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 real_value GTY(())
  47 {
  48   /* Use the same underlying type for all bit-fields, so as to make
  49      sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
  50      be miscomputed.  */
  51   unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
  52   unsigned int decimal : 1;
  53   unsigned int sign : 1;
  54   unsigned int signalling : 1;
  55   unsigned int canonical : 1;
  56   unsigned int uexp : EXP_BITS;
  57   unsigned long sig[SIGSZ];
  58 };
  59
  60 #define REAL_EXP(REAL) \
  61   ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
  62    - (1 << (EXP_BITS - 1)))
  63 #define SET_REAL_EXP(REAL, EXP) \
  64   ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
  65
  66 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  67    needs to be a macro.  We do need to continue to have a structure tag
  68    so that other headers can forward declare it.  */
  69 #define REAL_VALUE_TYPE struct real_value
  70
  71 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  72    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  73    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  74
  75 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  76 #define REAL_WIDTH \
  77   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  78    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  79
  80 /* Verify the guess.  */
  81 extern char test_real_width
  82   [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
  83
  84 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  85    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  86    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  87
  88    A number of places assume that there are always at least two 'w'
  89    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  90
  91 #if REAL_WIDTH == 1
  92 # define CONST_DOUBLE_FORMAT     "ww"
  93 #else
  94 # if REAL_WIDTH == 2
  95 #  define CONST_DOUBLE_FORMAT    "ww"
  96 # else
  97 #  if REAL_WIDTH == 3
  98 #   define CONST_DOUBLE_FORMAT   "www"
  99 #  else
 100 #   if REAL_WIDTH == 4
 101 #    define CONST_DOUBLE_FORMAT  "wwww"
 102 #   else
 103 #    if REAL_WIDTH == 5
 104 #     define CONST_DOUBLE_FORMAT "wwwww"
 105 #    else
 106 #     if REAL_WIDTH == 6
 107 #      define CONST_DOUBLE_FORMAT "wwwwww"
 108 #     else
 109        #error "REAL_WIDTH > 6 not supported"
 110 #     endif
 111 #    endif
 112 #   endif
 113 #  endif
 114 # endif
 115 #endif
 116
 117
 118 /* Describes the properties of the specific target format in use.  */
 119 struct real_format
 120 {
 121   /* Move to and from the target bytes.  */
 122   void (*encode) (const struct real_format *, long *,
 123                   const REAL_VALUE_TYPE *);
 124   void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
 125                   const long *);
 126
 127   /* The radix of the exponent and digits of the significand.  */
 128   int b;
 129
 130   /* Size of the significand in digits of radix B.  */
 131   int p;
 132
 133   /* Size of the significant of a NaN, in digits of radix B.  */
 134   int pnan;
 135
 136   /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
 137   int emin;
 138
 139   /* The maximum integer, x, such that b**(x-1) is representable.  */
 140   int emax;
 141
 142   /* The bit position of the sign bit, for determining whether a value
 143      is positive/negative, or -1 for a complex encoding.  */
 144   int signbit_ro;
 145
 146   /* The bit position of the sign bit, for changing the sign of a number,
 147      or -1 for a complex encoding.  */
 148   int signbit_rw;
 149
 150   /* Properties of the format.  */
 151   bool has_nans;
 152   bool has_inf;
 153   bool has_denorm;
 154   bool has_signed_zero;
 155   bool qnan_msb_set;
 156   bool canonical_nan_lsbs_set;
 157 };
 158
 159
 160 /* The target format used for each floating point mode.
 161    Float modes are followed by decimal float modes, with entries for
 162    float modes indexed by (MODE - first float mode), and entries for
 163    decimal float modes indexed by (MODE - first decimal float mode) +
 164    the number of float modes.  */
 165 extern const struct real_format *
 166   real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
 167                        + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
 168
 169 #define REAL_MODE_FORMAT(MODE)                                          \
 170   (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)                     \
 171                         ? ((MODE - MIN_MODE_DECIMAL_FLOAT)              \
 172                            + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))     \
 173                         : (MODE - MIN_MODE_FLOAT)])
 174
 175 /* The following macro determines whether the floating point format is
 176    composite, i.e. may contain non-consecutive mantissa bits, in which
 177    case compile-time FP overflow may not model run-time overflow.  */
 178 #define REAL_MODE_FORMAT_COMPOSITE_P(MODE) \
 179         ((REAL_MODE_FORMAT(MODE))->pnan < (REAL_MODE_FORMAT (MODE))->p)
 180
 181 /* Declare functions in real.c.  */
 182
 183 /* Binary or unary arithmetic on tree_code.  */
 184 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 185                              const REAL_VALUE_TYPE *);
 186
 187 /* Compare reals by tree_code.  */
 188 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 189
 190 /* Determine whether a floating-point value X is infinite.  */
 191 extern bool real_isinf (const REAL_VALUE_TYPE *);
 192
 193 /* Determine whether a floating-point value X is a NaN.  */
 194 extern bool real_isnan (const REAL_VALUE_TYPE *);
 195
 196 /* Determine whether a floating-point value X is finite.  */
 197 extern bool real_isfinite (const REAL_VALUE_TYPE *);
 198
 199 /* Determine whether a floating-point value X is negative.  */
 200 extern bool real_isneg (const REAL_VALUE_TYPE *);
 201
 202 /* Determine whether a floating-point value X is minus zero.  */
 203 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 204
 205 /* Compare two floating-point objects for bitwise identity.  */
 206 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 207
 208 /* Extend or truncate to a new mode.  */
 209 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 210                           const REAL_VALUE_TYPE *);
 211
 212 /* Return true if truncating to NEW is exact.  */
 213 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 214
 215 /* Render R as a decimal floating point constant.  */
 216 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 217                              size_t, int);
 218
 219 /* Render R as a hexadecimal floating point constant.  */
 220 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 221                                  size_t, size_t, int);
 222
 223 /* Render R as an integer.  */
 224 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 225 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 226                               const REAL_VALUE_TYPE *);
 227
 228 /* Initialize R from a decimal or hexadecimal string.  Return -1 if
 229    the value underflows, +1 if overflows, and 0 otherwise.  */
 230 extern int real_from_string (REAL_VALUE_TYPE *, const char *);
 231 /* Wrapper to allow different internal representation for decimal floats. */
 232 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
 233
 234 /* Initialize R from an integer pair HIGH/LOW.  */
 235 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 236                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 237
 238 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 239                                 const struct real_format *);
 240 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 241
 242 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 243                                   const struct real_format *);
 244 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 245                               enum machine_mode);
 246
 247 extern void real_inf (REAL_VALUE_TYPE *);
 248
 249 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 250
 251 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 252
 253 extern void real_2expN (REAL_VALUE_TYPE *, int, enum machine_mode);
 254
 255 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 256
 257
 258 /* Target formats defined in real.c.  */
 259 extern const struct real_format ieee_single_format;
 260 extern const struct real_format mips_single_format;
 261 extern const struct real_format motorola_single_format;
 262 extern const struct real_format ieee_double_format;
 263 extern const struct real_format mips_double_format;
 264 extern const struct real_format motorola_double_format;
 265 extern const struct real_format ieee_extended_motorola_format;
 266 extern const struct real_format ieee_extended_intel_96_format;
 267 extern const struct real_format ieee_extended_intel_96_round_53_format;
 268 extern const struct real_format ieee_extended_intel_128_format;
 269 extern const struct real_format ibm_extended_format;
 270 extern const struct real_format mips_extended_format;
 271 extern const struct real_format ieee_quad_format;
 272 extern const struct real_format mips_quad_format;
 273 extern const struct real_format vax_f_format;
 274 extern const struct real_format vax_d_format;
 275 extern const struct real_format vax_g_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, -1 and 0.5.  */
 378
 379 extern REAL_VALUE_TYPE dconst0;
 380 extern REAL_VALUE_TYPE dconst1;
 381 extern REAL_VALUE_TYPE dconst2;
 382 extern REAL_VALUE_TYPE dconstm1;
 383 extern REAL_VALUE_TYPE dconsthalf;
 384
 385 /* Enumerate the special constant values we need. */
 386 enum real_value_const {
 387   rv_e,
 388   rv_third,
 389   rv_sqrt2,
 390   rv_max
 391 };
 392
 393 /* Function to return a real value special constant.  */
 394 extern const REAL_VALUE_TYPE * get_real_const (enum real_value_const);
 395
 396 /* Function to return a real value (not a tree node)
 397    from a given integer constant.  */
 398 REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
 399
 400 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 401 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 402   ((to) = *CONST_DOUBLE_REAL_VALUE (from))
 403
 404 /* Return a CONST_DOUBLE with value R and mode M.  */
 405 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 406   const_double_from_real_value (r, m)
 407 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 408
 409 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 410 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 411
 412 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 413 extern tree build_real (tree, REAL_VALUE_TYPE);
 414
 415 /* Calculate R as the square root of X in the given machine mode.  */
 416 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 417                        const REAL_VALUE_TYPE *);
 418
 419 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 420 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 421                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 422
 423 /* Standard round to integer value functions.  */
 424 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 425                         const REAL_VALUE_TYPE *);
 426 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 427                         const REAL_VALUE_TYPE *);
 428 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 429                        const REAL_VALUE_TYPE *);
 430 extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
 431                         const REAL_VALUE_TYPE *);
 432
 433 /* Set the sign of R to the sign of X.  */
 434 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 435
 436 #ifndef GENERATOR_FILE
 437 /* Convert between MPFR and REAL_VALUE_TYPE.  The caller is
 438    responsible for initializing and clearing the MPFR parameter.  */
 439
 440 extern void real_from_mpfr (REAL_VALUE_TYPE *, mpfr_srcptr, tree, mp_rnd_t);
 441 extern void mpfr_from_real (mpfr_ptr, const REAL_VALUE_TYPE *, mp_rnd_t);
 442 #endif
 443
 444 /* Check whether the real constant value given is an integer.  */
 445 extern bool real_isinteger (const REAL_VALUE_TYPE *c, enum machine_mode mode);
 446
 447 /* Write into BUF the maximum representable finite floating-point
 448    number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
 449    float string.  BUF must be large enough to contain the result.  */
 450 extern void get_max_float (const struct real_format *, char *, size_t);
 451 #endif /* ! GCC_REAL_H */