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 "machmode.h"
  25
  26 /* An expanded form of the represented number.  */
  27
  28 /* Enumerate the special cases of numbers that we encounter.  */
  29 enum real_value_class {
  30   rvc_zero,
  31   rvc_normal,
  32   rvc_inf,
  33   rvc_nan
  34 };
  35
  36 #define SIGNIFICAND_BITS        (128 + HOST_BITS_PER_LONG)
  37 #define EXP_BITS                (32 - 6)
  38 #define MAX_EXP                 ((1 << (EXP_BITS - 1)) - 1)
  39 #define SIGSZ                   (SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
  40 #define SIG_MSB                 ((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
  41
  42 struct real_value GTY(())
  43 {
  44   /* Use the same underlying type for all bit-fields, so as to make
  45      sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
  46      be miscomputed.  */
  47   unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
  48   unsigned int decimal : 1;
  49   unsigned int sign : 1;
  50   unsigned int signalling : 1;
  51   unsigned int canonical : 1;
  52   unsigned int uexp : EXP_BITS;
  53   unsigned long sig[SIGSZ];
  54 };
  55
  56 #define REAL_EXP(REAL) \
  57   ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
  58    - (1 << (EXP_BITS - 1)))
  59 #define SET_REAL_EXP(REAL, EXP) \
  60   ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
  61
  62 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  63    needs to be a macro.  We do need to continue to have a structure tag
  64    so that other headers can forward declare it.  */
  65 #define REAL_VALUE_TYPE struct real_value
  66
  67 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  68    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  69    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  70
  71 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  72 #define REAL_WIDTH \
  73   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  74    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  75
  76 /* Verify the guess.  */
  77 extern char test_real_width
  78   [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
  79
  80 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  81    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  82    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  83
  84    A number of places assume that there are always at least two 'w'
  85    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  86
  87 #if REAL_WIDTH == 1
  88 # define CONST_DOUBLE_FORMAT     "ww"
  89 #else
  90 # if REAL_WIDTH == 2
  91 #  define CONST_DOUBLE_FORMAT    "ww"
  92 # else
  93 #  if REAL_WIDTH == 3
  94 #   define CONST_DOUBLE_FORMAT   "www"
  95 #  else
  96 #   if REAL_WIDTH == 4
  97 #    define CONST_DOUBLE_FORMAT  "wwww"
  98 #   else
  99 #    if REAL_WIDTH == 5
 100 #     define CONST_DOUBLE_FORMAT "wwwww"
 101 #    else
 102 #     if REAL_WIDTH == 6
 103 #      define CONST_DOUBLE_FORMAT "wwwwww"
 104 #     else
 105        #error "REAL_WIDTH > 6 not supported"
 106 #     endif
 107 #    endif
 108 #   endif
 109 #  endif
 110 # endif
 111 #endif
 112
 113
 114 /* Describes the properties of the specific target format in use.  */
 115 struct real_format
 116 {
 117   /* Move to and from the target bytes.  */
 118   void (*encode) (const struct real_format *, long *,
 119                   const REAL_VALUE_TYPE *);
 120   void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
 121                   const long *);
 122
 123   /* The radix of the exponent and digits of the significand.  */
 124   int b;
 125
 126   /* log2(b).  */
 127   int log2_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   /* Properties of the format.  */
 150   bool has_nans;
 151   bool has_inf;
 152   bool has_denorm;
 153   bool has_signed_zero;
 154   bool qnan_msb_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 negative.  */
 195 extern bool real_isneg (const REAL_VALUE_TYPE *);
 196
 197 /* Determine whether a floating-point value X is minus zero.  */
 198 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 199
 200 /* Compare two floating-point objects for bitwise identity.  */
 201 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 202
 203 /* Extend or truncate to a new mode.  */
 204 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 205                           const REAL_VALUE_TYPE *);
 206
 207 /* Return true if truncating to NEW is exact.  */
 208 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 209
 210 /* Render R as a decimal floating point constant.  */
 211 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 212                              size_t, int);
 213
 214 /* Render R as a hexadecimal floating point constant.  */
 215 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 216                                  size_t, size_t, int);
 217
 218 /* Render R as an integer.  */
 219 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 220 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 221                               const REAL_VALUE_TYPE *);
 222
 223 /* Initialize R from a decimal or hexadecimal string.  */
 224 extern void real_from_string (REAL_VALUE_TYPE *, const char *);
 225 /* Wrapper to allow different internal representation for decimal floats. */
 226 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
 227
 228 /* Initialize R from an integer pair HIGH/LOW.  */
 229 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 230                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 231
 232 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 233                                 const struct real_format *);
 234 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 235
 236 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 237                                   const struct real_format *);
 238 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 239                               enum machine_mode);
 240
 241 extern void real_inf (REAL_VALUE_TYPE *);
 242
 243 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 244
 245 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 246
 247 extern void real_2expN (REAL_VALUE_TYPE *, int);
 248
 249 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 250
 251
 252 /* Target formats defined in real.c.  */
 253 extern const struct real_format ieee_single_format;
 254 extern const struct real_format mips_single_format;
 255 extern const struct real_format ieee_double_format;
 256 extern const struct real_format mips_double_format;
 257 extern const struct real_format ieee_extended_motorola_format;
 258 extern const struct real_format ieee_extended_intel_96_format;
 259 extern const struct real_format ieee_extended_intel_96_round_53_format;
 260 extern const struct real_format ieee_extended_intel_128_format;
 261 extern const struct real_format ibm_extended_format;
 262 extern const struct real_format mips_extended_format;
 263 extern const struct real_format ieee_quad_format;
 264 extern const struct real_format mips_quad_format;
 265 extern const struct real_format vax_f_format;
 266 extern const struct real_format vax_d_format;
 267 extern const struct real_format vax_g_format;
 268 extern const struct real_format i370_single_format;
 269 extern const struct real_format i370_double_format;
 270 extern const struct real_format c4x_single_format;
 271 extern const struct real_format c4x_extended_format;
 272 extern const struct real_format real_internal_format;
 273 extern const struct real_format decimal_single_format;
 274 extern const struct real_format decimal_double_format;
 275 extern const struct real_format decimal_quad_format;
 276
 277
 278 /* ====================================================================== */
 279 /* Crap.  */
 280
 281 #define REAL_ARITHMETIC(value, code, d1, d2) \
 282   real_arithmetic (&(value), code, &(d1), &(d2))
 283
 284 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 285 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 286 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 287
 288 /* Determine whether a floating-point value X is infinite.  */
 289 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 290
 291 /* Determine whether a floating-point value X is a NaN.  */
 292 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 293
 294 /* Determine whether a floating-point value X is negative.  */
 295 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 296
 297 /* Determine whether a floating-point value X is minus zero.  */
 298 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 299
 300 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 301 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 302   real_to_target (OUT, &(IN),                                           \
 303                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 304
 305 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 306   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 307
 308 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 309 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 310   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 311
 312 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 313   real_from_integer (&(r), mode, lo, hi, 0)
 314
 315 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 316   real_from_integer (&(r), mode, lo, hi, 1)
 317
 318 /* Real values to IEEE 754R decimal floats.  */
 319
 320 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 321 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
 322   real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
 323
 324 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
 325   real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
 326
 327 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 328 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
 329   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
 330
 331 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 332                                             REAL_VALUE_TYPE);
 333
 334 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 335   real_to_integer2 (plow, phigh, &(r))
 336
 337 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 338                                          const REAL_VALUE_TYPE *);
 339
 340 #define REAL_VALUE_NEGATE(X) \
 341   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 342
 343 #define REAL_VALUE_ABS(X) \
 344   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 345
 346 extern int significand_size (enum machine_mode);
 347
 348 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
 349
 350 #define REAL_VALUE_ATOF(s, m) \
 351   real_from_string2 (s, m)
 352
 353 #define CONST_DOUBLE_ATOF(s, m) \
 354   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 355
 356 #define REAL_VALUE_FIX(r) \
 357   real_to_integer (&(r))
 358
 359 /* ??? Not quite right.  */
 360 #define REAL_VALUE_UNSIGNED_FIX(r) \
 361   real_to_integer (&(r))
 362
 363 /* ??? These were added for Paranoia support.  */
 364
 365 /* Return floor log2(R).  */
 366 extern int real_exponent (const REAL_VALUE_TYPE *);
 367
 368 /* R = A * 2**EXP.  */
 369 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 370
 371 /* **** End of software floating point emulator interface macros **** */
 372 \f
 373 /* Constant real values 0, 1, 2, 3, 10, -1, -2, 0.5 and 1/3.  */
 374
 375 extern REAL_VALUE_TYPE dconst0;
 376 extern REAL_VALUE_TYPE dconst1;
 377 extern REAL_VALUE_TYPE dconst2;
 378 extern REAL_VALUE_TYPE dconst3;
 379 extern REAL_VALUE_TYPE dconst10;
 380 extern REAL_VALUE_TYPE dconstm1;
 381 extern REAL_VALUE_TYPE dconstm2;
 382 extern REAL_VALUE_TYPE dconsthalf;
 383 extern REAL_VALUE_TYPE dconstthird;
 384 extern REAL_VALUE_TYPE dconstpi;
 385 extern REAL_VALUE_TYPE dconste;
 386
 387 /* Function to return a real value (not a tree node)
 388    from a given integer constant.  */
 389 REAL_VALUE_TYPE real_value_from_int_cst (tree, tree);
 390
 391 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 392 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 393   ((to) = *CONST_DOUBLE_REAL_VALUE (from))
 394
 395 /* Return a CONST_DOUBLE with value R and mode M.  */
 396 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 397   const_double_from_real_value (r, m)
 398 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 399
 400 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 401 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 402
 403 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 404 extern tree build_real (tree, REAL_VALUE_TYPE);
 405
 406 /* Calculate R as the square root of X in the given machine mode.  */
 407 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 408                        const REAL_VALUE_TYPE *);
 409
 410 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 411 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 412                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 413
 414 /* Standard round to integer value functions.  */
 415 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 416                         const REAL_VALUE_TYPE *);
 417 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 418                         const REAL_VALUE_TYPE *);
 419 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 420                        const REAL_VALUE_TYPE *);
 421 extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
 422                         const REAL_VALUE_TYPE *);
 423
 424 /* Set the sign of R to the sign of X.  */
 425 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 426
 427 #endif /* ! GCC_REAL_H */