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 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 2, 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 COPYING.  If not, write to the Free
  19    Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20    02110-1301, USA.  */
  21
  22 #ifndef GCC_REAL_H
  23 #define GCC_REAL_H
  24
  25 #include "machmode.h"
  26
  27 /* An expanded form of the represented number.  */
  28
  29 /* Enumerate the special cases of numbers that we encounter.  */
  30 enum real_value_class {
  31   rvc_zero,
  32   rvc_normal,
  33   rvc_inf,
  34   rvc_nan
  35 };
  36
  37 #define SIGNIFICAND_BITS        (128 + HOST_BITS_PER_LONG)
  38 #define EXP_BITS                (32 - 6)
  39 #define MAX_EXP                 ((1 << (EXP_BITS - 1)) - 1)
  40 #define SIGSZ                   (SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
  41 #define SIG_MSB                 ((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
  42
  43 struct real_value GTY(())
  44 {
  45   /* Use the same underlying type for all bit-fields, so as to make
  46      sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
  47      be miscomputed.  */
  48   unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
  49   unsigned int decimal : 1;
  50   unsigned int sign : 1;
  51   unsigned int signalling : 1;
  52   unsigned int canonical : 1;
  53   unsigned int uexp : EXP_BITS;
  54   unsigned long sig[SIGSZ];
  55 };
  56
  57 #define REAL_EXP(REAL) \
  58   ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
  59    - (1 << (EXP_BITS - 1)))
  60 #define SET_REAL_EXP(REAL, EXP) \
  61   ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
  62
  63 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  64    needs to be a macro.  We do need to continue to have a structure tag
  65    so that other headers can forward declare it.  */
  66 #define REAL_VALUE_TYPE struct real_value
  67
  68 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  69    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  70    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  71
  72 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  73 #define REAL_WIDTH \
  74   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  75    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  76
  77 /* Verify the guess.  */
  78 extern char test_real_width
  79   [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
  80
  81 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  82    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  83    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  84
  85    A number of places assume that there are always at least two 'w'
  86    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  87
  88 #if REAL_WIDTH == 1
  89 # define CONST_DOUBLE_FORMAT     "ww"
  90 #else
  91 # if REAL_WIDTH == 2
  92 #  define CONST_DOUBLE_FORMAT    "ww"
  93 # else
  94 #  if REAL_WIDTH == 3
  95 #   define CONST_DOUBLE_FORMAT   "www"
  96 #  else
  97 #   if REAL_WIDTH == 4
  98 #    define CONST_DOUBLE_FORMAT  "wwww"
  99 #   else
 100 #    if REAL_WIDTH == 5
 101 #     define CONST_DOUBLE_FORMAT "wwwww"
 102 #    else
 103 #     if REAL_WIDTH == 6
 104 #      define CONST_DOUBLE_FORMAT "wwwwww"
 105 #     else
 106        #error "REAL_WIDTH > 6 not supported"
 107 #     endif
 108 #    endif
 109 #   endif
 110 #  endif
 111 # endif
 112 #endif
 113
 114
 115 /* Describes the properties of the specific target format in use.  */
 116 struct real_format
 117 {
 118   /* Move to and from the target bytes.  */
 119   void (*encode) (const struct real_format *, long *,
 120                   const REAL_VALUE_TYPE *);
 121   void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
 122                   const long *);
 123
 124   /* The radix of the exponent and digits of the significand.  */
 125   int b;
 126
 127   /* log2(b).  */
 128   int log2_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 };
 157
 158
 159 /* The target format used for each floating point mode.
 160    Float modes are followed by decimal float modes, with entries for
 161    float modes indexed by (MODE - first float mode), and entries for
 162    decimal float modes indexed by (MODE - first decimal float mode) +
 163    the number of float modes.  */
 164 extern const struct real_format *
 165   real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
 166                        + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
 167
 168 #define REAL_MODE_FORMAT(MODE)                                          \
 169   (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)                     \
 170                         ? ((MODE - MIN_MODE_DECIMAL_FLOAT)              \
 171                            + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))     \
 172                         : (MODE - MIN_MODE_FLOAT)])
 173
 174 /* The following macro determines whether the floating point format is
 175    composite, i.e. may contain non-consecutive mantissa bits, in which
 176    case compile-time FP overflow may not model run-time overflow.  */
 177 #define REAL_MODE_FORMAT_COMPOSITE_P(MODE) \
 178         ((REAL_MODE_FORMAT(MODE))->pnan < (REAL_MODE_FORMAT (MODE))->p)
 179
 180 /* Declare functions in real.c.  */
 181
 182 /* Binary or unary arithmetic on tree_code.  */
 183 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 184                              const REAL_VALUE_TYPE *);
 185
 186 /* Compare reals by tree_code.  */
 187 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 188
 189 /* Determine whether a floating-point value X is infinite.  */
 190 extern bool real_isinf (const REAL_VALUE_TYPE *);
 191
 192 /* Determine whether a floating-point value X is a NaN.  */
 193 extern bool real_isnan (const REAL_VALUE_TYPE *);
 194
 195 /* Determine whether a floating-point value X is negative.  */
 196 extern bool real_isneg (const REAL_VALUE_TYPE *);
 197
 198 /* Determine whether a floating-point value X is minus zero.  */
 199 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 200
 201 /* Compare two floating-point objects for bitwise identity.  */
 202 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 203
 204 /* Extend or truncate to a new mode.  */
 205 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 206                           const REAL_VALUE_TYPE *);
 207
 208 /* Return true if truncating to NEW is exact.  */
 209 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 210
 211 /* Render R as a decimal floating point constant.  */
 212 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 213                              size_t, int);
 214
 215 /* Render R as a hexadecimal floating point constant.  */
 216 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 217                                  size_t, size_t, int);
 218
 219 /* Render R as an integer.  */
 220 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 221 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 222                               const REAL_VALUE_TYPE *);
 223
 224 /* Initialize R from a decimal or hexadecimal string.  */
 225 extern void real_from_string (REAL_VALUE_TYPE *, const char *);
 226 /* Wrapper to allow different internal representation for decimal floats. */
 227 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
 228
 229 /* Initialize R from an integer pair HIGH/LOW.  */
 230 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 231                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 232
 233 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 234                                 const struct real_format *);
 235 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 236
 237 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 238                                   const struct real_format *);
 239 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 240                               enum machine_mode);
 241
 242 extern void real_inf (REAL_VALUE_TYPE *);
 243
 244 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 245
 246 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 247
 248 extern void real_2expN (REAL_VALUE_TYPE *, int);
 249
 250 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 251
 252
 253 /* Target formats defined in real.c.  */
 254 extern const struct real_format ieee_single_format;
 255 extern const struct real_format mips_single_format;
 256 extern const struct real_format ieee_double_format;
 257 extern const struct real_format mips_double_format;
 258 extern const struct real_format ieee_extended_motorola_format;
 259 extern const struct real_format ieee_extended_intel_96_format;
 260 extern const struct real_format ieee_extended_intel_96_round_53_format;
 261 extern const struct real_format ieee_extended_intel_128_format;
 262 extern const struct real_format ibm_extended_format;
 263 extern const struct real_format mips_extended_format;
 264 extern const struct real_format ieee_quad_format;
 265 extern const struct real_format mips_quad_format;
 266 extern const struct real_format vax_f_format;
 267 extern const struct real_format vax_d_format;
 268 extern const struct real_format vax_g_format;
 269 extern const struct real_format i370_single_format;
 270 extern const struct real_format i370_double_format;
 271 extern const struct real_format c4x_single_format;
 272 extern const struct real_format c4x_extended_format;
 273 extern const struct real_format real_internal_format;
 274 extern const struct real_format decimal_single_format;
 275 extern const struct real_format decimal_double_format;
 276 extern const struct real_format decimal_quad_format;
 277
 278
 279 /* ====================================================================== */
 280 /* Crap.  */
 281
 282 #define REAL_ARITHMETIC(value, code, d1, d2) \
 283   real_arithmetic (&(value), code, &(d1), &(d2))
 284
 285 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 286 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 287 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 288
 289 /* Determine whether a floating-point value X is infinite.  */
 290 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 291
 292 /* Determine whether a floating-point value X is a NaN.  */
 293 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 294
 295 /* Determine whether a floating-point value X is negative.  */
 296 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 297
 298 /* Determine whether a floating-point value X is minus zero.  */
 299 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 300
 301 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 302 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 303   real_to_target (OUT, &(IN),                                           \
 304                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 305
 306 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 307   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 308
 309 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 310 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 311   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 312
 313 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 314   real_from_integer (&(r), mode, lo, hi, 0)
 315
 316 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 317   real_from_integer (&(r), mode, lo, hi, 1)
 318
 319 /* Real values to IEEE 754R decimal floats.  */
 320
 321 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 322 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
 323   real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
 324
 325 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
 326   real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
 327
 328 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 329 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
 330   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
 331
 332 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 333                                             REAL_VALUE_TYPE);
 334
 335 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 336   real_to_integer2 (plow, phigh, &(r))
 337
 338 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 339                                          const REAL_VALUE_TYPE *);
 340
 341 #define REAL_VALUE_NEGATE(X) \
 342   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 343
 344 #define REAL_VALUE_ABS(X) \
 345   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 346
 347 extern int significand_size (enum machine_mode);
 348
 349 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
 350
 351 #define REAL_VALUE_ATOF(s, m) \
 352   real_from_string2 (s, m)
 353
 354 #define CONST_DOUBLE_ATOF(s, m) \
 355   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 356
 357 #define REAL_VALUE_FIX(r) \
 358   real_to_integer (&(r))
 359
 360 /* ??? Not quite right.  */
 361 #define REAL_VALUE_UNSIGNED_FIX(r) \
 362   real_to_integer (&(r))
 363
 364 /* ??? These were added for Paranoia support.  */
 365
 366 /* Return floor log2(R).  */
 367 extern int real_exponent (const REAL_VALUE_TYPE *);
 368
 369 /* R = A * 2**EXP.  */
 370 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 371
 372 /* **** End of software floating point emulator interface macros **** */
 373 \f
 374 /* Constant real values 0, 1, 2, 3, 10, -1, -2, 0.5 and 1/3.  */
 375
 376 extern REAL_VALUE_TYPE dconst0;
 377 extern REAL_VALUE_TYPE dconst1;
 378 extern REAL_VALUE_TYPE dconst2;
 379 extern REAL_VALUE_TYPE dconst3;
 380 extern REAL_VALUE_TYPE dconst10;
 381 extern REAL_VALUE_TYPE dconstm1;
 382 extern REAL_VALUE_TYPE dconstm2;
 383 extern REAL_VALUE_TYPE dconsthalf;
 384 extern REAL_VALUE_TYPE dconstthird;
 385 extern REAL_VALUE_TYPE dconstpi;
 386 extern REAL_VALUE_TYPE dconste;
 387
 388 /* Function to return a real value (not a tree node)
 389    from a given integer constant.  */
 390 REAL_VALUE_TYPE real_value_from_int_cst (tree, tree);
 391
 392 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 393 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 394   ((to) = *CONST_DOUBLE_REAL_VALUE (from))
 395
 396 /* Return a CONST_DOUBLE with value R and mode M.  */
 397 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 398   const_double_from_real_value (r, m)
 399 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 400
 401 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 402 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 403
 404 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 405 extern tree build_real (tree, REAL_VALUE_TYPE);
 406
 407 /* Calculate R as the square root of X in the given machine mode.  */
 408 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 409                        const REAL_VALUE_TYPE *);
 410
 411 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 412 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 413                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 414
 415 /* Standard round to integer value functions.  */
 416 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 417                         const REAL_VALUE_TYPE *);
 418 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 419                         const REAL_VALUE_TYPE *);
 420 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 421                        const REAL_VALUE_TYPE *);
 422 extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
 423                         const REAL_VALUE_TYPE *);
 424
 425 /* Set the sign of R to the sign of X.  */
 426 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 427
 428 #endif /* ! GCC_REAL_H */