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 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   ENUM_BITFIELD (real_value_class) class : 2;
  46   unsigned int sign : 1;
  47   unsigned int signalling : 1;
  48   unsigned int canonical : 1;
  49   signed int exp : EXP_BITS;
  50   unsigned long sig[SIGSZ];
  51 };
  52
  53 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  54    needs to be a macro.  We do need to continue to have a structure tag
  55    so that other headers can forward declare it.  */
  56 #define REAL_VALUE_TYPE struct real_value
  57
  58 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  59    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  60    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  61
  62 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  63 #define REAL_WIDTH \
  64   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  65    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  66
  67 /* Verify the guess.  */
  68 extern char test_real_width
  69   [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
  70
  71 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  72    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  73    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  74
  75    A number of places assume that there are always at least two 'w'
  76    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  77
  78 #if REAL_WIDTH == 1
  79 # define CONST_DOUBLE_FORMAT     "ww"
  80 #else
  81 # if REAL_WIDTH == 2
  82 #  define CONST_DOUBLE_FORMAT    "ww"
  83 # else
  84 #  if REAL_WIDTH == 3
  85 #   define CONST_DOUBLE_FORMAT   "www"
  86 #  else
  87 #   if REAL_WIDTH == 4
  88 #    define CONST_DOUBLE_FORMAT  "wwww"
  89 #   else
  90 #    if REAL_WIDTH == 5
  91 #     define CONST_DOUBLE_FORMAT "wwwww"
  92 #    else
  93 #     if REAL_WIDTH == 6
  94 #      define CONST_DOUBLE_FORMAT "wwwwww"
  95 #     else
  96        #error "REAL_WIDTH > 6 not supported"
  97 #     endif
  98 #    endif
  99 #   endif
 100 #  endif
 101 # endif
 102 #endif
 103
 104
 105 /* Describes the properties of the specific target format in use.  */
 106 struct real_format
 107 {
 108   /* Move to and from the target bytes.  */
 109   void (*encode) PARAMS ((const struct real_format *, long *,
 110                           const REAL_VALUE_TYPE *));
 111   void (*decode) PARAMS ((const struct real_format *, REAL_VALUE_TYPE *,
 112                           const long *));
 113
 114   /* The radix of the exponent and digits of the significand.  */
 115   int b;
 116
 117   /* log2(b).  */
 118   int log2_b;
 119
 120   /* Size of the significand in digits of radix B.  */
 121   int p;
 122
 123   /* Size of the significant of a NaN, in digits of radix B.  */
 124   int pnan;
 125
 126   /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
 127   int emin;
 128
 129   /* The maximum integer, x, such that b**(x-1) is representable.  */
 130   int emax;
 131
 132   /* The bit position of the sign bit, or -1 for a complex encoding.  */
 133   int signbit;
 134
 135   /* Properties of the format.  */
 136   bool has_nans;
 137   bool has_inf;
 138   bool has_denorm;
 139   bool has_signed_zero;
 140   bool qnan_msb_set;
 141 };
 142
 143
 144 /* The target format used for each floating floating point mode.
 145    Indexed by MODE - QFmode.  */
 146 extern const struct real_format *real_format_for_mode[TFmode - QFmode + 1];
 147
 148
 149 /* Declare functions in real.c.  */
 150
 151 /* Binary or unary arithmetic on tree_code.  */
 152 extern void real_arithmetic     PARAMS ((REAL_VALUE_TYPE *, int,
 153                                          const REAL_VALUE_TYPE *,
 154                                          const REAL_VALUE_TYPE *));
 155
 156 /* Compare reals by tree_code.  */
 157 extern bool real_compare        PARAMS ((int, const REAL_VALUE_TYPE *,
 158                                          const REAL_VALUE_TYPE *));
 159
 160 /* Determine whether a floating-point value X is infinite.  */
 161 extern bool real_isinf          PARAMS ((const REAL_VALUE_TYPE *));
 162
 163 /* Determine whether a floating-point value X is a NaN.  */
 164 extern bool real_isnan          PARAMS ((const REAL_VALUE_TYPE *));
 165
 166 /* Determine whether a floating-point value X is negative.  */
 167 extern bool real_isneg          PARAMS ((const REAL_VALUE_TYPE *));
 168
 169 /* Determine whether a floating-point value X is minus zero.  */
 170 extern bool real_isnegzero      PARAMS ((const REAL_VALUE_TYPE *));
 171
 172 /* Compare two floating-point objects for bitwise identity.  */
 173 extern bool real_identical      PARAMS ((const REAL_VALUE_TYPE *,
 174                                          const REAL_VALUE_TYPE *));
 175
 176 /* Extend or truncate to a new mode.  */
 177 extern void real_convert        PARAMS ((REAL_VALUE_TYPE *,
 178                                          enum machine_mode,
 179                                          const REAL_VALUE_TYPE *));
 180
 181 /* Return true if truncating to NEW is exact.  */
 182 extern bool exact_real_truncate PARAMS ((enum machine_mode,
 183                                          const REAL_VALUE_TYPE *));
 184
 185 /* Render R as a decimal floating point constant.  */
 186 extern void real_to_decimal     PARAMS ((char *, const REAL_VALUE_TYPE *,
 187                                          size_t, size_t, int));
 188
 189 /* Render R as a hexadecimal floating point constant.  */
 190 extern void real_to_hexadecimal PARAMS ((char *, const REAL_VALUE_TYPE *,
 191                                          size_t, size_t, int));
 192
 193 /* Render R as an integer.  */
 194 extern HOST_WIDE_INT real_to_integer PARAMS ((const REAL_VALUE_TYPE *));
 195 extern void real_to_integer2 PARAMS ((HOST_WIDE_INT *, HOST_WIDE_INT *,
 196                                       const REAL_VALUE_TYPE *));
 197
 198 /* Initialize R from a decimal or hexadecimal string.  */
 199 extern void real_from_string    PARAMS ((REAL_VALUE_TYPE *, const char *));
 200
 201 /* Initialize R from an integer pair HIGH/LOW.  */
 202 extern void real_from_integer   PARAMS ((REAL_VALUE_TYPE *,
 203                                          enum machine_mode,
 204                                          unsigned HOST_WIDE_INT,
 205                                          HOST_WIDE_INT, int));
 206
 207 extern long real_to_target_fmt  PARAMS ((long *, const REAL_VALUE_TYPE *,
 208                                          const struct real_format *));
 209 extern long real_to_target      PARAMS ((long *, const REAL_VALUE_TYPE *,
 210                                          enum machine_mode));
 211
 212 extern void real_from_target_fmt PARAMS ((REAL_VALUE_TYPE *, const long *,
 213                                           const struct real_format *));
 214 extern void real_from_target    PARAMS ((REAL_VALUE_TYPE *, const long *,
 215                                          enum machine_mode));
 216
 217 extern void real_inf            PARAMS ((REAL_VALUE_TYPE *));
 218
 219 extern bool real_nan            PARAMS ((REAL_VALUE_TYPE *, const char *,
 220                                          int, enum machine_mode));
 221
 222 extern void real_2expN          PARAMS ((REAL_VALUE_TYPE *, int));
 223
 224 extern unsigned int real_hash   PARAMS ((const REAL_VALUE_TYPE *));
 225
 226
 227 /* Target formats defined in real.c.  */
 228 extern const struct real_format ieee_single_format;
 229 extern const struct real_format mips_single_format;
 230 extern const struct real_format ieee_double_format;
 231 extern const struct real_format mips_double_format;
 232 extern const struct real_format ieee_extended_motorola_format;
 233 extern const struct real_format ieee_extended_intel_96_format;
 234 extern const struct real_format ieee_extended_intel_128_format;
 235 extern const struct real_format ibm_extended_format;
 236 extern const struct real_format mips_extended_format;
 237 extern const struct real_format ieee_quad_format;
 238 extern const struct real_format mips_quad_format;
 239 extern const struct real_format vax_f_format;
 240 extern const struct real_format vax_d_format;
 241 extern const struct real_format vax_g_format;
 242 extern const struct real_format i370_single_format;
 243 extern const struct real_format i370_double_format;
 244 extern const struct real_format c4x_single_format;
 245 extern const struct real_format c4x_extended_format;
 246 extern const struct real_format real_internal_format;
 247
 248
 249 /* ====================================================================== */
 250 /* Crap.  */
 251
 252 #define REAL_ARITHMETIC(value, code, d1, d2) \
 253   real_arithmetic (&(value), code, &(d1), &(d2))
 254
 255 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 256 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 257 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 258
 259 /* Determine whether a floating-point value X is infinite.  */
 260 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 261
 262 /* Determine whether a floating-point value X is a NaN.  */
 263 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 264
 265 /* Determine whether a floating-point value X is negative.  */
 266 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 267
 268 /* Determine whether a floating-point value X is minus zero.  */
 269 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 270
 271 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 272 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 273   real_to_target (OUT, &(IN),                                           \
 274                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 275
 276 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 277   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 278
 279 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 280 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 281   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 282
 283 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 284   real_from_integer (&(r), mode, lo, hi, 0)
 285
 286 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 287   real_from_integer (&(r), mode, lo, hi, 1)
 288
 289 extern REAL_VALUE_TYPE real_value_truncate PARAMS ((enum machine_mode,
 290                                                     REAL_VALUE_TYPE));
 291
 292 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 293   real_to_integer2 (plow, phigh, &(r))
 294
 295 extern REAL_VALUE_TYPE real_arithmetic2 PARAMS ((int, const REAL_VALUE_TYPE *,
 296                                                  const REAL_VALUE_TYPE *));
 297
 298 #define REAL_VALUE_NEGATE(X) \
 299   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 300
 301 #define REAL_VALUE_ABS(X) \
 302   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 303
 304 extern int significand_size PARAMS ((enum machine_mode));
 305
 306 extern REAL_VALUE_TYPE real_from_string2 PARAMS ((const char *,
 307                                                   enum machine_mode));
 308
 309 #define REAL_VALUE_ATOF(s, m) \
 310   real_from_string2 (s, m)
 311
 312 #define CONST_DOUBLE_ATOF(s, m) \
 313   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 314
 315 #define REAL_VALUE_FIX(r) \
 316   real_to_integer (&(r))
 317
 318 /* ??? Not quite right.  */
 319 #define REAL_VALUE_UNSIGNED_FIX(r) \
 320   real_to_integer (&(r))
 321
 322 /* ??? These were added for Paranoia support.  */
 323
 324 /* Return floor log2(R).  */
 325 extern int real_exponent        PARAMS ((const REAL_VALUE_TYPE *));
 326
 327 /* R = A * 2**EXP.  */
 328 extern void real_ldexp          PARAMS ((REAL_VALUE_TYPE *,
 329                                          const REAL_VALUE_TYPE *, int));
 330
 331 /* **** End of software floating point emulator interface macros **** */
 332 \f
 333 /* Constant real values 0, 1, 2, -1, -2 and 0.5.  */
 334
 335 extern REAL_VALUE_TYPE dconst0;
 336 extern REAL_VALUE_TYPE dconst1;
 337 extern REAL_VALUE_TYPE dconst2;
 338 extern REAL_VALUE_TYPE dconstm1;
 339 extern REAL_VALUE_TYPE dconstm2;
 340 extern REAL_VALUE_TYPE dconsthalf;
 341
 342 /* Function to return a real value (not a tree node)
 343    from a given integer constant.  */
 344 REAL_VALUE_TYPE real_value_from_int_cst PARAMS ((union tree_node *,
 345                                                  union tree_node *));
 346
 347 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 348 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 349   memcpy (&(to), &CONST_DOUBLE_LOW ((from)), sizeof (REAL_VALUE_TYPE))
 350
 351 /* Return a CONST_DOUBLE with value R and mode M.  */
 352 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 353   const_double_from_real_value (r, m)
 354 extern rtx const_double_from_real_value PARAMS ((REAL_VALUE_TYPE,
 355                                                  enum machine_mode));
 356
 357 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 358 extern bool exact_real_inverse  PARAMS ((enum machine_mode, REAL_VALUE_TYPE *));
 359
 360 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 361 extern tree build_real                  PARAMS ((tree, REAL_VALUE_TYPE));
 362
 363 /* Calculate R as the square root of X in the given machine mode.  */
 364 extern bool real_sqrt                   PARAMS ((REAL_VALUE_TYPE *,
 365                                                  enum machine_mode,
 366                                                  const REAL_VALUE_TYPE *));
 367
 368 #endif /* ! GCC_REAL_H */