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   /* Default rounding mode for operations on this format.  */
 151   bool round_towards_zero;
 152   bool has_sign_dependent_rounding;
 153
 154   /* Properties of the format.  */
 155   bool has_nans;
 156   bool has_inf;
 157   bool has_denorm;
 158   bool has_signed_zero;
 159   bool qnan_msb_set;
 160   bool canonical_nan_lsbs_set;
 161 };
 162
 163
 164 /* The target format used for each floating point mode.
 165    Float modes are followed by decimal float modes, with entries for
 166    float modes indexed by (MODE - first float mode), and entries for
 167    decimal float modes indexed by (MODE - first decimal float mode) +
 168    the number of float modes.  */
 169 extern const struct real_format *
 170   real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
 171                        + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
 172
 173 #define REAL_MODE_FORMAT(MODE)                                          \
 174   (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)                     \
 175                         ? (((MODE) - MIN_MODE_DECIMAL_FLOAT)            \
 176                            + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))     \
 177                         : ((MODE) - MIN_MODE_FLOAT)])
 178
 179 #define FLOAT_MODE_FORMAT(MODE) \
 180   (REAL_MODE_FORMAT (SCALAR_FLOAT_MODE_P (MODE)? (MODE) \
 181                                                : GET_MODE_INNER (MODE)))
 182
 183 /* The following macro determines whether the floating point format is
 184    composite, i.e. may contain non-consecutive mantissa bits, in which
 185    case compile-time FP overflow may not model run-time overflow.  */
 186 #define MODE_COMPOSITE_P(MODE) \
 187   (FLOAT_MODE_P (MODE) \
 188    && FLOAT_MODE_FORMAT (MODE)->pnan < FLOAT_MODE_FORMAT (MODE)->p)
 189
 190 /* Accessor macros for format properties.  */
 191 #define MODE_HAS_NANS(MODE) \
 192   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_nans)
 193 #define MODE_HAS_INFINITIES(MODE) \
 194   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_inf)
 195 #define MODE_HAS_SIGNED_ZEROS(MODE) \
 196   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_signed_zero)
 197 #define MODE_HAS_SIGN_DEPENDENT_ROUNDING(MODE) \
 198   (FLOAT_MODE_P (MODE) \
 199    && FLOAT_MODE_FORMAT (MODE)->has_sign_dependent_rounding)
 200
 201
 202 /* Declare functions in real.c.  */
 203
 204 /* Binary or unary arithmetic on tree_code.  */
 205 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 206                              const REAL_VALUE_TYPE *);
 207
 208 /* Compare reals by tree_code.  */
 209 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 210
 211 /* Determine whether a floating-point value X is infinite.  */
 212 extern bool real_isinf (const REAL_VALUE_TYPE *);
 213
 214 /* Determine whether a floating-point value X is a NaN.  */
 215 extern bool real_isnan (const REAL_VALUE_TYPE *);
 216
 217 /* Determine whether a floating-point value X is finite.  */
 218 extern bool real_isfinite (const REAL_VALUE_TYPE *);
 219
 220 /* Determine whether a floating-point value X is negative.  */
 221 extern bool real_isneg (const REAL_VALUE_TYPE *);
 222
 223 /* Determine whether a floating-point value X is minus zero.  */
 224 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 225
 226 /* Compare two floating-point objects for bitwise identity.  */
 227 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 228
 229 /* Extend or truncate to a new mode.  */
 230 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 231                           const REAL_VALUE_TYPE *);
 232
 233 /* Return true if truncating to NEW is exact.  */
 234 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 235
 236 /* Render R as a decimal floating point constant.  */
 237 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 238                              size_t, int);
 239
 240 /* Render R as a decimal floating point constant, rounded so as to be
 241    parsed back to the same value when interpreted in mode MODE.  */
 242 extern void real_to_decimal_for_mode (char *, const REAL_VALUE_TYPE *, size_t,
 243                                       size_t, int, enum machine_mode);
 244
 245 /* Render R as a hexadecimal floating point constant.  */
 246 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 247                                  size_t, size_t, int);
 248
 249 /* Render R as an integer.  */
 250 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 251 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 252                               const REAL_VALUE_TYPE *);
 253
 254 /* Initialize R from a decimal or hexadecimal string.  Return -1 if
 255    the value underflows, +1 if overflows, and 0 otherwise.  */
 256 extern int real_from_string (REAL_VALUE_TYPE *, const char *);
 257 /* Wrapper to allow different internal representation for decimal floats. */
 258 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
 259
 260 /* Initialize R from an integer pair HIGH/LOW.  */
 261 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 262                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 263
 264 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 265                                 const struct real_format *);
 266 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 267
 268 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 269                                   const struct real_format *);
 270 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 271                               enum machine_mode);
 272
 273 extern void real_inf (REAL_VALUE_TYPE *);
 274
 275 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 276
 277 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 278
 279 extern void real_2expN (REAL_VALUE_TYPE *, int, enum machine_mode);
 280
 281 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 282
 283
 284 /* Target formats defined in real.c.  */
 285 extern const struct real_format ieee_single_format;
 286 extern const struct real_format mips_single_format;
 287 extern const struct real_format motorola_single_format;
 288 extern const struct real_format spu_single_format;
 289 extern const struct real_format ieee_double_format;
 290 extern const struct real_format mips_double_format;
 291 extern const struct real_format motorola_double_format;
 292 extern const struct real_format ieee_extended_motorola_format;
 293 extern const struct real_format ieee_extended_intel_96_format;
 294 extern const struct real_format ieee_extended_intel_96_round_53_format;
 295 extern const struct real_format ieee_extended_intel_128_format;
 296 extern const struct real_format ibm_extended_format;
 297 extern const struct real_format mips_extended_format;
 298 extern const struct real_format ieee_quad_format;
 299 extern const struct real_format mips_quad_format;
 300 extern const struct real_format vax_f_format;
 301 extern const struct real_format vax_d_format;
 302 extern const struct real_format vax_g_format;
 303 extern const struct real_format real_internal_format;
 304 extern const struct real_format decimal_single_format;
 305 extern const struct real_format decimal_double_format;
 306 extern const struct real_format decimal_quad_format;
 307
 308
 309 /* ====================================================================== */
 310 /* Crap.  */
 311
 312 #define REAL_ARITHMETIC(value, code, d1, d2) \
 313   real_arithmetic (&(value), code, &(d1), &(d2))
 314
 315 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 316 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 317 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 318
 319 /* Determine whether a floating-point value X is infinite.  */
 320 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 321
 322 /* Determine whether a floating-point value X is a NaN.  */
 323 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 324
 325 /* Determine whether a floating-point value X is negative.  */
 326 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 327
 328 /* Determine whether a floating-point value X is minus zero.  */
 329 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 330
 331 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 332 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 333   real_to_target (OUT, &(IN),                                           \
 334                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 335
 336 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 337   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 338
 339 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 340 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 341   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 342
 343 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 344   real_from_integer (&(r), mode, lo, hi, 0)
 345
 346 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 347   real_from_integer (&(r), mode, lo, hi, 1)
 348
 349 /* Real values to IEEE 754 decimal floats.  */
 350
 351 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 352 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
 353   real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
 354
 355 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
 356   real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
 357
 358 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 359 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
 360   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
 361
 362 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 363                                             REAL_VALUE_TYPE);
 364
 365 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 366   real_to_integer2 (plow, phigh, &(r))
 367
 368 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 369                                          const REAL_VALUE_TYPE *);
 370
 371 #define REAL_VALUE_NEGATE(X) \
 372   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 373
 374 #define REAL_VALUE_ABS(X) \
 375   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 376
 377 extern int significand_size (enum machine_mode);
 378
 379 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
 380
 381 #define REAL_VALUE_ATOF(s, m) \
 382   real_from_string2 (s, m)
 383
 384 #define CONST_DOUBLE_ATOF(s, m) \
 385   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 386
 387 #define REAL_VALUE_FIX(r) \
 388   real_to_integer (&(r))
 389
 390 /* ??? Not quite right.  */
 391 #define REAL_VALUE_UNSIGNED_FIX(r) \
 392   real_to_integer (&(r))
 393
 394 /* ??? These were added for Paranoia support.  */
 395
 396 /* Return floor log2(R).  */
 397 extern int real_exponent (const REAL_VALUE_TYPE *);
 398
 399 /* R = A * 2**EXP.  */
 400 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 401
 402 /* **** End of software floating point emulator interface macros **** */
 403 \f
 404 /* Constant real values 0, 1, 2, -1 and 0.5.  */
 405
 406 extern REAL_VALUE_TYPE dconst0;
 407 extern REAL_VALUE_TYPE dconst1;
 408 extern REAL_VALUE_TYPE dconst2;
 409 extern REAL_VALUE_TYPE dconstm1;
 410 extern REAL_VALUE_TYPE dconsthalf;
 411
 412 #define dconst_e()  (*dconst_e_ptr ())
 413 #define dconst_third()  (*dconst_third_ptr ())
 414 #define dconst_sqrt2()  (*dconst_sqrt2_ptr ())
 415
 416 /* Function to return the real value special constant 'e'.  */
 417 extern const REAL_VALUE_TYPE * dconst_e_ptr (void);
 418
 419 /* Returns the special REAL_VALUE_TYPE corresponding to 1/3.  */
 420 extern const REAL_VALUE_TYPE * dconst_third_ptr (void);
 421
 422 /* Returns the special REAL_VALUE_TYPE corresponding to sqrt(2).  */
 423 extern const REAL_VALUE_TYPE * dconst_sqrt2_ptr (void);
 424
 425 /* Function to return a real value (not a tree node)
 426    from a given integer constant.  */
 427 REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
 428
 429 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 430 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 431   ((to) = *CONST_DOUBLE_REAL_VALUE (from))
 432
 433 /* Return a CONST_DOUBLE with value R and mode M.  */
 434 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 435   const_double_from_real_value (r, m)
 436 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 437
 438 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 439 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 440
 441 /* Return true if arithmetic on values in IMODE that were promoted
 442    from values in TMODE is equivalent to direct arithmetic on values
 443    in TMODE.  */
 444 bool real_can_shorten_arithmetic (enum machine_mode, enum machine_mode);
 445
 446 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 447 extern tree build_real (tree, REAL_VALUE_TYPE);
 448
 449 /* Calculate R as the square root of X in the given machine mode.  */
 450 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 451                        const 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 *, enum 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 *, enum machine_mode,
 459                         const REAL_VALUE_TYPE *);
 460 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 461                         const REAL_VALUE_TYPE *);
 462 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 463                        const REAL_VALUE_TYPE *);
 464 extern void real_round (REAL_VALUE_TYPE *, enum 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 #ifndef GENERATOR_FILE
 471 /* Convert between MPFR and REAL_VALUE_TYPE.  The caller is
 472    responsible for initializing and clearing the MPFR parameter.  */
 473
 474 extern void real_from_mpfr (REAL_VALUE_TYPE *, mpfr_srcptr, tree, mp_rnd_t);
 475 extern void mpfr_from_real (mpfr_ptr, const REAL_VALUE_TYPE *, mp_rnd_t);
 476 #endif
 477
 478 /* Check whether the real constant value given is an integer.  */
 479 extern bool real_isinteger (const REAL_VALUE_TYPE *c, enum machine_mode mode);
 480
 481 /* Write into BUF the maximum representable finite floating-point
 482    number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
 483    float string.  BUF must be large enough to contain the result.  */
 484 extern void get_max_float (const struct real_format *, char *, size_t);
 485 #endif /* ! GCC_REAL_H */