2015-05-22 Pascal Obry <obry@adacore.com>
[official-gcc.git] / gcc / real.h
blob37a8499baa18e9cedb4eb43784ad198cc0ddf18a
1 /* Definitions of floating-point access for GNU compiler.
2 Copyright (C) 1989-2015 Free Software Foundation, Inc.
4 This file is part of GCC.
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.
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.
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/>. */
20 #ifndef GCC_REAL_H
21 #define GCC_REAL_H
23 #include "machmode.h"
24 #include "signop.h"
25 #include "wide-int.h"
26 #include "insn-modes.h"
28 /* An expanded form of the represented number. */
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
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))
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];
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)))
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
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. */
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 */
77 /* Verify the guess. */
78 extern char test_real_width
79 [sizeof (REAL_VALUE_TYPE) <= REAL_WIDTH * sizeof (HOST_WIDE_INT) ? 1 : -1];
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).
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. */
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
115 /* Describes the properties of the specific target format in use. */
116 struct real_format
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 *);
124 /* The radix of the exponent and digits of the significand. */
125 int b;
127 /* Size of the significand in digits of radix B. */
128 int p;
130 /* Size of the significant of a NaN, in digits of radix B. */
131 int pnan;
133 /* The minimum negative integer, x, such that b**(x-1) is normalized. */
134 int emin;
136 /* The maximum integer, x, such that b**(x-1) is representable. */
137 int emax;
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;
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;
147 /* Default rounding mode for operations on this format. */
148 bool round_towards_zero;
149 bool has_sign_dependent_rounding;
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 const char *name;
162 /* The target format used for each floating point mode.
163 Float modes are followed by decimal float modes, with entries for
164 float modes indexed by (MODE - first float mode), and entries for
165 decimal float modes indexed by (MODE - first decimal float mode) +
166 the number of float modes. */
167 extern const struct real_format *
168 real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
169 + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
171 #define REAL_MODE_FORMAT(MODE) \
172 (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE) \
173 ? (((MODE) - MIN_MODE_DECIMAL_FLOAT) \
174 + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1)) \
175 : ((MODE) - MIN_MODE_FLOAT)])
177 #define FLOAT_MODE_FORMAT(MODE) \
178 (REAL_MODE_FORMAT (SCALAR_FLOAT_MODE_P (MODE)? (MODE) \
179 : GET_MODE_INNER (MODE)))
181 /* The following macro determines whether the floating point format is
182 composite, i.e. may contain non-consecutive mantissa bits, in which
183 case compile-time FP overflow may not model run-time overflow. */
184 #define MODE_COMPOSITE_P(MODE) \
185 (FLOAT_MODE_P (MODE) \
186 && FLOAT_MODE_FORMAT (MODE)->pnan < FLOAT_MODE_FORMAT (MODE)->p)
188 /* Accessor macros for format properties. */
189 #define MODE_HAS_NANS(MODE) \
190 (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_nans)
191 #define MODE_HAS_INFINITIES(MODE) \
192 (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_inf)
193 #define MODE_HAS_SIGNED_ZEROS(MODE) \
194 (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_signed_zero)
195 #define MODE_HAS_SIGN_DEPENDENT_ROUNDING(MODE) \
196 (FLOAT_MODE_P (MODE) \
197 && FLOAT_MODE_FORMAT (MODE)->has_sign_dependent_rounding)
199 /* Declare functions in real.c. */
201 /* True if the given mode has a NaN representation and the treatment of
202 NaN operands is important. Certain optimizations, such as folding
203 x * 0 into 0, are not correct for NaN operands, and are normally
204 disabled for modes with NaNs. The user can ask for them to be
205 done anyway using the -funsafe-math-optimizations switch. */
206 extern bool HONOR_NANS (machine_mode);
207 extern bool HONOR_NANS (const_tree);
208 extern bool HONOR_NANS (const_rtx);
210 /* Like HONOR_NANs, but true if we honor signaling NaNs (or sNaNs). */
211 extern bool HONOR_SNANS (machine_mode);
212 extern bool HONOR_SNANS (const_tree);
213 extern bool HONOR_SNANS (const_rtx);
215 /* As for HONOR_NANS, but true if the mode can represent infinity and
216 the treatment of infinite values is important. */
217 extern bool HONOR_INFINITIES (machine_mode);
218 extern bool HONOR_INFINITIES (const_tree);
219 extern bool HONOR_INFINITIES (const_rtx);
221 /* Like HONOR_NANS, but true if the given mode distinguishes between
222 positive and negative zero, and the sign of zero is important. */
223 extern bool HONOR_SIGNED_ZEROS (machine_mode);
224 extern bool HONOR_SIGNED_ZEROS (const_tree);
225 extern bool HONOR_SIGNED_ZEROS (const_rtx);
227 /* Like HONOR_NANS, but true if given mode supports sign-dependent rounding,
228 and the rounding mode is important. */
229 extern bool HONOR_SIGN_DEPENDENT_ROUNDING (machine_mode);
230 extern bool HONOR_SIGN_DEPENDENT_ROUNDING (const_tree);
231 extern bool HONOR_SIGN_DEPENDENT_ROUNDING (const_rtx);
233 /* Binary or unary arithmetic on tree_code. */
234 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
235 const REAL_VALUE_TYPE *);
237 /* Compare reals by tree_code. */
238 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
240 /* Determine whether a floating-point value X is infinite. */
241 extern bool real_isinf (const REAL_VALUE_TYPE *);
243 /* Determine whether a floating-point value X is a NaN. */
244 extern bool real_isnan (const REAL_VALUE_TYPE *);
246 /* Determine whether a floating-point value X is finite. */
247 extern bool real_isfinite (const REAL_VALUE_TYPE *);
249 /* Determine whether a floating-point value X is negative. */
250 extern bool real_isneg (const REAL_VALUE_TYPE *);
252 /* Determine whether a floating-point value X is minus zero. */
253 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
255 /* Compare two floating-point objects for bitwise identity. */
256 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
258 /* Extend or truncate to a new mode. */
259 extern void real_convert (REAL_VALUE_TYPE *, machine_mode,
260 const REAL_VALUE_TYPE *);
262 /* Return true if truncating to NEW is exact. */
263 extern bool exact_real_truncate (machine_mode, const REAL_VALUE_TYPE *);
265 /* Render R as a decimal floating point constant. */
266 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
267 size_t, int);
269 /* Render R as a decimal floating point constant, rounded so as to be
270 parsed back to the same value when interpreted in mode MODE. */
271 extern void real_to_decimal_for_mode (char *, const REAL_VALUE_TYPE *, size_t,
272 size_t, int, machine_mode);
274 /* Render R as a hexadecimal floating point constant. */
275 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
276 size_t, size_t, int);
278 /* Render R as an integer. */
279 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
281 /* Initialize R from a decimal or hexadecimal string. Return -1 if
282 the value underflows, +1 if overflows, and 0 otherwise. */
283 extern int real_from_string (REAL_VALUE_TYPE *, const char *);
284 /* Wrapper to allow different internal representation for decimal floats. */
285 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, machine_mode);
287 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
288 const struct real_format *);
289 extern long real_to_target (long *, const REAL_VALUE_TYPE *, machine_mode);
291 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
292 const struct real_format *);
293 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
294 machine_mode);
296 extern void real_inf (REAL_VALUE_TYPE *);
298 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, machine_mode);
300 extern void real_maxval (REAL_VALUE_TYPE *, int, machine_mode);
302 extern void real_2expN (REAL_VALUE_TYPE *, int, machine_mode);
304 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
307 /* Target formats defined in real.c. */
308 extern const struct real_format ieee_single_format;
309 extern const struct real_format mips_single_format;
310 extern const struct real_format motorola_single_format;
311 extern const struct real_format spu_single_format;
312 extern const struct real_format ieee_double_format;
313 extern const struct real_format mips_double_format;
314 extern const struct real_format motorola_double_format;
315 extern const struct real_format ieee_extended_motorola_format;
316 extern const struct real_format ieee_extended_intel_96_format;
317 extern const struct real_format ieee_extended_intel_96_round_53_format;
318 extern const struct real_format ieee_extended_intel_128_format;
319 extern const struct real_format ibm_extended_format;
320 extern const struct real_format mips_extended_format;
321 extern const struct real_format ieee_quad_format;
322 extern const struct real_format mips_quad_format;
323 extern const struct real_format vax_f_format;
324 extern const struct real_format vax_d_format;
325 extern const struct real_format vax_g_format;
326 extern const struct real_format real_internal_format;
327 extern const struct real_format decimal_single_format;
328 extern const struct real_format decimal_double_format;
329 extern const struct real_format decimal_quad_format;
330 extern const struct real_format ieee_half_format;
331 extern const struct real_format arm_half_format;
334 /* ====================================================================== */
335 /* Crap. */
337 #define REAL_ARITHMETIC(value, code, d1, d2) \
338 real_arithmetic (&(value), code, &(d1), &(d2))
340 #define REAL_VALUES_IDENTICAL(x, y) real_identical (&(x), &(y))
341 #define REAL_VALUES_EQUAL(x, y) real_compare (EQ_EXPR, &(x), &(y))
342 #define REAL_VALUES_LESS(x, y) real_compare (LT_EXPR, &(x), &(y))
344 /* Determine whether a floating-point value X is infinite. */
345 #define REAL_VALUE_ISINF(x) real_isinf (&(x))
347 /* Determine whether a floating-point value X is a NaN. */
348 #define REAL_VALUE_ISNAN(x) real_isnan (&(x))
350 /* Determine whether a floating-point value X is negative. */
351 #define REAL_VALUE_NEGATIVE(x) real_isneg (&(x))
353 /* Determine whether a floating-point value X is minus zero. */
354 #define REAL_VALUE_MINUS_ZERO(x) real_isnegzero (&(x))
356 /* IN is a REAL_VALUE_TYPE. OUT is an array of longs. */
357 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT) \
358 real_to_target (OUT, &(IN), \
359 mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
361 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
362 real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
364 /* IN is a REAL_VALUE_TYPE. OUT is a long. */
365 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
366 ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
368 /* Real values to IEEE 754 decimal floats. */
370 /* IN is a REAL_VALUE_TYPE. OUT is an array of longs. */
371 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
372 real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
374 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
375 real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
377 /* IN is a REAL_VALUE_TYPE. OUT is a long. */
378 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
379 ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
381 extern REAL_VALUE_TYPE real_value_truncate (machine_mode,
382 REAL_VALUE_TYPE);
384 extern REAL_VALUE_TYPE real_value_negate (const REAL_VALUE_TYPE *);
385 extern REAL_VALUE_TYPE real_value_abs (const REAL_VALUE_TYPE *);
387 extern int significand_size (machine_mode);
389 extern REAL_VALUE_TYPE real_from_string2 (const char *, machine_mode);
391 #define REAL_VALUE_ATOF(s, m) \
392 real_from_string2 (s, m)
394 #define CONST_DOUBLE_ATOF(s, m) \
395 CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
397 #define REAL_VALUE_FIX(r) \
398 real_to_integer (&(r))
400 /* ??? Not quite right. */
401 #define REAL_VALUE_UNSIGNED_FIX(r) \
402 real_to_integer (&(r))
404 /* ??? These were added for Paranoia support. */
406 /* Return floor log2(R). */
407 extern int real_exponent (const REAL_VALUE_TYPE *);
409 /* R = A * 2**EXP. */
410 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
412 /* **** End of software floating point emulator interface macros **** */
414 /* Constant real values 0, 1, 2, -1 and 0.5. */
416 extern REAL_VALUE_TYPE dconst0;
417 extern REAL_VALUE_TYPE dconst1;
418 extern REAL_VALUE_TYPE dconst2;
419 extern REAL_VALUE_TYPE dconstm1;
420 extern REAL_VALUE_TYPE dconsthalf;
422 #define dconst_e() (*dconst_e_ptr ())
423 #define dconst_third() (*dconst_third_ptr ())
424 #define dconst_sqrt2() (*dconst_sqrt2_ptr ())
426 /* Function to return the real value special constant 'e'. */
427 extern const REAL_VALUE_TYPE * dconst_e_ptr (void);
429 /* Returns the special REAL_VALUE_TYPE corresponding to 1/3. */
430 extern const REAL_VALUE_TYPE * dconst_third_ptr (void);
432 /* Returns the special REAL_VALUE_TYPE corresponding to sqrt(2). */
433 extern const REAL_VALUE_TYPE * dconst_sqrt2_ptr (void);
435 /* Function to return a real value (not a tree node)
436 from a given integer constant. */
437 REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
439 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents. */
440 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
441 ((to) = *CONST_DOUBLE_REAL_VALUE (from))
443 /* Return a CONST_DOUBLE with value R and mode M. */
444 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
445 const_double_from_real_value (r, m)
446 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, machine_mode);
448 /* Replace R by 1/R in the given machine mode, if the result is exact. */
449 extern bool exact_real_inverse (machine_mode, REAL_VALUE_TYPE *);
451 /* Return true if arithmetic on values in IMODE that were promoted
452 from values in TMODE is equivalent to direct arithmetic on values
453 in TMODE. */
454 bool real_can_shorten_arithmetic (machine_mode, machine_mode);
456 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node. */
457 extern tree build_real (tree, REAL_VALUE_TYPE);
459 /* Calculate R as X raised to the integer exponent N in mode MODE. */
460 extern bool real_powi (REAL_VALUE_TYPE *, machine_mode,
461 const REAL_VALUE_TYPE *, HOST_WIDE_INT);
463 /* Standard round to integer value functions. */
464 extern void real_trunc (REAL_VALUE_TYPE *, machine_mode,
465 const REAL_VALUE_TYPE *);
466 extern void real_floor (REAL_VALUE_TYPE *, machine_mode,
467 const REAL_VALUE_TYPE *);
468 extern void real_ceil (REAL_VALUE_TYPE *, machine_mode,
469 const REAL_VALUE_TYPE *);
470 extern void real_round (REAL_VALUE_TYPE *, machine_mode,
471 const REAL_VALUE_TYPE *);
473 /* Set the sign of R to the sign of X. */
474 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
476 /* Check whether the real constant value given is an integer. */
477 extern bool real_isinteger (const REAL_VALUE_TYPE *c, machine_mode mode);
479 /* Write into BUF the maximum representable finite floating-point
480 number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
481 float string. BUF must be large enough to contain the result. */
482 extern void get_max_float (const struct real_format *, char *, size_t);
484 #ifndef GENERATOR_FILE
485 /* real related routines. */
486 extern wide_int real_to_integer (const REAL_VALUE_TYPE *, bool *, int);
487 extern void real_from_integer (REAL_VALUE_TYPE *, machine_mode,
488 const wide_int_ref &, signop);
489 #endif
491 #endif /* ! GCC_REAL_H */