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1 /* Definitions of floating-point access for GNU compiler.
2 Copyright (C) 1989-2014 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
10
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
19
20 #ifndef GCC_REAL_H
21 #define GCC_REAL_H
22
23 #include "machmode.h"
24 #include "signop.h"
25 #include "wide-int.h"
26 #include "insn-modes.h"
27
28 /* An expanded form of the represented number. */
29
30 /* Enumerate the special cases of numbers that we encounter. */
31 enum real_value_class {
32 rvc_zero,
33 rvc_normal,
34 rvc_inf,
35 rvc_nan
36 };
37
38 #define SIGNIFICAND_BITS (128 + HOST_BITS_PER_LONG)
39 #define EXP_BITS (32 - 6)
40 #define MAX_EXP ((1 << (EXP_BITS - 1)) - 1)
41 #define SIGSZ (SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
42 #define SIG_MSB ((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
43
44 struct GTY(()) real_value {
45 /* Use the same underlying type for all bit-fields, so as to make
46 sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
47 be miscomputed. */
48 unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
49 unsigned int decimal : 1;
50 unsigned int sign : 1;
51 unsigned int signalling : 1;
52 unsigned int canonical : 1;
53 unsigned int uexp : EXP_BITS;
54 unsigned long sig[SIGSZ];
55 };
56
57 #define REAL_EXP(REAL) \
58 ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
59 - (1 << (EXP_BITS - 1)))
60 #define SET_REAL_EXP(REAL, EXP) \
61 ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
62
63 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
64 needs to be a macro. We do need to continue to have a structure tag
65 so that other headers can forward declare it. */
66 #define REAL_VALUE_TYPE struct real_value
67
68 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
69 consecutive "w" slots. Moreover, we've got to compute the number of "w"
70 slots at preprocessor time, which means we can't use sizeof. Guess. */
71
72 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
73 #define REAL_WIDTH \
74 (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
75 + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
76
77 /* Verify the guess. */
78 extern char test_real_width
79 [sizeof (REAL_VALUE_TYPE) <= REAL_WIDTH * sizeof (HOST_WIDE_INT) ? 1 : -1];
80
81 /* Calculate the format for CONST_DOUBLE. We need as many slots as
82 are necessary to overlay a REAL_VALUE_TYPE on them. This could be
83 as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
84
85 A number of places assume that there are always at least two 'w'
86 slots in a CONST_DOUBLE, so we provide them even if one would suffice. */
87
88 #if REAL_WIDTH == 1
89 # define CONST_DOUBLE_FORMAT "ww"
90 #else
91 # if REAL_WIDTH == 2
92 # define CONST_DOUBLE_FORMAT "ww"
93 # else
94 # if REAL_WIDTH == 3
95 # define CONST_DOUBLE_FORMAT "www"
96 # else
97 # if REAL_WIDTH == 4
98 # define CONST_DOUBLE_FORMAT "wwww"
99 # else
100 # if REAL_WIDTH == 5
101 # define CONST_DOUBLE_FORMAT "wwwww"
102 # else
103 # if REAL_WIDTH == 6
104 # define CONST_DOUBLE_FORMAT "wwwwww"
105 # else
106 #error "REAL_WIDTH > 6 not supported"
107 # endif
108 # endif
109 # endif
110 # endif
111 # endif
112 #endif
113
114
115 /* Describes the properties of the specific target format in use. */
116 struct real_format
117 {
118 /* Move to and from the target bytes. */
119 void (*encode) (const struct real_format *, long *,
120 const REAL_VALUE_TYPE *);
121 void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
122 const long *);
123
124 /* The radix of the exponent and digits of the significand. */
125 int b;
126
127 /* Size of the significand in digits of radix B. */
128 int p;
129
130 /* Size of the significant of a NaN, in digits of radix B. */
131 int pnan;
132
133 /* The minimum negative integer, x, such that b**(x-1) is normalized. */
134 int emin;
135
136 /* The maximum integer, x, such that b**(x-1) is representable. */
137 int emax;
138
139 /* The bit position of the sign bit, for determining whether a value
140 is positive/negative, or -1 for a complex encoding. */
141 int signbit_ro;
142
143 /* The bit position of the sign bit, for changing the sign of a number,
144 or -1 for a complex encoding. */
145 int signbit_rw;
146
147 /* Default rounding mode for operations on this format. */
148 bool round_towards_zero;
149 bool has_sign_dependent_rounding;
150
151 /* Properties of the format. */
152 bool has_nans;
153 bool has_inf;
154 bool has_denorm;
155 bool has_signed_zero;
156 bool qnan_msb_set;
157 bool canonical_nan_lsbs_set;
158 };
159
160
161 /* The target format used for each floating point mode.
162 Float modes are followed by decimal float modes, with entries for
163 float modes indexed by (MODE - first float mode), and entries for
164 decimal float modes indexed by (MODE - first decimal float mode) +
165 the number of float modes. */
166 extern const struct real_format *
167 real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
168 + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
169
170 #define REAL_MODE_FORMAT(MODE) \
171 (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE) \
172 ? (((MODE) - MIN_MODE_DECIMAL_FLOAT) \
173 + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1)) \
174 : ((MODE) - MIN_MODE_FLOAT)])
175
176 #define FLOAT_MODE_FORMAT(MODE) \
177 (REAL_MODE_FORMAT (SCALAR_FLOAT_MODE_P (MODE)? (MODE) \
178 : GET_MODE_INNER (MODE)))
179
180 /* The following macro determines whether the floating point format is
181 composite, i.e. may contain non-consecutive mantissa bits, in which
182 case compile-time FP overflow may not model run-time overflow. */
183 #define MODE_COMPOSITE_P(MODE) \
184 (FLOAT_MODE_P (MODE) \
185 && FLOAT_MODE_FORMAT (MODE)->pnan < FLOAT_MODE_FORMAT (MODE)->p)
186
187 /* Accessor macros for format properties. */
188 #define MODE_HAS_NANS(MODE) \
189 (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_nans)
190 #define MODE_HAS_INFINITIES(MODE) \
191 (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_inf)
192 #define MODE_HAS_SIGNED_ZEROS(MODE) \
193 (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_signed_zero)
194 #define MODE_HAS_SIGN_DEPENDENT_ROUNDING(MODE) \
195 (FLOAT_MODE_P (MODE) \
196 && FLOAT_MODE_FORMAT (MODE)->has_sign_dependent_rounding)
197
198 /* True if the given mode has a NaN representation and the treatment of
199 NaN operands is important. Certain optimizations, such as folding
200 x * 0 into 0, are not correct for NaN operands, and are normally
201 disabled for modes with NaNs. The user can ask for them to be
202 done anyway using the -funsafe-math-optimizations switch. */
203 #define HONOR_NANS(MODE) \
204 (MODE_HAS_NANS (MODE) && !flag_finite_math_only)
205
206 /* Like HONOR_NANs, but true if we honor signaling NaNs (or sNaNs). */
207 #define HONOR_SNANS(MODE) (flag_signaling_nans && HONOR_NANS (MODE))
208
209 /* As for HONOR_NANS, but true if the mode can represent infinity and
210 the treatment of infinite values is important. */
211 #define HONOR_INFINITIES(MODE) \
212 (MODE_HAS_INFINITIES (MODE) && !flag_finite_math_only)
213
214 /* Like HONOR_NANS, but true if the given mode distinguishes between
215 positive and negative zero, and the sign of zero is important. */
216 #define HONOR_SIGNED_ZEROS(MODE) \
217 (MODE_HAS_SIGNED_ZEROS (MODE) && flag_signed_zeros)
218
219 /* Like HONOR_NANS, but true if given mode supports sign-dependent rounding,
220 and the rounding mode is important. */
221 #define HONOR_SIGN_DEPENDENT_ROUNDING(MODE) \
222 (MODE_HAS_SIGN_DEPENDENT_ROUNDING (MODE) && flag_rounding_math)
223
224 /* Declare functions in real.c. */
225
226 /* Binary or unary arithmetic on tree_code. */
227 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
228 const REAL_VALUE_TYPE *);
229
230 /* Compare reals by tree_code. */
231 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
232
233 /* Determine whether a floating-point value X is infinite. */
234 extern bool real_isinf (const REAL_VALUE_TYPE *);
235
236 /* Determine whether a floating-point value X is a NaN. */
237 extern bool real_isnan (const REAL_VALUE_TYPE *);
238
239 /* Determine whether a floating-point value X is finite. */
240 extern bool real_isfinite (const REAL_VALUE_TYPE *);
241
242 /* Determine whether a floating-point value X is negative. */
243 extern bool real_isneg (const REAL_VALUE_TYPE *);
244
245 /* Determine whether a floating-point value X is minus zero. */
246 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
247
248 /* Compare two floating-point objects for bitwise identity. */
249 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
250
251 /* Extend or truncate to a new mode. */
252 extern void real_convert (REAL_VALUE_TYPE *, machine_mode,
253 const REAL_VALUE_TYPE *);
254
255 /* Return true if truncating to NEW is exact. */
256 extern bool exact_real_truncate (machine_mode, const REAL_VALUE_TYPE *);
257
258 /* Render R as a decimal floating point constant. */
259 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
260 size_t, int);
261
262 /* Render R as a decimal floating point constant, rounded so as to be
263 parsed back to the same value when interpreted in mode MODE. */
264 extern void real_to_decimal_for_mode (char *, const REAL_VALUE_TYPE *, size_t,
265 size_t, int, machine_mode);
266
267 /* Render R as a hexadecimal floating point constant. */
268 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
269 size_t, size_t, int);
270
271 /* Render R as an integer. */
272 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
273
274 /* Initialize R from a decimal or hexadecimal string. Return -1 if
275 the value underflows, +1 if overflows, and 0 otherwise. */
276 extern int real_from_string (REAL_VALUE_TYPE *, const char *);
277 /* Wrapper to allow different internal representation for decimal floats. */
278 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, machine_mode);
279
280 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
281 const struct real_format *);
282 extern long real_to_target (long *, const REAL_VALUE_TYPE *, machine_mode);
283
284 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
285 const struct real_format *);
286 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
287 machine_mode);
288
289 extern void real_inf (REAL_VALUE_TYPE *);
290
291 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, machine_mode);
292
293 extern void real_maxval (REAL_VALUE_TYPE *, int, machine_mode);
294
295 extern void real_2expN (REAL_VALUE_TYPE *, int, machine_mode);
296
297 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
298
299
300 /* Target formats defined in real.c. */
301 extern const struct real_format ieee_single_format;
302 extern const struct real_format mips_single_format;
303 extern const struct real_format motorola_single_format;
304 extern const struct real_format spu_single_format;
305 extern const struct real_format ieee_double_format;
306 extern const struct real_format mips_double_format;
307 extern const struct real_format motorola_double_format;
308 extern const struct real_format ieee_extended_motorola_format;
309 extern const struct real_format ieee_extended_intel_96_format;
310 extern const struct real_format ieee_extended_intel_96_round_53_format;
311 extern const struct real_format ieee_extended_intel_128_format;
312 extern const struct real_format ibm_extended_format;
313 extern const struct real_format mips_extended_format;
314 extern const struct real_format ieee_quad_format;
315 extern const struct real_format mips_quad_format;
316 extern const struct real_format vax_f_format;
317 extern const struct real_format vax_d_format;
318 extern const struct real_format vax_g_format;
319 extern const struct real_format real_internal_format;
320 extern const struct real_format decimal_single_format;
321 extern const struct real_format decimal_double_format;
322 extern const struct real_format decimal_quad_format;
323 extern const struct real_format ieee_half_format;
324 extern const struct real_format arm_half_format;
325
326
327 /* ====================================================================== */
328 /* Crap. */
329
330 #define REAL_ARITHMETIC(value, code, d1, d2) \
331 real_arithmetic (&(value), code, &(d1), &(d2))
332
333 #define REAL_VALUES_IDENTICAL(x, y) real_identical (&(x), &(y))
334 #define REAL_VALUES_EQUAL(x, y) real_compare (EQ_EXPR, &(x), &(y))
335 #define REAL_VALUES_LESS(x, y) real_compare (LT_EXPR, &(x), &(y))
336
337 /* Determine whether a floating-point value X is infinite. */
338 #define REAL_VALUE_ISINF(x) real_isinf (&(x))
339
340 /* Determine whether a floating-point value X is a NaN. */
341 #define REAL_VALUE_ISNAN(x) real_isnan (&(x))
342
343 /* Determine whether a floating-point value X is negative. */
344 #define REAL_VALUE_NEGATIVE(x) real_isneg (&(x))
345
346 /* Determine whether a floating-point value X is minus zero. */
347 #define REAL_VALUE_MINUS_ZERO(x) real_isnegzero (&(x))
348
349 /* IN is a REAL_VALUE_TYPE. OUT is an array of longs. */
350 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT) \
351 real_to_target (OUT, &(IN), \
352 mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
353
354 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
355 real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
356
357 /* IN is a REAL_VALUE_TYPE. OUT is a long. */
358 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
359 ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
360
361 /* Real values to IEEE 754 decimal floats. */
362
363 /* IN is a REAL_VALUE_TYPE. OUT is an array of longs. */
364 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
365 real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
366
367 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
368 real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
369
370 /* IN is a REAL_VALUE_TYPE. OUT is a long. */
371 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
372 ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
373
374 extern REAL_VALUE_TYPE real_value_truncate (machine_mode,
375 REAL_VALUE_TYPE);
376
377 extern REAL_VALUE_TYPE real_value_negate (const REAL_VALUE_TYPE *);
378 extern REAL_VALUE_TYPE real_value_abs (const REAL_VALUE_TYPE *);
379
380 extern int significand_size (machine_mode);
381
382 extern REAL_VALUE_TYPE real_from_string2 (const char *, machine_mode);
383
384 #define REAL_VALUE_ATOF(s, m) \
385 real_from_string2 (s, m)
386
387 #define CONST_DOUBLE_ATOF(s, m) \
388 CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
389
390 #define REAL_VALUE_FIX(r) \
391 real_to_integer (&(r))
392
393 /* ??? Not quite right. */
394 #define REAL_VALUE_UNSIGNED_FIX(r) \
395 real_to_integer (&(r))
396
397 /* ??? These were added for Paranoia support. */
398
399 /* Return floor log2(R). */
400 extern int real_exponent (const REAL_VALUE_TYPE *);
401
402 /* R = A * 2**EXP. */
403 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
404
405 /* **** End of software floating point emulator interface macros **** */
406 \f
407 /* Constant real values 0, 1, 2, -1 and 0.5. */
408
409 extern REAL_VALUE_TYPE dconst0;
410 extern REAL_VALUE_TYPE dconst1;
411 extern REAL_VALUE_TYPE dconst2;
412 extern REAL_VALUE_TYPE dconstm1;
413 extern REAL_VALUE_TYPE dconsthalf;
414
415 #define dconst_e() (*dconst_e_ptr ())
416 #define dconst_third() (*dconst_third_ptr ())
417 #define dconst_sqrt2() (*dconst_sqrt2_ptr ())
418
419 /* Function to return the real value special constant 'e'. */
420 extern const REAL_VALUE_TYPE * dconst_e_ptr (void);
421
422 /* Returns the special REAL_VALUE_TYPE corresponding to 1/3. */
423 extern const REAL_VALUE_TYPE * dconst_third_ptr (void);
424
425 /* Returns the special REAL_VALUE_TYPE corresponding to sqrt(2). */
426 extern const REAL_VALUE_TYPE * dconst_sqrt2_ptr (void);
427
428 /* Function to return a real value (not a tree node)
429 from a given integer constant. */
430 REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
431
432 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents. */
433 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
434 ((to) = *CONST_DOUBLE_REAL_VALUE (from))
435
436 /* Return a CONST_DOUBLE with value R and mode M. */
437 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
438 const_double_from_real_value (r, m)
439 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, machine_mode);
440
441 /* Replace R by 1/R in the given machine mode, if the result is exact. */
442 extern bool exact_real_inverse (machine_mode, REAL_VALUE_TYPE *);
443
444 /* Return true if arithmetic on values in IMODE that were promoted
445 from values in TMODE is equivalent to direct arithmetic on values
446 in TMODE. */
447 bool real_can_shorten_arithmetic (machine_mode, machine_mode);
448
449 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node. */
450 extern tree build_real (tree, REAL_VALUE_TYPE);
451
452 /* Calculate R as X raised to the integer exponent N in mode MODE. */
453 extern bool real_powi (REAL_VALUE_TYPE *, machine_mode,
454 const REAL_VALUE_TYPE *, HOST_WIDE_INT);
455
456 /* Standard round to integer value functions. */
457 extern void real_trunc (REAL_VALUE_TYPE *, machine_mode,
458 const REAL_VALUE_TYPE *);
459 extern void real_floor (REAL_VALUE_TYPE *, machine_mode,
460 const REAL_VALUE_TYPE *);
461 extern void real_ceil (REAL_VALUE_TYPE *, machine_mode,
462 const REAL_VALUE_TYPE *);
463 extern void real_round (REAL_VALUE_TYPE *, machine_mode,
464 const REAL_VALUE_TYPE *);
465
466 /* Set the sign of R to the sign of X. */
467 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
468
469 /* Check whether the real constant value given is an integer. */
470 extern bool real_isinteger (const REAL_VALUE_TYPE *c, machine_mode mode);
471
472 /* Write into BUF the maximum representable finite floating-point
473 number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
474 float string. BUF must be large enough to contain the result. */
475 extern void get_max_float (const struct real_format *, char *, size_t);
476
477 #ifndef GENERATOR_FILE
478 /* real related routines. */
479 extern wide_int real_to_integer (const REAL_VALUE_TYPE *, bool *, int);
480 extern void real_from_integer (REAL_VALUE_TYPE *, machine_mode,
481 const wide_int_ref &, signop);
482 #endif
483
484 #endif /* ! GCC_REAL_H */