gcc/real.h

   1 /* Definitions of floating-point access for GNU compiler.
   2    Copyright (C) 1989, 1991, 1994, 1996, 1997, 1998, 1999,
   3    2000, 2002, 2003, 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
   4
   5    This file is part of GCC.
   6
   7    GCC is free software; you can redistribute it and/or modify it under
   8    the terms of the GNU General Public License as published by the Free
   9    Software Foundation; either version 3, or (at your option) any later
  10    version.
  11
  12    GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13    WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15    for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GCC; see the file COPYING3.  If not see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GCC_REAL_H
  22 #define GCC_REAL_H
  23
  24 #ifndef GENERATOR_FILE
  25 #include <gmp.h>
  26 #include <mpfr.h>
  27 #endif
  28 #include "machmode.h"
  29
  30 /* An expanded form of the represented number.  */
  31
  32 /* Enumerate the special cases of numbers that we encounter.  */
  33 enum real_value_class {
  34   rvc_zero,
  35   rvc_normal,
  36   rvc_inf,
  37   rvc_nan
  38 };
  39
  40 #define SIGNIFICAND_BITS        (128 + HOST_BITS_PER_LONG)
  41 #define EXP_BITS                (32 - 6)
  42 #define MAX_EXP                 ((1 << (EXP_BITS - 1)) - 1)
  43 #define SIGSZ                   (SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
  44 #define SIG_MSB                 ((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
  45
  46 struct GTY(()) real_value {
  47   /* Use the same underlying type for all bit-fields, so as to make
  48      sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
  49      be miscomputed.  */
  50   unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
  51   unsigned int decimal : 1;
  52   unsigned int sign : 1;
  53   unsigned int signalling : 1;
  54   unsigned int canonical : 1;
  55   unsigned int uexp : EXP_BITS;
  56   unsigned long sig[SIGSZ];
  57 };
  58
  59 #define REAL_EXP(REAL) \
  60   ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
  61    - (1 << (EXP_BITS - 1)))
  62 #define SET_REAL_EXP(REAL, EXP) \
  63   ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
  64
  65 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  66    needs to be a macro.  We do need to continue to have a structure tag
  67    so that other headers can forward declare it.  */
  68 #define REAL_VALUE_TYPE struct real_value
  69
  70 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  71    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  72    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  73
  74 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  75 #define REAL_WIDTH \
  76   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  77    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  78
  79 /* Verify the guess.  */
  80 extern char test_real_width
  81   [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
  82
  83 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  84    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  85    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  86
  87    A number of places assume that there are always at least two 'w'
  88    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  89
  90 #if REAL_WIDTH == 1
  91 # define CONST_DOUBLE_FORMAT     "ww"
  92 #else
  93 # if REAL_WIDTH == 2
  94 #  define CONST_DOUBLE_FORMAT    "ww"
  95 # else
  96 #  if REAL_WIDTH == 3
  97 #   define CONST_DOUBLE_FORMAT   "www"
  98 #  else
  99 #   if REAL_WIDTH == 4
 100 #    define CONST_DOUBLE_FORMAT  "wwww"
 101 #   else
 102 #    if REAL_WIDTH == 5
 103 #     define CONST_DOUBLE_FORMAT "wwwww"
 104 #    else
 105 #     if REAL_WIDTH == 6
 106 #      define CONST_DOUBLE_FORMAT "wwwwww"
 107 #     else
 108        #error "REAL_WIDTH > 6 not supported"
 109 #     endif
 110 #    endif
 111 #   endif
 112 #  endif
 113 # endif
 114 #endif
 115
 116
 117 /* Describes the properties of the specific target format in use.  */
 118 struct real_format
 119 {
 120   /* Move to and from the target bytes.  */
 121   void (*encode) (const struct real_format *, long *,
 122                   const REAL_VALUE_TYPE *);
 123   void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
 124                   const long *);
 125
 126   /* The radix of the exponent and digits of the significand.  */
 127   int b;
 128
 129   /* Size of the significand in digits of radix B.  */
 130   int p;
 131
 132   /* Size of the significant of a NaN, in digits of radix B.  */
 133   int pnan;
 134
 135   /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
 136   int emin;
 137
 138   /* The maximum integer, x, such that b**(x-1) is representable.  */
 139   int emax;
 140
 141   /* The bit position of the sign bit, for determining whether a value
 142      is positive/negative, or -1 for a complex encoding.  */
 143   int signbit_ro;
 144
 145   /* The bit position of the sign bit, for changing the sign of a number,
 146      or -1 for a complex encoding.  */
 147   int signbit_rw;
 148
 149   /* Default rounding mode for operations on this format.  */
 150   bool round_towards_zero;
 151   bool has_sign_dependent_rounding;
 152
 153   /* Properties of the format.  */
 154   bool has_nans;
 155   bool has_inf;
 156   bool has_denorm;
 157   bool has_signed_zero;
 158   bool qnan_msb_set;
 159   bool canonical_nan_lsbs_set;
 160 };
 161
 162
 163 /* The target format used for each floating point mode.
 164    Float modes are followed by decimal float modes, with entries for
 165    float modes indexed by (MODE - first float mode), and entries for
 166    decimal float modes indexed by (MODE - first decimal float mode) +
 167    the number of float modes.  */
 168 extern const struct real_format *
 169   real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
 170                        + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
 171
 172 #define REAL_MODE_FORMAT(MODE)                                          \
 173   (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)                     \
 174                         ? (((MODE) - MIN_MODE_DECIMAL_FLOAT)            \
 175                            + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))     \
 176                         : ((MODE) - MIN_MODE_FLOAT)])
 177
 178 #define FLOAT_MODE_FORMAT(MODE) \
 179   (REAL_MODE_FORMAT (SCALAR_FLOAT_MODE_P (MODE)? (MODE) \
 180                                                : GET_MODE_INNER (MODE)))
 181
 182 /* The following macro determines whether the floating point format is
 183    composite, i.e. may contain non-consecutive mantissa bits, in which
 184    case compile-time FP overflow may not model run-time overflow.  */
 185 #define MODE_COMPOSITE_P(MODE) \
 186   (FLOAT_MODE_P (MODE) \
 187    && FLOAT_MODE_FORMAT (MODE)->pnan < FLOAT_MODE_FORMAT (MODE)->p)
 188
 189 /* Accessor macros for format properties.  */
 190 #define MODE_HAS_NANS(MODE) \
 191   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_nans)
 192 #define MODE_HAS_INFINITIES(MODE) \
 193   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_inf)
 194 #define MODE_HAS_SIGNED_ZEROS(MODE) \
 195   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_signed_zero)
 196 #define MODE_HAS_SIGN_DEPENDENT_ROUNDING(MODE) \
 197   (FLOAT_MODE_P (MODE) \
 198    && FLOAT_MODE_FORMAT (MODE)->has_sign_dependent_rounding)
 199
 200
 201 /* Declare functions in real.c.  */
 202
 203 /* Binary or unary arithmetic on tree_code.  */
 204 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 205                              const REAL_VALUE_TYPE *);
 206
 207 /* Compare reals by tree_code.  */
 208 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 209
 210 /* Determine whether a floating-point value X is infinite.  */
 211 extern bool real_isinf (const REAL_VALUE_TYPE *);
 212
 213 /* Determine whether a floating-point value X is a NaN.  */
 214 extern bool real_isnan (const REAL_VALUE_TYPE *);
 215
 216 /* Determine whether a floating-point value X is finite.  */
 217 extern bool real_isfinite (const REAL_VALUE_TYPE *);
 218
 219 /* Determine whether a floating-point value X is negative.  */
 220 extern bool real_isneg (const REAL_VALUE_TYPE *);
 221
 222 /* Determine whether a floating-point value X is minus zero.  */
 223 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 224
 225 /* Compare two floating-point objects for bitwise identity.  */
 226 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 227
 228 /* Extend or truncate to a new mode.  */
 229 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 230                           const REAL_VALUE_TYPE *);
 231
 232 /* Return true if truncating to NEW is exact.  */
 233 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 234
 235 /* Render R as a decimal floating point constant.  */
 236 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 237                              size_t, int);
 238
 239 /* Render R as a decimal floating point constant, rounded so as to be
 240    parsed back to the same value when interpreted in mode MODE.  */
 241 extern void real_to_decimal_for_mode (char *, const REAL_VALUE_TYPE *, size_t,
 242                                       size_t, int, enum machine_mode);
 243
 244 /* Render R as a hexadecimal floating point constant.  */
 245 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 246                                  size_t, size_t, int);
 247
 248 /* Render R as an integer.  */
 249 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 250 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 251                               const REAL_VALUE_TYPE *);
 252
 253 /* Initialize R from a decimal or hexadecimal string.  Return -1 if
 254    the value underflows, +1 if overflows, and 0 otherwise.  */
 255 extern int real_from_string (REAL_VALUE_TYPE *, const char *);
 256 /* Wrapper to allow different internal representation for decimal floats. */
 257 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
 258
 259 /* Initialize R from an integer pair HIGH/LOW.  */
 260 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 261                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 262
 263 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 264                                 const struct real_format *);
 265 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 266
 267 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 268                                   const struct real_format *);
 269 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 270                               enum machine_mode);
 271
 272 extern void real_inf (REAL_VALUE_TYPE *);
 273
 274 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 275
 276 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 277
 278 extern void real_2expN (REAL_VALUE_TYPE *, int, enum machine_mode);
 279
 280 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 281
 282
 283 /* Target formats defined in real.c.  */
 284 extern const struct real_format ieee_single_format;
 285 extern const struct real_format mips_single_format;
 286 extern const struct real_format motorola_single_format;
 287 extern const struct real_format spu_single_format;
 288 extern const struct real_format ieee_double_format;
 289 extern const struct real_format mips_double_format;
 290 extern const struct real_format motorola_double_format;
 291 extern const struct real_format ieee_extended_motorola_format;
 292 extern const struct real_format ieee_extended_intel_96_format;
 293 extern const struct real_format ieee_extended_intel_96_round_53_format;
 294 extern const struct real_format ieee_extended_intel_128_format;
 295 extern const struct real_format ibm_extended_format;
 296 extern const struct real_format mips_extended_format;
 297 extern const struct real_format ieee_quad_format;
 298 extern const struct real_format mips_quad_format;
 299 extern const struct real_format vax_f_format;
 300 extern const struct real_format vax_d_format;
 301 extern const struct real_format vax_g_format;
 302 extern const struct real_format real_internal_format;
 303 extern const struct real_format decimal_single_format;
 304 extern const struct real_format decimal_double_format;
 305 extern const struct real_format decimal_quad_format;
 306
 307
 308 /* ====================================================================== */
 309 /* Crap.  */
 310
 311 #define REAL_ARITHMETIC(value, code, d1, d2) \
 312   real_arithmetic (&(value), code, &(d1), &(d2))
 313
 314 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 315 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 316 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 317
 318 /* Determine whether a floating-point value X is infinite.  */
 319 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 320
 321 /* Determine whether a floating-point value X is a NaN.  */
 322 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 323
 324 /* Determine whether a floating-point value X is negative.  */
 325 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 326
 327 /* Determine whether a floating-point value X is minus zero.  */
 328 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 329
 330 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 331 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 332   real_to_target (OUT, &(IN),                                           \
 333                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 334
 335 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 336   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 337
 338 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 339 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 340   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 341
 342 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 343   real_from_integer (&(r), mode, lo, hi, 0)
 344
 345 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 346   real_from_integer (&(r), mode, lo, hi, 1)
 347
 348 /* Real values to IEEE 754 decimal floats.  */
 349
 350 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 351 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
 352   real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
 353
 354 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
 355   real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
 356
 357 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 358 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
 359   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
 360
 361 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 362                                             REAL_VALUE_TYPE);
 363
 364 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 365   real_to_integer2 (plow, phigh, &(r))
 366
 367 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 368                                          const REAL_VALUE_TYPE *);
 369
 370 #define REAL_VALUE_NEGATE(X) \
 371   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 372
 373 #define REAL_VALUE_ABS(X) \
 374   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 375
 376 extern int significand_size (enum machine_mode);
 377
 378 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
 379
 380 #define REAL_VALUE_ATOF(s, m) \
 381   real_from_string2 (s, m)
 382
 383 #define CONST_DOUBLE_ATOF(s, m) \
 384   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 385
 386 #define REAL_VALUE_FIX(r) \
 387   real_to_integer (&(r))
 388
 389 /* ??? Not quite right.  */
 390 #define REAL_VALUE_UNSIGNED_FIX(r) \
 391   real_to_integer (&(r))
 392
 393 /* ??? These were added for Paranoia support.  */
 394
 395 /* Return floor log2(R).  */
 396 extern int real_exponent (const REAL_VALUE_TYPE *);
 397
 398 /* R = A * 2**EXP.  */
 399 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 400
 401 /* **** End of software floating point emulator interface macros **** */
 402 \f
 403 /* Constant real values 0, 1, 2, -1 and 0.5.  */
 404
 405 extern REAL_VALUE_TYPE dconst0;
 406 extern REAL_VALUE_TYPE dconst1;
 407 extern REAL_VALUE_TYPE dconst2;
 408 extern REAL_VALUE_TYPE dconstm1;
 409 extern REAL_VALUE_TYPE dconsthalf;
 410
 411 #define dconst_e()  (*dconst_e_ptr ())
 412 #define dconst_third()  (*dconst_third_ptr ())
 413 #define dconst_sqrt2()  (*dconst_sqrt2_ptr ())
 414
 415 /* Function to return the real value special constant 'e'.  */
 416 extern const REAL_VALUE_TYPE * dconst_e_ptr (void);
 417
 418 /* Returns the special REAL_VALUE_TYPE corresponding to 1/3.  */
 419 extern const REAL_VALUE_TYPE * dconst_third_ptr (void);
 420
 421 /* Returns the special REAL_VALUE_TYPE corresponding to sqrt(2).  */
 422 extern const REAL_VALUE_TYPE * dconst_sqrt2_ptr (void);
 423
 424 /* Function to return a real value (not a tree node)
 425    from a given integer constant.  */
 426 REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
 427
 428 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 429 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 430   ((to) = *CONST_DOUBLE_REAL_VALUE (from))
 431
 432 /* Return a CONST_DOUBLE with value R and mode M.  */
 433 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 434   const_double_from_real_value (r, m)
 435 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 436
 437 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 438 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 439
 440 /* Return true if arithmetic on values in IMODE that were promoted
 441    from values in TMODE is equivalent to direct arithmetic on values
 442    in TMODE.  */
 443 bool real_can_shorten_arithmetic (enum machine_mode, enum machine_mode);
 444
 445 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 446 extern tree build_real (tree, REAL_VALUE_TYPE);
 447
 448 /* Calculate R as the square root of X in the given machine mode.  */
 449 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 450                        const REAL_VALUE_TYPE *);
 451
 452 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 453 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 454                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 455
 456 /* Standard round to integer value functions.  */
 457 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 458                         const REAL_VALUE_TYPE *);
 459 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 460                         const REAL_VALUE_TYPE *);
 461 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 462                        const REAL_VALUE_TYPE *);
 463 extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
 464                         const REAL_VALUE_TYPE *);
 465
 466 /* Set the sign of R to the sign of X.  */
 467 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 468
 469 #ifndef GENERATOR_FILE
 470 /* Convert between MPFR and REAL_VALUE_TYPE.  The caller is
 471    responsible for initializing and clearing the MPFR parameter.  */
 472
 473 extern void real_from_mpfr (REAL_VALUE_TYPE *, mpfr_srcptr, tree, mp_rnd_t);
 474 extern void mpfr_from_real (mpfr_ptr, const REAL_VALUE_TYPE *, mp_rnd_t);
 475 #endif
 476
 477 /* Check whether the real constant value given is an integer.  */
 478 extern bool real_isinteger (const REAL_VALUE_TYPE *c, enum machine_mode mode);
 479
 480 /* Write into BUF the maximum representable finite floating-point
 481    number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
 482    float string.  BUF must be large enough to contain the result.  */
 483 extern void get_max_float (const struct real_format *, char *, size_t);
 484 #endif /* ! GCC_REAL_H */