8841 AH |
12881 | |
12882 | vector float vec_xor (vector float, vector float); | |
b0b343db JJ |
12883 | vector float vec_xor (vector float, vector bool int); |
12884 | vector float vec_xor (vector bool int, vector float); | |
12885 | vector bool int vec_xor (vector bool int, vector bool int); | |
12886 | vector signed int vec_xor (vector bool int, vector signed int); | |
12887 | vector signed int vec_xor (vector signed int, vector bool int); | |
333c8841 | 12888 | vector signed int vec_xor (vector signed int, vector signed int); |
b0b343db JJ |
12889 | vector unsigned int vec_xor (vector bool int, vector unsigned int); |
12890 | vector unsigned int vec_xor (vector unsigned int, vector bool int); | |
333c8841 | 12891 | vector unsigned int vec_xor (vector unsigned int, vector unsigned int); |
b0b343db JJ |
12892 | vector bool short vec_xor (vector bool short, vector bool short); |
12893 | vector signed short vec_xor (vector bool short, vector signed short); | |
12894 | vector signed short vec_xor (vector signed short, vector bool short); | |
333c8841 | 12895 | vector signed short vec_xor (vector signed short, vector signed short); |
b0b343db | 12896 | vector unsigned short vec_xor (vector bool short, |
924fcc4e JM |
12897 | vector unsigned short); |
12898 | vector unsigned short vec_xor (vector unsigned short, | |
b0b343db | 12899 | vector bool short); |
6e5bb5ad JM |
12900 | vector unsigned short vec_xor (vector unsigned short, |
12901 | vector unsigned short); | |
b0b343db JJ |
12902 | vector signed char vec_xor (vector bool char, vector signed char); |
12903 | vector bool char vec_xor (vector bool char, vector bool char); | |
12904 | vector signed char vec_xor (vector signed char, vector bool char); | |
333c8841 | 12905 | vector signed char vec_xor (vector signed char, vector signed char); |
b0b343db JJ |
12906 | vector unsigned char vec_xor (vector bool char, vector unsigned char); |
12907 | vector unsigned char vec_xor (vector unsigned char, vector bool char); | |
924fcc4e JM |
12908 | vector unsigned char vec_xor (vector unsigned char, |
12909 | vector unsigned char); | |
333c8841 | 12910 | |
b0b343db JJ |
12911 | int vec_all_eq (vector signed char, vector bool char); |
12912 | int vec_all_eq (vector signed char, vector signed char); | |
12913 | int vec_all_eq (vector unsigned char, vector bool char); | |
12914 | int vec_all_eq (vector unsigned char, vector unsigned char); | |
12915 | int vec_all_eq (vector bool char, vector bool char); | |
12916 | int vec_all_eq (vector bool char, vector unsigned char); | |
12917 | int vec_all_eq (vector bool char, vector signed char); | |
12918 | int vec_all_eq (vector signed short, vector bool short); | |
12919 | int vec_all_eq (vector signed short, vector signed short); | |
12920 | int vec_all_eq (vector unsigned short, vector bool short); | |
12921 | int vec_all_eq (vector unsigned short, vector unsigned short); | |
12922 | int vec_all_eq (vector bool short, vector bool short); | |
12923 | int vec_all_eq (vector bool short, vector unsigned short); | |
12924 | int vec_all_eq (vector bool short, vector signed short); | |
12925 | int vec_all_eq (vector pixel, vector pixel); | |
12926 | int vec_all_eq (vector signed int, vector bool int); | |
12927 | int vec_all_eq (vector signed int, vector signed int); | |
12928 | int vec_all_eq (vector unsigned int, vector bool int); | |
12929 | int vec_all_eq (vector unsigned int, vector unsigned int); | |
12930 | int vec_all_eq (vector bool int, vector bool int); | |
12931 | int vec_all_eq (vector bool int, vector unsigned int); | |
12932 | int vec_all_eq (vector bool int, vector signed int); | |
12933 | int vec_all_eq (vector float, vector float); | |
12934 | ||
12935 | int vec_all_ge (vector bool char, vector unsigned char); | |
12936 | int vec_all_ge (vector unsigned char, vector bool char); | |
12937 | int vec_all_ge (vector unsigned char, vector unsigned char); | |
12938 | int vec_all_ge (vector bool char, vector signed char); | |
12939 | int vec_all_ge (vector signed char, vector bool char); | |
12940 | int vec_all_ge (vector signed char, vector signed char); | |
12941 | int vec_all_ge (vector bool short, vector unsigned short); | |
12942 | int vec_all_ge (vector unsigned short, vector bool short); | |
12943 | int vec_all_ge (vector unsigned short, vector unsigned short); | |
12944 | int vec_all_ge (vector signed short, vector signed short); | |
12945 | int vec_all_ge (vector bool short, vector signed short); | |
12946 | int vec_all_ge (vector signed short, vector bool short); | |
12947 | int vec_all_ge (vector bool int, vector unsigned int); | |
12948 | int vec_all_ge (vector unsigned int, vector bool int); | |
12949 | int vec_all_ge (vector unsigned int, vector unsigned int); | |
12950 | int vec_all_ge (vector bool int, vector signed int); | |
12951 | int vec_all_ge (vector signed int, vector bool int); | |
12952 | int vec_all_ge (vector signed int, vector signed int); | |
12953 | int vec_all_ge (vector float, vector float); | |
12954 | ||
12955 | int vec_all_gt (vector bool char, vector unsigned char); | |
12956 | int vec_all_gt (vector unsigned char, vector bool char); | |
12957 | int vec_all_gt (vector unsigned char, vector unsigned char); | |
12958 | int vec_all_gt (vector bool char, vector signed char); | |
12959 | int vec_all_gt (vector signed char, vector bool char); | |
12960 | int vec_all_gt (vector signed char, vector signed char); | |
12961 | int vec_all_gt (vector bool short, vector unsigned short); | |
12962 | int vec_all_gt (vector unsigned short, vector bool short); | |
12963 | int vec_all_gt (vector unsigned short, vector unsigned short); | |
12964 | int vec_all_gt (vector bool short, vector signed short); | |
12965 | int vec_all_gt (vector signed short, vector bool short); | |
12966 | int vec_all_gt (vector signed short, vector signed short); | |
12967 | int vec_all_gt (vector bool int, vector unsigned int); | |
12968 | int vec_all_gt (vector unsigned int, vector bool int); | |
12969 | int vec_all_gt (vector unsigned int, vector unsigned int); | |
12970 | int vec_all_gt (vector bool int, vector signed int); | |
12971 | int vec_all_gt (vector signed int, vector bool int); | |
12972 | int vec_all_gt (vector signed int, vector signed int); | |
12973 | int vec_all_gt (vector float, vector float); | |
12974 | ||
12975 | int vec_all_in (vector float, vector float); | |
12976 | ||
12977 | int vec_all_le (vector bool char, vector unsigned char); | |
12978 | int vec_all_le (vector unsigned char, vector bool char); | |
12979 | int vec_all_le (vector unsigned char, vector unsigned char); | |
12980 | int vec_all_le (vector bool char, vector signed char); | |
12981 | int vec_all_le (vector signed char, vector bool char); | |
12982 | int vec_all_le (vector signed char, vector signed char); | |
12983 | int vec_all_le (vector bool short, vector unsigned short); | |
12984 | int vec_all_le (vector unsigned short, vector bool short); | |
12985 | int vec_all_le (vector unsigned short, vector unsigned short); | |
12986 | int vec_all_le (vector bool short, vector signed short); | |
12987 | int vec_all_le (vector signed short, vector bool short); | |
12988 | int vec_all_le (vector signed short, vector signed short); | |
12989 | int vec_all_le (vector bool int, vector unsigned int); | |
12990 | int vec_all_le (vector unsigned int, vector bool int); | |
12991 | int vec_all_le (vector unsigned int, vector unsigned int); | |
12992 | int vec_all_le (vector bool int, vector signed int); | |
12993 | int vec_all_le (vector signed int, vector bool int); | |
12994 | int vec_all_le (vector signed int, vector signed int); | |
12995 | int vec_all_le (vector float, vector float); | |
12996 | ||
12997 | int vec_all_lt (vector bool char, vector unsigned char); | |
12998 | int vec_all_lt (vector unsigned char, vector bool char); | |
12999 | int vec_all_lt (vector unsigned char, vector unsigned char); | |
13000 | int vec_all_lt (vector bool char, vector signed char); | |
13001 | int vec_all_lt (vector signed char, vector bool char); | |
13002 | int vec_all_lt (vector signed char, vector signed char); | |
13003 | int vec_all_lt (vector bool short, vector unsigned short); | |
13004 | int vec_all_lt (vector unsigned short, vector bool short); | |
13005 | int vec_all_lt (vector unsigned short, vector unsigned short); | |
13006 | int vec_all_lt (vector bool short, vector signed short); | |
13007 | int vec_all_lt (vector signed short, vector bool short); | |
13008 | int vec_all_lt (vector signed short, vector signed short); | |
13009 | int vec_all_lt (vector bool int, vector unsigned int); | |
13010 | int vec_all_lt (vector unsigned int, vector bool int); | |
13011 | int vec_all_lt (vector unsigned int, vector unsigned int); | |
13012 | int vec_all_lt (vector bool int, vector signed int); | |
13013 | int vec_all_lt (vector signed int, vector bool int); | |
13014 | int vec_all_lt (vector signed int, vector signed int); | |
13015 | int vec_all_lt (vector float, vector float); | |
13016 | ||
13017 | int vec_all_nan (vector float); | |
13018 | ||
13019 | int vec_all_ne (vector signed char, vector bool char); | |
13020 | int vec_all_ne (vector signed char, vector signed char); | |
13021 | int vec_all_ne (vector unsigned char, vector bool char); | |
13022 | int vec_all_ne (vector unsigned char, vector unsigned char); | |
13023 | int vec_all_ne (vector bool char, vector bool char); | |
13024 | int vec_all_ne (vector bool char, vector unsigned char); | |
13025 | int vec_all_ne (vector bool char, vector signed char); | |
13026 | int vec_all_ne (vector signed short, vector bool short); | |
13027 | int vec_all_ne (vector signed short, vector signed short); | |
13028 | int vec_all_ne (vector unsigned short, vector bool short); | |
13029 | int vec_all_ne (vector unsigned short, vector unsigned short); | |
13030 | int vec_all_ne (vector bool short, vector bool short); | |
13031 | int vec_all_ne (vector bool short, vector unsigned short); | |
13032 | int vec_all_ne (vector bool short, vector signed short); | |
13033 | int vec_all_ne (vector pixel, vector pixel); | |
13034 | int vec_all_ne (vector signed int, vector bool int); | |
13035 | int vec_all_ne (vector signed int, vector signed int); | |
13036 | int vec_all_ne (vector unsigned int, vector bool int); | |
13037 | int vec_all_ne (vector unsigned int, vector unsigned int); | |
13038 | int vec_all_ne (vector bool int, vector bool int); | |
13039 | int vec_all_ne (vector bool int, vector unsigned int); | |
13040 | int vec_all_ne (vector bool int, vector signed int); | |
13041 | int vec_all_ne (vector float, vector float); | |
13042 | ||
13043 | int vec_all_nge (vector float, vector float); | |
13044 | ||
13045 | int vec_all_ngt (vector float, vector float); | |
13046 | ||
13047 | int vec_all_nle (vector float, vector float); | |
13048 | ||
13049 | int vec_all_nlt (vector float, vector float); | |
13050 | ||
13051 | int vec_all_numeric (vector float); | |
13052 | ||
13053 | int vec_any_eq (vector signed char, vector bool char); | |
13054 | int vec_any_eq (vector signed char, vector signed char); | |
13055 | int vec_any_eq (vector unsigned char, vector bool char); | |
13056 | int vec_any_eq (vector unsigned char, vector unsigned char); | |
13057 | int vec_any_eq (vector bool char, vector bool char); | |
13058 | int vec_any_eq (vector bool char, vector unsigned char); | |
13059 | int vec_any_eq (vector bool char, vector signed char); | |
13060 | int vec_any_eq (vector signed short, vector bool short); | |
13061 | int vec_any_eq (vector signed short, vector signed short); | |
13062 | int vec_any_eq (vector unsigned short, vector bool short); | |
13063 | int vec_any_eq (vector unsigned short, vector unsigned short); | |
13064 | int vec_any_eq (vector bool short, vector bool short); | |
13065 | int vec_any_eq (vector bool short, vector unsigned short); | |
13066 | int vec_any_eq (vector bool short, vector signed short); | |
13067 | int vec_any_eq (vector pixel, vector pixel); | |
13068 | int vec_any_eq (vector signed int, vector bool int); | |
13069 | int vec_any_eq (vector signed int, vector signed int); | |
13070 | int vec_any_eq (vector unsigned int, vector bool int); | |
13071 | int vec_any_eq (vector unsigned int, vector unsigned int); | |
13072 | int vec_any_eq (vector bool int, vector bool int); | |
13073 | int vec_any_eq (vector bool int, vector unsigned int); | |
13074 | int vec_any_eq (vector bool int, vector signed int); | |
13075 | int vec_any_eq (vector float, vector float); | |
13076 | ||
13077 | int vec_any_ge (vector signed char, vector bool char); | |
13078 | int vec_any_ge (vector unsigned char, vector bool char); | |
13079 | int vec_any_ge (vector unsigned char, vector unsigned char); | |
13080 | int vec_any_ge (vector signed char, vector signed char); | |
13081 | int vec_any_ge (vector bool char, vector unsigned char); | |
13082 | int vec_any_ge (vector bool char, vector signed char); | |
13083 | int vec_any_ge (vector unsigned short, vector bool short); | |
13084 | int vec_any_ge (vector unsigned short, vector unsigned short); | |
13085 | int vec_any_ge (vector signed short, vector signed short); | |
13086 | int vec_any_ge (vector signed short, vector bool short); | |
13087 | int vec_any_ge (vector bool short, vector unsigned short); | |
13088 | int vec_any_ge (vector bool short, vector signed short); | |
13089 | int vec_any_ge (vector signed int, vector bool int); | |
13090 | int vec_any_ge (vector unsigned int, vector bool int); | |
13091 | int vec_any_ge (vector unsigned int, vector unsigned int); | |
13092 | int vec_any_ge (vector signed int, vector signed int); | |
13093 | int vec_any_ge (vector bool int, vector unsigned int); | |
13094 | int vec_any_ge (vector bool int, vector signed int); | |
13095 | int vec_any_ge (vector float, vector float); | |
13096 | ||
13097 | int vec_any_gt (vector bool char, vector unsigned char); | |
13098 | int vec_any_gt (vector unsigned char, vector bool char); | |
13099 | int vec_any_gt (vector unsigned char, vector unsigned char); | |
13100 | int vec_any_gt (vector bool char, vector signed char); | |
13101 | int vec_any_gt (vector signed char, vector bool char); | |
13102 | int vec_any_gt (vector signed char, vector signed char); | |
13103 | int vec_any_gt (vector bool short, vector unsigned short); | |
13104 | int vec_any_gt (vector unsigned short, vector bool short); | |
13105 | int vec_any_gt (vector unsigned short, vector unsigned short); | |
13106 | int vec_any_gt (vector bool short, vector signed short); | |
13107 | int vec_any_gt (vector signed short, vector bool short); | |
13108 | int vec_any_gt (vector signed short, vector signed short); | |
13109 | int vec_any_gt (vector bool int, vector unsigned int); | |
13110 | int vec_any_gt (vector unsigned int, vector bool int); | |
13111 | int vec_any_gt (vector unsigned int, vector unsigned int); | |
13112 | int vec_any_gt (vector bool int, vector signed int); | |
13113 | int vec_any_gt (vector signed int, vector bool int); | |
13114 | int vec_any_gt (vector signed int, vector signed int); | |
13115 | int vec_any_gt (vector float, vector float); | |
13116 | ||
13117 | int vec_any_le (vector bool char, vector unsigned char); | |
13118 | int vec_any_le (vector unsigned char, vector bool char); | |
13119 | int vec_any_le (vector unsigned char, vector unsigned char); | |
13120 | int vec_any_le (vector bool char, vector signed char); | |
13121 | int vec_any_le (vector signed char, vector bool char); | |
13122 | int vec_any_le (vector signed char, vector signed char); | |
13123 | int vec_any_le (vector bool short, vector unsigned short); | |
13124 | int vec_any_le (vector unsigned short, vector bool short); | |
13125 | int vec_any_le (vector unsigned short, vector unsigned short); | |
13126 | int vec_any_le (vector bool short, vector signed short); | |
13127 | int vec_any_le (vector signed short, vector bool short); | |
13128 | int vec_any_le (vector signed short, vector signed short); | |
13129 | int vec_any_le (vector bool int, vector unsigned int); | |
13130 | int vec_any_le (vector unsigned int, vector bool int); | |
13131 | int vec_any_le (vector unsigned int, vector unsigned int); | |
13132 | int vec_any_le (vector bool int, vector signed int); | |
13133 | int vec_any_le (vector signed int, vector bool int); | |
13134 | int vec_any_le (vector signed int, vector signed int); | |
13135 | int vec_any_le (vector float, vector float); | |
13136 | ||
13137 | int vec_any_lt (vector bool char, vector unsigned char); | |
13138 | int vec_any_lt (vector unsigned char, vector bool char); | |
13139 | int vec_any_lt (vector unsigned char, vector unsigned char); | |
13140 | int vec_any_lt (vector bool char, vector signed char); | |
13141 | int vec_any_lt (vector signed char, vector bool char); | |
13142 | int vec_any_lt (vector signed char, vector signed char); | |
13143 | int vec_any_lt (vector bool short, vector unsigned short); | |
13144 | int vec_any_lt (vector unsigned short, vector bool short); | |
13145 | int vec_any_lt (vector unsigned short, vector unsigned short); | |
13146 | int vec_any_lt (vector bool short, vector signed short); | |
13147 | int vec_any_lt (vector signed short, vector bool short); | |
13148 | int vec_any_lt (vector signed short, vector signed short); | |
13149 | int vec_any_lt (vector bool int, vector unsigned int); | |
13150 | int vec_any_lt (vector unsigned int, vector bool int); | |
13151 | int vec_any_lt (vector unsigned int, vector unsigned int); | |
13152 | int vec_any_lt (vector bool int, vector signed int); | |
13153 | int vec_any_lt (vector signed int, vector bool int); | |
13154 | int vec_any_lt (vector signed int, vector signed int); | |
13155 | int vec_any_lt (vector float, vector float); | |
13156 | ||
13157 | int vec_any_nan (vector float); | |
13158 | ||
13159 | int vec_any_ne (vector signed char, vector bool char); | |
13160 | int vec_any_ne (vector signed char, vector signed char); | |
13161 | int vec_any_ne (vector unsigned char, vector bool char); | |
13162 | int vec_any_ne (vector unsigned char, vector unsigned char); | |
13163 | int vec_any_ne (vector bool char, vector bool char); | |
13164 | int vec_any_ne (vector bool char, vector unsigned char); | |
13165 | int vec_any_ne (vector bool char, vector signed char); | |
13166 | int vec_any_ne (vector signed short, vector bool short); | |
13167 | int vec_any_ne (vector signed short, vector signed short); | |
13168 | int vec_any_ne (vector unsigned short, vector bool short); | |
13169 | int vec_any_ne (vector unsigned short, vector unsigned short); | |
13170 | int vec_any_ne (vector bool short, vector bool short); | |
13171 | int vec_any_ne (vector bool short, vector unsigned short); | |
13172 | int vec_any_ne (vector bool short, vector signed short); | |
13173 | int vec_any_ne (vector pixel, vector pixel); | |
13174 | int vec_any_ne (vector signed int, vector bool int); | |
13175 | int vec_any_ne (vector signed int, vector signed int); | |
13176 | int vec_any_ne (vector unsigned int, vector bool int); | |
13177 | int vec_any_ne (vector unsigned int, vector unsigned int); | |
13178 | int vec_any_ne (vector bool int, vector bool int); | |
13179 | int vec_any_ne (vector bool int, vector unsigned int); | |
13180 | int vec_any_ne (vector bool int, vector signed int); | |
13181 | int vec_any_ne (vector float, vector float); | |
13182 | ||
13183 | int vec_any_nge (vector float, vector float); | |
13184 | ||
13185 | int vec_any_ngt (vector float, vector float); | |
13186 | ||
13187 | int vec_any_nle (vector float, vector float); | |
13188 | ||
13189 | int vec_any_nlt (vector float, vector float); | |
13190 | ||
13191 | int vec_any_numeric (vector float); | |
13192 | ||
13193 | int vec_any_out (vector float, vector float); | |
333c8841 AH |
13194 | @end smallexample |
13195 | ||
29e6733c MM |
13196 | If the vector/scalar (VSX) instruction set is available, the following |
13197 | additional functions are available: | |
13198 | ||
13199 | @smallexample | |
13200 | vector double vec_abs (vector double); | |
13201 | vector double vec_add (vector double, vector double); | |
13202 | vector double vec_and (vector double, vector double); | |
13203 | vector double vec_and (vector double, vector bool long); | |
13204 | vector double vec_and (vector bool long, vector double); | |
13205 | vector double vec_andc (vector double, vector double); | |
13206 | vector double vec_andc (vector double, vector bool long); | |
13207 | vector double vec_andc (vector bool long, vector double); | |
13208 | vector double vec_ceil (vector double); | |
13209 | vector bool long vec_cmpeq (vector double, vector double); | |
13210 | vector bool long vec_cmpge (vector double, vector double); | |
13211 | vector bool long vec_cmpgt (vector double, vector double); | |
13212 | vector bool long vec_cmple (vector double, vector double); | |
13213 | vector bool long vec_cmplt (vector double, vector double); | |
13214 | vector float vec_div (vector float, vector float); | |
13215 | vector double vec_div (vector double, vector double); | |
13216 | vector double vec_floor (vector double); | |
c9485473 MM |
13217 | vector double vec_ld (int, const vector double *); |
13218 | vector double vec_ld (int, const double *); | |
13219 | vector double vec_ldl (int, const vector double *); | |
13220 | vector double vec_ldl (int, const double *); | |
13221 | vector unsigned char vec_lvsl (int, const volatile double *); | |
13222 | vector unsigned char vec_lvsr (int, const volatile double *); | |
29e6733c MM |
13223 | vector double vec_madd (vector double, vector double, vector double); |
13224 | vector double vec_max (vector double, vector double); | |
13225 | vector double vec_min (vector double, vector double); | |
13226 | vector float vec_msub (vector float, vector float, vector float); | |
13227 | vector double vec_msub (vector double, vector double, vector double); | |
13228 | vector float vec_mul (vector float, vector float); | |
13229 | vector double vec_mul (vector double, vector double); | |
13230 | vector float vec_nearbyint (vector float); | |
13231 | vector double vec_nearbyint (vector double); | |
13232 | vector float vec_nmadd (vector float, vector float, vector float); | |
13233 | vector double vec_nmadd (vector double, vector double, vector double); | |
13234 | vector double vec_nmsub (vector double, vector double, vector double); | |
13235 | vector double vec_nor (vector double, vector double); | |
13236 | vector double vec_or (vector double, vector double); | |
13237 | vector double vec_or (vector double, vector bool long); | |
13238 | vector double vec_or (vector bool long, vector double); | |
13239 | vector double vec_perm (vector double, | |
13240 | vector double, | |
13241 | vector unsigned char); | |
29e6733c | 13242 | vector double vec_rint (vector double); |
92902797 MM |
13243 | vector double vec_recip (vector double, vector double); |
13244 | vector double vec_rsqrt (vector double); | |
13245 | vector double vec_rsqrte (vector double); | |
29e6733c MM |
13246 | vector double vec_sel (vector double, vector double, vector bool long); |
13247 | vector double vec_sel (vector double, vector double, vector unsigned long); | |
13248 | vector double vec_sub (vector double, vector double); | |
13249 | vector float vec_sqrt (vector float); | |
13250 | vector double vec_sqrt (vector double); | |
c9485473 MM |
13251 | void vec_st (vector double, int, vector double *); |
13252 | void vec_st (vector double, int, double *); | |
29e6733c MM |
13253 | vector double vec_trunc (vector double); |
13254 | vector double vec_xor (vector double, vector double); | |
13255 | vector double vec_xor (vector double, vector bool long); | |
13256 | vector double vec_xor (vector bool long, vector double); | |
13257 | int vec_all_eq (vector double, vector double); | |
13258 | int vec_all_ge (vector double, vector double); | |
13259 | int vec_all_gt (vector double, vector double); | |
13260 | int vec_all_le (vector double, vector double); | |
13261 | int vec_all_lt (vector double, vector double); | |
13262 | int vec_all_nan (vector double); | |
13263 | int vec_all_ne (vector double, vector double); | |
13264 | int vec_all_nge (vector double, vector double); | |
13265 | int vec_all_ngt (vector double, vector double); | |
13266 | int vec_all_nle (vector double, vector double); | |
13267 | int vec_all_nlt (vector double, vector double); | |
13268 | int vec_all_numeric (vector double); | |
13269 | int vec_any_eq (vector double, vector double); | |
13270 | int vec_any_ge (vector double, vector double); | |
13271 | int vec_any_gt (vector double, vector double); | |
13272 | int vec_any_le (vector double, vector double); | |
13273 | int vec_any_lt (vector double, vector double); | |
13274 | int vec_any_nan (vector double); | |
13275 | int vec_any_ne (vector double, vector double); | |
13276 | int vec_any_nge (vector double, vector double); | |
13277 | int vec_any_ngt (vector double, vector double); | |
13278 | int vec_any_nle (vector double, vector double); | |
13279 | int vec_any_nlt (vector double, vector double); | |
13280 | int vec_any_numeric (vector double); | |
c9485473 MM |
13281 | |
13282 | vector double vec_vsx_ld (int, const vector double *); | |
13283 | vector double vec_vsx_ld (int, const double *); | |
13284 | vector float vec_vsx_ld (int, const vector float *); | |
13285 | vector float vec_vsx_ld (int, const float *); | |
13286 | vector bool int vec_vsx_ld (int, const vector bool int *); | |
13287 | vector signed int vec_vsx_ld (int, const vector signed int *); | |
13288 | vector signed int vec_vsx_ld (int, const int *); | |
13289 | vector signed int vec_vsx_ld (int, const long *); | |
13290 | vector unsigned int vec_vsx_ld (int, const vector unsigned int *); | |
13291 | vector unsigned int vec_vsx_ld (int, const unsigned int *); | |
13292 | vector unsigned int vec_vsx_ld (int, const unsigned long *); | |
13293 | vector bool short vec_vsx_ld (int, const vector bool short *); | |
13294 | vector pixel vec_vsx_ld (int, const vector pixel *); | |
13295 | vector signed short vec_vsx_ld (int, const vector signed short *); | |
13296 | vector signed short vec_vsx_ld (int, const short *); | |
13297 | vector unsigned short vec_vsx_ld (int, const vector unsigned short *); | |
13298 | vector unsigned short vec_vsx_ld (int, const unsigned short *); | |
13299 | vector bool char vec_vsx_ld (int, const vector bool char *); | |
13300 | vector signed char vec_vsx_ld (int, const vector signed char *); | |
13301 | vector signed char vec_vsx_ld (int, const signed char *); | |
13302 | vector unsigned char vec_vsx_ld (int, const vector unsigned char *); | |
13303 | vector unsigned char vec_vsx_ld (int, const unsigned char *); | |
13304 | ||
13305 | void vec_vsx_st (vector double, int, vector double *); | |
13306 | void vec_vsx_st (vector double, int, double *); | |
13307 | void vec_vsx_st (vector float, int, vector float *); | |
13308 | void vec_vsx_st (vector float, int, float *); | |
13309 | void vec_vsx_st (vector signed int, int, vector signed int *); | |
13310 | void vec_vsx_st (vector signed int, int, int *); | |
13311 | void vec_vsx_st (vector unsigned int, int, vector unsigned int *); | |
13312 | void vec_vsx_st (vector unsigned int, int, unsigned int *); | |
13313 | void vec_vsx_st (vector bool int, int, vector bool int *); | |
13314 | void vec_vsx_st (vector bool int, int, unsigned int *); | |
13315 | void vec_vsx_st (vector bool int, int, int *); | |
13316 | void vec_vsx_st (vector signed short, int, vector signed short *); | |
13317 | void vec_vsx_st (vector signed short, int, short *); | |
13318 | void vec_vsx_st (vector unsigned short, int, vector unsigned short *); | |
13319 | void vec_vsx_st (vector unsigned short, int, unsigned short *); | |
13320 | void vec_vsx_st (vector bool short, int, vector bool short *); | |
13321 | void vec_vsx_st (vector bool short, int, unsigned short *); | |
13322 | void vec_vsx_st (vector pixel, int, vector pixel *); | |
13323 | void vec_vsx_st (vector pixel, int, unsigned short *); | |
13324 | void vec_vsx_st (vector pixel, int, short *); | |
13325 | void vec_vsx_st (vector bool short, int, short *); | |
13326 | void vec_vsx_st (vector signed char, int, vector signed char *); | |
13327 | void vec_vsx_st (vector signed char, int, signed char *); | |
13328 | void vec_vsx_st (vector unsigned char, int, vector unsigned char *); | |
13329 | void vec_vsx_st (vector unsigned char, int, unsigned char *); | |
13330 | void vec_vsx_st (vector bool char, int, vector bool char *); | |
13331 | void vec_vsx_st (vector bool char, int, unsigned char *); | |
13332 | void vec_vsx_st (vector bool char, int, signed char *); | |
13333 | @end smallexample | |
13334 | ||
13335 | Note that the @samp{vec_ld} and @samp{vec_st} builtins will always | |
13336 | generate the Altivec @samp{LVX} and @samp{STVX} instructions even | |
13337 | if the VSX instruction set is available. The @samp{vec_vsx_ld} and | |
13338 | @samp{vec_vsx_st} builtins will always generate the VSX @samp{LXVD2X}, | |
13339 | @samp{LXVW4X}, @samp{STXVD2X}, and @samp{STXVW4X} instructions. | |
29e6733c MM |
13340 | |
13341 | GCC provides a few other builtins on Powerpc to access certain instructions: | |
13342 | @smallexample | |
13343 | float __builtin_recipdivf (float, float); | |
13344 | float __builtin_rsqrtf (float); | |
13345 | double __builtin_recipdiv (double, double); | |
92902797 | 13346 | double __builtin_rsqrt (double); |
29e6733c MM |
13347 | long __builtin_bpermd (long, long); |
13348 | int __builtin_bswap16 (int); | |
13349 | @end smallexample | |
13350 | ||
92902797 MM |
13351 | The @code{vec_rsqrt}, @code{__builtin_rsqrt}, and |
13352 | @code{__builtin_rsqrtf} functions generate multiple instructions to | |
13353 | implement the reciprocal sqrt functionality using reciprocal sqrt | |
13354 | estimate instructions. | |
13355 | ||
13356 | The @code{__builtin_recipdiv}, and @code{__builtin_recipdivf} | |
13357 | functions generate multiple instructions to implement division using | |
13358 | the reciprocal estimate instructions. | |
13359 | ||
65a324b4 NC |
13360 | @node RX Built-in Functions |
13361 | @subsection RX Built-in Functions | |
13362 | GCC supports some of the RX instructions which cannot be expressed in | |
13363 | the C programming language via the use of built-in functions. The | |
13364 | following functions are supported: | |
13365 | ||
13366 | @deftypefn {Built-in Function} void __builtin_rx_brk (void) | |
13367 | Generates the @code{brk} machine instruction. | |
13368 | @end deftypefn | |
13369 | ||
13370 | @deftypefn {Built-in Function} void __builtin_rx_clrpsw (int) | |
13371 | Generates the @code{clrpsw} machine instruction to clear the specified | |
13372 | bit in the processor status word. | |
13373 | @end deftypefn | |
13374 | ||
13375 | @deftypefn {Built-in Function} void __builtin_rx_int (int) | |
13376 | Generates the @code{int} machine instruction to generate an interrupt | |
13377 | with the specified value. | |
13378 | @end deftypefn | |
13379 | ||
13380 | @deftypefn {Built-in Function} void __builtin_rx_machi (int, int) | |
13381 | Generates the @code{machi} machine instruction to add the result of | |
13382 | multiplying the top 16-bits of the two arguments into the | |
13383 | accumulator. | |
13384 | @end deftypefn | |
13385 | ||
13386 | @deftypefn {Built-in Function} void __builtin_rx_maclo (int, int) | |
13387 | Generates the @code{maclo} machine instruction to add the result of | |
13388 | multiplying the bottom 16-bits of the two arguments into the | |
13389 | accumulator. | |
13390 | @end deftypefn | |
13391 | ||
13392 | @deftypefn {Built-in Function} void __builtin_rx_mulhi (int, int) | |
13393 | Generates the @code{mulhi} machine instruction to place the result of | |
13394 | multiplying the top 16-bits of the two arguments into the | |
13395 | accumulator. | |
13396 | @end deftypefn | |
13397 | ||
13398 | @deftypefn {Built-in Function} void __builtin_rx_mullo (int, int) | |
13399 | Generates the @code{mullo} machine instruction to place the result of | |
13400 | multiplying the bottom 16-bits of the two arguments into the | |
13401 | accumulator. | |
13402 | @end deftypefn | |
13403 | ||
13404 | @deftypefn {Built-in Function} int __builtin_rx_mvfachi (void) | |
13405 | Generates the @code{mvfachi} machine instruction to read the top | |
13406 | 32-bits of the accumulator. | |
13407 | @end deftypefn | |
13408 | ||
13409 | @deftypefn {Built-in Function} int __builtin_rx_mvfacmi (void) | |
13410 | Generates the @code{mvfacmi} machine instruction to read the middle | |
13411 | 32-bits of the accumulator. | |
13412 | @end deftypefn | |
13413 | ||
13414 | @deftypefn {Built-in Function} int __builtin_rx_mvfc (int) | |
13415 | Generates the @code{mvfc} machine instruction which reads the control | |
13416 | register specified in its argument and returns its value. | |
13417 | @end deftypefn | |
13418 | ||
13419 | @deftypefn {Built-in Function} void __builtin_rx_mvtachi (int) | |
13420 | Generates the @code{mvtachi} machine instruction to set the top | |
13421 | 32-bits of the accumulator. | |
13422 | @end deftypefn | |
13423 | ||
13424 | @deftypefn {Built-in Function} void __builtin_rx_mvtaclo (int) | |
13425 | Generates the @code{mvtaclo} machine instruction to set the bottom | |
13426 | 32-bits of the accumulator. | |
13427 | @end deftypefn | |
13428 | ||
13429 | @deftypefn {Built-in Function} void __builtin_rx_mvtc (int reg, int val) | |
13430 | Generates the @code{mvtc} machine instruction which sets control | |
13431 | register number @code{reg} to @code{val}. | |
13432 | @end deftypefn | |
13433 | ||
13434 | @deftypefn {Built-in Function} void __builtin_rx_mvtipl (int) | |
13435 | Generates the @code{mvtipl} machine instruction set the interrupt | |
13436 | priority level. | |
13437 | @end deftypefn | |
13438 | ||
13439 | @deftypefn {Built-in Function} void __builtin_rx_racw (int) | |
13440 | Generates the @code{racw} machine instruction to round the accumulator | |
13441 | according to the specified mode. | |
13442 | @end deftypefn | |
13443 | ||
13444 | @deftypefn {Built-in Function} int __builtin_rx_revw (int) | |
13445 | Generates the @code{revw} machine instruction which swaps the bytes in | |
13446 | the argument so that bits 0--7 now occupy bits 8--15 and vice versa, | |
13447 | and also bits 16--23 occupy bits 24--31 and vice versa. | |
13448 | @end deftypefn | |
13449 | ||
13450 | @deftypefn {Built-in Function} void __builtin_rx_rmpa (void) | |
13451 | Generates the @code{rmpa} machine instruction which initiates a | |
13452 | repeated multiply and accumulate sequence. | |
13453 | @end deftypefn | |
13454 | ||
13455 | @deftypefn {Built-in Function} void __builtin_rx_round (float) | |
13456 | Generates the @code{round} machine instruction which returns the | |
13457 | floating point argument rounded according to the current rounding mode | |
13458 | set in the floating point status word register. | |
13459 | @end deftypefn | |
13460 | ||
13461 | @deftypefn {Built-in Function} int __builtin_rx_sat (int) | |
13462 | Generates the @code{sat} machine instruction which returns the | |
13463 | saturated value of the argument. | |
13464 | @end deftypefn | |
13465 | ||
13466 | @deftypefn {Built-in Function} void __builtin_rx_setpsw (int) | |
13467 | Generates the @code{setpsw} machine instruction to set the specified | |
13468 | bit in the processor status word. | |
13469 | @end deftypefn | |
13470 | ||
13471 | @deftypefn {Built-in Function} void __builtin_rx_wait (void) | |
13472 | Generates the @code{wait} machine instruction. | |
13473 | @end deftypefn | |
13474 | ||
c5145ceb JM |
13475 | @node SPARC VIS Built-in Functions |
13476 | @subsection SPARC VIS Built-in Functions | |
13477 | ||
13478 | GCC supports SIMD operations on the SPARC using both the generic vector | |
2fd13506 | 13479 | extensions (@pxref{Vector Extensions}) as well as built-in functions for |
c5145ceb JM |
13480 | the SPARC Visual Instruction Set (VIS). When you use the @option{-mvis} |
13481 | switch, the VIS extension is exposed as the following built-in functions: | |
13482 | ||
13483 | @smallexample | |
f14e0262 | 13484 | typedef int v1si __attribute__ ((vector_size (4))); |
c5145ceb JM |
13485 | typedef int v2si __attribute__ ((vector_size (8))); |
13486 | typedef short v4hi __attribute__ ((vector_size (8))); | |
13487 | typedef short v2hi __attribute__ ((vector_size (4))); | |
47640f40 DM |
13488 | typedef unsigned char v8qi __attribute__ ((vector_size (8))); |
13489 | typedef unsigned char v4qi __attribute__ ((vector_size (4))); | |
c5145ceb | 13490 | |
10b859c0 DM |
13491 | void __builtin_vis_write_gsr (int64_t); |
13492 | int64_t __builtin_vis_read_gsr (void); | |
13493 | ||
c5145ceb | 13494 | void * __builtin_vis_alignaddr (void *, long); |
47640f40 | 13495 | void * __builtin_vis_alignaddrl (void *, long); |
c5145ceb JM |
13496 | int64_t __builtin_vis_faligndatadi (int64_t, int64_t); |
13497 | v2si __builtin_vis_faligndatav2si (v2si, v2si); | |
13498 | v4hi __builtin_vis_faligndatav4hi (v4si, v4si); | |
13499 | v8qi __builtin_vis_faligndatav8qi (v8qi, v8qi); | |
13500 | ||
13501 | v4hi __builtin_vis_fexpand (v4qi); | |
13502 | ||
13503 | v4hi __builtin_vis_fmul8x16 (v4qi, v4hi); | |
47640f40 DM |
13504 | v4hi __builtin_vis_fmul8x16au (v4qi, v2hi); |
13505 | v4hi __builtin_vis_fmul8x16al (v4qi, v2hi); | |
c5145ceb JM |
13506 | v4hi __builtin_vis_fmul8sux16 (v8qi, v4hi); |
13507 | v4hi __builtin_vis_fmul8ulx16 (v8qi, v4hi); | |
13508 | v2si __builtin_vis_fmuld8sux16 (v4qi, v2hi); | |
13509 | v2si __builtin_vis_fmuld8ulx16 (v4qi, v2hi); | |
13510 | ||
13511 | v4qi __builtin_vis_fpack16 (v4hi); | |
47640f40 | 13512 | v8qi __builtin_vis_fpack32 (v2si, v8qi); |
c5145ceb JM |
13513 | v2hi __builtin_vis_fpackfix (v2si); |
13514 | v8qi __builtin_vis_fpmerge (v4qi, v4qi); | |
13515 | ||
13516 | int64_t __builtin_vis_pdist (v8qi, v8qi, int64_t); | |
b1e4f4dd | 13517 | |
cb8bbba8 DM |
13518 | long __builtin_vis_edge8 (void *, void *); |
13519 | long __builtin_vis_edge8l (void *, void *); | |
13520 | long __builtin_vis_edge16 (void *, void *); | |
13521 | long __builtin_vis_edge16l (void *, void *); | |
13522 | long __builtin_vis_edge32 (void *, void *); | |
13523 | long __builtin_vis_edge32l (void *, void *); | |
13524 | ||
13525 | long __builtin_vis_fcmple16 (v4hi, v4hi); | |
13526 | long __builtin_vis_fcmple32 (v2si, v2si); | |
13527 | long __builtin_vis_fcmpne16 (v4hi, v4hi); | |
13528 | long __builtin_vis_fcmpne32 (v2si, v2si); | |
13529 | long __builtin_vis_fcmpgt16 (v4hi, v4hi); | |
13530 | long __builtin_vis_fcmpgt32 (v2si, v2si); | |
13531 | long __builtin_vis_fcmpeq16 (v4hi, v4hi); | |
13532 | long __builtin_vis_fcmpeq32 (v2si, v2si); | |
f14e0262 DM |
13533 | |
13534 | v4hi __builtin_vis_fpadd16 (v4hi, v4hi); | |
13535 | v2hi __builtin_vis_fpadd16s (v2hi, v2hi); | |
13536 | v2si __builtin_vis_fpadd32 (v2si, v2si); | |
13537 | v1si __builtin_vis_fpadd32s (v1si, v1si); | |
13538 | v4hi __builtin_vis_fpsub16 (v4hi, v4hi); | |
13539 | v2hi __builtin_vis_fpsub16s (v2hi, v2hi); | |
13540 | v2si __builtin_vis_fpsub32 (v2si, v2si); | |
13541 | v1si __builtin_vis_fpsub32s (v1si, v1si); | |
1ec01ab2 DM |
13542 | |
13543 | long __builtin_vis_array8 (long, long); | |
13544 | long __builtin_vis_array16 (long, long); | |
13545 | long __builtin_vis_array32 (long, long); | |
c5145ceb JM |
13546 | @end smallexample |
13547 | ||
96d7b15f DM |
13548 | When you use the @option{-mvis2} switch, the VIS version 2.0 built-in |
13549 | functions also become available: | |
c4728c6b DM |
13550 | |
13551 | @smallexample | |
13552 | long __builtin_vis_bmask (long, long); | |
13553 | int64_t __builtin_vis_bshuffledi (int64_t, int64_t); | |
13554 | v2si __builtin_vis_bshufflev2si (v2si, v2si); | |
13555 | v4hi __builtin_vis_bshufflev2si (v4hi, v4hi); | |
13556 | v8qi __builtin_vis_bshufflev2si (v8qi, v8qi); | |
13557 | ||
13558 | long __builtin_vis_edge8n (void *, void *); | |
13559 | long __builtin_vis_edge8ln (void *, void *); | |
13560 | long __builtin_vis_edge16n (void *, void *); | |
13561 | long __builtin_vis_edge16ln (void *, void *); | |
13562 | long __builtin_vis_edge32n (void *, void *); | |
13563 | long __builtin_vis_edge32ln (void *, void *); | |
13564 | @end smallexample | |
13565 | ||
96d7b15f DM |
13566 | When you use the @option{-mvis3} switch, the VIS version 3.0 built-in |
13567 | functions also become available: | |
13568 | ||
13569 | @smallexample | |
13570 | void __builtin_vis_cmask8 (long); | |
13571 | void __builtin_vis_cmask16 (long); | |
13572 | void __builtin_vis_cmask32 (long); | |
13573 | ||
13574 | v4hi __builtin_vis_fchksm16 (v4hi, v4hi); | |
13575 | ||
13576 | v4hi __builtin_vis_fsll16 (v4hi, v4hi); | |
13577 | v4hi __builtin_vis_fslas16 (v4hi, v4hi); | |
13578 | v4hi __builtin_vis_fsrl16 (v4hi, v4hi); | |
13579 | v4hi __builtin_vis_fsra16 (v4hi, v4hi); | |
13580 | v2si __builtin_vis_fsll16 (v2si, v2si); | |
13581 | v2si __builtin_vis_fslas16 (v2si, v2si); | |
13582 | v2si __builtin_vis_fsrl16 (v2si, v2si); | |
13583 | v2si __builtin_vis_fsra16 (v2si, v2si); | |
13584 | ||
13585 | long __builtin_vis_pdistn (v8qi, v8qi); | |
13586 | ||
13587 | v4hi __builtin_vis_fmean16 (v4hi, v4hi); | |
13588 | ||
13589 | int64_t __builtin_vis_fpadd64 (int64_t, int64_t); | |
13590 | int64_t __builtin_vis_fpsub64 (int64_t, int64_t); | |
13591 | ||
13592 | v4hi __builtin_vis_fpadds16 (v4hi, v4hi); | |
13593 | v2hi __builtin_vis_fpadds16s (v2hi, v2hi); | |
13594 | v4hi __builtin_vis_fpsubs16 (v4hi, v4hi); | |
13595 | v2hi __builtin_vis_fpsubs16s (v2hi, v2hi); | |
13596 | v2si __builtin_vis_fpadds32 (v2si, v2si); | |
13597 | v1si __builtin_vis_fpadds32s (v1si, v1si); | |
13598 | v2si __builtin_vis_fpsubs32 (v2si, v2si); | |
13599 | v1si __builtin_vis_fpsubs32s (v1si, v1si); | |
13600 | ||
13601 | long __builtin_vis_fucmple8 (v8qi, v8qi); | |
13602 | long __builtin_vis_fucmpne8 (v8qi, v8qi); | |
13603 | long __builtin_vis_fucmpgt8 (v8qi, v8qi); | |
13604 | long __builtin_vis_fucmpeq8 (v8qi, v8qi); | |
facb3fd7 DM |
13605 | |
13606 | float __builtin_vis_fhadds (float, float); | |
13607 | double __builtin_vis_fhaddd (double, double); | |
13608 | float __builtin_vis_fhsubs (float, float); | |
13609 | double __builtin_vis_fhsubd (double, double); | |
13610 | float __builtin_vis_fnhadds (float, float); | |
13611 | double __builtin_vis_fnhaddd (double, double); | |
13612 | ||
13613 | int64_t __builtin_vis_umulxhi (int64_t, int64_t); | |
13614 | int64_t __builtin_vis_xmulx (int64_t, int64_t); | |
13615 | int64_t __builtin_vis_xmulxhi (int64_t, int64_t); | |
96d7b15f DM |
13616 | @end smallexample |
13617 | ||
85d9c13c TS |
13618 | @node SPU Built-in Functions |
13619 | @subsection SPU Built-in Functions | |
13620 | ||
13621 | GCC provides extensions for the SPU processor as described in the | |
13622 | Sony/Toshiba/IBM SPU Language Extensions Specification, which can be | |
13623 | found at @uref{http://cell.scei.co.jp/} or | |
13624 | @uref{http://www.ibm.com/developerworks/power/cell/}. GCC's | |
13625 | implementation differs in several ways. | |
13626 | ||
13627 | @itemize @bullet | |
13628 | ||
13629 | @item | |
13630 | The optional extension of specifying vector constants in parentheses is | |
13631 | not supported. | |
13632 | ||
13633 | @item | |
13634 | A vector initializer requires no cast if the vector constant is of the | |
13635 | same type as the variable it is initializing. | |
13636 | ||
13637 | @item | |
13638 | If @code{signed} or @code{unsigned} is omitted, the signedness of the | |
13639 | vector type is the default signedness of the base type. The default | |
13640 | varies depending on the operating system, so a portable program should | |
13641 | always specify the signedness. | |
13642 | ||
13643 | @item | |
13644 | By default, the keyword @code{__vector} is added. The macro | |
13645 | @code{vector} is defined in @code{<spu_intrinsics.h>} and can be | |
13646 | undefined. | |
13647 | ||
13648 | @item | |
13649 | GCC allows using a @code{typedef} name as the type specifier for a | |
13650 | vector type. | |
13651 | ||
13652 | @item | |
13653 | For C, overloaded functions are implemented with macros so the following | |
13654 | does not work: | |
13655 | ||
13656 | @smallexample | |
13657 | spu_add ((vector signed int)@{1, 2, 3, 4@}, foo); | |
13658 | @end smallexample | |
13659 | ||
13660 | Since @code{spu_add} is a macro, the vector constant in the example | |
13661 | is treated as four separate arguments. Wrap the entire argument in | |
13662 | parentheses for this to work. | |
13663 | ||
13664 | @item | |
13665 | The extended version of @code{__builtin_expect} is not supported. | |
13666 | ||
13667 | @end itemize | |
13668 | ||
5681c208 | 13669 | @emph{Note:} Only the interface described in the aforementioned |
85d9c13c TS |
13670 | specification is supported. Internally, GCC uses built-in functions to |
13671 | implement the required functionality, but these are not supported and | |
13672 | are subject to change without notice. | |
13673 | ||
bcead286 BS |
13674 | @node TI C6X Built-in Functions |
13675 | @subsection TI C6X Built-in Functions | |
13676 | ||
13677 | GCC provides intrinsics to access certain instructions of the TI C6X | |
13678 | processors. These intrinsics, listed below, are available after | |
13679 | inclusion of the @code{c6x_intrinsics.h} header file. They map directly | |
13680 | to C6X instructions. | |
13681 | ||
13682 | @smallexample | |
13683 | ||
13684 | int _sadd (int, int) | |
13685 | int _ssub (int, int) | |
13686 | int _sadd2 (int, int) | |
13687 | int _ssub2 (int, int) | |
13688 | long long _mpy2 (int, int) | |
13689 | long long _smpy2 (int, int) | |
13690 | int _add4 (int, int) | |
13691 | int _sub4 (int, int) | |
13692 | int _saddu4 (int, int) | |
13693 | ||
13694 | int _smpy (int, int) | |
13695 | int _smpyh (int, int) | |
13696 | int _smpyhl (int, int) | |
13697 | int _smpylh (int, int) | |
13698 | ||
13699 | int _sshl (int, int) | |
13700 | int _subc (int, int) | |
13701 | ||
13702 | int _avg2 (int, int) | |
13703 | int _avgu4 (int, int) | |
13704 | ||
13705 | int _clrr (int, int) | |
13706 | int _extr (int, int) | |
13707 | int _extru (int, int) | |
13708 | int _abs (int) | |
13709 | int _abs2 (int) | |
13710 | ||
13711 | @end smallexample | |
13712 | ||
a2bec818 DJ |
13713 | @node Target Format Checks |
13714 | @section Format Checks Specific to Particular Target Machines | |
13715 | ||
13716 | For some target machines, GCC supports additional options to the | |
13717 | format attribute | |
13718 | (@pxref{Function Attributes,,Declaring Attributes of Functions}). | |
13719 | ||
13720 | @menu | |
13721 | * Solaris Format Checks:: | |
91ebb981 | 13722 | * Darwin Format Checks:: |
a2bec818 DJ |
13723 | @end menu |
13724 | ||
13725 | @node Solaris Format Checks | |
13726 | @subsection Solaris Format Checks | |
13727 | ||
13728 | Solaris targets support the @code{cmn_err} (or @code{__cmn_err__}) format | |
13729 | check. @code{cmn_err} accepts a subset of the standard @code{printf} | |
13730 | conversions, and the two-argument @code{%b} conversion for displaying | |
13731 | bit-fields. See the Solaris man page for @code{cmn_err} for more information. | |
13732 | ||
91ebb981 IS |
13733 | @node Darwin Format Checks |
13734 | @subsection Darwin Format Checks | |
13735 | ||
ff2ce160 | 13736 | Darwin targets support the @code{CFString} (or @code{__CFString__}) in the format |
91ebb981 IS |
13737 | attribute context. Declarations made with such attribution will be parsed for correct syntax |
13738 | and format argument types. However, parsing of the format string itself is currently undefined | |
ff2ce160 | 13739 | and will not be carried out by this version of the compiler. |
91ebb981 IS |
13740 | |
13741 | Additionally, @code{CFStringRefs} (defined by the @code{CoreFoundation} headers) may | |
13742 | also be used as format arguments. Note that the relevant headers are only likely to be | |
13743 | available on Darwin (OSX) installations. On such installations, the XCode and system | |
13744 | documentation provide descriptions of @code{CFString}, @code{CFStringRefs} and | |
13745 | associated functions. | |
13746 | ||
0168a849 SS |
13747 | @node Pragmas |
13748 | @section Pragmas Accepted by GCC | |
13749 | @cindex pragmas | |
ab940b73 | 13750 | @cindex @code{#pragma} |
0168a849 SS |
13751 | |
13752 | GCC supports several types of pragmas, primarily in order to compile | |
13753 | code originally written for other compilers. Note that in general | |
13754 | we do not recommend the use of pragmas; @xref{Function Attributes}, | |
13755 | for further explanation. | |
13756 | ||
13757 | @menu | |
13758 | * ARM Pragmas:: | |
38b2d076 | 13759 | * M32C Pragmas:: |
e2491744 | 13760 | * MeP Pragmas:: |
a5c76ee6 | 13761 | * RS/6000 and PowerPC Pragmas:: |
0168a849 | 13762 | * Darwin Pragmas:: |
07a43492 | 13763 | * Solaris Pragmas:: |
84b8b0e0 | 13764 | * Symbol-Renaming Pragmas:: |
467cecf3 | 13765 | * Structure-Packing Pragmas:: |
52eb57df | 13766 | * Weak Pragmas:: |
79cf5994 | 13767 | * Diagnostic Pragmas:: |
b9e75696 | 13768 | * Visibility Pragmas:: |
20cef83a | 13769 | * Push/Pop Macro Pragmas:: |
ab442df7 | 13770 | * Function Specific Option Pragmas:: |
0168a849 SS |
13771 | @end menu |
13772 | ||
13773 | @node ARM Pragmas | |
13774 | @subsection ARM Pragmas | |
13775 | ||
13776 | The ARM target defines pragmas for controlling the default addition of | |
13777 | @code{long_call} and @code{short_call} attributes to functions. | |
13778 | @xref{Function Attributes}, for information about the effects of these | |
13779 | attributes. | |
13780 | ||
13781 | @table @code | |
13782 | @item long_calls | |
13783 | @cindex pragma, long_calls | |
13784 | Set all subsequent functions to have the @code{long_call} attribute. | |
13785 | ||
13786 | @item no_long_calls | |
13787 | @cindex pragma, no_long_calls | |
13788 | Set all subsequent functions to have the @code{short_call} attribute. | |
13789 | ||
13790 | @item long_calls_off | |
13791 | @cindex pragma, long_calls_off | |
13792 | Do not affect the @code{long_call} or @code{short_call} attributes of | |
13793 | subsequent functions. | |
13794 | @end table | |
13795 | ||
38b2d076 DD |
13796 | @node M32C Pragmas |
13797 | @subsection M32C Pragmas | |
13798 | ||
13799 | @table @code | |
f6052f86 | 13800 | @item GCC memregs @var{number} |
38b2d076 | 13801 | @cindex pragma, memregs |
bcbc9564 | 13802 | Overrides the command-line option @code{-memregs=} for the current |
38b2d076 DD |
13803 | file. Use with care! This pragma must be before any function in the |
13804 | file, and mixing different memregs values in different objects may | |
13805 | make them incompatible. This pragma is useful when a | |
13806 | performance-critical function uses a memreg for temporary values, | |
13807 | as it may allow you to reduce the number of memregs used. | |
13808 | ||
f6052f86 DD |
13809 | @item ADDRESS @var{name} @var{address} |
13810 | @cindex pragma, address | |
13811 | For any declared symbols matching @var{name}, this does three things | |
13812 | to that symbol: it forces the symbol to be located at the given | |
13813 | address (a number), it forces the symbol to be volatile, and it | |
13814 | changes the symbol's scope to be static. This pragma exists for | |
13815 | compatibility with other compilers, but note that the common | |
13816 | @code{1234H} numeric syntax is not supported (use @code{0x1234} | |
13817 | instead). Example: | |
13818 | ||
13819 | @example | |
13820 | #pragma ADDRESS port3 0x103 | |
13821 | char port3; | |
13822 | @end example | |
13823 | ||
38b2d076 DD |
13824 | @end table |
13825 | ||
e2491744 DD |
13826 | @node MeP Pragmas |
13827 | @subsection MeP Pragmas | |
13828 | ||
13829 | @table @code | |
13830 | ||
13831 | @item custom io_volatile (on|off) | |
13832 | @cindex pragma, custom io_volatile | |
13833 | Overrides the command line option @code{-mio-volatile} for the current | |
13834 | file. Note that for compatibility with future GCC releases, this | |
13835 | option should only be used once before any @code{io} variables in each | |
13836 | file. | |
13837 | ||
13838 | @item GCC coprocessor available @var{registers} | |
13839 | @cindex pragma, coprocessor available | |
13840 | Specifies which coprocessor registers are available to the register | |
13841 | allocator. @var{registers} may be a single register, register range | |
13842 | separated by ellipses, or comma-separated list of those. Example: | |
13843 | ||
13844 | @example | |
13845 | #pragma GCC coprocessor available $c0...$c10, $c28 | |
13846 | @end example | |
13847 | ||
13848 | @item GCC coprocessor call_saved @var{registers} | |
13849 | @cindex pragma, coprocessor call_saved | |
13850 | Specifies which coprocessor registers are to be saved and restored by | |
13851 | any function using them. @var{registers} may be a single register, | |
13852 | register range separated by ellipses, or comma-separated list of | |
13853 | those. Example: | |
13854 | ||
13855 | @example | |
13856 | #pragma GCC coprocessor call_saved $c4...$c6, $c31 | |
13857 | @end example | |
13858 | ||
13859 | @item GCC coprocessor subclass '(A|B|C|D)' = @var{registers} | |
13860 | @cindex pragma, coprocessor subclass | |
13861 | Creates and defines a register class. These register classes can be | |
13862 | used by inline @code{asm} constructs. @var{registers} may be a single | |
13863 | register, register range separated by ellipses, or comma-separated | |
13864 | list of those. Example: | |
13865 | ||
13866 | @example | |
13867 | #pragma GCC coprocessor subclass 'B' = $c2, $c4, $c6 | |
13868 | ||
13869 | asm ("cpfoo %0" : "=B" (x)); | |
13870 | @end example | |
13871 | ||
13872 | @item GCC disinterrupt @var{name} , @var{name} @dots{} | |
13873 | @cindex pragma, disinterrupt | |
13874 | For the named functions, the compiler adds code to disable interrupts | |
13875 | for the duration of those functions. Any functions so named, which | |
13876 | are not encountered in the source, cause a warning that the pragma was | |
13877 | not used. Examples: | |
13878 | ||
13879 | @example | |
13880 | #pragma disinterrupt foo | |
13881 | #pragma disinterrupt bar, grill | |
ddaa3488 | 13882 | int foo () @{ @dots{} @} |
e2491744 DD |
13883 | @end example |
13884 | ||
13885 | @item GCC call @var{name} , @var{name} @dots{} | |
13886 | @cindex pragma, call | |
13887 | For the named functions, the compiler always uses a register-indirect | |
13888 | call model when calling the named functions. Examples: | |
13889 | ||
13890 | @example | |
13891 | extern int foo (); | |
13892 | #pragma call foo | |
13893 | @end example | |
13894 | ||
13895 | @end table | |
13896 | ||
a5c76ee6 ZW |
13897 | @node RS/6000 and PowerPC Pragmas |
13898 | @subsection RS/6000 and PowerPC Pragmas | |
13899 | ||
13900 | The RS/6000 and PowerPC targets define one pragma for controlling | |
13901 | whether or not the @code{longcall} attribute is added to function | |
13902 | declarations by default. This pragma overrides the @option{-mlongcall} | |
95b1627e | 13903 | option, but not the @code{longcall} and @code{shortcall} attributes. |
a5c76ee6 ZW |
13904 | @xref{RS/6000 and PowerPC Options}, for more information about when long |
13905 | calls are and are not necessary. | |
13906 | ||
13907 | @table @code | |
13908 | @item longcall (1) | |
13909 | @cindex pragma, longcall | |
13910 | Apply the @code{longcall} attribute to all subsequent function | |
13911 | declarations. | |
13912 | ||
13913 | @item longcall (0) | |
13914 | Do not apply the @code{longcall} attribute to subsequent function | |
13915 | declarations. | |
13916 | @end table | |
13917 | ||
0168a849 | 13918 | @c Describe h8300 pragmas here. |
0168a849 SS |
13919 | @c Describe sh pragmas here. |
13920 | @c Describe v850 pragmas here. | |
13921 | ||
13922 | @node Darwin Pragmas | |
13923 | @subsection Darwin Pragmas | |
13924 | ||
13925 | The following pragmas are available for all architectures running the | |
13926 | Darwin operating system. These are useful for compatibility with other | |
85ebf0c6 | 13927 | Mac OS compilers. |
0168a849 SS |
13928 | |
13929 | @table @code | |
13930 | @item mark @var{tokens}@dots{} | |
13931 | @cindex pragma, mark | |
13932 | This pragma is accepted, but has no effect. | |
13933 | ||
13934 | @item options align=@var{alignment} | |
13935 | @cindex pragma, options align | |
13936 | This pragma sets the alignment of fields in structures. The values of | |
13937 | @var{alignment} may be @code{mac68k}, to emulate m68k alignment, or | |
13938 | @code{power}, to emulate PowerPC alignment. Uses of this pragma nest | |
13939 | properly; to restore the previous setting, use @code{reset} for the | |
13940 | @var{alignment}. | |
13941 | ||
13942 | @item segment @var{tokens}@dots{} | |
13943 | @cindex pragma, segment | |
13944 | This pragma is accepted, but has no effect. | |
13945 | ||
13946 | @item unused (@var{var} [, @var{var}]@dots{}) | |
13947 | @cindex pragma, unused | |
13948 | This pragma declares variables to be possibly unused. GCC will not | |
13949 | produce warnings for the listed variables. The effect is similar to | |
13950 | that of the @code{unused} attribute, except that this pragma may appear | |
13951 | anywhere within the variables' scopes. | |
13952 | @end table | |
13953 | ||
07a43492 DJ |
13954 | @node Solaris Pragmas |
13955 | @subsection Solaris Pragmas | |
13956 | ||
13957 | The Solaris target supports @code{#pragma redefine_extname} | |
13958 | (@pxref{Symbol-Renaming Pragmas}). It also supports additional | |
13959 | @code{#pragma} directives for compatibility with the system compiler. | |
13960 | ||
13961 | @table @code | |
13962 | @item align @var{alignment} (@var{variable} [, @var{variable}]...) | |
13963 | @cindex pragma, align | |
13964 | ||
13965 | Increase the minimum alignment of each @var{variable} to @var{alignment}. | |
13966 | This is the same as GCC's @code{aligned} attribute @pxref{Variable | |
b5b3e36a | 13967 | Attributes}). Macro expansion occurs on the arguments to this pragma |
0ee2ea09 | 13968 | when compiling C and Objective-C@. It does not currently occur when |
b5b3e36a DJ |
13969 | compiling C++, but this is a bug which may be fixed in a future |
13970 | release. | |
07a43492 DJ |
13971 | |
13972 | @item fini (@var{function} [, @var{function}]...) | |
13973 | @cindex pragma, fini | |
13974 | ||
13975 | This pragma causes each listed @var{function} to be called after | |
13976 | main, or during shared module unloading, by adding a call to the | |
13977 | @code{.fini} section. | |
13978 | ||
13979 | @item init (@var{function} [, @var{function}]...) | |
13980 | @cindex pragma, init | |
13981 | ||
13982 | This pragma causes each listed @var{function} to be called during | |
13983 | initialization (before @code{main}) or during shared module loading, by | |
13984 | adding a call to the @code{.init} section. | |
13985 | ||
13986 | @end table | |
13987 | ||
84b8b0e0 ZW |
13988 | @node Symbol-Renaming Pragmas |
13989 | @subsection Symbol-Renaming Pragmas | |
41c64394 | 13990 | |
84b8b0e0 ZW |
13991 | For compatibility with the Solaris and Tru64 UNIX system headers, GCC |
13992 | supports two @code{#pragma} directives which change the name used in | |
ff2ce160 MS |
13993 | assembly for a given declaration. @code{#pragma extern_prefix} is only |
13994 | available on platforms whose system headers need it. To get this effect | |
c54d7dc9 | 13995 | on all platforms supported by GCC, use the asm labels extension (@pxref{Asm |
84b8b0e0 | 13996 | Labels}). |
41c64394 RH |
13997 | |
13998 | @table @code | |
13999 | @item redefine_extname @var{oldname} @var{newname} | |
14000 | @cindex pragma, redefine_extname | |
14001 | ||
84b8b0e0 ZW |
14002 | This pragma gives the C function @var{oldname} the assembly symbol |
14003 | @var{newname}. The preprocessor macro @code{__PRAGMA_REDEFINE_EXTNAME} | |
c54d7dc9 | 14004 | will be defined if this pragma is available (currently on all platforms). |
41c64394 | 14005 | |
41c64394 RH |
14006 | @item extern_prefix @var{string} |
14007 | @cindex pragma, extern_prefix | |
14008 | ||
84b8b0e0 ZW |
14009 | This pragma causes all subsequent external function and variable |
14010 | declarations to have @var{string} prepended to their assembly symbols. | |
14011 | This effect may be terminated with another @code{extern_prefix} pragma | |
14012 | whose argument is an empty string. The preprocessor macro | |
14013 | @code{__PRAGMA_EXTERN_PREFIX} will be defined if this pragma is | |
8a36672b | 14014 | available (currently only on Tru64 UNIX)@. |
41c64394 RH |
14015 | @end table |
14016 | ||
84b8b0e0 ZW |
14017 | These pragmas and the asm labels extension interact in a complicated |
14018 | manner. Here are some corner cases you may want to be aware of. | |
14019 | ||
14020 | @enumerate | |
14021 | @item Both pragmas silently apply only to declarations with external | |
14022 | linkage. Asm labels do not have this restriction. | |
14023 | ||
14024 | @item In C++, both pragmas silently apply only to declarations with | |
14025 | ``C'' linkage. Again, asm labels do not have this restriction. | |
14026 | ||
14027 | @item If any of the three ways of changing the assembly name of a | |
14028 | declaration is applied to a declaration whose assembly name has | |
14029 | already been determined (either by a previous use of one of these | |
14030 | features, or because the compiler needed the assembly name in order to | |
14031 | generate code), and the new name is different, a warning issues and | |
14032 | the name does not change. | |
14033 | ||
14034 | @item The @var{oldname} used by @code{#pragma redefine_extname} is | |
14035 | always the C-language name. | |
14036 | ||
14037 | @item If @code{#pragma extern_prefix} is in effect, and a declaration | |
14038 | occurs with an asm label attached, the prefix is silently ignored for | |
14039 | that declaration. | |
14040 | ||
14041 | @item If @code{#pragma extern_prefix} and @code{#pragma redefine_extname} | |
14042 | apply to the same declaration, whichever triggered first wins, and a | |
14043 | warning issues if they contradict each other. (We would like to have | |
14044 | @code{#pragma redefine_extname} always win, for consistency with asm | |
14045 | labels, but if @code{#pragma extern_prefix} triggers first we have no | |
14046 | way of knowing that that happened.) | |
14047 | @end enumerate | |
14048 | ||
467cecf3 JB |
14049 | @node Structure-Packing Pragmas |
14050 | @subsection Structure-Packing Pragmas | |
14051 | ||
20cef83a DS |
14052 | For compatibility with Microsoft Windows compilers, GCC supports a |
14053 | set of @code{#pragma} directives which change the maximum alignment of | |
14054 | members of structures (other than zero-width bitfields), unions, and | |
14055 | classes subsequently defined. The @var{n} value below always is required | |
14056 | to be a small power of two and specifies the new alignment in bytes. | |
467cecf3 JB |
14057 | |
14058 | @enumerate | |
14059 | @item @code{#pragma pack(@var{n})} simply sets the new alignment. | |
14060 | @item @code{#pragma pack()} sets the alignment to the one that was in | |
bcbc9564 | 14061 | effect when compilation started (see also command-line option |
917e11d7 | 14062 | @option{-fpack-struct[=@var{n}]} @pxref{Code Gen Options}). |
467cecf3 JB |
14063 | @item @code{#pragma pack(push[,@var{n}])} pushes the current alignment |
14064 | setting on an internal stack and then optionally sets the new alignment. | |
14065 | @item @code{#pragma pack(pop)} restores the alignment setting to the one | |
14066 | saved at the top of the internal stack (and removes that stack entry). | |
14067 | Note that @code{#pragma pack([@var{n}])} does not influence this internal | |
14068 | stack; thus it is possible to have @code{#pragma pack(push)} followed by | |
14069 | multiple @code{#pragma pack(@var{n})} instances and finalized by a single | |
14070 | @code{#pragma pack(pop)}. | |
14071 | @end enumerate | |
14072 | ||
021efafc | 14073 | Some targets, e.g.@: i386 and powerpc, support the @code{ms_struct} |
6bb7beac EC |
14074 | @code{#pragma} which lays out a structure as the documented |
14075 | @code{__attribute__ ((ms_struct))}. | |
14076 | @enumerate | |
14077 | @item @code{#pragma ms_struct on} turns on the layout for structures | |
14078 | declared. | |
14079 | @item @code{#pragma ms_struct off} turns off the layout for structures | |
14080 | declared. | |
14081 | @item @code{#pragma ms_struct reset} goes back to the default layout. | |
14082 | @end enumerate | |
14083 | ||
52eb57df RH |
14084 | @node Weak Pragmas |
14085 | @subsection Weak Pragmas | |
14086 | ||
14087 | For compatibility with SVR4, GCC supports a set of @code{#pragma} | |
14088 | directives for declaring symbols to be weak, and defining weak | |
14089 | aliases. | |
14090 | ||
14091 | @table @code | |
14092 | @item #pragma weak @var{symbol} | |
14093 | @cindex pragma, weak | |
14094 | This pragma declares @var{symbol} to be weak, as if the declaration | |
14095 | had the attribute of the same name. The pragma may appear before | |
e8ba94fc | 14096 | or after the declaration of @var{symbol}. It is not an error for |
52eb57df RH |
14097 | @var{symbol} to never be defined at all. |
14098 | ||
14099 | @item #pragma weak @var{symbol1} = @var{symbol2} | |
14100 | This pragma declares @var{symbol1} to be a weak alias of @var{symbol2}. | |
14101 | It is an error if @var{symbol2} is not defined in the current | |
14102 | translation unit. | |
14103 | @end table | |
14104 | ||
79cf5994 DD |
14105 | @node Diagnostic Pragmas |
14106 | @subsection Diagnostic Pragmas | |
14107 | ||
14108 | GCC allows the user to selectively enable or disable certain types of | |
14109 | diagnostics, and change the kind of the diagnostic. For example, a | |
14110 | project's policy might require that all sources compile with | |
14111 | @option{-Werror} but certain files might have exceptions allowing | |
14112 | specific types of warnings. Or, a project might selectively enable | |
14113 | diagnostics and treat them as errors depending on which preprocessor | |
14114 | macros are defined. | |
14115 | ||
14116 | @table @code | |
14117 | @item #pragma GCC diagnostic @var{kind} @var{option} | |
14118 | @cindex pragma, diagnostic | |
14119 | ||
14120 | Modifies the disposition of a diagnostic. Note that not all | |
1eaf20ec | 14121 | diagnostics are modifiable; at the moment only warnings (normally |
923158be | 14122 | controlled by @samp{-W@dots{}}) can be controlled, and not all of them. |
79cf5994 DD |
14123 | Use @option{-fdiagnostics-show-option} to determine which diagnostics |
14124 | are controllable and which option controls them. | |
14125 | ||
14126 | @var{kind} is @samp{error} to treat this diagnostic as an error, | |
14127 | @samp{warning} to treat it like a warning (even if @option{-Werror} is | |
14128 | in effect), or @samp{ignored} if the diagnostic is to be ignored. | |
bcbc9564 | 14129 | @var{option} is a double quoted string which matches the command-line |
79cf5994 DD |
14130 | option. |
14131 | ||
14132 | @example | |
14133 | #pragma GCC diagnostic warning "-Wformat" | |
c116cd05 MLI |
14134 | #pragma GCC diagnostic error "-Wformat" |
14135 | #pragma GCC diagnostic ignored "-Wformat" | |
79cf5994 DD |
14136 | @end example |
14137 | ||
cd7fe53b DD |
14138 | Note that these pragmas override any command-line options. GCC keeps |
14139 | track of the location of each pragma, and issues diagnostics according | |
14140 | to the state as of that point in the source file. Thus, pragmas occurring | |
14141 | after a line do not affect diagnostics caused by that line. | |
14142 | ||
14143 | @item #pragma GCC diagnostic push | |
14144 | @itemx #pragma GCC diagnostic pop | |
14145 | ||
14146 | Causes GCC to remember the state of the diagnostics as of each | |
14147 | @code{push}, and restore to that point at each @code{pop}. If a | |
14148 | @code{pop} has no matching @code{push}, the command line options are | |
14149 | restored. | |
14150 | ||
14151 | @example | |
14152 | #pragma GCC diagnostic error "-Wuninitialized" | |
14153 | foo(a); /* error is given for this one */ | |
14154 | #pragma GCC diagnostic push | |
14155 | #pragma GCC diagnostic ignored "-Wuninitialized" | |
14156 | foo(b); /* no diagnostic for this one */ | |
14157 | #pragma GCC diagnostic pop | |
14158 | foo(c); /* error is given for this one */ | |
14159 | #pragma GCC diagnostic pop | |
14160 | foo(d); /* depends on command line options */ | |
14161 | @end example | |
79cf5994 DD |
14162 | |
14163 | @end table | |
14164 | ||
0d48657d SB |
14165 | GCC also offers a simple mechanism for printing messages during |
14166 | compilation. | |
14167 | ||
14168 | @table @code | |
14169 | @item #pragma message @var{string} | |
14170 | @cindex pragma, diagnostic | |
14171 | ||
14172 | Prints @var{string} as a compiler message on compilation. The message | |
14173 | is informational only, and is neither a compilation warning nor an error. | |
14174 | ||
14175 | @smallexample | |
14176 | #pragma message "Compiling " __FILE__ "..." | |
14177 | @end smallexample | |
14178 | ||
14179 | @var{string} may be parenthesized, and is printed with location | |
14180 | information. For example, | |
14181 | ||
14182 | @smallexample | |
14183 | #define DO_PRAGMA(x) _Pragma (#x) | |
14184 | #define TODO(x) DO_PRAGMA(message ("TODO - " #x)) | |
14185 | ||
14186 | TODO(Remember to fix this) | |
14187 | @end smallexample | |
14188 | ||
14189 | prints @samp{/tmp/file.c:4: note: #pragma message: | |
14190 | TODO - Remember to fix this}. | |
14191 | ||
14192 | @end table | |
14193 | ||
b9e75696 JM |
14194 | @node Visibility Pragmas |
14195 | @subsection Visibility Pragmas | |
14196 | ||
14197 | @table @code | |
14198 | @item #pragma GCC visibility push(@var{visibility}) | |
14199 | @itemx #pragma GCC visibility pop | |
14200 | @cindex pragma, visibility | |
14201 | ||
14202 | This pragma allows the user to set the visibility for multiple | |
14203 | declarations without having to give each a visibility attribute | |
14204 | @xref{Function Attributes}, for more information about visibility and | |
14205 | the attribute syntax. | |
14206 | ||
14207 | In C++, @samp{#pragma GCC visibility} affects only namespace-scope | |
14208 | declarations. Class members and template specializations are not | |
14209 | affected; if you want to override the visibility for a particular | |
14210 | member or instantiation, you must use an attribute. | |
14211 | ||
14212 | @end table | |
14213 | ||
20cef83a DS |
14214 | |
14215 | @node Push/Pop Macro Pragmas | |
14216 | @subsection Push/Pop Macro Pragmas | |
14217 | ||
14218 | For compatibility with Microsoft Windows compilers, GCC supports | |
14219 | @samp{#pragma push_macro(@var{"macro_name"})} | |
14220 | and @samp{#pragma pop_macro(@var{"macro_name"})}. | |
14221 | ||
14222 | @table @code | |
14223 | @item #pragma push_macro(@var{"macro_name"}) | |
14224 | @cindex pragma, push_macro | |
14225 | This pragma saves the value of the macro named as @var{macro_name} to | |
14226 | the top of the stack for this macro. | |
14227 | ||
14228 | @item #pragma pop_macro(@var{"macro_name"}) | |
14229 | @cindex pragma, pop_macro | |
14230 | This pragma sets the value of the macro named as @var{macro_name} to | |
14231 | the value on top of the stack for this macro. If the stack for | |
14232 | @var{macro_name} is empty, the value of the macro remains unchanged. | |
14233 | @end table | |
14234 | ||
14235 | For example: | |
14236 | ||
14237 | @smallexample | |
14238 | #define X 1 | |
14239 | #pragma push_macro("X") | |
14240 | #undef X | |
14241 | #define X -1 | |
14242 | #pragma pop_macro("X") | |
ff2ce160 | 14243 | int x [X]; |
20cef83a DS |
14244 | @end smallexample |
14245 | ||
14246 | In this example, the definition of X as 1 is saved by @code{#pragma | |
14247 | push_macro} and restored by @code{#pragma pop_macro}. | |
14248 | ||
ab442df7 MM |
14249 | @node Function Specific Option Pragmas |
14250 | @subsection Function Specific Option Pragmas | |
14251 | ||
14252 | @table @code | |
5779e713 MM |
14253 | @item #pragma GCC target (@var{"string"}...) |
14254 | @cindex pragma GCC target | |
ab442df7 MM |
14255 | |
14256 | This pragma allows you to set target specific options for functions | |
14257 | defined later in the source file. One or more strings can be | |
14258 | specified. Each function that is defined after this point will be as | |
5779e713 | 14259 | if @code{attribute((target("STRING")))} was specified for that |
ab442df7 MM |
14260 | function. The parenthesis around the options is optional. |
14261 | @xref{Function Attributes}, for more information about the | |
5779e713 | 14262 | @code{target} attribute and the attribute syntax. |
ab442df7 | 14263 | |
fd438373 MM |
14264 | The @code{#pragma GCC target} attribute is not implemented in GCC versions earlier |
14265 | than 4.4 for the i386/x86_64 and 4.6 for the PowerPC backends. At | |
14266 | present, it is not implemented for other backends. | |
ab442df7 MM |
14267 | @end table |
14268 | ||
ab442df7 MM |
14269 | @table @code |
14270 | @item #pragma GCC optimize (@var{"string"}...) | |
14271 | @cindex pragma GCC optimize | |
14272 | ||
14273 | This pragma allows you to set global optimization options for functions | |
14274 | defined later in the source file. One or more strings can be | |
14275 | specified. Each function that is defined after this point will be as | |
14276 | if @code{attribute((optimize("STRING")))} was specified for that | |
14277 | function. The parenthesis around the options is optional. | |
14278 | @xref{Function Attributes}, for more information about the | |
14279 | @code{optimize} attribute and the attribute syntax. | |
14280 | ||
14281 | The @samp{#pragma GCC optimize} pragma is not implemented in GCC | |
14282 | versions earlier than 4.4. | |
14283 | @end table | |
14284 | ||
14285 | @table @code | |
5779e713 MM |
14286 | @item #pragma GCC push_options |
14287 | @itemx #pragma GCC pop_options | |
14288 | @cindex pragma GCC push_options | |
14289 | @cindex pragma GCC pop_options | |
14290 | ||
14291 | These pragmas maintain a stack of the current target and optimization | |
14292 | options. It is intended for include files where you temporarily want | |
14293 | to switch to using a different @samp{#pragma GCC target} or | |
14294 | @samp{#pragma GCC optimize} and then to pop back to the previous | |
14295 | options. | |
14296 | ||
14297 | The @samp{#pragma GCC push_options} and @samp{#pragma GCC pop_options} | |
14298 | pragmas are not implemented in GCC versions earlier than 4.4. | |
ab442df7 MM |
14299 | @end table |
14300 | ||
14301 | @table @code | |
5779e713 MM |
14302 | @item #pragma GCC reset_options |
14303 | @cindex pragma GCC reset_options | |
ab442df7 | 14304 | |
5779e713 MM |
14305 | This pragma clears the current @code{#pragma GCC target} and |
14306 | @code{#pragma GCC optimize} to use the default switches as specified | |
14307 | on the command line. | |
14308 | ||
14309 | The @samp{#pragma GCC reset_options} pragma is not implemented in GCC | |
14310 | versions earlier than 4.4. | |
ab442df7 MM |
14311 | @end table |
14312 | ||
3e96a2fd | 14313 | @node Unnamed Fields |
2fbebc71 | 14314 | @section Unnamed struct/union fields within structs/unions |
ab940b73 RW |
14315 | @cindex @code{struct} |
14316 | @cindex @code{union} | |
3e96a2fd | 14317 | |
48b0b196 | 14318 | As permitted by ISO C11 and for compatibility with other compilers, |
4bdd0a60 | 14319 | GCC allows you to define |
3e96a2fd DD |
14320 | a structure or union that contains, as fields, structures and unions |
14321 | without names. For example: | |
14322 | ||
3ab51846 | 14323 | @smallexample |
3e96a2fd DD |
14324 | struct @{ |
14325 | int a; | |
14326 | union @{ | |
14327 | int b; | |
14328 | float c; | |
14329 | @}; | |
14330 | int d; | |
14331 | @} foo; | |
3ab51846 | 14332 | @end smallexample |
3e96a2fd DD |
14333 | |
14334 | In this example, the user would be able to access members of the unnamed | |
14335 | union with code like @samp{foo.b}. Note that only unnamed structs and | |
14336 | unions are allowed, you may not have, for example, an unnamed | |
14337 | @code{int}. | |
14338 | ||
14339 | You must never create such structures that cause ambiguous field definitions. | |
14340 | For example, this structure: | |
14341 | ||
3ab51846 | 14342 | @smallexample |
3e96a2fd DD |
14343 | struct @{ |
14344 | int a; | |
14345 | struct @{ | |
14346 | int a; | |
14347 | @}; | |
14348 | @} foo; | |
3ab51846 | 14349 | @end smallexample |
3e96a2fd DD |
14350 | |
14351 | It is ambiguous which @code{a} is being referred to with @samp{foo.a}. | |
492fc0ee | 14352 | The compiler gives errors for such constructs. |
3e96a2fd | 14353 | |
2fbebc71 JM |
14354 | @opindex fms-extensions |
14355 | Unless @option{-fms-extensions} is used, the unnamed field must be a | |
14356 | structure or union definition without a tag (for example, @samp{struct | |
ff8e2159 | 14357 | @{ int a; @};}). If @option{-fms-extensions} is used, the field may |
2fbebc71 JM |
14358 | also be a definition with a tag such as @samp{struct foo @{ int a; |
14359 | @};}, a reference to a previously defined structure or union such as | |
14360 | @samp{struct foo;}, or a reference to a @code{typedef} name for a | |
ff8e2159 | 14361 | previously defined structure or union type. |
2fbebc71 | 14362 | |
478a1c5b ILT |
14363 | @opindex fplan9-extensions |
14364 | The option @option{-fplan9-extensions} enables | |
14365 | @option{-fms-extensions} as well as two other extensions. First, a | |
14366 | pointer to a structure is automatically converted to a pointer to an | |
14367 | anonymous field for assignments and function calls. For example: | |
14368 | ||
14369 | @smallexample | |
14370 | struct s1 @{ int a; @}; | |
14371 | struct s2 @{ struct s1; @}; | |
14372 | extern void f1 (struct s1 *); | |
14373 | void f2 (struct s2 *p) @{ f1 (p); @} | |
14374 | @end smallexample | |
14375 | ||
14376 | In the call to @code{f1} inside @code{f2}, the pointer @code{p} is | |
14377 | converted into a pointer to the anonymous field. | |
14378 | ||
14379 | Second, when the type of an anonymous field is a @code{typedef} for a | |
14380 | @code{struct} or @code{union}, code may refer to the field using the | |
14381 | name of the @code{typedef}. | |
14382 | ||
14383 | @smallexample | |
14384 | typedef struct @{ int a; @} s1; | |
14385 | struct s2 @{ s1; @}; | |
14386 | s1 f1 (struct s2 *p) @{ return p->s1; @} | |
14387 | @end smallexample | |
14388 | ||
14389 | These usages are only permitted when they are not ambiguous. | |
14390 | ||
3d78f2e9 RH |
14391 | @node Thread-Local |
14392 | @section Thread-Local Storage | |
14393 | @cindex Thread-Local Storage | |
9217ef40 | 14394 | @cindex @acronym{TLS} |
ab940b73 | 14395 | @cindex @code{__thread} |
3d78f2e9 | 14396 | |
9217ef40 RH |
14397 | Thread-local storage (@acronym{TLS}) is a mechanism by which variables |
14398 | are allocated such that there is one instance of the variable per extant | |
3d78f2e9 RH |
14399 | thread. The run-time model GCC uses to implement this originates |
14400 | in the IA-64 processor-specific ABI, but has since been migrated | |
14401 | to other processors as well. It requires significant support from | |
14402 | the linker (@command{ld}), dynamic linker (@command{ld.so}), and | |
14403 | system libraries (@file{libc.so} and @file{libpthread.so}), so it | |
9217ef40 | 14404 | is not available everywhere. |
3d78f2e9 RH |
14405 | |
14406 | At the user level, the extension is visible with a new storage | |
14407 | class keyword: @code{__thread}. For example: | |
14408 | ||
3ab51846 | 14409 | @smallexample |
3d78f2e9 RH |
14410 | __thread int i; |
14411 | extern __thread struct state s; | |
14412 | static __thread char *p; | |
3ab51846 | 14413 | @end smallexample |
3d78f2e9 RH |
14414 | |
14415 | The @code{__thread} specifier may be used alone, with the @code{extern} | |
14416 | or @code{static} specifiers, but with no other storage class specifier. | |
14417 | When used with @code{extern} or @code{static}, @code{__thread} must appear | |
14418 | immediately after the other storage class specifier. | |
14419 | ||
14420 | The @code{__thread} specifier may be applied to any global, file-scoped | |
244c2241 RH |
14421 | static, function-scoped static, or static data member of a class. It may |
14422 | not be applied to block-scoped automatic or non-static data member. | |
3d78f2e9 RH |
14423 | |
14424 | When the address-of operator is applied to a thread-local variable, it is | |
14425 | evaluated at run-time and returns the address of the current thread's | |
14426 | instance of that variable. An address so obtained may be used by any | |
14427 | thread. When a thread terminates, any pointers to thread-local variables | |
14428 | in that thread become invalid. | |
14429 | ||
14430 | No static initialization may refer to the address of a thread-local variable. | |
14431 | ||
244c2241 RH |
14432 | In C++, if an initializer is present for a thread-local variable, it must |
14433 | be a @var{constant-expression}, as defined in 5.19.2 of the ANSI/ISO C++ | |
14434 | standard. | |
3d78f2e9 | 14435 | |
419d1d37 | 14436 | See @uref{http://www.akkadia.org/drepper/tls.pdf, |
3d78f2e9 RH |
14437 | ELF Handling For Thread-Local Storage} for a detailed explanation of |
14438 | the four thread-local storage addressing models, and how the run-time | |
14439 | is expected to function. | |
14440 | ||
9217ef40 RH |
14441 | @menu |
14442 | * C99 Thread-Local Edits:: | |
14443 | * C++98 Thread-Local Edits:: | |
14444 | @end menu | |
14445 | ||
14446 | @node C99 Thread-Local Edits | |
14447 | @subsection ISO/IEC 9899:1999 Edits for Thread-Local Storage | |
14448 | ||
14449 | The following are a set of changes to ISO/IEC 9899:1999 (aka C99) | |
14450 | that document the exact semantics of the language extension. | |
14451 | ||
14452 | @itemize @bullet | |
14453 | @item | |
14454 | @cite{5.1.2 Execution environments} | |
14455 | ||
14456 | Add new text after paragraph 1 | |
14457 | ||
14458 | @quotation | |
14459 | Within either execution environment, a @dfn{thread} is a flow of | |
14460 | control within a program. It is implementation defined whether | |
14461 | or not there may be more than one thread associated with a program. | |
14462 | It is implementation defined how threads beyond the first are | |
14463 | created, the name and type of the function called at thread | |
14464 | startup, and how threads may be terminated. However, objects | |
14465 | with thread storage duration shall be initialized before thread | |
14466 | startup. | |
14467 | @end quotation | |
14468 | ||
14469 | @item | |
14470 | @cite{6.2.4 Storage durations of objects} | |
14471 | ||
14472 | Add new text before paragraph 3 | |
14473 | ||
14474 | @quotation | |
14475 | An object whose identifier is declared with the storage-class | |
14476 | specifier @w{@code{__thread}} has @dfn{thread storage duration}. | |
14477 | Its lifetime is the entire execution of the thread, and its | |
14478 | stored value is initialized only once, prior to thread startup. | |
14479 | @end quotation | |
14480 | ||
14481 | @item | |
14482 | @cite{6.4.1 Keywords} | |
14483 | ||
14484 | Add @code{__thread}. | |
14485 | ||
14486 | @item | |
14487 | @cite{6.7.1 Storage-class specifiers} | |
14488 | ||
14489 | Add @code{__thread} to the list of storage class specifiers in | |
14490 | paragraph 1. | |
14491 | ||
14492 | Change paragraph 2 to | |
14493 | ||
14494 | @quotation | |
14495 | With the exception of @code{__thread}, at most one storage-class | |
14496 | specifier may be given [@dots{}]. The @code{__thread} specifier may | |
14497 | be used alone, or immediately following @code{extern} or | |
14498 | @code{static}. | |
14499 | @end quotation | |
14500 | ||
14501 | Add new text after paragraph 6 | |
14502 | ||
14503 | @quotation | |
14504 | The declaration of an identifier for a variable that has | |
14505 | block scope that specifies @code{__thread} shall also | |
14506 | specify either @code{extern} or @code{static}. | |
14507 | ||
14508 | The @code{__thread} specifier shall be used only with | |
14509 | variables. | |
14510 | @end quotation | |
14511 | @end itemize | |
14512 | ||
14513 | @node C++98 Thread-Local Edits | |
14514 | @subsection ISO/IEC 14882:1998 Edits for Thread-Local Storage | |
14515 | ||
14516 | The following are a set of changes to ISO/IEC 14882:1998 (aka C++98) | |
14517 | that document the exact semantics of the language extension. | |
14518 | ||
14519 | @itemize @bullet | |
8d23a2c8 | 14520 | @item |
9217ef40 RH |
14521 | @b{[intro.execution]} |
14522 | ||
14523 | New text after paragraph 4 | |
14524 | ||
14525 | @quotation | |
14526 | A @dfn{thread} is a flow of control within the abstract machine. | |
14527 | It is implementation defined whether or not there may be more than | |
14528 | one thread. | |
14529 | @end quotation | |
14530 | ||
14531 | New text after paragraph 7 | |
14532 | ||
14533 | @quotation | |
95b1627e | 14534 | It is unspecified whether additional action must be taken to |
9217ef40 RH |
14535 | ensure when and whether side effects are visible to other threads. |
14536 | @end quotation | |
14537 | ||
14538 | @item | |
14539 | @b{[lex.key]} | |
14540 | ||
14541 | Add @code{__thread}. | |
14542 | ||
14543 | @item | |
14544 | @b{[basic.start.main]} | |
14545 | ||
14546 | Add after paragraph 5 | |
14547 | ||
14548 | @quotation | |
14549 | The thread that begins execution at the @code{main} function is called | |
95b1627e | 14550 | the @dfn{main thread}. It is implementation defined how functions |
9217ef40 RH |
14551 | beginning threads other than the main thread are designated or typed. |
14552 | A function so designated, as well as the @code{main} function, is called | |
14553 | a @dfn{thread startup function}. It is implementation defined what | |
14554 | happens if a thread startup function returns. It is implementation | |
14555 | defined what happens to other threads when any thread calls @code{exit}. | |
14556 | @end quotation | |
14557 | ||
14558 | @item | |
14559 | @b{[basic.start.init]} | |
14560 | ||
14561 | Add after paragraph 4 | |
14562 | ||
14563 | @quotation | |
14564 | The storage for an object of thread storage duration shall be | |
c0478a66 | 14565 | statically initialized before the first statement of the thread startup |
9217ef40 RH |
14566 | function. An object of thread storage duration shall not require |
14567 | dynamic initialization. | |
14568 | @end quotation | |
14569 | ||
14570 | @item | |
14571 | @b{[basic.start.term]} | |
14572 | ||
14573 | Add after paragraph 3 | |
14574 | ||
14575 | @quotation | |
244c2241 RH |
14576 | The type of an object with thread storage duration shall not have a |
14577 | non-trivial destructor, nor shall it be an array type whose elements | |
14578 | (directly or indirectly) have non-trivial destructors. | |
9217ef40 RH |
14579 | @end quotation |
14580 | ||
14581 | @item | |
14582 | @b{[basic.stc]} | |
14583 | ||
14584 | Add ``thread storage duration'' to the list in paragraph 1. | |
14585 | ||
14586 | Change paragraph 2 | |
14587 | ||
14588 | @quotation | |
14589 | Thread, static, and automatic storage durations are associated with | |
14590 | objects introduced by declarations [@dots{}]. | |
14591 | @end quotation | |
14592 | ||
14593 | Add @code{__thread} to the list of specifiers in paragraph 3. | |
14594 | ||
14595 | @item | |
14596 | @b{[basic.stc.thread]} | |
14597 | ||
14598 | New section before @b{[basic.stc.static]} | |
14599 | ||
14600 | @quotation | |
63519d23 | 14601 | The keyword @code{__thread} applied to a non-local object gives the |
9217ef40 RH |
14602 | object thread storage duration. |
14603 | ||
14604 | A local variable or class data member declared both @code{static} | |
14605 | and @code{__thread} gives the variable or member thread storage | |
14606 | duration. | |
14607 | @end quotation | |
14608 | ||
14609 | @item | |
14610 | @b{[basic.stc.static]} | |
14611 | ||
14612 | Change paragraph 1 | |
14613 | ||
14614 | @quotation | |
14615 | All objects which have neither thread storage duration, dynamic | |
14616 | storage duration nor are local [@dots{}]. | |
14617 | @end quotation | |
14618 | ||
14619 | @item | |
14620 | @b{[dcl.stc]} | |
14621 | ||
14622 | Add @code{__thread} to the list in paragraph 1. | |
14623 | ||
14624 | Change paragraph 1 | |
14625 | ||
14626 | @quotation | |
14627 | With the exception of @code{__thread}, at most one | |
14628 | @var{storage-class-specifier} shall appear in a given | |
14629 | @var{decl-specifier-seq}. The @code{__thread} specifier may | |
14630 | be used alone, or immediately following the @code{extern} or | |
14631 | @code{static} specifiers. [@dots{}] | |
14632 | @end quotation | |
14633 | ||
14634 | Add after paragraph 5 | |
14635 | ||
14636 | @quotation | |
14637 | The @code{__thread} specifier can be applied only to the names of objects | |
14638 | and to anonymous unions. | |
14639 | @end quotation | |
14640 | ||
14641 | @item | |
14642 | @b{[class.mem]} | |
14643 | ||
14644 | Add after paragraph 6 | |
14645 | ||
14646 | @quotation | |
14647 | Non-@code{static} members shall not be @code{__thread}. | |
14648 | @end quotation | |
14649 | @end itemize | |
14650 | ||
f7fd775f JW |
14651 | @node Binary constants |
14652 | @section Binary constants using the @samp{0b} prefix | |
14653 | @cindex Binary constants using the @samp{0b} prefix | |
14654 | ||
14655 | Integer constants can be written as binary constants, consisting of a | |
14656 | sequence of @samp{0} and @samp{1} digits, prefixed by @samp{0b} or | |
14657 | @samp{0B}. This is particularly useful in environments that operate a | |
14658 | lot on the bit-level (like microcontrollers). | |
14659 | ||
14660 | The following statements are identical: | |
14661 | ||
14662 | @smallexample | |
14663 | i = 42; | |
14664 | i = 0x2a; | |
14665 | i = 052; | |
14666 | i = 0b101010; | |
14667 | @end smallexample | |
14668 | ||
14669 | The type of these constants follows the same rules as for octal or | |
14670 | hexadecimal integer constants, so suffixes like @samp{L} or @samp{UL} | |
14671 | can be applied. | |
14672 | ||
c1f7febf RK |
14673 | @node C++ Extensions |
14674 | @chapter Extensions to the C++ Language | |
14675 | @cindex extensions, C++ language | |
14676 | @cindex C++ language extensions | |
14677 | ||
14678 | The GNU compiler provides these extensions to the C++ language (and you | |
14679 | can also use most of the C language extensions in your C++ programs). If you | |
14680 | want to write code that checks whether these features are available, you can | |
14681 | test for the GNU compiler the same way as for C programs: check for a | |
14682 | predefined macro @code{__GNUC__}. You can also use @code{__GNUG__} to | |
48795525 GP |
14683 | test specifically for GNU C++ (@pxref{Common Predefined Macros,, |
14684 | Predefined Macros,cpp,The GNU C Preprocessor}). | |
c1f7febf RK |
14685 | |
14686 | @menu | |
8f0fe813 | 14687 | * C++ Volatiles:: What constitutes an access to a volatile object. |
49419c8f | 14688 | * Restricted Pointers:: C99 restricted pointers and references. |
7a81cf7f | 14689 | * Vague Linkage:: Where G++ puts inlines, vtables and such. |
c1f7febf | 14690 | * C++ Interface:: You can use a single C++ header file for both |
e6f3b89d | 14691 | declarations and definitions. |
c1f7febf | 14692 | * Template Instantiation:: Methods for ensuring that exactly one copy of |
e6f3b89d | 14693 | each needed template instantiation is emitted. |
0ded1f18 JM |
14694 | * Bound member functions:: You can extract a function pointer to the |
14695 | method denoted by a @samp{->*} or @samp{.*} expression. | |
e6f3b89d | 14696 | * C++ Attributes:: Variable, function, and type attributes for C++ only. |
664a90c0 | 14697 | * Namespace Association:: Strong using-directives for namespace association. |
cb68ec50 | 14698 | * Type Traits:: Compiler support for type traits |
1f730ff7 | 14699 | * Java Exceptions:: Tweaking exception handling to work with Java. |
90ea7324 | 14700 | * Deprecated Features:: Things will disappear from g++. |
e6f3b89d | 14701 | * Backwards Compatibility:: Compatibilities with earlier definitions of C++. |
c1f7febf RK |
14702 | @end menu |
14703 | ||
8f0fe813 NS |
14704 | @node C++ Volatiles |
14705 | @section When is a Volatile C++ Object Accessed? | |
02cac427 NS |
14706 | @cindex accessing volatiles |
14707 | @cindex volatile read | |
14708 | @cindex volatile write | |
14709 | @cindex volatile access | |
14710 | ||
8f0fe813 NS |
14711 | The C++ standard differs from the C standard in its treatment of |
14712 | volatile objects. It fails to specify what constitutes a volatile | |
14713 | access, except to say that C++ should behave in a similar manner to C | |
14714 | with respect to volatiles, where possible. However, the different | |
c4c8962b | 14715 | lvalueness of expressions between C and C++ complicate the behavior. |
8f0fe813 | 14716 | G++ behaves the same as GCC for volatile access, @xref{C |
c4c8962b | 14717 | Extensions,,Volatiles}, for a description of GCC's behavior. |
02cac427 | 14718 | |
8f0fe813 NS |
14719 | The C and C++ language specifications differ when an object is |
14720 | accessed in a void context: | |
02cac427 | 14721 | |
3ab51846 | 14722 | @smallexample |
c771326b | 14723 | volatile int *src = @var{somevalue}; |
02cac427 | 14724 | *src; |
3ab51846 | 14725 | @end smallexample |
02cac427 | 14726 | |
8f0fe813 NS |
14727 | The C++ standard specifies that such expressions do not undergo lvalue |
14728 | to rvalue conversion, and that the type of the dereferenced object may | |
14729 | be incomplete. The C++ standard does not specify explicitly that it | |
14730 | is lvalue to rvalue conversion which is responsible for causing an | |
14731 | access. There is reason to believe that it is, because otherwise | |
14732 | certain simple expressions become undefined. However, because it | |
14733 | would surprise most programmers, G++ treats dereferencing a pointer to | |
14734 | volatile object of complete type as GCC would do for an equivalent | |
14735 | type in C@. When the object has incomplete type, G++ issues a | |
14736 | warning; if you wish to force an error, you must force a conversion to | |
14737 | rvalue with, for instance, a static cast. | |
02cac427 | 14738 | |
f0523f02 | 14739 | When using a reference to volatile, G++ does not treat equivalent |
02cac427 | 14740 | expressions as accesses to volatiles, but instead issues a warning that |
767094dd | 14741 | no volatile is accessed. The rationale for this is that otherwise it |
02cac427 NS |
14742 | becomes difficult to determine where volatile access occur, and not |
14743 | possible to ignore the return value from functions returning volatile | |
767094dd | 14744 | references. Again, if you wish to force a read, cast the reference to |
02cac427 NS |
14745 | an rvalue. |
14746 | ||
c4c8962b | 14747 | G++ implements the same behavior as GCC does when assigning to a |
8f0fe813 NS |
14748 | volatile object -- there is no reread of the assigned-to object, the |
14749 | assigned rvalue is reused. Note that in C++ assignment expressions | |
14750 | are lvalues, and if used as an lvalue, the volatile object will be | |
14751 | referred to. For instance, @var{vref} will refer to @var{vobj}, as | |
14752 | expected, in the following example: | |
14753 | ||
14754 | @smallexample | |
14755 | volatile int vobj; | |
14756 | volatile int &vref = vobj = @var{something}; | |
14757 | @end smallexample | |
14758 | ||
535233a8 NS |
14759 | @node Restricted Pointers |
14760 | @section Restricting Pointer Aliasing | |
14761 | @cindex restricted pointers | |
14762 | @cindex restricted references | |
14763 | @cindex restricted this pointer | |
14764 | ||
2dd76960 | 14765 | As with the C front end, G++ understands the C99 feature of restricted pointers, |
535233a8 | 14766 | specified with the @code{__restrict__}, or @code{__restrict} type |
767094dd | 14767 | qualifier. Because you cannot compile C++ by specifying the @option{-std=c99} |
535233a8 NS |
14768 | language flag, @code{restrict} is not a keyword in C++. |
14769 | ||
14770 | In addition to allowing restricted pointers, you can specify restricted | |
14771 | references, which indicate that the reference is not aliased in the local | |
14772 | context. | |
14773 | ||
3ab51846 | 14774 | @smallexample |
535233a8 NS |
14775 | void fn (int *__restrict__ rptr, int &__restrict__ rref) |
14776 | @{ | |
0d893a63 | 14777 | /* @r{@dots{}} */ |
535233a8 | 14778 | @} |
3ab51846 | 14779 | @end smallexample |
535233a8 NS |
14780 | |
14781 | @noindent | |
14782 | In the body of @code{fn}, @var{rptr} points to an unaliased integer and | |
14783 | @var{rref} refers to a (different) unaliased integer. | |
14784 | ||
14785 | You may also specify whether a member function's @var{this} pointer is | |
14786 | unaliased by using @code{__restrict__} as a member function qualifier. | |
14787 | ||
3ab51846 | 14788 | @smallexample |
535233a8 NS |
14789 | void T::fn () __restrict__ |
14790 | @{ | |
0d893a63 | 14791 | /* @r{@dots{}} */ |
535233a8 | 14792 | @} |
3ab51846 | 14793 | @end smallexample |
535233a8 NS |
14794 | |
14795 | @noindent | |
14796 | Within the body of @code{T::fn}, @var{this} will have the effective | |
767094dd | 14797 | definition @code{T *__restrict__ const this}. Notice that the |
535233a8 NS |
14798 | interpretation of a @code{__restrict__} member function qualifier is |
14799 | different to that of @code{const} or @code{volatile} qualifier, in that it | |
767094dd | 14800 | is applied to the pointer rather than the object. This is consistent with |
535233a8 NS |
14801 | other compilers which implement restricted pointers. |
14802 | ||
14803 | As with all outermost parameter qualifiers, @code{__restrict__} is | |
767094dd | 14804 | ignored in function definition matching. This means you only need to |
535233a8 NS |
14805 | specify @code{__restrict__} in a function definition, rather than |
14806 | in a function prototype as well. | |
14807 | ||
7a81cf7f JM |
14808 | @node Vague Linkage |
14809 | @section Vague Linkage | |
14810 | @cindex vague linkage | |
14811 | ||
14812 | There are several constructs in C++ which require space in the object | |
14813 | file but are not clearly tied to a single translation unit. We say that | |
14814 | these constructs have ``vague linkage''. Typically such constructs are | |
14815 | emitted wherever they are needed, though sometimes we can be more | |
14816 | clever. | |
14817 | ||
14818 | @table @asis | |
14819 | @item Inline Functions | |
14820 | Inline functions are typically defined in a header file which can be | |
14821 | included in many different compilations. Hopefully they can usually be | |
14822 | inlined, but sometimes an out-of-line copy is necessary, if the address | |
14823 | of the function is taken or if inlining fails. In general, we emit an | |
14824 | out-of-line copy in all translation units where one is needed. As an | |
14825 | exception, we only emit inline virtual functions with the vtable, since | |
14826 | it will always require a copy. | |
14827 | ||
14828 | Local static variables and string constants used in an inline function | |
14829 | are also considered to have vague linkage, since they must be shared | |
14830 | between all inlined and out-of-line instances of the function. | |
14831 | ||
14832 | @item VTables | |
14833 | @cindex vtable | |
14834 | C++ virtual functions are implemented in most compilers using a lookup | |
14835 | table, known as a vtable. The vtable contains pointers to the virtual | |
14836 | functions provided by a class, and each object of the class contains a | |
14837 | pointer to its vtable (or vtables, in some multiple-inheritance | |
14838 | situations). If the class declares any non-inline, non-pure virtual | |
14839 | functions, the first one is chosen as the ``key method'' for the class, | |
14840 | and the vtable is only emitted in the translation unit where the key | |
14841 | method is defined. | |
14842 | ||
14843 | @emph{Note:} If the chosen key method is later defined as inline, the | |
14844 | vtable will still be emitted in every translation unit which defines it. | |
14845 | Make sure that any inline virtuals are declared inline in the class | |
14846 | body, even if they are not defined there. | |
14847 | ||
ab940b73 RW |
14848 | @item @code{type_info} objects |
14849 | @cindex @code{type_info} | |
7a81cf7f JM |
14850 | @cindex RTTI |
14851 | C++ requires information about types to be written out in order to | |
14852 | implement @samp{dynamic_cast}, @samp{typeid} and exception handling. | |
ab940b73 | 14853 | For polymorphic classes (classes with virtual functions), the @samp{type_info} |
7a81cf7f JM |
14854 | object is written out along with the vtable so that @samp{dynamic_cast} |
14855 | can determine the dynamic type of a class object at runtime. For all | |
ab940b73 | 14856 | other types, we write out the @samp{type_info} object when it is used: when |
7a81cf7f JM |
14857 | applying @samp{typeid} to an expression, throwing an object, or |
14858 | referring to a type in a catch clause or exception specification. | |
14859 | ||
14860 | @item Template Instantiations | |
14861 | Most everything in this section also applies to template instantiations, | |
14862 | but there are other options as well. | |
14863 | @xref{Template Instantiation,,Where's the Template?}. | |
14864 | ||
14865 | @end table | |
14866 | ||
14867 | When used with GNU ld version 2.8 or later on an ELF system such as | |
95fef11f | 14868 | GNU/Linux or Solaris 2, or on Microsoft Windows, duplicate copies of |
7a81cf7f JM |
14869 | these constructs will be discarded at link time. This is known as |
14870 | COMDAT support. | |
14871 | ||
14872 | On targets that don't support COMDAT, but do support weak symbols, GCC | |
14873 | will use them. This way one copy will override all the others, but | |
14874 | the unused copies will still take up space in the executable. | |
14875 | ||
14876 | For targets which do not support either COMDAT or weak symbols, | |
14877 | most entities with vague linkage will be emitted as local symbols to | |
14878 | avoid duplicate definition errors from the linker. This will not happen | |
14879 | for local statics in inlines, however, as having multiple copies will | |
14880 | almost certainly break things. | |
14881 | ||
14882 | @xref{C++ Interface,,Declarations and Definitions in One Header}, for | |
14883 | another way to control placement of these constructs. | |
14884 | ||
c1f7febf | 14885 | @node C++ Interface |
fc72b380 | 14886 | @section #pragma interface and implementation |
c1f7febf RK |
14887 | |
14888 | @cindex interface and implementation headers, C++ | |
14889 | @cindex C++ interface and implementation headers | |
c1f7febf | 14890 | @cindex pragmas, interface and implementation |
c1f7febf | 14891 | |
fc72b380 JM |
14892 | @code{#pragma interface} and @code{#pragma implementation} provide the |
14893 | user with a way of explicitly directing the compiler to emit entities | |
14894 | with vague linkage (and debugging information) in a particular | |
14895 | translation unit. | |
c1f7febf | 14896 | |
fc72b380 JM |
14897 | @emph{Note:} As of GCC 2.7.2, these @code{#pragma}s are not useful in |
14898 | most cases, because of COMDAT support and the ``key method'' heuristic | |
14899 | mentioned in @ref{Vague Linkage}. Using them can actually cause your | |
27ef2cdd | 14900 | program to grow due to unnecessary out-of-line copies of inline |
fc72b380 JM |
14901 | functions. Currently (3.4) the only benefit of these |
14902 | @code{#pragma}s is reduced duplication of debugging information, and | |
14903 | that should be addressed soon on DWARF 2 targets with the use of | |
14904 | COMDAT groups. | |
c1f7febf RK |
14905 | |
14906 | @table @code | |
14907 | @item #pragma interface | |
14908 | @itemx #pragma interface "@var{subdir}/@var{objects}.h" | |
14909 | @kindex #pragma interface | |
14910 | Use this directive in @emph{header files} that define object classes, to save | |
14911 | space in most of the object files that use those classes. Normally, | |
14912 | local copies of certain information (backup copies of inline member | |
14913 | functions, debugging information, and the internal tables that implement | |
14914 | virtual functions) must be kept in each object file that includes class | |
14915 | definitions. You can use this pragma to avoid such duplication. When a | |
14916 | header file containing @samp{#pragma interface} is included in a | |
14917 | compilation, this auxiliary information will not be generated (unless | |
14918 | the main input source file itself uses @samp{#pragma implementation}). | |
14919 | Instead, the object files will contain references to be resolved at link | |
14920 | time. | |
14921 | ||
14922 | The second form of this directive is useful for the case where you have | |
14923 | multiple headers with the same name in different directories. If you | |
14924 | use this form, you must specify the same string to @samp{#pragma | |
14925 | implementation}. | |
14926 | ||
14927 | @item #pragma implementation | |
14928 | @itemx #pragma implementation "@var{objects}.h" | |
14929 | @kindex #pragma implementation | |
14930 | Use this pragma in a @emph{main input file}, when you want full output from | |
14931 | included header files to be generated (and made globally visible). The | |
14932 | included header file, in turn, should use @samp{#pragma interface}. | |
14933 | Backup copies of inline member functions, debugging information, and the | |
14934 | internal tables used to implement virtual functions are all generated in | |
14935 | implementation files. | |
14936 | ||
14937 | @cindex implied @code{#pragma implementation} | |
14938 | @cindex @code{#pragma implementation}, implied | |
14939 | @cindex naming convention, implementation headers | |
14940 | If you use @samp{#pragma implementation} with no argument, it applies to | |
14941 | an include file with the same basename@footnote{A file's @dfn{basename} | |
14942 | was the name stripped of all leading path information and of trailing | |
14943 | suffixes, such as @samp{.h} or @samp{.C} or @samp{.cc}.} as your source | |
14944 | file. For example, in @file{allclass.cc}, giving just | |
14945 | @samp{#pragma implementation} | |
14946 | by itself is equivalent to @samp{#pragma implementation "allclass.h"}. | |
14947 | ||
14948 | In versions of GNU C++ prior to 2.6.0 @file{allclass.h} was treated as | |
14949 | an implementation file whenever you would include it from | |
14950 | @file{allclass.cc} even if you never specified @samp{#pragma | |
14951 | implementation}. This was deemed to be more trouble than it was worth, | |
14952 | however, and disabled. | |
14953 | ||
c1f7febf RK |
14954 | Use the string argument if you want a single implementation file to |
14955 | include code from multiple header files. (You must also use | |
14956 | @samp{#include} to include the header file; @samp{#pragma | |
14957 | implementation} only specifies how to use the file---it doesn't actually | |
14958 | include it.) | |
14959 | ||
14960 | There is no way to split up the contents of a single header file into | |
14961 | multiple implementation files. | |
14962 | @end table | |
14963 | ||
14964 | @cindex inlining and C++ pragmas | |
14965 | @cindex C++ pragmas, effect on inlining | |
14966 | @cindex pragmas in C++, effect on inlining | |
14967 | @samp{#pragma implementation} and @samp{#pragma interface} also have an | |
14968 | effect on function inlining. | |
14969 | ||
14970 | If you define a class in a header file marked with @samp{#pragma | |
fc72b380 JM |
14971 | interface}, the effect on an inline function defined in that class is |
14972 | similar to an explicit @code{extern} declaration---the compiler emits | |
14973 | no code at all to define an independent version of the function. Its | |
14974 | definition is used only for inlining with its callers. | |
c1f7febf | 14975 | |
84330467 | 14976 | @opindex fno-implement-inlines |
c1f7febf RK |
14977 | Conversely, when you include the same header file in a main source file |
14978 | that declares it as @samp{#pragma implementation}, the compiler emits | |
14979 | code for the function itself; this defines a version of the function | |
14980 | that can be found via pointers (or by callers compiled without | |
14981 | inlining). If all calls to the function can be inlined, you can avoid | |
84330467 | 14982 | emitting the function by compiling with @option{-fno-implement-inlines}. |
c1f7febf RK |
14983 | If any calls were not inlined, you will get linker errors. |
14984 | ||
14985 | @node Template Instantiation | |
14986 | @section Where's the Template? | |
c1f7febf RK |
14987 | @cindex template instantiation |
14988 | ||
14989 | C++ templates are the first language feature to require more | |
14990 | intelligence from the environment than one usually finds on a UNIX | |
14991 | system. Somehow the compiler and linker have to make sure that each | |
14992 | template instance occurs exactly once in the executable if it is needed, | |
14993 | and not at all otherwise. There are two basic approaches to this | |
962e6e00 | 14994 | problem, which are referred to as the Borland model and the Cfront model. |
c1f7febf RK |
14995 | |
14996 | @table @asis | |
14997 | @item Borland model | |
14998 | Borland C++ solved the template instantiation problem by adding the code | |
469b759e JM |
14999 | equivalent of common blocks to their linker; the compiler emits template |
15000 | instances in each translation unit that uses them, and the linker | |
15001 | collapses them together. The advantage of this model is that the linker | |
15002 | only has to consider the object files themselves; there is no external | |
15003 | complexity to worry about. This disadvantage is that compilation time | |
15004 | is increased because the template code is being compiled repeatedly. | |
15005 | Code written for this model tends to include definitions of all | |
15006 | templates in the header file, since they must be seen to be | |
15007 | instantiated. | |
c1f7febf RK |
15008 | |
15009 | @item Cfront model | |
15010 | The AT&T C++ translator, Cfront, solved the template instantiation | |
15011 | problem by creating the notion of a template repository, an | |
469b759e JM |
15012 | automatically maintained place where template instances are stored. A |
15013 | more modern version of the repository works as follows: As individual | |
15014 | object files are built, the compiler places any template definitions and | |
15015 | instantiations encountered in the repository. At link time, the link | |
15016 | wrapper adds in the objects in the repository and compiles any needed | |
15017 | instances that were not previously emitted. The advantages of this | |
15018 | model are more optimal compilation speed and the ability to use the | |
15019 | system linker; to implement the Borland model a compiler vendor also | |
c1f7febf | 15020 | needs to replace the linker. The disadvantages are vastly increased |
469b759e JM |
15021 | complexity, and thus potential for error; for some code this can be |
15022 | just as transparent, but in practice it can been very difficult to build | |
c1f7febf | 15023 | multiple programs in one directory and one program in multiple |
469b759e JM |
15024 | directories. Code written for this model tends to separate definitions |
15025 | of non-inline member templates into a separate file, which should be | |
15026 | compiled separately. | |
c1f7febf RK |
15027 | @end table |
15028 | ||
469b759e | 15029 | When used with GNU ld version 2.8 or later on an ELF system such as |
2dd76960 JM |
15030 | GNU/Linux or Solaris 2, or on Microsoft Windows, G++ supports the |
15031 | Borland model. On other systems, G++ implements neither automatic | |
a4b3b54a | 15032 | model. |
469b759e | 15033 | |
2dd76960 | 15034 | A future version of G++ will support a hybrid model whereby the compiler |
469b759e JM |
15035 | will emit any instantiations for which the template definition is |
15036 | included in the compile, and store template definitions and | |
15037 | instantiation context information into the object file for the rest. | |
15038 | The link wrapper will extract that information as necessary and invoke | |
15039 | the compiler to produce the remaining instantiations. The linker will | |
15040 | then combine duplicate instantiations. | |
15041 | ||
15042 | In the mean time, you have the following options for dealing with | |
15043 | template instantiations: | |
c1f7febf RK |
15044 | |
15045 | @enumerate | |
d863830b | 15046 | @item |
84330467 JM |
15047 | @opindex frepo |
15048 | Compile your template-using code with @option{-frepo}. The compiler will | |
d863830b JL |
15049 | generate files with the extension @samp{.rpo} listing all of the |
15050 | template instantiations used in the corresponding object files which | |
15051 | could be instantiated there; the link wrapper, @samp{collect2}, will | |
15052 | then update the @samp{.rpo} files to tell the compiler where to place | |
15053 | those instantiations and rebuild any affected object files. The | |
15054 | link-time overhead is negligible after the first pass, as the compiler | |
15055 | will continue to place the instantiations in the same files. | |
15056 | ||
15057 | This is your best option for application code written for the Borland | |
15058 | model, as it will just work. Code written for the Cfront model will | |
15059 | need to be modified so that the template definitions are available at | |
15060 | one or more points of instantiation; usually this is as simple as adding | |
15061 | @code{#include <tmethods.cc>} to the end of each template header. | |
15062 | ||
15063 | For library code, if you want the library to provide all of the template | |
15064 | instantiations it needs, just try to link all of its object files | |
15065 | together; the link will fail, but cause the instantiations to be | |
15066 | generated as a side effect. Be warned, however, that this may cause | |
15067 | conflicts if multiple libraries try to provide the same instantiations. | |
15068 | For greater control, use explicit instantiation as described in the next | |
15069 | option. | |
15070 | ||
c1f7febf | 15071 | @item |
84330467 JM |
15072 | @opindex fno-implicit-templates |
15073 | Compile your code with @option{-fno-implicit-templates} to disable the | |
c1f7febf RK |
15074 | implicit generation of template instances, and explicitly instantiate |
15075 | all the ones you use. This approach requires more knowledge of exactly | |
15076 | which instances you need than do the others, but it's less | |
15077 | mysterious and allows greater control. You can scatter the explicit | |
15078 | instantiations throughout your program, perhaps putting them in the | |
15079 | translation units where the instances are used or the translation units | |
15080 | that define the templates themselves; you can put all of the explicit | |
15081 | instantiations you need into one big file; or you can create small files | |
15082 | like | |
15083 | ||
3ab51846 | 15084 | @smallexample |
c1f7febf RK |
15085 | #include "Foo.h" |
15086 | #include "Foo.cc" | |
15087 | ||
15088 | template class Foo<int>; | |
15089 | template ostream& operator << | |
15090 | (ostream&, const Foo<int>&); | |
3ab51846 | 15091 | @end smallexample |
c1f7febf RK |
15092 | |
15093 | for each of the instances you need, and create a template instantiation | |
15094 | library from those. | |
15095 | ||
15096 | If you are using Cfront-model code, you can probably get away with not | |
84330467 | 15097 | using @option{-fno-implicit-templates} when compiling files that don't |
c1f7febf RK |
15098 | @samp{#include} the member template definitions. |
15099 | ||
15100 | If you use one big file to do the instantiations, you may want to | |
84330467 | 15101 | compile it without @option{-fno-implicit-templates} so you get all of the |
c1f7febf RK |
15102 | instances required by your explicit instantiations (but not by any |
15103 | other files) without having to specify them as well. | |
15104 | ||
2dd76960 | 15105 | G++ has extended the template instantiation syntax given in the ISO |
6d9c4c83 | 15106 | standard to allow forward declaration of explicit instantiations |
4003d7f9 | 15107 | (with @code{extern}), instantiation of the compiler support data for a |
e979f9e8 | 15108 | template class (i.e.@: the vtable) without instantiating any of its |
4003d7f9 JM |
15109 | members (with @code{inline}), and instantiation of only the static data |
15110 | members of a template class, without the support data or member | |
15111 | functions (with (@code{static}): | |
c1f7febf | 15112 | |
3ab51846 | 15113 | @smallexample |
c1f7febf | 15114 | extern template int max (int, int); |
c1f7febf | 15115 | inline template class Foo<int>; |
4003d7f9 | 15116 | static template class Foo<int>; |
3ab51846 | 15117 | @end smallexample |
c1f7febf RK |
15118 | |
15119 | @item | |
2dd76960 | 15120 | Do nothing. Pretend G++ does implement automatic instantiation |
c1f7febf RK |
15121 | management. Code written for the Borland model will work fine, but |
15122 | each translation unit will contain instances of each of the templates it | |
15123 | uses. In a large program, this can lead to an unacceptable amount of code | |
15124 | duplication. | |
c1f7febf RK |
15125 | @end enumerate |
15126 | ||
0ded1f18 JM |
15127 | @node Bound member functions |
15128 | @section Extracting the function pointer from a bound pointer to member function | |
0ded1f18 JM |
15129 | @cindex pmf |
15130 | @cindex pointer to member function | |
15131 | @cindex bound pointer to member function | |
15132 | ||
15133 | In C++, pointer to member functions (PMFs) are implemented using a wide | |
15134 | pointer of sorts to handle all the possible call mechanisms; the PMF | |
15135 | needs to store information about how to adjust the @samp{this} pointer, | |
15136 | and if the function pointed to is virtual, where to find the vtable, and | |
15137 | where in the vtable to look for the member function. If you are using | |
15138 | PMFs in an inner loop, you should really reconsider that decision. If | |
15139 | that is not an option, you can extract the pointer to the function that | |
15140 | would be called for a given object/PMF pair and call it directly inside | |
15141 | the inner loop, to save a bit of time. | |
15142 | ||
15143 | Note that you will still be paying the penalty for the call through a | |
15144 | function pointer; on most modern architectures, such a call defeats the | |
161d7b59 | 15145 | branch prediction features of the CPU@. This is also true of normal |
0ded1f18 JM |
15146 | virtual function calls. |
15147 | ||
15148 | The syntax for this extension is | |
15149 | ||
3ab51846 | 15150 | @smallexample |
0ded1f18 JM |
15151 | extern A a; |
15152 | extern int (A::*fp)(); | |
15153 | typedef int (*fptr)(A *); | |
15154 | ||
15155 | fptr p = (fptr)(a.*fp); | |
3ab51846 | 15156 | @end smallexample |
0ded1f18 | 15157 | |
e979f9e8 | 15158 | For PMF constants (i.e.@: expressions of the form @samp{&Klasse::Member}), |
767094dd | 15159 | no object is needed to obtain the address of the function. They can be |
0fb6bbf5 ML |
15160 | converted to function pointers directly: |
15161 | ||
3ab51846 | 15162 | @smallexample |
0fb6bbf5 | 15163 | fptr p1 = (fptr)(&A::foo); |
3ab51846 | 15164 | @end smallexample |
0fb6bbf5 | 15165 | |
84330467 JM |
15166 | @opindex Wno-pmf-conversions |
15167 | You must specify @option{-Wno-pmf-conversions} to use this extension. | |
0ded1f18 | 15168 | |
5c25e11d PE |
15169 | @node C++ Attributes |
15170 | @section C++-Specific Variable, Function, and Type Attributes | |
15171 | ||
15172 | Some attributes only make sense for C++ programs. | |
15173 | ||
15174 | @table @code | |
15175 | @item init_priority (@var{priority}) | |
ab940b73 | 15176 | @cindex @code{init_priority} attribute |
5c25e11d PE |
15177 | |
15178 | ||
15179 | In Standard C++, objects defined at namespace scope are guaranteed to be | |
15180 | initialized in an order in strict accordance with that of their definitions | |
15181 | @emph{in a given translation unit}. No guarantee is made for initializations | |
15182 | across translation units. However, GNU C++ allows users to control the | |
3844cd2e | 15183 | order of initialization of objects defined at namespace scope with the |
5c25e11d PE |
15184 | @code{init_priority} attribute by specifying a relative @var{priority}, |
15185 | a constant integral expression currently bounded between 101 and 65535 | |
15186 | inclusive. Lower numbers indicate a higher priority. | |
15187 | ||
15188 | In the following example, @code{A} would normally be created before | |
15189 | @code{B}, but the @code{init_priority} attribute has reversed that order: | |
15190 | ||
478c9e72 | 15191 | @smallexample |
5c25e11d PE |
15192 | Some_Class A __attribute__ ((init_priority (2000))); |
15193 | Some_Class B __attribute__ ((init_priority (543))); | |
478c9e72 | 15194 | @end smallexample |
5c25e11d PE |
15195 | |
15196 | @noindent | |
15197 | Note that the particular values of @var{priority} do not matter; only their | |
15198 | relative ordering. | |
15199 | ||
60c87482 | 15200 | @item java_interface |
ab940b73 | 15201 | @cindex @code{java_interface} attribute |
60c87482 | 15202 | |
02f52e19 | 15203 | This type attribute informs C++ that the class is a Java interface. It may |
60c87482 | 15204 | only be applied to classes declared within an @code{extern "Java"} block. |
02f52e19 AJ |
15205 | Calls to methods declared in this interface will be dispatched using GCJ's |
15206 | interface table mechanism, instead of regular virtual table dispatch. | |
60c87482 | 15207 | |
5c25e11d PE |
15208 | @end table |
15209 | ||
38bb2b65 | 15210 | See also @ref{Namespace Association}. |
86098eb8 | 15211 | |
664a90c0 JM |
15212 | @node Namespace Association |
15213 | @section Namespace Association | |
86098eb8 | 15214 | |
fea77ed9 MM |
15215 | @strong{Caution:} The semantics of this extension are not fully |
15216 | defined. Users should refrain from using this extension as its | |
15217 | semantics may change subtly over time. It is possible that this | |
664a90c0 | 15218 | extension will be removed in future versions of G++. |
fea77ed9 | 15219 | |
86098eb8 JM |
15220 | A using-directive with @code{__attribute ((strong))} is stronger |
15221 | than a normal using-directive in two ways: | |
15222 | ||
15223 | @itemize @bullet | |
15224 | @item | |
664a90c0 JM |
15225 | Templates from the used namespace can be specialized and explicitly |
15226 | instantiated as though they were members of the using namespace. | |
86098eb8 JM |
15227 | |
15228 | @item | |
15229 | The using namespace is considered an associated namespace of all | |
15230 | templates in the used namespace for purposes of argument-dependent | |
15231 | name lookup. | |
15232 | @end itemize | |
15233 | ||
664a90c0 JM |
15234 | The used namespace must be nested within the using namespace so that |
15235 | normal unqualified lookup works properly. | |
15236 | ||
86098eb8 JM |
15237 | This is useful for composing a namespace transparently from |
15238 | implementation namespaces. For example: | |
15239 | ||
15240 | @smallexample | |
15241 | namespace std @{ | |
15242 | namespace debug @{ | |
15243 | template <class T> struct A @{ @}; | |
15244 | @} | |
15245 | using namespace debug __attribute ((__strong__)); | |
cd1a8088 | 15246 | template <> struct A<int> @{ @}; // @r{ok to specialize} |
86098eb8 JM |
15247 | |
15248 | template <class T> void f (A<T>); | |
15249 | @} | |
15250 | ||
15251 | int main() | |
15252 | @{ | |
cd1a8088 | 15253 | f (std::A<float>()); // @r{lookup finds} std::f |
86098eb8 JM |
15254 | f (std::A<int>()); |
15255 | @} | |
15256 | @end smallexample | |
15257 | ||
cb68ec50 PC |
15258 | @node Type Traits |
15259 | @section Type Traits | |
15260 | ||
15261 | The C++ front-end implements syntactic extensions that allow to | |
15262 | determine at compile time various characteristics of a type (or of a | |
15263 | pair of types). | |
15264 | ||
15265 | @table @code | |
15266 | @item __has_nothrow_assign (type) | |
b29441ec PC |
15267 | If @code{type} is const qualified or is a reference type then the trait is |
15268 | false. Otherwise if @code{__has_trivial_assign (type)} is true then the trait | |
15269 | is true, else if @code{type} is a cv class or union type with copy assignment | |
15270 | operators that are known not to throw an exception then the trait is true, | |
ff2ce160 | 15271 | else it is false. Requires: @code{type} shall be a complete type, |
5307cbaa | 15272 | (possibly cv-qualified) @code{void}, or an array of unknown bound. |
cb68ec50 PC |
15273 | |
15274 | @item __has_nothrow_copy (type) | |
15275 | If @code{__has_trivial_copy (type)} is true then the trait is true, else if | |
15276 | @code{type} is a cv class or union type with copy constructors that | |
15277 | are known not to throw an exception then the trait is true, else it is false. | |
5307cbaa PC |
15278 | Requires: @code{type} shall be a complete type, (possibly cv-qualified) |
15279 | @code{void}, or an array of unknown bound. | |
cb68ec50 PC |
15280 | |
15281 | @item __has_nothrow_constructor (type) | |
15282 | If @code{__has_trivial_constructor (type)} is true then the trait is | |
15283 | true, else if @code{type} is a cv class or union type (or array | |
15284 | thereof) with a default constructor that is known not to throw an | |
ff2ce160 MS |
15285 | exception then the trait is true, else it is false. Requires: |
15286 | @code{type} shall be a complete type, (possibly cv-qualified) | |
5307cbaa | 15287 | @code{void}, or an array of unknown bound. |
cb68ec50 PC |
15288 | |
15289 | @item __has_trivial_assign (type) | |
15290 | If @code{type} is const qualified or is a reference type then the trait is | |
15291 | false. Otherwise if @code{__is_pod (type)} is true then the trait is | |
15292 | true, else if @code{type} is a cv class or union type with a trivial | |
15293 | copy assignment ([class.copy]) then the trait is true, else it is | |
ff2ce160 | 15294 | false. Requires: @code{type} shall be a complete type, (possibly |
5307cbaa | 15295 | cv-qualified) @code{void}, or an array of unknown bound. |
cb68ec50 PC |
15296 | |
15297 | @item __has_trivial_copy (type) | |
ff2ce160 | 15298 | If @code{__is_pod (type)} is true or @code{type} is a reference type |
cb68ec50 PC |
15299 | then the trait is true, else if @code{type} is a cv class or union type |
15300 | with a trivial copy constructor ([class.copy]) then the trait | |
15301 | is true, else it is false. Requires: @code{type} shall be a complete | |
5307cbaa | 15302 | type, (possibly cv-qualified) @code{void}, or an array of unknown bound. |
cb68ec50 PC |
15303 | |
15304 | @item __has_trivial_constructor (type) | |
15305 | If @code{__is_pod (type)} is true then the trait is true, else if | |
15306 | @code{type} is a cv class or union type (or array thereof) with a | |
15307 | trivial default constructor ([class.ctor]) then the trait is true, | |
5307cbaa PC |
15308 | else it is false. Requires: @code{type} shall be a complete |
15309 | type, (possibly cv-qualified) @code{void}, or an array of unknown bound. | |
cb68ec50 PC |
15310 | |
15311 | @item __has_trivial_destructor (type) | |
15312 | If @code{__is_pod (type)} is true or @code{type} is a reference type then | |
15313 | the trait is true, else if @code{type} is a cv class or union type (or | |
15314 | array thereof) with a trivial destructor ([class.dtor]) then the trait | |
15315 | is true, else it is false. Requires: @code{type} shall be a complete | |
5307cbaa | 15316 | type, (possibly cv-qualified) @code{void}, or an array of unknown bound. |
cb68ec50 PC |
15317 | |
15318 | @item __has_virtual_destructor (type) | |
15319 | If @code{type} is a class type with a virtual destructor | |
15320 | ([class.dtor]) then the trait is true, else it is false. Requires: | |
5307cbaa PC |
15321 | @code{type} shall be a complete type, (possibly cv-qualified) |
15322 | @code{void}, or an array of unknown bound. | |
cb68ec50 PC |
15323 | |
15324 | @item __is_abstract (type) | |
15325 | If @code{type} is an abstract class ([class.abstract]) then the trait | |
15326 | is true, else it is false. Requires: @code{type} shall be a complete | |
5307cbaa | 15327 | type, (possibly cv-qualified) @code{void}, or an array of unknown bound. |
cb68ec50 PC |
15328 | |
15329 | @item __is_base_of (base_type, derived_type) | |
15330 | If @code{base_type} is a base class of @code{derived_type} | |
15331 | ([class.derived]) then the trait is true, otherwise it is false. | |
15332 | Top-level cv qualifications of @code{base_type} and | |
15333 | @code{derived_type} are ignored. For the purposes of this trait, a | |
15334 | class type is considered is own base. Requires: if @code{__is_class | |
15335 | (base_type)} and @code{__is_class (derived_type)} are true and | |
15336 | @code{base_type} and @code{derived_type} are not the same type | |
15337 | (disregarding cv-qualifiers), @code{derived_type} shall be a complete | |
15338 | type. Diagnostic is produced if this requirement is not met. | |
15339 | ||
15340 | @item __is_class (type) | |
15341 | If @code{type} is a cv class type, and not a union type | |
d1facce0 | 15342 | ([basic.compound]) the trait is true, else it is false. |
cb68ec50 PC |
15343 | |
15344 | @item __is_empty (type) | |
15345 | If @code{__is_class (type)} is false then the trait is false. | |
15346 | Otherwise @code{type} is considered empty if and only if: @code{type} | |
15347 | has no non-static data members, or all non-static data members, if | |
d1facce0 | 15348 | any, are bit-fields of length 0, and @code{type} has no virtual |
cb68ec50 | 15349 | members, and @code{type} has no virtual base classes, and @code{type} |
ff2ce160 | 15350 | has no base classes @code{base_type} for which |
cb68ec50 | 15351 | @code{__is_empty (base_type)} is false. Requires: @code{type} shall |
5307cbaa PC |
15352 | be a complete type, (possibly cv-qualified) @code{void}, or an array |
15353 | of unknown bound. | |
cb68ec50 PC |
15354 | |
15355 | @item __is_enum (type) | |
d1facce0 | 15356 | If @code{type} is a cv enumeration type ([basic.compound]) the trait is |
cb68ec50 PC |
15357 | true, else it is false. |
15358 | ||
5307cbaa PC |
15359 | @item __is_literal_type (type) |
15360 | If @code{type} is a literal type ([basic.types]) the trait is | |
15361 | true, else it is false. Requires: @code{type} shall be a complete type, | |
15362 | (possibly cv-qualified) @code{void}, or an array of unknown bound. | |
15363 | ||
cb68ec50 PC |
15364 | @item __is_pod (type) |
15365 | If @code{type} is a cv POD type ([basic.types]) then the trait is true, | |
5307cbaa PC |
15366 | else it is false. Requires: @code{type} shall be a complete type, |
15367 | (possibly cv-qualified) @code{void}, or an array of unknown bound. | |
cb68ec50 PC |
15368 | |
15369 | @item __is_polymorphic (type) | |
15370 | If @code{type} is a polymorphic class ([class.virtual]) then the trait | |
15371 | is true, else it is false. Requires: @code{type} shall be a complete | |
5307cbaa PC |
15372 | type, (possibly cv-qualified) @code{void}, or an array of unknown bound. |
15373 | ||
15374 | @item __is_standard_layout (type) | |
15375 | If @code{type} is a standard-layout type ([basic.types]) the trait is | |
15376 | true, else it is false. Requires: @code{type} shall be a complete | |
15377 | type, (possibly cv-qualified) @code{void}, or an array of unknown bound. | |
15378 | ||
15379 | @item __is_trivial (type) | |
15380 | If @code{type} is a trivial type ([basic.types]) the trait is | |
15381 | true, else it is false. Requires: @code{type} shall be a complete | |
15382 | type, (possibly cv-qualified) @code{void}, or an array of unknown bound. | |
cb68ec50 PC |
15383 | |
15384 | @item __is_union (type) | |
d1facce0 | 15385 | If @code{type} is a cv union type ([basic.compound]) the trait is |
cb68ec50 PC |
15386 | true, else it is false. |
15387 | ||
74e883ce PC |
15388 | @item __underlying_type (type) |
15389 | The underlying type of @code{type}. Requires: @code{type} shall be | |
15390 | an enumeration type ([dcl.enum]). | |
15391 | ||
cb68ec50 PC |
15392 | @end table |
15393 | ||
1f730ff7 ZW |
15394 | @node Java Exceptions |
15395 | @section Java Exceptions | |
15396 | ||
15397 | The Java language uses a slightly different exception handling model | |
15398 | from C++. Normally, GNU C++ will automatically detect when you are | |
15399 | writing C++ code that uses Java exceptions, and handle them | |
15400 | appropriately. However, if C++ code only needs to execute destructors | |
15401 | when Java exceptions are thrown through it, GCC will guess incorrectly. | |
9c34dbbf | 15402 | Sample problematic code is: |
1f730ff7 | 15403 | |
478c9e72 | 15404 | @smallexample |
1f730ff7 | 15405 | struct S @{ ~S(); @}; |
cd1a8088 | 15406 | extern void bar(); // @r{is written in Java, and may throw exceptions} |
1f730ff7 ZW |
15407 | void foo() |
15408 | @{ | |
15409 | S s; | |
15410 | bar(); | |
15411 | @} | |
478c9e72 | 15412 | @end smallexample |
1f730ff7 ZW |
15413 | |
15414 | @noindent | |
15415 | The usual effect of an incorrect guess is a link failure, complaining of | |
15416 | a missing routine called @samp{__gxx_personality_v0}. | |
15417 | ||
15418 | You can inform the compiler that Java exceptions are to be used in a | |
15419 | translation unit, irrespective of what it might think, by writing | |
15420 | @samp{@w{#pragma GCC java_exceptions}} at the head of the file. This | |
15421 | @samp{#pragma} must appear before any functions that throw or catch | |
15422 | exceptions, or run destructors when exceptions are thrown through them. | |
15423 | ||
15424 | You cannot mix Java and C++ exceptions in the same translation unit. It | |
15425 | is believed to be safe to throw a C++ exception from one file through | |
9c34dbbf ZW |
15426 | another file compiled for the Java exception model, or vice versa, but |
15427 | there may be bugs in this area. | |
1f730ff7 | 15428 | |
e6f3b89d PE |
15429 | @node Deprecated Features |
15430 | @section Deprecated Features | |
15431 | ||
15432 | In the past, the GNU C++ compiler was extended to experiment with new | |
767094dd | 15433 | features, at a time when the C++ language was still evolving. Now that |
e6f3b89d | 15434 | the C++ standard is complete, some of those features are superseded by |
767094dd JM |
15435 | superior alternatives. Using the old features might cause a warning in |
15436 | some cases that the feature will be dropped in the future. In other | |
e6f3b89d PE |
15437 | cases, the feature might be gone already. |
15438 | ||
15439 | While the list below is not exhaustive, it documents some of the options | |
15440 | that are now deprecated: | |
15441 | ||
15442 | @table @code | |
15443 | @item -fexternal-templates | |
15444 | @itemx -falt-external-templates | |
2dd76960 | 15445 | These are two of the many ways for G++ to implement template |
767094dd | 15446 | instantiation. @xref{Template Instantiation}. The C++ standard clearly |
e6f3b89d | 15447 | defines how template definitions have to be organized across |
2dd76960 | 15448 | implementation units. G++ has an implicit instantiation mechanism that |
e6f3b89d PE |
15449 | should work just fine for standard-conforming code. |
15450 | ||
15451 | @item -fstrict-prototype | |
15452 | @itemx -fno-strict-prototype | |
15453 | Previously it was possible to use an empty prototype parameter list to | |
15454 | indicate an unspecified number of parameters (like C), rather than no | |
767094dd | 15455 | parameters, as C++ demands. This feature has been removed, except where |
38bb2b65 | 15456 | it is required for backwards compatibility. @xref{Backwards Compatibility}. |
e6f3b89d PE |
15457 | @end table |
15458 | ||
ae209f28 NS |
15459 | G++ allows a virtual function returning @samp{void *} to be overridden |
15460 | by one returning a different pointer type. This extension to the | |
15461 | covariant return type rules is now deprecated and will be removed from a | |
15462 | future version. | |
15463 | ||
8ff24a79 MM |
15464 | The G++ minimum and maximum operators (@samp{<?} and @samp{>?}) and |
15465 | their compound forms (@samp{<?=}) and @samp{>?=}) have been deprecated | |
32e26ece GK |
15466 | and are now removed from G++. Code using these operators should be |
15467 | modified to use @code{std::min} and @code{std::max} instead. | |
8ff24a79 | 15468 | |
ad1a6d45 | 15469 | The named return value extension has been deprecated, and is now |
2dd76960 | 15470 | removed from G++. |
e6f3b89d | 15471 | |
82c18d5c | 15472 | The use of initializer lists with new expressions has been deprecated, |
2dd76960 | 15473 | and is now removed from G++. |
ad1a6d45 NS |
15474 | |
15475 | Floating and complex non-type template parameters have been deprecated, | |
2dd76960 | 15476 | and are now removed from G++. |
ad1a6d45 | 15477 | |
90ea7324 | 15478 | The implicit typename extension has been deprecated and is now |
2dd76960 | 15479 | removed from G++. |
90ea7324 | 15480 | |
1eaf20ec | 15481 | The use of default arguments in function pointers, function typedefs |
90ea7324 | 15482 | and other places where they are not permitted by the standard is |
2dd76960 | 15483 | deprecated and will be removed from a future version of G++. |
82c18d5c | 15484 | |
6871294a JW |
15485 | G++ allows floating-point literals to appear in integral constant expressions, |
15486 | e.g. @samp{ enum E @{ e = int(2.2 * 3.7) @} } | |
15487 | This extension is deprecated and will be removed from a future version. | |
15488 | ||
15489 | G++ allows static data members of const floating-point type to be declared | |
15490 | with an initializer in a class definition. The standard only allows | |
15491 | initializers for static members of const integral types and const | |
15492 | enumeration types so this extension has been deprecated and will be removed | |
15493 | from a future version. | |
15494 | ||
e6f3b89d PE |
15495 | @node Backwards Compatibility |
15496 | @section Backwards Compatibility | |
15497 | @cindex Backwards Compatibility | |
15498 | @cindex ARM [Annotated C++ Reference Manual] | |
15499 | ||
aee96fe9 | 15500 | Now that there is a definitive ISO standard C++, G++ has a specification |
767094dd | 15501 | to adhere to. The C++ language evolved over time, and features that |
e6f3b89d | 15502 | used to be acceptable in previous drafts of the standard, such as the ARM |
767094dd | 15503 | [Annotated C++ Reference Manual], are no longer accepted. In order to allow |
aee96fe9 | 15504 | compilation of C++ written to such drafts, G++ contains some backwards |
767094dd | 15505 | compatibilities. @emph{All such backwards compatibility features are |
aee96fe9 | 15506 | liable to disappear in future versions of G++.} They should be considered |
38bb2b65 | 15507 | deprecated. @xref{Deprecated Features}. |
e6f3b89d PE |
15508 | |
15509 | @table @code | |
15510 | @item For scope | |
15511 | If a variable is declared at for scope, it used to remain in scope until | |
15512 | the end of the scope which contained the for statement (rather than just | |
aee96fe9 | 15513 | within the for scope). G++ retains this, but issues a warning, if such a |
e6f3b89d PE |
15514 | variable is accessed outside the for scope. |
15515 | ||
ad1a6d45 | 15516 | @item Implicit C language |
630d3d5a | 15517 | Old C system header files did not contain an @code{extern "C" @{@dots{}@}} |
767094dd JM |
15518 | scope to set the language. On such systems, all header files are |
15519 | implicitly scoped inside a C language scope. Also, an empty prototype | |
e6f3b89d PE |
15520 | @code{()} will be treated as an unspecified number of arguments, rather |
15521 | than no arguments, as C++ demands. | |
15522 | @end table |