1 /* Definitions of floating-point access for GNU compiler.
2 Copyright (C) 1989-2016 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 /* An expanded form of the represented number. */
24
25 /* Enumerate the special cases of numbers that we encounter. */
26 enum real_value_class {
27 rvc_zero,
28 rvc_normal,
29 rvc_inf,
30 rvc_nan
31 };
32
33 #define SIGNIFICAND_BITS (128 + HOST_BITS_PER_LONG)
34 #define EXP_BITS (32 - 6)
35 #define MAX_EXP ((1 << (EXP_BITS - 1)) - 1)
36 #define SIGSZ (SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
37 #define SIG_MSB ((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
38
39 struct GTY(()) real_value {
40 /* Use the same underlying type for all bit-fields, so as to make
41 sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
42 be miscomputed. */
43 unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
44 unsigned int decimal : 1;
45 unsigned int sign : 1;
46 unsigned int signalling : 1;
47 unsigned int canonical : 1;
48 unsigned int uexp : EXP_BITS;
49 unsigned long sig[SIGSZ];
50 };
51
52 #define REAL_EXP(REAL) \
53 ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
54 - (1 << (EXP_BITS - 1)))
55 #define SET_REAL_EXP(REAL, EXP) \
56 ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
57
58 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
59 needs to be a macro. We do need to continue to have a structure tag
60 so that other headers can forward declare it. */
61 #define REAL_VALUE_TYPE struct real_value
62
63 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
64 consecutive "w" slots. Moreover, we've got to compute the number of "w"
65 slots at preprocessor time, which means we can't use sizeof. Guess. */
66
67 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
68 #define REAL_WIDTH \
69 (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
70 + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
71
72 /* Verify the guess. */
73 extern char test_real_width
74 [sizeof (REAL_VALUE_TYPE) <= REAL_WIDTH * sizeof (HOST_WIDE_INT) ? 1 : -1];
75
76 /* Calculate the format for CONST_DOUBLE. We need as many slots as
77 are necessary to overlay a REAL_VALUE_TYPE on them. This could be
78 as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
79
80 A number of places assume that there are always at least two 'w'
81 slots in a CONST_DOUBLE, so we provide them even if one would suffice. */
82
83 #if REAL_WIDTH == 1
84 # define CONST_DOUBLE_FORMAT "ww"
85 #else
86 # if REAL_WIDTH == 2
87 # define CONST_DOUBLE_FORMAT "ww"
88 # else
89 # if REAL_WIDTH == 3
90 # define CONST_DOUBLE_FORMAT "www"
91 # else
92 # if REAL_WIDTH == 4
93 # define CONST_DOUBLE_FORMAT "wwww"
94 # else
95 # if REAL_WIDTH == 5
96 # define CONST_DOUBLE_FORMAT "wwwww"
97 # else
98 # if REAL_WIDTH == 6
99 # define CONST_DOUBLE_FORMAT "wwwwww"
100 # else
101 #error "REAL_WIDTH > 6 not supported"
102 # endif
103 # endif
104 # endif
105 # endif
106 # endif
107 #endif
108
109
110 /* Describes the properties of the specific target format in use. */
111 struct real_format
112 {
113 /* Move to and from the target bytes. */
114 void (*encode) (const struct real_format *, long *,
115 const REAL_VALUE_TYPE *);
116 void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
117 const long *);
118
119 /* The radix of the exponent and digits of the significand. */
120 int b;
121
122 /* Size of the significand in digits of radix B. */
123 int p;
124
125 /* Size of the significant of a NaN, in digits of radix B. */
126 int pnan;
127
128 /* The minimum negative integer, x, such that b**(x-1) is normalized. */
129 int emin;
130
131 /* The maximum integer, x, such that b**(x-1) is representable. */
132 int emax;
133
134 /* The bit position of the sign bit, for determining whether a value
135 is positive/negative, or -1 for a complex encoding. */
136 int signbit_ro;
137
138 /* The bit position of the sign bit, for changing the sign of a number,
139 or -1 for a complex encoding. */
140 int signbit_rw;
141
142 /* Default rounding mode for operations on this format. */
143 bool round_towards_zero;
144 bool has_sign_dependent_rounding;
145
146 /* Properties of the format. */
147 bool has_nans;
148 bool has_inf;
149 bool has_denorm;
150 bool has_signed_zero;
151 bool qnan_msb_set;
152 bool canonical_nan_lsbs_set;
153 const char *name;
154 };
155
156
157 /* The target format used for each floating point mode.
158 Float modes are followed by decimal float modes, with entries for
159 float modes indexed by (MODE - first float mode), and entries for
160 decimal float modes indexed by (MODE - first decimal float mode) +
161 the number of float modes. */
162 extern const struct real_format *
163 real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
164 + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
165
166 #define REAL_MODE_FORMAT(MODE) \
167 (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE) \
168 ? (((MODE) - MIN_MODE_DECIMAL_FLOAT) \
169 + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1)) \
170 : GET_MODE_CLASS (MODE) == MODE_FLOAT \
171 ? ((MODE) - MIN_MODE_FLOAT) \
172 : (gcc_unreachable (), 0)])
173
174 #define FLOAT_MODE_FORMAT(MODE) \
175 (REAL_MODE_FORMAT (SCALAR_FLOAT_MODE_P (MODE)? (MODE) \
176 : GET_MODE_INNER (MODE)))
177
178 /* The following macro determines whether the floating point format is
179 composite, i.e. may contain non-consecutive mantissa bits, in which
180 case compile-time FP overflow may not model run-time overflow. */
181 #define MODE_COMPOSITE_P(MODE) \
182 (FLOAT_MODE_P (MODE) \
183 && FLOAT_MODE_FORMAT (MODE)->pnan < FLOAT_MODE_FORMAT (MODE)->p)
184
185 /* Accessor macros for format properties. */
186 #define MODE_HAS_NANS(MODE) \
187 (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_nans)
188 #define MODE_HAS_INFINITIES(MODE) \
189 (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_inf)
190 #define MODE_HAS_SIGNED_ZEROS(MODE) \
191 (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_signed_zero)
192 #define MODE_HAS_SIGN_DEPENDENT_ROUNDING(MODE) \
193 (FLOAT_MODE_P (MODE) \
194 && FLOAT_MODE_FORMAT (MODE)->has_sign_dependent_rounding)
195
196 /* This class allows functions in this file to accept a floating-point
197 format as either a mode or an explicit real_format pointer. In the
198 former case the mode must be VOIDmode (which means "no particular
199 format") or must satisfy SCALAR_FLOAT_MODE_P. */
200 class format_helper
201 {
202 public:
format_helper(const real_format * format)203 format_helper (const real_format *format) : m_format (format) {}
204 format_helper (machine_mode m);
205 const real_format *operator-> () const { return m_format; }
206 operator const real_format *() const { return m_format; }
207
decimal_p()208 bool decimal_p () const { return m_format && m_format->b == 10; }
209
210 private:
211 const real_format *m_format;
212 };
213
format_helper(machine_mode m)214 inline format_helper::format_helper (machine_mode m)
215 : m_format (m == VOIDmode ? 0 : REAL_MODE_FORMAT (m))
216 {}
217
218 /* Declare functions in real.c. */
219
220 /* True if the given mode has a NaN representation and the treatment of
221 NaN operands is important. Certain optimizations, such as folding
222 x * 0 into 0, are not correct for NaN operands, and are normally
223 disabled for modes with NaNs. The user can ask for them to be
224 done anyway using the -funsafe-math-optimizations switch. */
225 extern bool HONOR_NANS (machine_mode);
226 extern bool HONOR_NANS (const_tree);
227 extern bool HONOR_NANS (const_rtx);
228
229 /* Like HONOR_NANs, but true if we honor signaling NaNs (or sNaNs). */
230 extern bool HONOR_SNANS (machine_mode);
231 extern bool HONOR_SNANS (const_tree);
232 extern bool HONOR_SNANS (const_rtx);
233
234 /* As for HONOR_NANS, but true if the mode can represent infinity and
235 the treatment of infinite values is important. */
236 extern bool HONOR_INFINITIES (machine_mode);
237 extern bool HONOR_INFINITIES (const_tree);
238 extern bool HONOR_INFINITIES (const_rtx);
239
240 /* Like HONOR_NANS, but true if the given mode distinguishes between
241 positive and negative zero, and the sign of zero is important. */
242 extern bool HONOR_SIGNED_ZEROS (machine_mode);
243 extern bool HONOR_SIGNED_ZEROS (const_tree);
244 extern bool HONOR_SIGNED_ZEROS (const_rtx);
245
246 /* Like HONOR_NANS, but true if given mode supports sign-dependent rounding,
247 and the rounding mode is important. */
248 extern bool HONOR_SIGN_DEPENDENT_ROUNDING (machine_mode);
249 extern bool HONOR_SIGN_DEPENDENT_ROUNDING (const_tree);
250 extern bool HONOR_SIGN_DEPENDENT_ROUNDING (const_rtx);
251
252 /* Binary or unary arithmetic on tree_code. */
253 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
254 const REAL_VALUE_TYPE *);
255
256 /* Compare reals by tree_code. */
257 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
258
259 /* Determine whether a floating-point value X is infinite. */
260 extern bool real_isinf (const REAL_VALUE_TYPE *);
261
262 /* Determine whether a floating-point value X is a NaN. */
263 extern bool real_isnan (const REAL_VALUE_TYPE *);
264
265 /* Determine whether a floating-point value X is a signaling NaN. */
266 extern bool real_issignaling_nan (const REAL_VALUE_TYPE *);
267
268 /* Determine whether a floating-point value X is finite. */
269 extern bool real_isfinite (const REAL_VALUE_TYPE *);
270
271 /* Determine whether a floating-point value X is negative. */
272 extern bool real_isneg (const REAL_VALUE_TYPE *);
273
274 /* Determine whether a floating-point value X is minus zero. */
275 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
276
277 /* Test relationships between reals. */
278 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
279 extern bool real_equal (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
280 extern bool real_less (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
281
282 /* Extend or truncate to a new format. */
283 extern void real_convert (REAL_VALUE_TYPE *, format_helper,
284 const REAL_VALUE_TYPE *);
285
286 /* Return true if truncating to NEW is exact. */
287 extern bool exact_real_truncate (format_helper, const REAL_VALUE_TYPE *);
288
289 /* Render R as a decimal floating point constant. */
290 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
291 size_t, int);
292
293 /* Render R as a decimal floating point constant, rounded so as to be
294 parsed back to the same value when interpreted in mode MODE. */
295 extern void real_to_decimal_for_mode (char *, const REAL_VALUE_TYPE *, size_t,
296 size_t, int, machine_mode);
297
298 /* Render R as a hexadecimal floating point constant. */
299 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
300 size_t, size_t, int);
301
302 /* Render R as an integer. */
303 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
304
305 /* Initialize R from a decimal or hexadecimal string. Return -1 if
306 the value underflows, +1 if overflows, and 0 otherwise. */
307 extern int real_from_string (REAL_VALUE_TYPE *, const char *);
308 /* Wrapper to allow different internal representation for decimal floats. */
309 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, format_helper);
310
311 extern long real_to_target (long *, const REAL_VALUE_TYPE *, format_helper);
312
313 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
314 format_helper);
315
316 extern void real_inf (REAL_VALUE_TYPE *);
317
318 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, format_helper);
319
320 extern void real_maxval (REAL_VALUE_TYPE *, int, machine_mode);
321
322 extern void real_2expN (REAL_VALUE_TYPE *, int, format_helper);
323
324 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
325
326
327 /* Target formats defined in real.c. */
328 extern const struct real_format ieee_single_format;
329 extern const struct real_format mips_single_format;
330 extern const struct real_format motorola_single_format;
331 extern const struct real_format spu_single_format;
332 extern const struct real_format ieee_double_format;
333 extern const struct real_format mips_double_format;
334 extern const struct real_format motorola_double_format;
335 extern const struct real_format ieee_extended_motorola_format;
336 extern const struct real_format ieee_extended_intel_96_format;
337 extern const struct real_format ieee_extended_intel_96_round_53_format;
338 extern const struct real_format ieee_extended_intel_128_format;
339 extern const struct real_format ibm_extended_format;
340 extern const struct real_format mips_extended_format;
341 extern const struct real_format ieee_quad_format;
342 extern const struct real_format mips_quad_format;
343 extern const struct real_format vax_f_format;
344 extern const struct real_format vax_d_format;
345 extern const struct real_format vax_g_format;
346 extern const struct real_format real_internal_format;
347 extern const struct real_format decimal_single_format;
348 extern const struct real_format decimal_double_format;
349 extern const struct real_format decimal_quad_format;
350 extern const struct real_format ieee_half_format;
351 extern const struct real_format arm_half_format;
352
353
354 /* ====================================================================== */
355 /* Crap. */
356
357 /* Determine whether a floating-point value X is infinite. */
358 #define REAL_VALUE_ISINF(x) real_isinf (&(x))
359
360 /* Determine whether a floating-point value X is a NaN. */
361 #define REAL_VALUE_ISNAN(x) real_isnan (&(x))
362
363 /* Determine whether a floating-point value X is a signaling NaN. */
364 #define REAL_VALUE_ISSIGNALING_NAN(x) real_issignaling_nan (&(x))
365
366 /* Determine whether a floating-point value X is negative. */
367 #define REAL_VALUE_NEGATIVE(x) real_isneg (&(x))
368
369 /* Determine whether a floating-point value X is minus zero. */
370 #define REAL_VALUE_MINUS_ZERO(x) real_isnegzero (&(x))
371
372 /* IN is a REAL_VALUE_TYPE. OUT is an array of longs. */
373 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT) \
374 real_to_target (OUT, &(IN), \
375 mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
376
377 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
378 real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
379
380 /* IN is a REAL_VALUE_TYPE. OUT is a long. */
381 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
382 ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
383
384 /* Real values to IEEE 754 decimal floats. */
385
386 /* IN is a REAL_VALUE_TYPE. OUT is an array of longs. */
387 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
388 real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
389
390 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
391 real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
392
393 /* IN is a REAL_VALUE_TYPE. OUT is a long. */
394 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
395 ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
396
397 extern REAL_VALUE_TYPE real_value_truncate (format_helper, REAL_VALUE_TYPE);
398
399 extern REAL_VALUE_TYPE real_value_negate (const REAL_VALUE_TYPE *);
400 extern REAL_VALUE_TYPE real_value_abs (const REAL_VALUE_TYPE *);
401
402 extern int significand_size (format_helper);
403
404 extern REAL_VALUE_TYPE real_from_string2 (const char *, format_helper);
405
406 #define REAL_VALUE_ATOF(s, m) \
407 real_from_string2 (s, m)
408
409 #define CONST_DOUBLE_ATOF(s, m) \
410 const_double_from_real_value (real_from_string2 (s, m), m)
411
412 #define REAL_VALUE_FIX(r) \
413 real_to_integer (&(r))
414
415 /* ??? Not quite right. */
416 #define REAL_VALUE_UNSIGNED_FIX(r) \
417 real_to_integer (&(r))
418
419 /* ??? These were added for Paranoia support. */
420
421 /* Return floor log2(R). */
422 extern int real_exponent (const REAL_VALUE_TYPE *);
423
424 /* R = A * 2**EXP. */
425 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
426
427 /* **** End of software floating point emulator interface macros **** */
428
429 /* Constant real values 0, 1, 2, -1 and 0.5. */
430
431 extern REAL_VALUE_TYPE dconst0;
432 extern REAL_VALUE_TYPE dconst1;
433 extern REAL_VALUE_TYPE dconst2;
434 extern REAL_VALUE_TYPE dconstm1;
435 extern REAL_VALUE_TYPE dconsthalf;
436
437 #define dconst_e() (*dconst_e_ptr ())
438 #define dconst_third() (*dconst_third_ptr ())
439 #define dconst_quarter() (*dconst_quarter_ptr ())
440 #define dconst_sixth() (*dconst_sixth_ptr ())
441 #define dconst_ninth() (*dconst_ninth_ptr ())
442 #define dconst_sqrt2() (*dconst_sqrt2_ptr ())
443
444 /* Function to return the real value special constant 'e'. */
445 extern const REAL_VALUE_TYPE * dconst_e_ptr (void);
446
447 /* Returns a cached REAL_VALUE_TYPE corresponding to 1/n, for various n. */
448 extern const REAL_VALUE_TYPE *dconst_third_ptr (void);
449 extern const REAL_VALUE_TYPE *dconst_quarter_ptr (void);
450 extern const REAL_VALUE_TYPE *dconst_sixth_ptr (void);
451 extern const REAL_VALUE_TYPE *dconst_ninth_ptr (void);
452
453 /* Returns the special REAL_VALUE_TYPE corresponding to sqrt(2). */
454 extern const REAL_VALUE_TYPE * dconst_sqrt2_ptr (void);
455
456 /* Function to return a real value (not a tree node)
457 from a given integer constant. */
458 REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
459
460 /* Return a CONST_DOUBLE with value R and mode M. */
461 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, machine_mode);
462
463 /* Replace R by 1/R in the given format, if the result is exact. */
464 extern bool exact_real_inverse (format_helper, REAL_VALUE_TYPE *);
465
466 /* Return true if arithmetic on values in IMODE that were promoted
467 from values in TMODE is equivalent to direct arithmetic on values
468 in TMODE. */
469 bool real_can_shorten_arithmetic (machine_mode, machine_mode);
470
471 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node. */
472 extern tree build_real (tree, REAL_VALUE_TYPE);
473
474 /* Likewise, but first truncate the value to the type. */
475 extern tree build_real_truncate (tree, REAL_VALUE_TYPE);
476
477 /* Calculate R as X raised to the integer exponent N in format FMT. */
478 extern bool real_powi (REAL_VALUE_TYPE *, format_helper,
479 const REAL_VALUE_TYPE *, HOST_WIDE_INT);
480
481 /* Standard round to integer value functions. */
482 extern void real_trunc (REAL_VALUE_TYPE *, format_helper,
483 const REAL_VALUE_TYPE *);
484 extern void real_floor (REAL_VALUE_TYPE *, format_helper,
485 const REAL_VALUE_TYPE *);
486 extern void real_ceil (REAL_VALUE_TYPE *, format_helper,
487 const REAL_VALUE_TYPE *);
488 extern void real_round (REAL_VALUE_TYPE *, format_helper,
489 const REAL_VALUE_TYPE *);
490
491 /* Set the sign of R to the sign of X. */
492 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
493
494 /* Check whether the real constant value given is an integer. */
495 extern bool real_isinteger (const REAL_VALUE_TYPE *, format_helper);
496 extern bool real_isinteger (const REAL_VALUE_TYPE *, HOST_WIDE_INT *);
497
498 /* Write into BUF the maximum representable finite floating-point
499 number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
500 float string. BUF must be large enough to contain the result. */
501 extern void get_max_float (const struct real_format *, char *, size_t);
502
503 #ifndef GENERATOR_FILE
504 /* real related routines. */
505 extern wide_int real_to_integer (const REAL_VALUE_TYPE *, bool *, int);
506 extern void real_from_integer (REAL_VALUE_TYPE *, format_helper,
507 const wide_int_ref &, signop);
508 #endif
509
510 #endif /* ! GCC_REAL_H */
511