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 #ifdef HAVE_mpc
  28 #include <mpc.h>
  29 #endif
  30 #endif
  31 #include "machmode.h"
  32
  33 /* An expanded form of the represented number.  */
  34
  35 /* Enumerate the special cases of numbers that we encounter.  */
  36 enum real_value_class {
  37   rvc_zero,
  38   rvc_normal,
  39   rvc_inf,
  40   rvc_nan
  41 };
  42
  43 #define SIGNIFICAND_BITS        (128 + HOST_BITS_PER_LONG)
  44 #define EXP_BITS                (32 - 6)
  45 #define MAX_EXP                 ((1 << (EXP_BITS - 1)) - 1)
  46 #define SIGSZ                   (SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
  47 #define SIG_MSB                 ((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
  48
  49 struct GTY(()) real_value {
  50   /* Use the same underlying type for all bit-fields, so as to make
  51      sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
  52      be miscomputed.  */
  53   unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
  54   unsigned int decimal : 1;
  55   unsigned int sign : 1;
  56   unsigned int signalling : 1;
  57   unsigned int canonical : 1;
  58   unsigned int uexp : EXP_BITS;
  59   unsigned long sig[SIGSZ];
  60 };
  61
  62 #define REAL_EXP(REAL) \
  63   ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
  64    - (1 << (EXP_BITS - 1)))
  65 #define SET_REAL_EXP(REAL, EXP) \
  66   ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
  67
  68 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  69    needs to be a macro.  We do need to continue to have a structure tag
  70    so that other headers can forward declare it.  */
  71 #define REAL_VALUE_TYPE struct real_value
  72
  73 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  74    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  75    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  76
  77 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  78 #define REAL_WIDTH \
  79   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  80    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  81
  82 /* Verify the guess.  */
  83 extern char test_real_width
  84   [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
  85
  86 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  87    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  88    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  89
  90    A number of places assume that there are always at least two 'w'
  91    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  92
  93 #if REAL_WIDTH == 1
  94 # define CONST_DOUBLE_FORMAT     "ww"
  95 #else
  96 # if REAL_WIDTH == 2
  97 #  define CONST_DOUBLE_FORMAT    "ww"
  98 # else
  99 #  if REAL_WIDTH == 3
 100 #   define CONST_DOUBLE_FORMAT   "www"
 101 #  else
 102 #   if REAL_WIDTH == 4
 103 #    define CONST_DOUBLE_FORMAT  "wwww"
 104 #   else
 105 #    if REAL_WIDTH == 5
 106 #     define CONST_DOUBLE_FORMAT "wwwww"
 107 #    else
 108 #     if REAL_WIDTH == 6
 109 #      define CONST_DOUBLE_FORMAT "wwwwww"
 110 #     else
 111        #error "REAL_WIDTH > 6 not supported"
 112 #     endif
 113 #    endif
 114 #   endif
 115 #  endif
 116 # endif
 117 #endif
 118
 119
 120 /* Describes the properties of the specific target format in use.  */
 121 struct real_format
 122 {
 123   /* Move to and from the target bytes.  */
 124   void (*encode) (const struct real_format *, long *,
 125                   const REAL_VALUE_TYPE *);
 126   void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
 127                   const long *);
 128
 129   /* The radix of the exponent and digits of the significand.  */
 130   int b;
 131
 132   /* Size of the significand in digits of radix B.  */
 133   int p;
 134
 135   /* Size of the significant of a NaN, in digits of radix B.  */
 136   int pnan;
 137
 138   /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
 139   int emin;
 140
 141   /* The maximum integer, x, such that b**(x-1) is representable.  */
 142   int emax;
 143
 144   /* The bit position of the sign bit, for determining whether a value
 145      is positive/negative, or -1 for a complex encoding.  */
 146   int signbit_ro;
 147
 148   /* The bit position of the sign bit, for changing the sign of a number,
 149      or -1 for a complex encoding.  */
 150   int signbit_rw;
 151
 152   /* Default rounding mode for operations on this format.  */
 153   bool round_towards_zero;
 154   bool has_sign_dependent_rounding;
 155
 156   /* Properties of the format.  */
 157   bool has_nans;
 158   bool has_inf;
 159   bool has_denorm;
 160   bool has_signed_zero;
 161   bool qnan_msb_set;
 162   bool canonical_nan_lsbs_set;
 163 };
 164
 165
 166 /* The target format used for each floating point mode.
 167    Float modes are followed by decimal float modes, with entries for
 168    float modes indexed by (MODE - first float mode), and entries for
 169    decimal float modes indexed by (MODE - first decimal float mode) +
 170    the number of float modes.  */
 171 extern const struct real_format *
 172   real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
 173                        + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
 174
 175 #define REAL_MODE_FORMAT(MODE)                                          \
 176   (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)                     \
 177                         ? (((MODE) - MIN_MODE_DECIMAL_FLOAT)            \
 178                            + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))     \
 179                         : ((MODE) - MIN_MODE_FLOAT)])
 180
 181 #define FLOAT_MODE_FORMAT(MODE) \
 182   (REAL_MODE_FORMAT (SCALAR_FLOAT_MODE_P (MODE)? (MODE) \
 183                                                : GET_MODE_INNER (MODE)))
 184
 185 /* The following macro determines whether the floating point format is
 186    composite, i.e. may contain non-consecutive mantissa bits, in which
 187    case compile-time FP overflow may not model run-time overflow.  */
 188 #define MODE_COMPOSITE_P(MODE) \
 189   (FLOAT_MODE_P (MODE) \
 190    && FLOAT_MODE_FORMAT (MODE)->pnan < FLOAT_MODE_FORMAT (MODE)->p)
 191
 192 /* Accessor macros for format properties.  */
 193 #define MODE_HAS_NANS(MODE) \
 194   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_nans)
 195 #define MODE_HAS_INFINITIES(MODE) \
 196   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_inf)
 197 #define MODE_HAS_SIGNED_ZEROS(MODE) \
 198   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_signed_zero)
 199 #define MODE_HAS_SIGN_DEPENDENT_ROUNDING(MODE) \
 200   (FLOAT_MODE_P (MODE) \
 201    && FLOAT_MODE_FORMAT (MODE)->has_sign_dependent_rounding)
 202
 203
 204 /* Declare functions in real.c.  */
 205
 206 /* Binary or unary arithmetic on tree_code.  */
 207 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 208                              const REAL_VALUE_TYPE *);
 209
 210 /* Compare reals by tree_code.  */
 211 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 212
 213 /* Determine whether a floating-point value X is infinite.  */
 214 extern bool real_isinf (const REAL_VALUE_TYPE *);
 215
 216 /* Determine whether a floating-point value X is a NaN.  */
 217 extern bool real_isnan (const REAL_VALUE_TYPE *);
 218
 219 /* Determine whether a floating-point value X is finite.  */
 220 extern bool real_isfinite (const REAL_VALUE_TYPE *);
 221
 222 /* Determine whether a floating-point value X is negative.  */
 223 extern bool real_isneg (const REAL_VALUE_TYPE *);
 224
 225 /* Determine whether a floating-point value X is minus zero.  */
 226 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 227
 228 /* Compare two floating-point objects for bitwise identity.  */
 229 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 230
 231 /* Extend or truncate to a new mode.  */
 232 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 233                           const REAL_VALUE_TYPE *);
 234
 235 /* Return true if truncating to NEW is exact.  */
 236 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 237
 238 /* Render R as a decimal floating point constant.  */
 239 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 240                              size_t, int);
 241
 242 /* Render R as a decimal floating point constant, rounded so as to be
 243    parsed back to the same value when interpreted in mode MODE.  */
 244 extern void real_to_decimal_for_mode (char *, const REAL_VALUE_TYPE *, size_t,
 245                                       size_t, int, enum machine_mode);
 246
 247 /* Render R as a hexadecimal floating point constant.  */
 248 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 249                                  size_t, size_t, int);
 250
 251 /* Render R as an integer.  */
 252 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 253 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 254                               const REAL_VALUE_TYPE *);
 255
 256 /* Initialize R from a decimal or hexadecimal string.  Return -1 if
 257    the value underflows, +1 if overflows, and 0 otherwise.  */
 258 extern int real_from_string (REAL_VALUE_TYPE *, const char *);
 259 /* Wrapper to allow different internal representation for decimal floats. */
 260 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
 261
 262 /* Initialize R from an integer pair HIGH/LOW.  */
 263 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 264                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 265
 266 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 267                                 const struct real_format *);
 268 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 269
 270 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 271                                   const struct real_format *);
 272 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 273                               enum machine_mode);
 274
 275 extern void real_inf (REAL_VALUE_TYPE *);
 276
 277 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 278
 279 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 280
 281 extern void real_2expN (REAL_VALUE_TYPE *, int, enum machine_mode);
 282
 283 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 284
 285
 286 /* Target formats defined in real.c.  */
 287 extern const struct real_format ieee_single_format;
 288 extern const struct real_format mips_single_format;
 289 extern const struct real_format motorola_single_format;
 290 extern const struct real_format spu_single_format;
 291 extern const struct real_format ieee_double_format;
 292 extern const struct real_format mips_double_format;
 293 extern const struct real_format motorola_double_format;
 294 extern const struct real_format ieee_extended_motorola_format;
 295 extern const struct real_format ieee_extended_intel_96_format;
 296 extern const struct real_format ieee_extended_intel_96_round_53_format;
 297 extern const struct real_format ieee_extended_intel_128_format;
 298 extern const struct real_format ibm_extended_format;
 299 extern const struct real_format mips_extended_format;
 300 extern const struct real_format ieee_quad_format;
 301 extern const struct real_format mips_quad_format;
 302 extern const struct real_format vax_f_format;
 303 extern const struct real_format vax_d_format;
 304 extern const struct real_format vax_g_format;
 305 extern const struct real_format real_internal_format;
 306 extern const struct real_format decimal_single_format;
 307 extern const struct real_format decimal_double_format;
 308 extern const struct real_format decimal_quad_format;
 309 extern const struct real_format ieee_half_format;
 310 extern const struct real_format arm_half_format;
 311
 312
 313 /* ====================================================================== */
 314 /* Crap.  */
 315
 316 #define REAL_ARITHMETIC(value, code, d1, d2) \
 317   real_arithmetic (&(value), code, &(d1), &(d2))
 318
 319 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 320 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 321 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 322
 323 /* Determine whether a floating-point value X is infinite.  */
 324 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 325
 326 /* Determine whether a floating-point value X is a NaN.  */
 327 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 328
 329 /* Determine whether a floating-point value X is negative.  */
 330 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 331
 332 /* Determine whether a floating-point value X is minus zero.  */
 333 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 334
 335 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 336 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 337   real_to_target (OUT, &(IN),                                           \
 338                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 339
 340 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 341   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 342
 343 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 344 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 345   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 346
 347 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 348   real_from_integer (&(r), mode, lo, hi, 0)
 349
 350 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 351   real_from_integer (&(r), mode, lo, hi, 1)
 352
 353 /* Real values to IEEE 754 decimal floats.  */
 354
 355 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 356 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
 357   real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
 358
 359 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
 360   real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
 361
 362 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 363 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
 364   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
 365
 366 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 367                                             REAL_VALUE_TYPE);
 368
 369 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 370   real_to_integer2 (plow, phigh, &(r))
 371
 372 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 373                                          const REAL_VALUE_TYPE *);
 374
 375 #define REAL_VALUE_NEGATE(X) \
 376   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 377
 378 #define REAL_VALUE_ABS(X) \
 379   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 380
 381 extern int significand_size (enum machine_mode);
 382
 383 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum 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, enum 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 (enum 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 (enum machine_mode, enum 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 the square root of X in the given machine mode.  */
 454 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 455                        const REAL_VALUE_TYPE *);
 456
 457 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 458 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 459                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 460
 461 /* Standard round to integer value functions.  */
 462 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 463                         const REAL_VALUE_TYPE *);
 464 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 465                         const REAL_VALUE_TYPE *);
 466 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 467                        const REAL_VALUE_TYPE *);
 468 extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
 469                         const REAL_VALUE_TYPE *);
 470
 471 /* Set the sign of R to the sign of X.  */
 472 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 473
 474 #ifndef GENERATOR_FILE
 475 /* Convert between MPFR and REAL_VALUE_TYPE.  The caller is
 476    responsible for initializing and clearing the MPFR parameter.  */
 477
 478 extern void real_from_mpfr (REAL_VALUE_TYPE *, mpfr_srcptr, tree, mp_rnd_t);
 479 extern void mpfr_from_real (mpfr_ptr, const REAL_VALUE_TYPE *, mp_rnd_t);
 480 #endif
 481
 482 /* Check whether the real constant value given is an integer.  */
 483 extern bool real_isinteger (const REAL_VALUE_TYPE *c, enum machine_mode mode);
 484
 485 /* Write into BUF the maximum representable finite floating-point
 486    number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
 487    float string.  BUF must be large enough to contain the result.  */
 488 extern void get_max_float (const struct real_format *, char *, size_t);
 489 #endif /* ! GCC_REAL_H */