gcc/real.h

   1 /* Definitions of floating-point access for GNU compiler.
   2    Copyright (C) 1989-2015 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                         : ((MODE) - MIN_MODE_FLOAT)])
 171
 172 #define FLOAT_MODE_FORMAT(MODE) \
 173   (REAL_MODE_FORMAT (SCALAR_FLOAT_MODE_P (MODE)? (MODE) \
 174                                                : GET_MODE_INNER (MODE)))
 175
 176 /* The following macro determines whether the floating point format is
 177    composite, i.e. may contain non-consecutive mantissa bits, in which
 178    case compile-time FP overflow may not model run-time overflow.  */
 179 #define MODE_COMPOSITE_P(MODE) \
 180   (FLOAT_MODE_P (MODE) \
 181    && FLOAT_MODE_FORMAT (MODE)->pnan < FLOAT_MODE_FORMAT (MODE)->p)
 182
 183 /* Accessor macros for format properties.  */
 184 #define MODE_HAS_NANS(MODE) \
 185   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_nans)
 186 #define MODE_HAS_INFINITIES(MODE) \
 187   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_inf)
 188 #define MODE_HAS_SIGNED_ZEROS(MODE) \
 189   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_signed_zero)
 190 #define MODE_HAS_SIGN_DEPENDENT_ROUNDING(MODE) \
 191   (FLOAT_MODE_P (MODE) \
 192    && FLOAT_MODE_FORMAT (MODE)->has_sign_dependent_rounding)
 193
 194 /* Declare functions in real.c.  */
 195
 196 /* True if the given mode has a NaN representation and the treatment of
 197    NaN operands is important.  Certain optimizations, such as folding
 198    x * 0 into 0, are not correct for NaN operands, and are normally
 199    disabled for modes with NaNs.  The user can ask for them to be
 200    done anyway using the -funsafe-math-optimizations switch.  */
 201 extern bool HONOR_NANS (machine_mode);
 202 extern bool HONOR_NANS (const_tree);
 203 extern bool HONOR_NANS (const_rtx);
 204
 205 /* Like HONOR_NANs, but true if we honor signaling NaNs (or sNaNs).  */
 206 extern bool HONOR_SNANS (machine_mode);
 207 extern bool HONOR_SNANS (const_tree);
 208 extern bool HONOR_SNANS (const_rtx);
 209
 210 /* As for HONOR_NANS, but true if the mode can represent infinity and
 211    the treatment of infinite values is important.  */
 212 extern bool HONOR_INFINITIES (machine_mode);
 213 extern bool HONOR_INFINITIES (const_tree);
 214 extern bool HONOR_INFINITIES (const_rtx);
 215
 216 /* Like HONOR_NANS, but true if the given mode distinguishes between
 217    positive and negative zero, and the sign of zero is important.  */
 218 extern bool HONOR_SIGNED_ZEROS (machine_mode);
 219 extern bool HONOR_SIGNED_ZEROS (const_tree);
 220 extern bool HONOR_SIGNED_ZEROS (const_rtx);
 221
 222 /* Like HONOR_NANS, but true if given mode supports sign-dependent rounding,
 223    and the rounding mode is important.  */
 224 extern bool HONOR_SIGN_DEPENDENT_ROUNDING (machine_mode);
 225 extern bool HONOR_SIGN_DEPENDENT_ROUNDING (const_tree);
 226 extern bool HONOR_SIGN_DEPENDENT_ROUNDING (const_rtx);
 227
 228 /* Binary or unary arithmetic on tree_code.  */
 229 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 230                              const REAL_VALUE_TYPE *);
 231
 232 /* Compare reals by tree_code.  */
 233 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 234
 235 /* Determine whether a floating-point value X is infinite.  */
 236 extern bool real_isinf (const REAL_VALUE_TYPE *);
 237
 238 /* Determine whether a floating-point value X is a NaN.  */
 239 extern bool real_isnan (const REAL_VALUE_TYPE *);
 240
 241 /* Determine whether a floating-point value X is finite.  */
 242 extern bool real_isfinite (const REAL_VALUE_TYPE *);
 243
 244 /* Determine whether a floating-point value X is negative.  */
 245 extern bool real_isneg (const REAL_VALUE_TYPE *);
 246
 247 /* Determine whether a floating-point value X is minus zero.  */
 248 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 249
 250 /* Test relationships between reals.  */
 251 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 252 extern bool real_equal (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 253
 254 /* Extend or truncate to a new mode.  */
 255 extern void real_convert (REAL_VALUE_TYPE *, machine_mode,
 256                           const REAL_VALUE_TYPE *);
 257
 258 /* Return true if truncating to NEW is exact.  */
 259 extern bool exact_real_truncate (machine_mode, const REAL_VALUE_TYPE *);
 260
 261 /* Render R as a decimal floating point constant.  */
 262 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 263                              size_t, int);
 264
 265 /* Render R as a decimal floating point constant, rounded so as to be
 266    parsed back to the same value when interpreted in mode MODE.  */
 267 extern void real_to_decimal_for_mode (char *, const REAL_VALUE_TYPE *, size_t,
 268                                       size_t, int, machine_mode);
 269
 270 /* Render R as a hexadecimal floating point constant.  */
 271 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 272                                  size_t, size_t, int);
 273
 274 /* Render R as an integer.  */
 275 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 276
 277 /* Initialize R from a decimal or hexadecimal string.  Return -1 if
 278    the value underflows, +1 if overflows, and 0 otherwise.  */
 279 extern int real_from_string (REAL_VALUE_TYPE *, const char *);
 280 /* Wrapper to allow different internal representation for decimal floats. */
 281 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, machine_mode);
 282
 283 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 284                                 const struct real_format *);
 285 extern long real_to_target (long *, const REAL_VALUE_TYPE *, machine_mode);
 286
 287 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 288                                   const struct real_format *);
 289 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 290                               machine_mode);
 291
 292 extern void real_inf (REAL_VALUE_TYPE *);
 293
 294 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, machine_mode);
 295
 296 extern void real_maxval (REAL_VALUE_TYPE *, int, machine_mode);
 297
 298 extern void real_2expN (REAL_VALUE_TYPE *, int, machine_mode);
 299
 300 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 301
 302
 303 /* Target formats defined in real.c.  */
 304 extern const struct real_format ieee_single_format;
 305 extern const struct real_format mips_single_format;
 306 extern const struct real_format motorola_single_format;
 307 extern const struct real_format spu_single_format;
 308 extern const struct real_format ieee_double_format;
 309 extern const struct real_format mips_double_format;
 310 extern const struct real_format motorola_double_format;
 311 extern const struct real_format ieee_extended_motorola_format;
 312 extern const struct real_format ieee_extended_intel_96_format;
 313 extern const struct real_format ieee_extended_intel_96_round_53_format;
 314 extern const struct real_format ieee_extended_intel_128_format;
 315 extern const struct real_format ibm_extended_format;
 316 extern const struct real_format mips_extended_format;
 317 extern const struct real_format ieee_quad_format;
 318 extern const struct real_format mips_quad_format;
 319 extern const struct real_format vax_f_format;
 320 extern const struct real_format vax_d_format;
 321 extern const struct real_format vax_g_format;
 322 extern const struct real_format real_internal_format;
 323 extern const struct real_format decimal_single_format;
 324 extern const struct real_format decimal_double_format;
 325 extern const struct real_format decimal_quad_format;
 326 extern const struct real_format ieee_half_format;
 327 extern const struct real_format arm_half_format;
 328
 329
 330 /* ====================================================================== */
 331 /* Crap.  */
 332
 333 #define REAL_ARITHMETIC(value, code, d1, d2) \
 334   real_arithmetic (&(value), code, &(d1), &(d2))
 335
 336 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 337
 338 /* Determine whether a floating-point value X is infinite.  */
 339 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 340
 341 /* Determine whether a floating-point value X is a NaN.  */
 342 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 343
 344 /* Determine whether a floating-point value X is negative.  */
 345 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 346
 347 /* Determine whether a floating-point value X is minus zero.  */
 348 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 349
 350 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 351 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 352   real_to_target (OUT, &(IN),                                           \
 353                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 354
 355 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 356   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 357
 358 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 359 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 360   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 361
 362 /* Real values to IEEE 754 decimal floats.  */
 363
 364 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 365 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
 366   real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
 367
 368 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
 369   real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
 370
 371 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 372 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
 373   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
 374
 375 extern REAL_VALUE_TYPE real_value_truncate (machine_mode,
 376                                             REAL_VALUE_TYPE);
 377
 378 extern REAL_VALUE_TYPE real_value_negate (const REAL_VALUE_TYPE *);
 379 extern REAL_VALUE_TYPE real_value_abs (const REAL_VALUE_TYPE *);
 380
 381 extern int significand_size (machine_mode);
 382
 383 extern REAL_VALUE_TYPE real_from_string2 (const char *, machine_mode);
 384
 385 #define REAL_VALUE_ATOF(s, m) \
 386   real_from_string2 (s, m)
 387
 388 #define CONST_DOUBLE_ATOF(s, m) \
 389   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 390
 391 #define REAL_VALUE_FIX(r) \
 392   real_to_integer (&(r))
 393
 394 /* ??? Not quite right.  */
 395 #define REAL_VALUE_UNSIGNED_FIX(r) \
 396   real_to_integer (&(r))
 397
 398 /* ??? These were added for Paranoia support.  */
 399
 400 /* Return floor log2(R).  */
 401 extern int real_exponent (const REAL_VALUE_TYPE *);
 402
 403 /* R = A * 2**EXP.  */
 404 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 405
 406 /* **** End of software floating point emulator interface macros **** */
 407 \f
 408 /* Constant real values 0, 1, 2, -1 and 0.5.  */
 409
 410 extern REAL_VALUE_TYPE dconst0;
 411 extern REAL_VALUE_TYPE dconst1;
 412 extern REAL_VALUE_TYPE dconst2;
 413 extern REAL_VALUE_TYPE dconstm1;
 414 extern REAL_VALUE_TYPE dconsthalf;
 415
 416 #define dconst_e()  (*dconst_e_ptr ())
 417 #define dconst_third()  (*dconst_third_ptr ())
 418 #define dconst_sqrt2()  (*dconst_sqrt2_ptr ())
 419
 420 /* Function to return the real value special constant 'e'.  */
 421 extern const REAL_VALUE_TYPE * dconst_e_ptr (void);
 422
 423 /* Returns the special REAL_VALUE_TYPE corresponding to 1/3.  */
 424 extern const REAL_VALUE_TYPE * dconst_third_ptr (void);
 425
 426 /* Returns the special REAL_VALUE_TYPE corresponding to sqrt(2).  */
 427 extern const REAL_VALUE_TYPE * dconst_sqrt2_ptr (void);
 428
 429 /* Function to return a real value (not a tree node)
 430    from a given integer constant.  */
 431 REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
 432
 433 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 434 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 435   ((to) = *CONST_DOUBLE_REAL_VALUE (from))
 436
 437 /* Return a CONST_DOUBLE with value R and mode M.  */
 438 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 439   const_double_from_real_value (r, m)
 440 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, machine_mode);
 441
 442 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 443 extern bool exact_real_inverse (machine_mode, REAL_VALUE_TYPE *);
 444
 445 /* Return true if arithmetic on values in IMODE that were promoted
 446    from values in TMODE is equivalent to direct arithmetic on values
 447    in TMODE.  */
 448 bool real_can_shorten_arithmetic (machine_mode, machine_mode);
 449
 450 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 451 extern tree build_real (tree, REAL_VALUE_TYPE);
 452
 453 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 454 extern bool real_powi (REAL_VALUE_TYPE *, machine_mode,
 455                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 456
 457 /* Standard round to integer value functions.  */
 458 extern void real_trunc (REAL_VALUE_TYPE *, machine_mode,
 459                         const REAL_VALUE_TYPE *);
 460 extern void real_floor (REAL_VALUE_TYPE *, machine_mode,
 461                         const REAL_VALUE_TYPE *);
 462 extern void real_ceil (REAL_VALUE_TYPE *, machine_mode,
 463                        const REAL_VALUE_TYPE *);
 464 extern void real_round (REAL_VALUE_TYPE *, machine_mode,
 465                         const REAL_VALUE_TYPE *);
 466
 467 /* Set the sign of R to the sign of X.  */
 468 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 469
 470 /* Check whether the real constant value given is an integer.  */
 471 extern bool real_isinteger (const REAL_VALUE_TYPE *c, machine_mode mode);
 472
 473 /* Write into BUF the maximum representable finite floating-point
 474    number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
 475    float string.  BUF must be large enough to contain the result.  */
 476 extern void get_max_float (const struct real_format *, char *, size_t);
 477
 478 #ifndef GENERATOR_FILE
 479 /* real related routines.  */
 480 extern wide_int real_to_integer (const REAL_VALUE_TYPE *, bool *, int);
 481 extern void real_from_integer (REAL_VALUE_TYPE *, machine_mode,
 482                                const wide_int_ref &, signop);
 483 #endif
 484
 485 #endif /* ! GCC_REAL_H */