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1 /* Definitions of Tensilica's Xtensa target machine for GNU compiler.
2 Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
4 Contributed by Bob Wilson (bwilson@tensilica.com) at Tensilica.
5
6 This file is part of GCC.
7
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
11 version.
12
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
21
22 /* Get Xtensa configuration settings */
23 #include "xtensa-config.h"
24
25 /* External variables defined in xtensa.c. */
26
27 extern unsigned xtensa_current_frame_size;
28
29 /* Macros used in the machine description to select various Xtensa
30 configuration options. */
31 #ifndef XCHAL_HAVE_MUL32_HIGH
32 #define XCHAL_HAVE_MUL32_HIGH 0
33 #endif
34 #ifndef XCHAL_HAVE_RELEASE_SYNC
35 #define XCHAL_HAVE_RELEASE_SYNC 0
36 #endif
37 #ifndef XCHAL_HAVE_S32C1I
38 #define XCHAL_HAVE_S32C1I 0
39 #endif
40 #ifndef XCHAL_HAVE_THREADPTR
41 #define XCHAL_HAVE_THREADPTR 0
42 #endif
43 #define TARGET_BIG_ENDIAN XCHAL_HAVE_BE
44 #define TARGET_DENSITY XCHAL_HAVE_DENSITY
45 #define TARGET_MAC16 XCHAL_HAVE_MAC16
46 #define TARGET_MUL16 XCHAL_HAVE_MUL16
47 #define TARGET_MUL32 XCHAL_HAVE_MUL32
48 #define TARGET_MUL32_HIGH XCHAL_HAVE_MUL32_HIGH
49 #define TARGET_DIV32 XCHAL_HAVE_DIV32
50 #define TARGET_NSA XCHAL_HAVE_NSA
51 #define TARGET_MINMAX XCHAL_HAVE_MINMAX
52 #define TARGET_SEXT XCHAL_HAVE_SEXT
53 #define TARGET_BOOLEANS XCHAL_HAVE_BOOLEANS
54 #define TARGET_HARD_FLOAT XCHAL_HAVE_FP
55 #define TARGET_HARD_FLOAT_DIV XCHAL_HAVE_FP_DIV
56 #define TARGET_HARD_FLOAT_RECIP XCHAL_HAVE_FP_RECIP
57 #define TARGET_HARD_FLOAT_SQRT XCHAL_HAVE_FP_SQRT
58 #define TARGET_HARD_FLOAT_RSQRT XCHAL_HAVE_FP_RSQRT
59 #define TARGET_ABS XCHAL_HAVE_ABS
60 #define TARGET_ADDX XCHAL_HAVE_ADDX
61 #define TARGET_RELEASE_SYNC XCHAL_HAVE_RELEASE_SYNC
62 #define TARGET_S32C1I XCHAL_HAVE_S32C1I
63 #define TARGET_ABSOLUTE_LITERALS XSHAL_USE_ABSOLUTE_LITERALS
64 #define TARGET_THREADPTR XCHAL_HAVE_THREADPTR
65
66 #define TARGET_DEFAULT \
67 ((XCHAL_HAVE_L32R ? 0 : MASK_CONST16) | \
68 MASK_SERIALIZE_VOLATILE)
69
70 #ifndef HAVE_AS_TLS
71 #define HAVE_AS_TLS 0
72 #endif
73
74 \f
75 /* Target CPU builtins. */
76 #define TARGET_CPU_CPP_BUILTINS() \
77 do { \
78 builtin_assert ("cpu=xtensa"); \
79 builtin_assert ("machine=xtensa"); \
80 builtin_define ("__xtensa__"); \
81 builtin_define ("__XTENSA__"); \
82 builtin_define ("__XTENSA_WINDOWED_ABI__"); \
83 builtin_define (TARGET_BIG_ENDIAN ? "__XTENSA_EB__" : "__XTENSA_EL__"); \
84 if (!TARGET_HARD_FLOAT) \
85 builtin_define ("__XTENSA_SOFT_FLOAT__"); \
86 } while (0)
87
88 #define CPP_SPEC " %(subtarget_cpp_spec) "
89
90 #ifndef SUBTARGET_CPP_SPEC
91 #define SUBTARGET_CPP_SPEC ""
92 #endif
93
94 #define EXTRA_SPECS \
95 { "subtarget_cpp_spec", SUBTARGET_CPP_SPEC },
96
97 /* Target machine storage layout */
98
99 /* Define this if most significant bit is lowest numbered
100 in instructions that operate on numbered bit-fields. */
101 #define BITS_BIG_ENDIAN (TARGET_BIG_ENDIAN != 0)
102
103 /* Define this if most significant byte of a word is the lowest numbered. */
104 #define BYTES_BIG_ENDIAN (TARGET_BIG_ENDIAN != 0)
105
106 /* Define this if most significant word of a multiword number is the lowest. */
107 #define WORDS_BIG_ENDIAN (TARGET_BIG_ENDIAN != 0)
108
109 #define MAX_BITS_PER_WORD 32
110
111 /* Width of a word, in units (bytes). */
112 #define UNITS_PER_WORD 4
113 #define MIN_UNITS_PER_WORD 4
114
115 /* Width of a floating point register. */
116 #define UNITS_PER_FPREG 4
117
118 /* Size in bits of various types on the target machine. */
119 #define INT_TYPE_SIZE 32
120 #define SHORT_TYPE_SIZE 16
121 #define LONG_TYPE_SIZE 32
122 #define LONG_LONG_TYPE_SIZE 64
123 #define FLOAT_TYPE_SIZE 32
124 #define DOUBLE_TYPE_SIZE 64
125 #define LONG_DOUBLE_TYPE_SIZE 64
126
127 /* Allocation boundary (in *bits*) for storing pointers in memory. */
128 #define POINTER_BOUNDARY 32
129
130 /* Allocation boundary (in *bits*) for storing arguments in argument list. */
131 #define PARM_BOUNDARY 32
132
133 /* Allocation boundary (in *bits*) for the code of a function. */
134 #define FUNCTION_BOUNDARY 32
135
136 /* Alignment of field after 'int : 0' in a structure. */
137 #define EMPTY_FIELD_BOUNDARY 32
138
139 /* Every structure's size must be a multiple of this. */
140 #define STRUCTURE_SIZE_BOUNDARY 8
141
142 /* There is no point aligning anything to a rounder boundary than this. */
143 #define BIGGEST_ALIGNMENT 128
144
145 /* Set this nonzero if move instructions will actually fail to work
146 when given unaligned data. */
147 #define STRICT_ALIGNMENT 1
148
149 /* Promote integer modes smaller than a word to SImode. Set UNSIGNEDP
150 for QImode, because there is no 8-bit load from memory with sign
151 extension. Otherwise, leave UNSIGNEDP alone, since Xtensa has 16-bit
152 loads both with and without sign extension. */
153 #define PROMOTE_MODE(MODE, UNSIGNEDP, TYPE) \
154 do { \
155 if (GET_MODE_CLASS (MODE) == MODE_INT \
156 && GET_MODE_SIZE (MODE) < UNITS_PER_WORD) \
157 { \
158 if ((MODE) == QImode) \
159 (UNSIGNEDP) = 1; \
160 (MODE) = SImode; \
161 } \
162 } while (0)
163
164 /* Imitate the way many other C compilers handle alignment of
165 bitfields and the structures that contain them. */
166 #define PCC_BITFIELD_TYPE_MATTERS 1
167
168 /* Disable the use of word-sized or smaller complex modes for structures,
169 and for function arguments in particular, where they cause problems with
170 register a7. The xtensa_copy_incoming_a7 function assumes that there is
171 a single reference to an argument in a7, but with small complex modes the
172 real and imaginary components may be extracted separately, leading to two
173 uses of the register, only one of which would be replaced. */
174 #define MEMBER_TYPE_FORCES_BLK(FIELD, MODE) \
175 ((MODE) == CQImode || (MODE) == CHImode)
176
177 /* Align string constants and constructors to at least a word boundary.
178 The typical use of this macro is to increase alignment for string
179 constants to be word aligned so that 'strcpy' calls that copy
180 constants can be done inline. */
181 #define CONSTANT_ALIGNMENT(EXP, ALIGN) \
182 ((TREE_CODE (EXP) == STRING_CST || TREE_CODE (EXP) == CONSTRUCTOR) \
183 && (ALIGN) < BITS_PER_WORD \
184 ? BITS_PER_WORD \
185 : (ALIGN))
186
187 /* Align arrays, unions and records to at least a word boundary.
188 One use of this macro is to increase alignment of medium-size
189 data to make it all fit in fewer cache lines. Another is to
190 cause character arrays to be word-aligned so that 'strcpy' calls
191 that copy constants to character arrays can be done inline. */
192 #undef DATA_ALIGNMENT
193 #define DATA_ALIGNMENT(TYPE, ALIGN) \
194 ((((ALIGN) < BITS_PER_WORD) \
195 && (TREE_CODE (TYPE) == ARRAY_TYPE \
196 || TREE_CODE (TYPE) == UNION_TYPE \
197 || TREE_CODE (TYPE) == RECORD_TYPE)) ? BITS_PER_WORD : (ALIGN))
198
199 /* Operations between registers always perform the operation
200 on the full register even if a narrower mode is specified. */
201 #define WORD_REGISTER_OPERATIONS
202
203 /* Xtensa loads are zero-extended by default. */
204 #define LOAD_EXTEND_OP(MODE) ZERO_EXTEND
205
206 /* Standard register usage. */
207
208 /* Number of actual hardware registers.
209 The hardware registers are assigned numbers for the compiler
210 from 0 to just below FIRST_PSEUDO_REGISTER.
211 All registers that the compiler knows about must be given numbers,
212 even those that are not normally considered general registers.
213
214 The fake frame pointer and argument pointer will never appear in
215 the generated code, since they will always be eliminated and replaced
216 by either the stack pointer or the hard frame pointer.
217
218 0 - 15 AR[0] - AR[15]
219 16 FRAME_POINTER (fake = initial sp)
220 17 ARG_POINTER (fake = initial sp + framesize)
221 18 BR[0] for floating-point CC
222 19 - 34 FR[0] - FR[15]
223 35 MAC16 accumulator */
224
225 #define FIRST_PSEUDO_REGISTER 36
226
227 /* Return the stabs register number to use for REGNO. */
228 #define DBX_REGISTER_NUMBER(REGNO) xtensa_dbx_register_number (REGNO)
229
230 /* 1 for registers that have pervasive standard uses
231 and are not available for the register allocator. */
232 #define FIXED_REGISTERS \
233 { \
234 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
235 1, 1, 0, \
236 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
237 0, \
238 }
239
240 /* 1 for registers not available across function calls.
241 These must include the FIXED_REGISTERS and also any
242 registers that can be used without being saved.
243 The latter must include the registers where values are returned
244 and the register where structure-value addresses are passed.
245 Aside from that, you can include as many other registers as you like. */
246 #define CALL_USED_REGISTERS \
247 { \
248 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, \
249 1, 1, 1, \
250 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, \
251 1, \
252 }
253
254 /* For non-leaf procedures on Xtensa processors, the allocation order
255 is as specified below by REG_ALLOC_ORDER. For leaf procedures, we
256 want to use the lowest numbered registers first to minimize
257 register window overflows. However, local-alloc is not smart
258 enough to consider conflicts with incoming arguments. If an
259 incoming argument in a2 is live throughout the function and
260 local-alloc decides to use a2, then the incoming argument must
261 either be spilled or copied to another register. To get around
262 this, we define ADJUST_REG_ALLOC_ORDER to redefine
263 reg_alloc_order for leaf functions such that lowest numbered
264 registers are used first with the exception that the incoming
265 argument registers are not used until after other register choices
266 have been exhausted. */
267
268 #define REG_ALLOC_ORDER \
269 { 8, 9, 10, 11, 12, 13, 14, 15, 7, 6, 5, 4, 3, 2, \
270 18, \
271 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, \
272 0, 1, 16, 17, \
273 35, \
274 }
275
276 #define ADJUST_REG_ALLOC_ORDER order_regs_for_local_alloc ()
277
278 /* For Xtensa, the only point of this is to prevent GCC from otherwise
279 giving preference to call-used registers. To minimize window
280 overflows for the AR registers, we want to give preference to the
281 lower-numbered AR registers. For other register files, which are
282 not windowed, we still prefer call-used registers, if there are any. */
283 extern const char xtensa_leaf_regs[FIRST_PSEUDO_REGISTER];
284 #define LEAF_REGISTERS xtensa_leaf_regs
285
286 /* For Xtensa, no remapping is necessary, but this macro must be
287 defined if LEAF_REGISTERS is defined. */
288 #define LEAF_REG_REMAP(REGNO) (REGNO)
289
290 /* This must be declared if LEAF_REGISTERS is set. */
291 extern int leaf_function;
292
293 /* Internal macros to classify a register number. */
294
295 /* 16 address registers + fake registers */
296 #define GP_REG_FIRST 0
297 #define GP_REG_LAST 17
298 #define GP_REG_NUM (GP_REG_LAST - GP_REG_FIRST + 1)
299
300 /* Coprocessor registers */
301 #define BR_REG_FIRST 18
302 #define BR_REG_LAST 18
303 #define BR_REG_NUM (BR_REG_LAST - BR_REG_FIRST + 1)
304
305 /* 16 floating-point registers */
306 #define FP_REG_FIRST 19
307 #define FP_REG_LAST 34
308 #define FP_REG_NUM (FP_REG_LAST - FP_REG_FIRST + 1)
309
310 /* MAC16 accumulator */
311 #define ACC_REG_FIRST 35
312 #define ACC_REG_LAST 35
313 #define ACC_REG_NUM (ACC_REG_LAST - ACC_REG_FIRST + 1)
314
315 #define GP_REG_P(REGNO) ((unsigned) ((REGNO) - GP_REG_FIRST) < GP_REG_NUM)
316 #define BR_REG_P(REGNO) ((unsigned) ((REGNO) - BR_REG_FIRST) < BR_REG_NUM)
317 #define FP_REG_P(REGNO) ((unsigned) ((REGNO) - FP_REG_FIRST) < FP_REG_NUM)
318 #define ACC_REG_P(REGNO) ((unsigned) ((REGNO) - ACC_REG_FIRST) < ACC_REG_NUM)
319
320 /* Return number of consecutive hard regs needed starting at reg REGNO
321 to hold something of mode MODE. */
322 #define HARD_REGNO_NREGS(REGNO, MODE) \
323 (FP_REG_P (REGNO) ? \
324 ((GET_MODE_SIZE (MODE) + UNITS_PER_FPREG - 1) / UNITS_PER_FPREG) : \
325 ((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
326
327 /* Value is 1 if hard register REGNO can hold a value of machine-mode
328 MODE. */
329 extern char xtensa_hard_regno_mode_ok[][FIRST_PSEUDO_REGISTER];
330
331 #define HARD_REGNO_MODE_OK(REGNO, MODE) \
332 xtensa_hard_regno_mode_ok[(int) (MODE)][(REGNO)]
333
334 /* Value is 1 if it is a good idea to tie two pseudo registers
335 when one has mode MODE1 and one has mode MODE2.
336 If HARD_REGNO_MODE_OK could produce different values for MODE1 and MODE2,
337 for any hard reg, then this must be 0 for correct output. */
338 #define MODES_TIEABLE_P(MODE1, MODE2) \
339 ((GET_MODE_CLASS (MODE1) == MODE_FLOAT || \
340 GET_MODE_CLASS (MODE1) == MODE_COMPLEX_FLOAT) \
341 == (GET_MODE_CLASS (MODE2) == MODE_FLOAT || \
342 GET_MODE_CLASS (MODE2) == MODE_COMPLEX_FLOAT))
343
344 /* Register to use for pushing function arguments. */
345 #define STACK_POINTER_REGNUM (GP_REG_FIRST + 1)
346
347 /* Base register for access to local variables of the function. */
348 #define HARD_FRAME_POINTER_REGNUM (GP_REG_FIRST + 7)
349
350 /* The register number of the frame pointer register, which is used to
351 access automatic variables in the stack frame. For Xtensa, this
352 register never appears in the output. It is always eliminated to
353 either the stack pointer or the hard frame pointer. */
354 #define FRAME_POINTER_REGNUM (GP_REG_FIRST + 16)
355
356 /* Base register for access to arguments of the function. */
357 #define ARG_POINTER_REGNUM (GP_REG_FIRST + 17)
358
359 /* For now we don't try to use the full set of boolean registers. Without
360 software pipelining of FP operations, there's not much to gain and it's
361 a real pain to get them reloaded. */
362 #define FPCC_REGNUM (BR_REG_FIRST + 0)
363
364 /* It is as good or better to call a constant function address than to
365 call an address kept in a register. */
366 #define NO_FUNCTION_CSE 1
367
368 /* Xtensa processors have "register windows". GCC does not currently
369 take advantage of the possibility for variable-sized windows; instead,
370 we use a fixed window size of 8. */
371
372 #define INCOMING_REGNO(OUT) \
373 ((GP_REG_P (OUT) && \
374 ((unsigned) ((OUT) - GP_REG_FIRST) >= WINDOW_SIZE)) ? \
375 (OUT) - WINDOW_SIZE : (OUT))
376
377 #define OUTGOING_REGNO(IN) \
378 ((GP_REG_P (IN) && \
379 ((unsigned) ((IN) - GP_REG_FIRST) < WINDOW_SIZE)) ? \
380 (IN) + WINDOW_SIZE : (IN))
381
382
383 /* Define the classes of registers for register constraints in the
384 machine description. */
385 enum reg_class
386 {
387 NO_REGS, /* no registers in set */
388 BR_REGS, /* coprocessor boolean registers */
389 FP_REGS, /* floating point registers */
390 ACC_REG, /* MAC16 accumulator */
391 SP_REG, /* sp register (aka a1) */
392 RL_REGS, /* preferred reload regs (not sp or fp) */
393 GR_REGS, /* integer registers except sp */
394 AR_REGS, /* all integer registers */
395 ALL_REGS, /* all registers */
396 LIM_REG_CLASSES /* max value + 1 */
397 };
398
399 #define N_REG_CLASSES (int) LIM_REG_CLASSES
400
401 #define GENERAL_REGS AR_REGS
402
403 /* An initializer containing the names of the register classes as C
404 string constants. These names are used in writing some of the
405 debugging dumps. */
406 #define REG_CLASS_NAMES \
407 { \
408 "NO_REGS", \
409 "BR_REGS", \
410 "FP_REGS", \
411 "ACC_REG", \
412 "SP_REG", \
413 "RL_REGS", \
414 "GR_REGS", \
415 "AR_REGS", \
416 "ALL_REGS" \
417 }
418
419 /* Contents of the register classes. The Nth integer specifies the
420 contents of class N. The way the integer MASK is interpreted is
421 that register R is in the class if 'MASK & (1 << R)' is 1. */
422 #define REG_CLASS_CONTENTS \
423 { \
424 { 0x00000000, 0x00000000 }, /* no registers */ \
425 { 0x00040000, 0x00000000 }, /* coprocessor boolean registers */ \
426 { 0xfff80000, 0x00000007 }, /* floating-point registers */ \
427 { 0x00000000, 0x00000008 }, /* MAC16 accumulator */ \
428 { 0x00000002, 0x00000000 }, /* stack pointer register */ \
429 { 0x0000ff7d, 0x00000000 }, /* preferred reload registers */ \
430 { 0x0000fffd, 0x00000000 }, /* general-purpose registers */ \
431 { 0x0003ffff, 0x00000000 }, /* integer registers */ \
432 { 0xffffffff, 0x0000000f } /* all registers */ \
433 }
434
435 #define IRA_COVER_CLASSES \
436 { \
437 BR_REGS, FP_REGS, ACC_REG, AR_REGS, LIM_REG_CLASSES \
438 }
439
440 /* A C expression whose value is a register class containing hard
441 register REGNO. In general there is more that one such class;
442 choose a class which is "minimal", meaning that no smaller class
443 also contains the register. */
444 extern const enum reg_class xtensa_regno_to_class[FIRST_PSEUDO_REGISTER];
445
446 #define REGNO_REG_CLASS(REGNO) xtensa_regno_to_class[ (REGNO) ]
447
448 /* Use the Xtensa AR register file for base registers.
449 No index registers. */
450 #define BASE_REG_CLASS AR_REGS
451 #define INDEX_REG_CLASS NO_REGS
452
453 /* The small_register_classes_for_mode_p hook must always return true for
454 Xtrnase, because all of the 16 AR registers may be explicitly used in
455 the RTL, as either incoming or outgoing arguments. */
456 #define TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P hook_bool_mode_true
457
458 #define PREFERRED_RELOAD_CLASS(X, CLASS) \
459 xtensa_preferred_reload_class (X, CLASS, 0)
460
461 #define PREFERRED_OUTPUT_RELOAD_CLASS(X, CLASS) \
462 xtensa_preferred_reload_class (X, CLASS, 1)
463
464 /* Return the maximum number of consecutive registers
465 needed to represent mode MODE in a register of class CLASS. */
466 #define CLASS_UNITS(mode, size) \
467 ((GET_MODE_SIZE (mode) + (size) - 1) / (size))
468
469 #define CLASS_MAX_NREGS(CLASS, MODE) \
470 (CLASS_UNITS (MODE, UNITS_PER_WORD))
471
472
473 /* Stack layout; function entry, exit and calling. */
474
475 #define STACK_GROWS_DOWNWARD
476
477 /* Offset within stack frame to start allocating local variables at. */
478 #define STARTING_FRAME_OFFSET \
479 crtl->outgoing_args_size
480
481 /* The ARG_POINTER and FRAME_POINTER are not real Xtensa registers, so
482 they are eliminated to either the stack pointer or hard frame pointer. */
483 #define ELIMINABLE_REGS \
484 {{ ARG_POINTER_REGNUM, STACK_POINTER_REGNUM}, \
485 { ARG_POINTER_REGNUM, HARD_FRAME_POINTER_REGNUM}, \
486 { FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM}, \
487 { FRAME_POINTER_REGNUM, HARD_FRAME_POINTER_REGNUM}}
488
489 /* Specify the initial difference between the specified pair of registers. */
490 #define INITIAL_ELIMINATION_OFFSET(FROM, TO, OFFSET) \
491 do { \
492 compute_frame_size (get_frame_size ()); \
493 switch (FROM) \
494 { \
495 case FRAME_POINTER_REGNUM: \
496 (OFFSET) = 0; \
497 break; \
498 case ARG_POINTER_REGNUM: \
499 (OFFSET) = xtensa_current_frame_size; \
500 break; \
501 default: \
502 gcc_unreachable (); \
503 } \
504 } while (0)
505
506 /* If defined, the maximum amount of space required for outgoing
507 arguments will be computed and placed into the variable
508 'crtl->outgoing_args_size'. No space will be pushed
509 onto the stack for each call; instead, the function prologue
510 should increase the stack frame size by this amount. */
511 #define ACCUMULATE_OUTGOING_ARGS 1
512
513 /* Offset from the argument pointer register to the first argument's
514 address. On some machines it may depend on the data type of the
515 function. If 'ARGS_GROW_DOWNWARD', this is the offset to the
516 location above the first argument's address. */
517 #define FIRST_PARM_OFFSET(FNDECL) 0
518
519 /* Align stack frames on 128 bits for Xtensa. This is necessary for
520 128-bit datatypes defined in TIE (e.g., for Vectra). */
521 #define STACK_BOUNDARY 128
522
523 /* Use a fixed register window size of 8. */
524 #define WINDOW_SIZE 8
525
526 /* Symbolic macros for the registers used to return integer, floating
527 point, and values of coprocessor and user-defined modes. */
528 #define GP_RETURN (GP_REG_FIRST + 2 + WINDOW_SIZE)
529 #define GP_OUTGOING_RETURN (GP_REG_FIRST + 2)
530
531 /* Symbolic macros for the first/last argument registers. */
532 #define GP_ARG_FIRST (GP_REG_FIRST + 2)
533 #define GP_ARG_LAST (GP_REG_FIRST + 7)
534 #define GP_OUTGOING_ARG_FIRST (GP_REG_FIRST + 2 + WINDOW_SIZE)
535 #define GP_OUTGOING_ARG_LAST (GP_REG_FIRST + 7 + WINDOW_SIZE)
536
537 #define MAX_ARGS_IN_REGISTERS 6
538
539 /* Don't worry about compatibility with PCC. */
540 #define DEFAULT_PCC_STRUCT_RETURN 0
541
542 /* Define how to find the value returned by a library function
543 assuming the value has mode MODE. Because we have defined
544 TARGET_PROMOTE_FUNCTION_MODE to promote everything, we have to
545 perform the same promotions as PROMOTE_MODE. */
546 #define XTENSA_LIBCALL_VALUE(MODE, OUTGOINGP) \
547 gen_rtx_REG ((GET_MODE_CLASS (MODE) == MODE_INT \
548 && GET_MODE_SIZE (MODE) < UNITS_PER_WORD) \
549 ? SImode : (MODE), \
550 OUTGOINGP ? GP_OUTGOING_RETURN : GP_RETURN)
551
552 #define LIBCALL_VALUE(MODE) \
553 XTENSA_LIBCALL_VALUE ((MODE), 0)
554
555 #define LIBCALL_OUTGOING_VALUE(MODE) \
556 XTENSA_LIBCALL_VALUE ((MODE), 1)
557
558 /* A C expression that is nonzero if REGNO is the number of a hard
559 register in which the values of called function may come back. A
560 register whose use for returning values is limited to serving as
561 the second of a pair (for a value of type 'double', say) need not
562 be recognized by this macro. If the machine has register windows,
563 so that the caller and the called function use different registers
564 for the return value, this macro should recognize only the caller's
565 register numbers. */
566 #define FUNCTION_VALUE_REGNO_P(N) \
567 ((N) == GP_RETURN)
568
569 /* A C expression that is nonzero if REGNO is the number of a hard
570 register in which function arguments are sometimes passed. This
571 does *not* include implicit arguments such as the static chain and
572 the structure-value address. On many machines, no registers can be
573 used for this purpose since all function arguments are pushed on
574 the stack. */
575 #define FUNCTION_ARG_REGNO_P(N) \
576 ((N) >= GP_OUTGOING_ARG_FIRST && (N) <= GP_OUTGOING_ARG_LAST)
577
578 /* Record the number of argument words seen so far, along with a flag to
579 indicate whether these are incoming arguments. (FUNCTION_INCOMING_ARG
580 is used for both incoming and outgoing args, so a separate flag is
581 needed. */
582 typedef struct xtensa_args
583 {
584 int arg_words;
585 int incoming;
586 } CUMULATIVE_ARGS;
587
588 #define INIT_CUMULATIVE_ARGS(CUM, FNTYPE, LIBNAME, INDIRECT, N_NAMED_ARGS) \
589 init_cumulative_args (&CUM, 0)
590
591 #define INIT_CUMULATIVE_INCOMING_ARGS(CUM, FNTYPE, LIBNAME) \
592 init_cumulative_args (&CUM, 1)
593
594 /* Profiling Xtensa code is typically done with the built-in profiling
595 feature of Tensilica's instruction set simulator, which does not
596 require any compiler support. Profiling code on a real (i.e.,
597 non-simulated) Xtensa processor is currently only supported by
598 GNU/Linux with glibc. The glibc version of _mcount doesn't require
599 counter variables. The _mcount function needs the current PC and
600 the current return address to identify an arc in the call graph.
601 Pass the current return address as the first argument; the current
602 PC is available as a0 in _mcount's register window. Both of these
603 values contain window size information in the two most significant
604 bits; we assume that _mcount will mask off those bits. The call to
605 _mcount uses a window size of 8 to make sure that it doesn't clobber
606 any incoming argument values. */
607
608 #define NO_PROFILE_COUNTERS 1
609
610 #define FUNCTION_PROFILER(FILE, LABELNO) \
611 do { \
612 fprintf (FILE, "\t%s\ta10, a0\n", TARGET_DENSITY ? "mov.n" : "mov"); \
613 if (flag_pic) \
614 { \
615 fprintf (FILE, "\tmovi\ta8, _mcount@PLT\n"); \
616 fprintf (FILE, "\tcallx8\ta8\n"); \
617 } \
618 else \
619 fprintf (FILE, "\tcall8\t_mcount\n"); \
620 } while (0)
621
622 /* Stack pointer value doesn't matter at exit. */
623 #define EXIT_IGNORE_STACK 1
624
625 /* Size in bytes of the trampoline, as an integer. Make sure this is
626 a multiple of TRAMPOLINE_ALIGNMENT to avoid -Wpadded warnings. */
627 #define TRAMPOLINE_SIZE (TARGET_CONST16 || TARGET_ABSOLUTE_LITERALS ? 60 : 52)
628
629 /* Alignment required for trampolines, in bits. */
630 #define TRAMPOLINE_ALIGNMENT 32
631
632 /* If defined, a C expression that produces the machine-specific code
633 to setup the stack so that arbitrary frames can be accessed.
634
635 On Xtensa, a stack back-trace must always begin from the stack pointer,
636 so that the register overflow save area can be located. However, the
637 stack-walking code in GCC always begins from the hard_frame_pointer
638 register, not the stack pointer. The frame pointer is usually equal
639 to the stack pointer, but the __builtin_return_address and
640 __builtin_frame_address functions will not work if count > 0 and
641 they are called from a routine that uses alloca. These functions
642 are not guaranteed to work at all if count > 0 so maybe that is OK.
643
644 A nicer solution would be to allow the architecture-specific files to
645 specify whether to start from the stack pointer or frame pointer. That
646 would also allow us to skip the machine->accesses_prev_frame stuff that
647 we currently need to ensure that there is a frame pointer when these
648 builtin functions are used. */
649
650 #define SETUP_FRAME_ADDRESSES xtensa_setup_frame_addresses
651
652 /* A C expression whose value is RTL representing the address in a
653 stack frame where the pointer to the caller's frame is stored.
654 Assume that FRAMEADDR is an RTL expression for the address of the
655 stack frame itself.
656
657 For Xtensa, there is no easy way to get the frame pointer if it is
658 not equivalent to the stack pointer. Moreover, the result of this
659 macro is used for continuing to walk back up the stack, so it must
660 return the stack pointer address. Thus, there is some inconsistency
661 here in that __builtin_frame_address will return the frame pointer
662 when count == 0 and the stack pointer when count > 0. */
663
664 #define DYNAMIC_CHAIN_ADDRESS(frame) \
665 gen_rtx_PLUS (Pmode, frame, GEN_INT (-3 * UNITS_PER_WORD))
666
667 /* Define this if the return address of a particular stack frame is
668 accessed from the frame pointer of the previous stack frame. */
669 #define RETURN_ADDR_IN_PREVIOUS_FRAME
670
671 /* A C expression whose value is RTL representing the value of the
672 return address for the frame COUNT steps up from the current
673 frame, after the prologue. */
674 #define RETURN_ADDR_RTX xtensa_return_addr
675
676 /* Addressing modes, and classification of registers for them. */
677
678 /* C expressions which are nonzero if register number NUM is suitable
679 for use as a base or index register in operand addresses. */
680
681 #define REGNO_OK_FOR_INDEX_P(NUM) 0
682 #define REGNO_OK_FOR_BASE_P(NUM) \
683 (GP_REG_P (NUM) || GP_REG_P ((unsigned) reg_renumber[NUM]))
684
685 /* C expressions that are nonzero if X (assumed to be a `reg' RTX) is
686 valid for use as a base or index register. */
687
688 #ifdef REG_OK_STRICT
689 #define REG_OK_STRICT_FLAG 1
690 #else
691 #define REG_OK_STRICT_FLAG 0
692 #endif
693
694 #define BASE_REG_P(X, STRICT) \
695 ((!(STRICT) && REGNO (X) >= FIRST_PSEUDO_REGISTER) \
696 || REGNO_OK_FOR_BASE_P (REGNO (X)))
697
698 #define REG_OK_FOR_INDEX_P(X) 0
699 #define REG_OK_FOR_BASE_P(X) BASE_REG_P (X, REG_OK_STRICT_FLAG)
700
701 /* Maximum number of registers that can appear in a valid memory address. */
702 #define MAX_REGS_PER_ADDRESS 1
703
704 /* A C expression that is 1 if the RTX X is a constant which is a
705 valid address. This is defined to be the same as 'CONSTANT_P (X)',
706 but rejecting CONST_DOUBLE. */
707 #define CONSTANT_ADDRESS_P(X) \
708 ((GET_CODE (X) == LABEL_REF || GET_CODE (X) == SYMBOL_REF \
709 || GET_CODE (X) == CONST_INT || GET_CODE (X) == HIGH \
710 || (GET_CODE (X) == CONST)))
711
712 /* Nonzero if the constant value X is a legitimate general operand.
713 It is given that X satisfies CONSTANT_P or is a CONST_DOUBLE. */
714 #define LEGITIMATE_CONSTANT_P(X) (! xtensa_tls_referenced_p (X))
715
716 /* A C expression that is nonzero if X is a legitimate immediate
717 operand on the target machine when generating position independent
718 code. */
719 #define LEGITIMATE_PIC_OPERAND_P(X) \
720 ((GET_CODE (X) != SYMBOL_REF \
721 || (SYMBOL_REF_LOCAL_P (X) && !SYMBOL_REF_EXTERNAL_P (X))) \
722 && GET_CODE (X) != LABEL_REF \
723 && GET_CODE (X) != CONST)
724
725 /* Treat constant-pool references as "mode dependent" since they can
726 only be accessed with SImode loads. This works around a bug in the
727 combiner where a constant pool reference is temporarily converted
728 to an HImode load, which is then assumed to zero-extend based on
729 our definition of LOAD_EXTEND_OP. This is wrong because the high
730 bits of a 16-bit value in the constant pool are now sign-extended
731 by default. */
732
733 #define GO_IF_MODE_DEPENDENT_ADDRESS(ADDR, LABEL) \
734 do { \
735 if (constantpool_address_p (ADDR)) \
736 goto LABEL; \
737 } while (0)
738
739 /* Specify the machine mode that this machine uses
740 for the index in the tablejump instruction. */
741 #define CASE_VECTOR_MODE (SImode)
742
743 /* Define this as 1 if 'char' should by default be signed; else as 0. */
744 #define DEFAULT_SIGNED_CHAR 0
745
746 /* Max number of bytes we can move from memory to memory
747 in one reasonably fast instruction. */
748 #define MOVE_MAX 4
749 #define MAX_MOVE_MAX 4
750
751 /* Prefer word-sized loads. */
752 #define SLOW_BYTE_ACCESS 1
753
754 /* Shift instructions ignore all but the low-order few bits. */
755 #define SHIFT_COUNT_TRUNCATED 1
756
757 /* Value is 1 if truncating an integer of INPREC bits to OUTPREC bits
758 is done just by pretending it is already truncated. */
759 #define TRULY_NOOP_TRUNCATION(OUTPREC, INPREC) 1
760
761 #define CLZ_DEFINED_VALUE_AT_ZERO(MODE, VALUE) ((VALUE) = 32, 1)
762 #define CTZ_DEFINED_VALUE_AT_ZERO(MODE, VALUE) ((VALUE) = -1, 1)
763
764 /* Specify the machine mode that pointers have.
765 After generation of rtl, the compiler makes no further distinction
766 between pointers and any other objects of this machine mode. */
767 #define Pmode SImode
768
769 /* A function address in a call instruction is a word address (for
770 indexing purposes) so give the MEM rtx a words's mode. */
771 #define FUNCTION_MODE SImode
772
773 /* A C expression for the cost of moving data from a register in
774 class FROM to one in class TO. The classes are expressed using
775 the enumeration values such as 'GENERAL_REGS'. A value of 2 is
776 the default; other values are interpreted relative to that. */
777 #define REGISTER_MOVE_COST(MODE, FROM, TO) \
778 (((FROM) == (TO) && (FROM) != BR_REGS && (TO) != BR_REGS) \
779 ? 2 \
780 : (reg_class_subset_p ((FROM), AR_REGS) \
781 && reg_class_subset_p ((TO), AR_REGS) \
782 ? 2 \
783 : (reg_class_subset_p ((FROM), AR_REGS) \
784 && (TO) == ACC_REG \
785 ? 3 \
786 : ((FROM) == ACC_REG \
787 && reg_class_subset_p ((TO), AR_REGS) \
788 ? 3 \
789 : 10))))
790
791 #define MEMORY_MOVE_COST(MODE, CLASS, IN) 4
792
793 #define BRANCH_COST(speed_p, predictable_p) 3
794
795 /* How to refer to registers in assembler output.
796 This sequence is indexed by compiler's hard-register-number (see above). */
797 #define REGISTER_NAMES \
798 { \
799 "a0", "sp", "a2", "a3", "a4", "a5", "a6", "a7", \
800 "a8", "a9", "a10", "a11", "a12", "a13", "a14", "a15", \
801 "fp", "argp", "b0", \
802 "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", \
803 "f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15", \
804 "acc" \
805 }
806
807 /* If defined, a C initializer for an array of structures containing a
808 name and a register number. This macro defines additional names
809 for hard registers, thus allowing the 'asm' option in declarations
810 to refer to registers using alternate names. */
811 #define ADDITIONAL_REGISTER_NAMES \
812 { \
813 { "a1", 1 + GP_REG_FIRST } \
814 }
815
816 #define PRINT_OPERAND(FILE, X, CODE) print_operand (FILE, X, CODE)
817 #define PRINT_OPERAND_ADDRESS(FILE, ADDR) print_operand_address (FILE, ADDR)
818
819 /* Globalizing directive for a label. */
820 #define GLOBAL_ASM_OP "\t.global\t"
821
822 /* Declare an uninitialized external linkage data object. */
823 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
824 asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN)
825
826 /* This is how to output an element of a case-vector that is absolute. */
827 #define ASM_OUTPUT_ADDR_VEC_ELT(STREAM, VALUE) \
828 fprintf (STREAM, "%s%sL%u\n", integer_asm_op (4, TRUE), \
829 LOCAL_LABEL_PREFIX, VALUE)
830
831 /* This is how to output an element of a case-vector that is relative.
832 This is used for pc-relative code. */
833 #define ASM_OUTPUT_ADDR_DIFF_ELT(STREAM, BODY, VALUE, REL) \
834 do { \
835 fprintf (STREAM, "%s%sL%u-%sL%u\n", integer_asm_op (4, TRUE), \
836 LOCAL_LABEL_PREFIX, (VALUE), \
837 LOCAL_LABEL_PREFIX, (REL)); \
838 } while (0)
839
840 /* This is how to output an assembler line that says to advance the
841 location counter to a multiple of 2**LOG bytes. */
842 #define ASM_OUTPUT_ALIGN(STREAM, LOG) \
843 do { \
844 if ((LOG) != 0) \
845 fprintf (STREAM, "\t.align\t%d\n", 1 << (LOG)); \
846 } while (0)
847
848 /* Indicate that jump tables go in the text section. This is
849 necessary when compiling PIC code. */
850 #define JUMP_TABLES_IN_TEXT_SECTION (flag_pic)
851
852
853 /* Define the strings to put out for each section in the object file. */
854 #define TEXT_SECTION_ASM_OP "\t.text"
855 #define DATA_SECTION_ASM_OP "\t.data"
856 #define BSS_SECTION_ASM_OP "\t.section\t.bss"
857
858
859 /* Define output to appear before the constant pool. */
860 #define ASM_OUTPUT_POOL_PROLOGUE(FILE, FUNNAME, FUNDECL, SIZE) \
861 do { \
862 if ((SIZE) > 0) \
863 { \
864 resolve_unique_section ((FUNDECL), 0, flag_function_sections); \
865 switch_to_section (function_section (FUNDECL)); \
866 fprintf (FILE, "\t.literal_position\n"); \
867 } \
868 } while (0)
869
870
871 /* A C statement (with or without semicolon) to output a constant in
872 the constant pool, if it needs special treatment. */
873 #define ASM_OUTPUT_SPECIAL_POOL_ENTRY(FILE, X, MODE, ALIGN, LABELNO, JUMPTO) \
874 do { \
875 xtensa_output_literal (FILE, X, MODE, LABELNO); \
876 goto JUMPTO; \
877 } while (0)
878
879 /* How to start an assembler comment. */
880 #define ASM_COMMENT_START "#"
881
882 /* Exception handling. Xtensa uses much of the standard DWARF2 unwinding
883 machinery, but the variable size register window save areas are too
884 complicated to efficiently describe with CFI entries. The CFA must
885 still be specified in DWARF so that DW_AT_frame_base is set correctly
886 for debugging. */
887 #define INCOMING_RETURN_ADDR_RTX gen_rtx_REG (Pmode, 0)
888 #define DWARF_FRAME_RETURN_COLUMN DWARF_FRAME_REGNUM (0)
889 #define DWARF_FRAME_REGISTERS 16
890 #define EH_RETURN_DATA_REGNO(N) ((N) < 2 ? (N) + 2 : INVALID_REGNUM)
891 #define ASM_PREFERRED_EH_DATA_FORMAT(CODE, GLOBAL) \
892 (flag_pic \
893 ? (((GLOBAL) ? DW_EH_PE_indirect : 0) \
894 | DW_EH_PE_pcrel | DW_EH_PE_sdata4) \
895 : DW_EH_PE_absptr)
896
897 /* Emit a PC-relative relocation. */
898 #define ASM_OUTPUT_DWARF_PCREL(FILE, SIZE, LABEL) \
899 do { \
900 fputs (integer_asm_op (SIZE, FALSE), FILE); \
901 assemble_name (FILE, LABEL); \
902 fputs ("@pcrel", FILE); \
903 } while (0)
904
905 /* Xtensa constant pool breaks the devices in crtstuff.c to control
906 section in where code resides. We have to write it as asm code. Use
907 a MOVI and let the assembler relax it -- for the .init and .fini
908 sections, the assembler knows to put the literal in the right
909 place. */
910 #define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC) \
911 asm (SECTION_OP "\n\
912 movi\ta8, " USER_LABEL_PREFIX #FUNC "\n\
913 callx8\ta8\n" \
914 TEXT_SECTION_ASM_OP);