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 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 #include <gmp.h>
  25 #include <mpfr.h>
  26 #include "machmode.h"
  27
  28 /* An expanded form of the represented number.  */
  29
  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
  36 };
  37
  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))
  43
  44 struct real_value GTY(())
  45 {
  46   /* Use the same underlying type for all bit-fields, so as to make
  47      sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
  48      be miscomputed.  */
  49   unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
  50   unsigned int decimal : 1;
  51   unsigned int sign : 1;
  52   unsigned int signalling : 1;
  53   unsigned int canonical : 1;
  54   unsigned int uexp : EXP_BITS;
  55   unsigned long sig[SIGSZ];
  56 };
  57
  58 #define REAL_EXP(REAL) \
  59   ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
  60    - (1 << (EXP_BITS - 1)))
  61 #define SET_REAL_EXP(REAL, EXP) \
  62   ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
  63
  64 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  65    needs to be a macro.  We do need to continue to have a structure tag
  66    so that other headers can forward declare it.  */
  67 #define REAL_VALUE_TYPE struct real_value
  68
  69 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  70    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  71    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  72
  73 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  74 #define REAL_WIDTH \
  75   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  76    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  77
  78 /* Verify the guess.  */
  79 extern char test_real_width
  80   [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
  81
  82 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  83    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  84    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  85
  86    A number of places assume that there are always at least two 'w'
  87    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  88
  89 #if REAL_WIDTH == 1
  90 # define CONST_DOUBLE_FORMAT     "ww"
  91 #else
  92 # if REAL_WIDTH == 2
  93 #  define CONST_DOUBLE_FORMAT    "ww"
  94 # else
  95 #  if REAL_WIDTH == 3
  96 #   define CONST_DOUBLE_FORMAT   "www"
  97 #  else
  98 #   if REAL_WIDTH == 4
  99 #    define CONST_DOUBLE_FORMAT  "wwww"
 100 #   else
 101 #    if REAL_WIDTH == 5
 102 #     define CONST_DOUBLE_FORMAT "wwwww"
 103 #    else
 104 #     if REAL_WIDTH == 6
 105 #      define CONST_DOUBLE_FORMAT "wwwwww"
 106 #     else
 107        #error "REAL_WIDTH > 6 not supported"
 108 #     endif
 109 #    endif
 110 #   endif
 111 #  endif
 112 # endif
 113 #endif
 114
 115
 116 /* Describes the properties of the specific target format in use.  */
 117 struct real_format
 118 {
 119   /* Move to and from the target bytes.  */
 120   void (*encode) (const struct real_format *, long *,
 121                   const REAL_VALUE_TYPE *);
 122   void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
 123                   const long *);
 124
 125   /* The radix of the exponent and digits of the significand.  */
 126   int b;
 127
 128   /* Size of the significand in digits of radix B.  */
 129   int p;
 130
 131   /* Size of the significant of a NaN, in digits of radix B.  */
 132   int pnan;
 133
 134   /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
 135   int emin;
 136
 137   /* The maximum integer, x, such that b**(x-1) is representable.  */
 138   int emax;
 139
 140   /* The bit position of the sign bit, for determining whether a value
 141      is positive/negative, or -1 for a complex encoding.  */
 142   int signbit_ro;
 143
 144   /* The bit position of the sign bit, for changing the sign of a number,
 145      or -1 for a complex encoding.  */
 146   int signbit_rw;
 147
 148   /* Properties of the format.  */
 149   bool has_nans;
 150   bool has_inf;
 151   bool has_denorm;
 152   bool has_signed_zero;
 153   bool qnan_msb_set;
 154   bool canonical_nan_lsbs_set;
 155 };
 156
 157
 158 /* The target format used for each floating point mode.
 159    Float modes are followed by decimal float modes, with entries for
 160    float modes indexed by (MODE - first float mode), and entries for
 161    decimal float modes indexed by (MODE - first decimal float mode) +
 162    the number of float modes.  */
 163 extern const struct real_format *
 164   real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
 165                        + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
 166
 167 #define REAL_MODE_FORMAT(MODE)                                          \
 168   (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)                     \
 169                         ? ((MODE - MIN_MODE_DECIMAL_FLOAT)              \
 170                            + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))     \
 171                         : (MODE - MIN_MODE_FLOAT)])
 172
 173 /* The following macro determines whether the floating point format is
 174    composite, i.e. may contain non-consecutive mantissa bits, in which
 175    case compile-time FP overflow may not model run-time overflow.  */
 176 #define REAL_MODE_FORMAT_COMPOSITE_P(MODE) \
 177         ((REAL_MODE_FORMAT(MODE))->pnan < (REAL_MODE_FORMAT (MODE))->p)
 178
 179 /* Declare functions in real.c.  */
 180
 181 /* Binary or unary arithmetic on tree_code.  */
 182 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 183                              const REAL_VALUE_TYPE *);
 184
 185 /* Compare reals by tree_code.  */
 186 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 187
 188 /* Determine whether a floating-point value X is infinite.  */
 189 extern bool real_isinf (const REAL_VALUE_TYPE *);
 190
 191 /* Determine whether a floating-point value X is a NaN.  */
 192 extern bool real_isnan (const REAL_VALUE_TYPE *);
 193
 194 /* Determine whether a floating-point value X is finite.  */
 195 extern bool real_isfinite (const REAL_VALUE_TYPE *);
 196
 197 /* Determine whether a floating-point value X is negative.  */
 198 extern bool real_isneg (const REAL_VALUE_TYPE *);
 199
 200 /* Determine whether a floating-point value X is minus zero.  */
 201 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 202
 203 /* Compare two floating-point objects for bitwise identity.  */
 204 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 205
 206 /* Extend or truncate to a new mode.  */
 207 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 208                           const REAL_VALUE_TYPE *);
 209
 210 /* Return true if truncating to NEW is exact.  */
 211 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 212
 213 /* Render R as a decimal floating point constant.  */
 214 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 215                              size_t, int);
 216
 217 /* Render R as a hexadecimal floating point constant.  */
 218 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 219                                  size_t, size_t, int);
 220
 221 /* Render R as an integer.  */
 222 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 223 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 224                               const REAL_VALUE_TYPE *);
 225
 226 /* Initialize R from a decimal or hexadecimal string.  Return -1 if
 227    the value underflows, +1 if overflows, and 0 otherwise.  */
 228 extern int real_from_string (REAL_VALUE_TYPE *, const char *);
 229 /* Wrapper to allow different internal representation for decimal floats. */
 230 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
 231
 232 /* Initialize R from an integer pair HIGH/LOW.  */
 233 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 234                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 235
 236 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 237                                 const struct real_format *);
 238 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 239
 240 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 241                                   const struct real_format *);
 242 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 243                               enum machine_mode);
 244
 245 extern void real_inf (REAL_VALUE_TYPE *);
 246
 247 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 248
 249 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 250
 251 extern void real_2expN (REAL_VALUE_TYPE *, int, enum machine_mode);
 252
 253 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 254
 255
 256 /* Target formats defined in real.c.  */
 257 extern const struct real_format ieee_single_format;
 258 extern const struct real_format mips_single_format;
 259 extern const struct real_format motorola_single_format;
 260 extern const struct real_format ieee_double_format;
 261 extern const struct real_format mips_double_format;
 262 extern const struct real_format motorola_double_format;
 263 extern const struct real_format ieee_extended_motorola_format;
 264 extern const struct real_format ieee_extended_intel_96_format;
 265 extern const struct real_format ieee_extended_intel_96_round_53_format;
 266 extern const struct real_format ieee_extended_intel_128_format;
 267 extern const struct real_format ibm_extended_format;
 268 extern const struct real_format mips_extended_format;
 269 extern const struct real_format ieee_quad_format;
 270 extern const struct real_format mips_quad_format;
 271 extern const struct real_format vax_f_format;
 272 extern const struct real_format vax_d_format;
 273 extern const struct real_format vax_g_format;
 274 extern const struct real_format c4x_single_format;
 275 extern const struct real_format c4x_extended_format;
 276 extern const struct real_format real_internal_format;
 277 extern const struct real_format decimal_single_format;
 278 extern const struct real_format decimal_double_format;
 279 extern const struct real_format decimal_quad_format;
 280
 281
 282 /* ====================================================================== */
 283 /* Crap.  */
 284
 285 #define REAL_ARITHMETIC(value, code, d1, d2) \
 286   real_arithmetic (&(value), code, &(d1), &(d2))
 287
 288 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 289 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 290 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 291
 292 /* Determine whether a floating-point value X is infinite.  */
 293 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 294
 295 /* Determine whether a floating-point value X is a NaN.  */
 296 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 297
 298 /* Determine whether a floating-point value X is negative.  */
 299 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 300
 301 /* Determine whether a floating-point value X is minus zero.  */
 302 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 303
 304 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 305 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 306   real_to_target (OUT, &(IN),                                           \
 307                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 308
 309 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 310   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 311
 312 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 313 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 314   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 315
 316 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 317   real_from_integer (&(r), mode, lo, hi, 0)
 318
 319 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 320   real_from_integer (&(r), mode, lo, hi, 1)
 321
 322 /* Real values to IEEE 754R decimal floats.  */
 323
 324 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 325 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
 326   real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
 327
 328 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
 329   real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
 330
 331 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 332 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
 333   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
 334
 335 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 336                                             REAL_VALUE_TYPE);
 337
 338 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 339   real_to_integer2 (plow, phigh, &(r))
 340
 341 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 342                                          const REAL_VALUE_TYPE *);
 343
 344 #define REAL_VALUE_NEGATE(X) \
 345   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 346
 347 #define REAL_VALUE_ABS(X) \
 348   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 349
 350 extern int significand_size (enum machine_mode);
 351
 352 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
 353
 354 #define REAL_VALUE_ATOF(s, m) \
 355   real_from_string2 (s, m)
 356
 357 #define CONST_DOUBLE_ATOF(s, m) \
 358   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 359
 360 #define REAL_VALUE_FIX(r) \
 361   real_to_integer (&(r))
 362
 363 /* ??? Not quite right.  */
 364 #define REAL_VALUE_UNSIGNED_FIX(r) \
 365   real_to_integer (&(r))
 366
 367 /* ??? These were added for Paranoia support.  */
 368
 369 /* Return floor log2(R).  */
 370 extern int real_exponent (const REAL_VALUE_TYPE *);
 371
 372 /* R = A * 2**EXP.  */
 373 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 374
 375 /* **** End of software floating point emulator interface macros **** */
 376 \f
 377 /* Constant real values 0, 1, 2, 3, 10, -1, -2, 0.5 and 1/3.  */
 378
 379 extern REAL_VALUE_TYPE dconst0;
 380 extern REAL_VALUE_TYPE dconst1;
 381 extern REAL_VALUE_TYPE dconst2;
 382 extern REAL_VALUE_TYPE dconst3;
 383 extern REAL_VALUE_TYPE dconst10;
 384 extern REAL_VALUE_TYPE dconstm1;
 385 extern REAL_VALUE_TYPE dconstm2;
 386 extern REAL_VALUE_TYPE dconsthalf;
 387 extern REAL_VALUE_TYPE dconstthird;
 388 extern REAL_VALUE_TYPE dconstsqrt2;
 389 extern REAL_VALUE_TYPE dconste;
 390
 391 /* Function to return a real value (not a tree node)
 392    from a given integer constant.  */
 393 REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
 394
 395 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 396 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 397   ((to) = *CONST_DOUBLE_REAL_VALUE (from))
 398
 399 /* Return a CONST_DOUBLE with value R and mode M.  */
 400 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 401   const_double_from_real_value (r, m)
 402 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 403
 404 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 405 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 406
 407 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 408 extern tree build_real (tree, REAL_VALUE_TYPE);
 409
 410 /* Calculate R as the square root of X in the given machine mode.  */
 411 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 412                        const REAL_VALUE_TYPE *);
 413
 414 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 415 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 416                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 417
 418 /* Standard round to integer value functions.  */
 419 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 420                         const REAL_VALUE_TYPE *);
 421 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 422                         const REAL_VALUE_TYPE *);
 423 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 424                        const REAL_VALUE_TYPE *);
 425 extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
 426                         const REAL_VALUE_TYPE *);
 427
 428 /* Set the sign of R to the sign of X.  */
 429 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 430
 431 /* Convert between MPFR and REAL_VALUE_TYPE.  The caller is
 432    responsible for initializing and clearing the MPFR parameter.  */
 433
 434 extern void real_from_mpfr (REAL_VALUE_TYPE *, mpfr_srcptr, tree, mp_rnd_t);
 435 extern void mpfr_from_real (mpfr_ptr, const REAL_VALUE_TYPE *, mp_rnd_t);
 436
 437 /* Check whether the real constant value given is an integer.  */
 438 extern bool real_isinteger (const REAL_VALUE_TYPE *c, enum machine_mode mode);
 439
 440 /* Write into BUF the maximum representable finite floating-point
 441    number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
 442    float string.  BUF must be large enough to contain the result.  */
 443 extern void get_max_float (const struct real_format *, char *, size_t);
 444 #endif /* ! GCC_REAL_H */