soft-fp/soft-fp.h

   1 /* Software floating-point emulation.
   2    Copyright (C) 1997-2016 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Richard Henderson (rth@cygnus.com),
   5                   Jakub Jelinek (jj@ultra.linux.cz),
   6                   David S. Miller (davem@redhat.com) and
   7                   Peter Maydell (pmaydell@chiark.greenend.org.uk).
   8
   9    The GNU C Library is free software; you can redistribute it and/or
  10    modify it under the terms of the GNU Lesser General Public
  11    License as published by the Free Software Foundation; either
  12    version 2.1 of the License, or (at your option) any later version.
  13
  14    In addition to the permissions in the GNU Lesser General Public
  15    License, the Free Software Foundation gives you unlimited
  16    permission to link the compiled version of this file into
  17    combinations with other programs, and to distribute those
  18    combinations without any restriction coming from the use of this
  19    file.  (The Lesser General Public License restrictions do apply in
  20    other respects; for example, they cover modification of the file,
  21    and distribution when not linked into a combine executable.)
  22
  23    The GNU C Library is distributed in the hope that it will be useful,
  24    but WITHOUT ANY WARRANTY; without even the implied warranty of
  25    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  26    Lesser General Public License for more details.
  27
  28    You should have received a copy of the GNU Lesser General Public
  29    License along with the GNU C Library; if not, see
  30    <http://www.gnu.org/licenses/>.  */
  31
  32 #ifndef SOFT_FP_H
  33 #define SOFT_FP_H       1
  34
  35 #ifdef _LIBC
  36 # include <sfp-machine.h>
  37 #elif defined __KERNEL__
  38 /* The Linux kernel uses asm/ names for architecture-specific
  39    files.  */
  40 # include <asm/sfp-machine.h>
  41 #else
  42 # include "sfp-machine.h"
  43 #endif
  44
  45 /* Allow sfp-machine to have its own byte order definitions.  */
  46 #ifndef __BYTE_ORDER
  47 # ifdef _LIBC
  48 #  include <endian.h>
  49 # else
  50 #  error "endianness not defined by sfp-machine.h"
  51 # endif
  52 #endif
  53
  54 /* For unreachable default cases in switch statements over bitwise OR
  55    of FP_CLS_* values.  */
  56 #if (defined __GNUC__                                                   \
  57      && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)))
  58 # define _FP_UNREACHABLE        __builtin_unreachable ()
  59 #else
  60 # define _FP_UNREACHABLE        abort ()
  61 #endif
  62
  63 #if ((defined __GNUC__                                                  \
  64       && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)))      \
  65      || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L))
  66 # define _FP_STATIC_ASSERT(expr, msg)           \
  67   _Static_assert ((expr), msg)
  68 #else
  69 # define _FP_STATIC_ASSERT(expr, msg)                                   \
  70   extern int (*__Static_assert_function (void))                         \
  71     [!!sizeof (struct { int __error_if_negative: (expr) ? 2 : -1; })]
  72 #endif
  73
  74 /* In the Linux kernel, some architectures have a single function that
  75    uses different kinds of unpacking and packing depending on the
  76    instruction being emulated, meaning it is not readily visible to
  77    the compiler that variables from _FP_DECL and _FP_FRAC_DECL_*
  78    macros are only used in cases where they were initialized.  */
  79 #ifdef __KERNEL__
  80 # define _FP_ZERO_INIT          = 0
  81 #else
  82 # define _FP_ZERO_INIT
  83 #endif
  84
  85 #define _FP_WORKBITS            3
  86 #define _FP_WORK_LSB            ((_FP_W_TYPE) 1 << 3)
  87 #define _FP_WORK_ROUND          ((_FP_W_TYPE) 1 << 2)
  88 #define _FP_WORK_GUARD          ((_FP_W_TYPE) 1 << 1)
  89 #define _FP_WORK_STICKY         ((_FP_W_TYPE) 1 << 0)
  90
  91 #ifndef FP_RND_NEAREST
  92 # define FP_RND_NEAREST         0
  93 # define FP_RND_ZERO            1
  94 # define FP_RND_PINF            2
  95 # define FP_RND_MINF            3
  96 #endif
  97 #ifndef FP_ROUNDMODE
  98 # define FP_ROUNDMODE           FP_RND_NEAREST
  99 #endif
 100
 101 /* By default don't care about exceptions.  */
 102 #ifndef FP_EX_INVALID
 103 # define FP_EX_INVALID          0
 104 #endif
 105 #ifndef FP_EX_OVERFLOW
 106 # define FP_EX_OVERFLOW         0
 107 #endif
 108 #ifndef FP_EX_UNDERFLOW
 109 # define FP_EX_UNDERFLOW        0
 110 #endif
 111 #ifndef FP_EX_DIVZERO
 112 # define FP_EX_DIVZERO          0
 113 #endif
 114 #ifndef FP_EX_INEXACT
 115 # define FP_EX_INEXACT          0
 116 #endif
 117 #ifndef FP_EX_DENORM
 118 # define FP_EX_DENORM           0
 119 #endif
 120
 121 /* Sub-exceptions of "invalid".  */
 122 /* Signaling NaN operand.  */
 123 #ifndef FP_EX_INVALID_SNAN
 124 # define FP_EX_INVALID_SNAN     0
 125 #endif
 126 /* Inf * 0.  */
 127 #ifndef FP_EX_INVALID_IMZ
 128 # define FP_EX_INVALID_IMZ      0
 129 #endif
 130 /* fma (Inf, 0, c).  */
 131 #ifndef FP_EX_INVALID_IMZ_FMA
 132 # define FP_EX_INVALID_IMZ_FMA  0
 133 #endif
 134 /* Inf - Inf.  */
 135 #ifndef FP_EX_INVALID_ISI
 136 # define FP_EX_INVALID_ISI      0
 137 #endif
 138 /* 0 / 0.  */
 139 #ifndef FP_EX_INVALID_ZDZ
 140 # define FP_EX_INVALID_ZDZ      0
 141 #endif
 142 /* Inf / Inf.  */
 143 #ifndef FP_EX_INVALID_IDI
 144 # define FP_EX_INVALID_IDI      0
 145 #endif
 146 /* sqrt (negative).  */
 147 #ifndef FP_EX_INVALID_SQRT
 148 # define FP_EX_INVALID_SQRT     0
 149 #endif
 150 /* Invalid conversion to integer.  */
 151 #ifndef FP_EX_INVALID_CVI
 152 # define FP_EX_INVALID_CVI      0
 153 #endif
 154 /* Invalid comparison.  */
 155 #ifndef FP_EX_INVALID_VC
 156 # define FP_EX_INVALID_VC       0
 157 #endif
 158
 159 /* _FP_STRUCT_LAYOUT may be defined as an attribute to determine the
 160    struct layout variant used for structures where bit-fields are used
 161    to access specific parts of binary floating-point numbers.  This is
 162    required for systems where the default ABI uses struct layout with
 163    differences in how consecutive bit-fields are laid out from the
 164    default expected by soft-fp.  */
 165 #ifndef _FP_STRUCT_LAYOUT
 166 # define _FP_STRUCT_LAYOUT
 167 #endif
 168
 169 #ifdef _FP_DECL_EX
 170 # define FP_DECL_EX                                     \
 171   int _fex = 0;                                         \
 172   _FP_DECL_EX
 173 #else
 174 # define FP_DECL_EX int _fex = 0
 175 #endif
 176
 177 /* Initialize any machine-specific state used in FP_ROUNDMODE,
 178    FP_TRAPPING_EXCEPTIONS or FP_HANDLE_EXCEPTIONS.  */
 179 #ifndef FP_INIT_ROUNDMODE
 180 # define FP_INIT_ROUNDMODE do {} while (0)
 181 #endif
 182
 183 /* Initialize any machine-specific state used in
 184    FP_TRAPPING_EXCEPTIONS or FP_HANDLE_EXCEPTIONS.  */
 185 #ifndef FP_INIT_TRAPPING_EXCEPTIONS
 186 # define FP_INIT_TRAPPING_EXCEPTIONS FP_INIT_ROUNDMODE
 187 #endif
 188
 189 /* Initialize any machine-specific state used in
 190    FP_HANDLE_EXCEPTIONS.  */
 191 #ifndef FP_INIT_EXCEPTIONS
 192 # define FP_INIT_EXCEPTIONS FP_INIT_TRAPPING_EXCEPTIONS
 193 #endif
 194
 195 #ifndef FP_HANDLE_EXCEPTIONS
 196 # define FP_HANDLE_EXCEPTIONS do {} while (0)
 197 #endif
 198
 199 /* Whether to flush subnormal inputs to zero with the same sign.  */
 200 #ifndef FP_DENORM_ZERO
 201 # define FP_DENORM_ZERO 0
 202 #endif
 203
 204 #ifndef FP_INHIBIT_RESULTS
 205 /* By default we write the results always.
 206    sfp-machine may override this and e.g.
 207    check if some exceptions are unmasked
 208    and inhibit it in such a case.  */
 209 # define FP_INHIBIT_RESULTS 0
 210 #endif
 211
 212 #define FP_SET_EXCEPTION(ex)                            \
 213   _fex |= (ex)
 214
 215 #define FP_CUR_EXCEPTIONS                               \
 216   (_fex)
 217
 218 #ifndef FP_TRAPPING_EXCEPTIONS
 219 # define FP_TRAPPING_EXCEPTIONS 0
 220 #endif
 221
 222 /* A file using soft-fp may define FP_NO_EXCEPTIONS before including
 223    soft-fp.h to indicate that, although a macro used there could raise
 224    exceptions, or do rounding and potentially thereby raise
 225    exceptions, for some arguments, for the particular arguments used
 226    in that file no exceptions or rounding can occur.  Such a file
 227    should not itself use macros relating to handling exceptions and
 228    rounding modes; this is only for indirect uses (in particular, in
 229    _FP_FROM_INT and the macros it calls).  */
 230 #ifdef FP_NO_EXCEPTIONS
 231
 232 # undef FP_SET_EXCEPTION
 233 # define FP_SET_EXCEPTION(ex) do {} while (0)
 234
 235 # undef FP_CUR_EXCEPTIONS
 236 # define FP_CUR_EXCEPTIONS 0
 237
 238 # undef FP_TRAPPING_EXCEPTIONS
 239 # define FP_TRAPPING_EXCEPTIONS 0
 240
 241 # undef FP_ROUNDMODE
 242 # define FP_ROUNDMODE FP_RND_ZERO
 243
 244 # undef _FP_TININESS_AFTER_ROUNDING
 245 # define _FP_TININESS_AFTER_ROUNDING 0
 246
 247 #endif
 248
 249 /* A file using soft-fp may define FP_NO_EXACT_UNDERFLOW before
 250    including soft-fp.h to indicate that, although a macro used there
 251    could allow for the case of exact underflow requiring the underflow
 252    exception to be raised if traps are enabled, for the particular
 253    arguments used in that file no exact underflow can occur.  */
 254 #ifdef FP_NO_EXACT_UNDERFLOW
 255 # undef FP_TRAPPING_EXCEPTIONS
 256 # define FP_TRAPPING_EXCEPTIONS 0
 257 #endif
 258
 259 #define _FP_ROUND_NEAREST(wc, X)                                \
 260   do                                                            \
 261     {                                                           \
 262       if ((_FP_FRAC_LOW_##wc (X) & 15) != _FP_WORK_ROUND)       \
 263         _FP_FRAC_ADDI_##wc (X, _FP_WORK_ROUND);                 \
 264     }                                                           \
 265   while (0)
 266
 267 #define _FP_ROUND_ZERO(wc, X)           (void) 0
 268
 269 #define _FP_ROUND_PINF(wc, X)                           \
 270   do                                                    \
 271     {                                                   \
 272       if (!X##_s && (_FP_FRAC_LOW_##wc (X) & 7))        \
 273         _FP_FRAC_ADDI_##wc (X, _FP_WORK_LSB);           \
 274     }                                                   \
 275   while (0)
 276
 277 #define _FP_ROUND_MINF(wc, X)                   \
 278   do                                            \
 279     {                                           \
 280       if (X##_s && (_FP_FRAC_LOW_##wc (X) & 7)) \
 281         _FP_FRAC_ADDI_##wc (X, _FP_WORK_LSB);   \
 282     }                                           \
 283   while (0)
 284
 285 #define _FP_ROUND(wc, X)                        \
 286   do                                            \
 287     {                                           \
 288       if (_FP_FRAC_LOW_##wc (X) & 7)            \
 289         {                                       \
 290           FP_SET_EXCEPTION (FP_EX_INEXACT);     \
 291           switch (FP_ROUNDMODE)                 \
 292             {                                   \
 293             case FP_RND_NEAREST:                \
 294               _FP_ROUND_NEAREST (wc, X);        \
 295               break;                            \
 296             case FP_RND_ZERO:                   \
 297               _FP_ROUND_ZERO (wc, X);           \
 298               break;                            \
 299             case FP_RND_PINF:                   \
 300               _FP_ROUND_PINF (wc, X);           \
 301               break;                            \
 302             case FP_RND_MINF:                   \
 303               _FP_ROUND_MINF (wc, X);           \
 304               break;                            \
 305             }                                   \
 306         }                                       \
 307     }                                           \
 308   while (0)
 309
 310 #define FP_CLS_NORMAL           0
 311 #define FP_CLS_ZERO             1
 312 #define FP_CLS_INF              2
 313 #define FP_CLS_NAN              3
 314
 315 #define _FP_CLS_COMBINE(x, y)   (((x) << 2) | (y))
 316
 317 #include "op-1.h"
 318 #include "op-2.h"
 319 #include "op-4.h"
 320 #include "op-8.h"
 321 #include "op-common.h"
 322
 323 /* Sigh.  Silly things longlong.h needs.  */
 324 #define UWtype          _FP_W_TYPE
 325 #define W_TYPE_SIZE     _FP_W_TYPE_SIZE
 326
 327 typedef int QItype __attribute__ ((mode (QI)));
 328 typedef int SItype __attribute__ ((mode (SI)));
 329 typedef int DItype __attribute__ ((mode (DI)));
 330 typedef unsigned int UQItype __attribute__ ((mode (QI)));
 331 typedef unsigned int USItype __attribute__ ((mode (SI)));
 332 typedef unsigned int UDItype __attribute__ ((mode (DI)));
 333 #if _FP_W_TYPE_SIZE == 32
 334 typedef unsigned int UHWtype __attribute__ ((mode (HI)));
 335 #elif _FP_W_TYPE_SIZE == 64
 336 typedef USItype UHWtype;
 337 #endif
 338
 339 #ifndef CMPtype
 340 # define CMPtype        int
 341 #endif
 342
 343 #define SI_BITS         (__CHAR_BIT__ * (int) sizeof (SItype))
 344 #define DI_BITS         (__CHAR_BIT__ * (int) sizeof (DItype))
 345
 346 #ifndef umul_ppmm
 347 # ifdef _LIBC
 348 #  include <stdlib/longlong.h>
 349 # else
 350 #  include "longlong.h"
 351 # endif
 352 #endif
 353
 354 #endif /* !SOFT_FP_H */