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, 59 Temple Place - Suite 330, Boston, MA
  20    02111-1307, 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 - 5)
  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 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, or -1 for a complex encoding.  */
 142   int signbit;
 143
 144   /* Properties of the format.  */
 145   bool has_nans;
 146   bool has_inf;
 147   bool has_denorm;
 148   bool has_signed_zero;
 149   bool qnan_msb_set;
 150 };
 151
 152
 153 /* The target format used for each floating floating point mode.
 154    Indexed by MODE - QFmode.  */
 155 extern const struct real_format *
 156   real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1];
 157
 158 #define REAL_MODE_FORMAT(MODE) (real_format_for_mode[(MODE) - MIN_MODE_FLOAT])
 159
 160 /* The following macro determines whether the floating point format is
 161    composite, i.e. may contain non-consecutive mantissa bits, in which
 162    case compile-time FP overflow may not model run-time overflow.  */
 163 #define REAL_MODE_FORMAT_COMPOSITE_P(MODE) \
 164         ((REAL_MODE_FORMAT(MODE))->pnan < (REAL_MODE_FORMAT (MODE))->p)
 165
 166 /* Declare functions in real.c.  */
 167
 168 /* Binary or unary arithmetic on tree_code.  */
 169 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 170                              const REAL_VALUE_TYPE *);
 171
 172 /* Compare reals by tree_code.  */
 173 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 174
 175 /* Determine whether a floating-point value X is infinite.  */
 176 extern bool real_isinf (const REAL_VALUE_TYPE *);
 177
 178 /* Determine whether a floating-point value X is a NaN.  */
 179 extern bool real_isnan (const REAL_VALUE_TYPE *);
 180
 181 /* Determine whether a floating-point value X is negative.  */
 182 extern bool real_isneg (const REAL_VALUE_TYPE *);
 183
 184 /* Determine whether a floating-point value X is minus zero.  */
 185 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 186
 187 /* Compare two floating-point objects for bitwise identity.  */
 188 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 189
 190 /* Extend or truncate to a new mode.  */
 191 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 192                           const REAL_VALUE_TYPE *);
 193
 194 /* Return true if truncating to NEW is exact.  */
 195 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 196
 197 /* Render R as a decimal floating point constant.  */
 198 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 199                              size_t, int);
 200
 201 /* Render R as a hexadecimal floating point constant.  */
 202 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 203                                  size_t, size_t, int);
 204
 205 /* Render R as an integer.  */
 206 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 207 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 208                               const REAL_VALUE_TYPE *);
 209
 210 /* Initialize R from a decimal or hexadecimal string.  */
 211 extern void real_from_string (REAL_VALUE_TYPE *, const char *);
 212
 213 /* Initialize R from an integer pair HIGH/LOW.  */
 214 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 215                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 216
 217 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 218                                 const struct real_format *);
 219 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 220
 221 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 222                                   const struct real_format *);
 223 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 224                               enum machine_mode);
 225
 226 extern void real_inf (REAL_VALUE_TYPE *);
 227
 228 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 229
 230 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 231
 232 extern void real_2expN (REAL_VALUE_TYPE *, int);
 233
 234 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 235
 236
 237 /* Target formats defined in real.c.  */
 238 extern const struct real_format ieee_single_format;
 239 extern const struct real_format mips_single_format;
 240 extern const struct real_format ieee_double_format;
 241 extern const struct real_format mips_double_format;
 242 extern const struct real_format ieee_extended_motorola_format;
 243 extern const struct real_format ieee_extended_intel_96_format;
 244 extern const struct real_format ieee_extended_intel_96_round_53_format;
 245 extern const struct real_format ieee_extended_intel_128_format;
 246 extern const struct real_format ibm_extended_format;
 247 extern const struct real_format mips_extended_format;
 248 extern const struct real_format ieee_quad_format;
 249 extern const struct real_format mips_quad_format;
 250 extern const struct real_format vax_f_format;
 251 extern const struct real_format vax_d_format;
 252 extern const struct real_format vax_g_format;
 253 extern const struct real_format i370_single_format;
 254 extern const struct real_format i370_double_format;
 255 extern const struct real_format c4x_single_format;
 256 extern const struct real_format c4x_extended_format;
 257 extern const struct real_format real_internal_format;
 258
 259
 260 /* ====================================================================== */
 261 /* Crap.  */
 262
 263 #define REAL_ARITHMETIC(value, code, d1, d2) \
 264   real_arithmetic (&(value), code, &(d1), &(d2))
 265
 266 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 267 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 268 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 269
 270 /* Determine whether a floating-point value X is infinite.  */
 271 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 272
 273 /* Determine whether a floating-point value X is a NaN.  */
 274 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 275
 276 /* Determine whether a floating-point value X is negative.  */
 277 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 278
 279 /* Determine whether a floating-point value X is minus zero.  */
 280 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 281
 282 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 283 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 284   real_to_target (OUT, &(IN),                                           \
 285                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 286
 287 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 288   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 289
 290 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 291 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 292   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 293
 294 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 295   real_from_integer (&(r), mode, lo, hi, 0)
 296
 297 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 298   real_from_integer (&(r), mode, lo, hi, 1)
 299
 300 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 301                                             REAL_VALUE_TYPE);
 302
 303 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 304   real_to_integer2 (plow, phigh, &(r))
 305
 306 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 307                                          const REAL_VALUE_TYPE *);
 308
 309 #define REAL_VALUE_NEGATE(X) \
 310   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 311
 312 #define REAL_VALUE_ABS(X) \
 313   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 314
 315 extern int significand_size (enum machine_mode);
 316
 317 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
 318
 319 #define REAL_VALUE_ATOF(s, m) \
 320   real_from_string2 (s, m)
 321
 322 #define CONST_DOUBLE_ATOF(s, m) \
 323   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 324
 325 #define REAL_VALUE_FIX(r) \
 326   real_to_integer (&(r))
 327
 328 /* ??? Not quite right.  */
 329 #define REAL_VALUE_UNSIGNED_FIX(r) \
 330   real_to_integer (&(r))
 331
 332 /* ??? These were added for Paranoia support.  */
 333
 334 /* Return floor log2(R).  */
 335 extern int real_exponent (const REAL_VALUE_TYPE *);
 336
 337 /* R = A * 2**EXP.  */
 338 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 339
 340 /* **** End of software floating point emulator interface macros **** */
 341 \f
 342 /* Constant real values 0, 1, 2, 3, 10, -1, -2, 0.5 and 1/3.  */
 343
 344 extern REAL_VALUE_TYPE dconst0;
 345 extern REAL_VALUE_TYPE dconst1;
 346 extern REAL_VALUE_TYPE dconst2;
 347 extern REAL_VALUE_TYPE dconst3;
 348 extern REAL_VALUE_TYPE dconst10;
 349 extern REAL_VALUE_TYPE dconstm1;
 350 extern REAL_VALUE_TYPE dconstm2;
 351 extern REAL_VALUE_TYPE dconsthalf;
 352 extern REAL_VALUE_TYPE dconstthird;
 353 extern REAL_VALUE_TYPE dconstpi;
 354 extern REAL_VALUE_TYPE dconste;
 355
 356 /* Function to return a real value (not a tree node)
 357    from a given integer constant.  */
 358 REAL_VALUE_TYPE real_value_from_int_cst (tree, tree);
 359
 360 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 361 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 362   memcpy (&(to), &CONST_DOUBLE_LOW ((from)), sizeof (REAL_VALUE_TYPE))
 363
 364 /* Return a CONST_DOUBLE with value R and mode M.  */
 365 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 366   const_double_from_real_value (r, m)
 367 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 368
 369 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 370 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 371
 372 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 373 extern tree build_real (tree, REAL_VALUE_TYPE);
 374
 375 /* Calculate R as the square root of X in the given machine mode.  */
 376 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 377                        const REAL_VALUE_TYPE *);
 378
 379 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 380 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 381                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 382
 383 /* Standard round to integer value functions.  */
 384 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 385                         const REAL_VALUE_TYPE *);
 386 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 387                         const REAL_VALUE_TYPE *);
 388 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 389                        const REAL_VALUE_TYPE *);
 390 extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
 391                         const REAL_VALUE_TYPE *);
 392
 393 /* Set the sign of R to the sign of X.  */
 394 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 395
 396 #endif /* ! GCC_REAL_H */