soft-fp/soft-fp.h

   1 /* Software floating-point emulation.
   2    Copyright (C) 1997-2015 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 /* In the Linux kernel, some architectures have a single function that
  64    uses different kinds of unpacking and packing depending on the
  65    instruction being emulated, meaning it is not readily visible to
  66    the compiler that variables from _FP_DECL and _FP_FRAC_DECL_*
  67    macros are only used in cases where they were initialized.  */
  68 #ifdef __KERNEL__
  69 # define _FP_ZERO_INIT          = 0
  70 #else
  71 # define _FP_ZERO_INIT
  72 #endif
  73
  74 #define _FP_WORKBITS            3
  75 #define _FP_WORK_LSB            ((_FP_W_TYPE) 1 << 3)
  76 #define _FP_WORK_ROUND          ((_FP_W_TYPE) 1 << 2)
  77 #define _FP_WORK_GUARD          ((_FP_W_TYPE) 1 << 1)
  78 #define _FP_WORK_STICKY         ((_FP_W_TYPE) 1 << 0)
  79
  80 #ifndef FP_RND_NEAREST
  81 # define FP_RND_NEAREST         0
  82 # define FP_RND_ZERO            1
  83 # define FP_RND_PINF            2
  84 # define FP_RND_MINF            3
  85 #endif
  86 #ifndef FP_ROUNDMODE
  87 # define FP_ROUNDMODE           FP_RND_NEAREST
  88 #endif
  89
  90 /* By default don't care about exceptions.  */
  91 #ifndef FP_EX_INVALID
  92 # define FP_EX_INVALID          0
  93 #endif
  94 #ifndef FP_EX_OVERFLOW
  95 # define FP_EX_OVERFLOW         0
  96 #endif
  97 #ifndef FP_EX_UNDERFLOW
  98 # define FP_EX_UNDERFLOW        0
  99 #endif
 100 #ifndef FP_EX_DIVZERO
 101 # define FP_EX_DIVZERO          0
 102 #endif
 103 #ifndef FP_EX_INEXACT
 104 # define FP_EX_INEXACT          0
 105 #endif
 106 #ifndef FP_EX_DENORM
 107 # define FP_EX_DENORM           0
 108 #endif
 109
 110 /* Sub-exceptions of "invalid".  */
 111 /* Signaling NaN operand.  */
 112 #ifndef FP_EX_INVALID_SNAN
 113 # define FP_EX_INVALID_SNAN     0
 114 #endif
 115 /* Inf * 0.  */
 116 #ifndef FP_EX_INVALID_IMZ
 117 # define FP_EX_INVALID_IMZ      0
 118 #endif
 119 /* fma (Inf, 0, c).  */
 120 #ifndef FP_EX_INVALID_IMZ_FMA
 121 # define FP_EX_INVALID_IMZ_FMA  0
 122 #endif
 123 /* Inf - Inf.  */
 124 #ifndef FP_EX_INVALID_ISI
 125 # define FP_EX_INVALID_ISI      0
 126 #endif
 127 /* 0 / 0.  */
 128 #ifndef FP_EX_INVALID_ZDZ
 129 # define FP_EX_INVALID_ZDZ      0
 130 #endif
 131 /* Inf / Inf.  */
 132 #ifndef FP_EX_INVALID_IDI
 133 # define FP_EX_INVALID_IDI      0
 134 #endif
 135 /* sqrt (negative).  */
 136 #ifndef FP_EX_INVALID_SQRT
 137 # define FP_EX_INVALID_SQRT     0
 138 #endif
 139 /* Invalid conversion to integer.  */
 140 #ifndef FP_EX_INVALID_CVI
 141 # define FP_EX_INVALID_CVI      0
 142 #endif
 143 /* Invalid comparison.  */
 144 #ifndef FP_EX_INVALID_VC
 145 # define FP_EX_INVALID_VC       0
 146 #endif
 147
 148 /* _FP_STRUCT_LAYOUT may be defined as an attribute to determine the
 149    struct layout variant used for structures where bit-fields are used
 150    to access specific parts of binary floating-point numbers.  This is
 151    required for systems where the default ABI uses struct layout with
 152    differences in how consecutive bit-fields are laid out from the
 153    default expected by soft-fp.  */
 154 #ifndef _FP_STRUCT_LAYOUT
 155 # define _FP_STRUCT_LAYOUT
 156 #endif
 157
 158 #ifdef _FP_DECL_EX
 159 # define FP_DECL_EX                                     \
 160   int _fex = 0;                                         \
 161   _FP_DECL_EX
 162 #else
 163 # define FP_DECL_EX int _fex = 0
 164 #endif
 165
 166 /* Initialize any machine-specific state used in FP_ROUNDMODE,
 167    FP_TRAPPING_EXCEPTIONS or FP_HANDLE_EXCEPTIONS.  */
 168 #ifndef FP_INIT_ROUNDMODE
 169 # define FP_INIT_ROUNDMODE do {} while (0)
 170 #endif
 171
 172 /* Initialize any machine-specific state used in
 173    FP_TRAPPING_EXCEPTIONS or FP_HANDLE_EXCEPTIONS.  */
 174 #ifndef FP_INIT_TRAPPING_EXCEPTIONS
 175 # define FP_INIT_TRAPPING_EXCEPTIONS FP_INIT_ROUNDMODE
 176 #endif
 177
 178 /* Initialize any machine-specific state used in
 179    FP_HANDLE_EXCEPTIONS.  */
 180 #ifndef FP_INIT_EXCEPTIONS
 181 # define FP_INIT_EXCEPTIONS FP_INIT_TRAPPING_EXCEPTIONS
 182 #endif
 183
 184 #ifndef FP_HANDLE_EXCEPTIONS
 185 # define FP_HANDLE_EXCEPTIONS do {} while (0)
 186 #endif
 187
 188 /* Whether to flush subnormal inputs to zero with the same sign.  */
 189 #ifndef FP_DENORM_ZERO
 190 # define FP_DENORM_ZERO 0
 191 #endif
 192
 193 #ifndef FP_INHIBIT_RESULTS
 194 /* By default we write the results always.
 195    sfp-machine may override this and e.g.
 196    check if some exceptions are unmasked
 197    and inhibit it in such a case.  */
 198 # define FP_INHIBIT_RESULTS 0
 199 #endif
 200
 201 #define FP_SET_EXCEPTION(ex)                            \
 202   _fex |= (ex)
 203
 204 #define FP_CUR_EXCEPTIONS                               \
 205   (_fex)
 206
 207 #ifndef FP_TRAPPING_EXCEPTIONS
 208 # define FP_TRAPPING_EXCEPTIONS 0
 209 #endif
 210
 211 /* A file using soft-fp may define FP_NO_EXCEPTIONS before including
 212    soft-fp.h to indicate that, although a macro used there could raise
 213    exceptions, or do rounding and potentially thereby raise
 214    exceptions, for some arguments, for the particular arguments used
 215    in that file no exceptions or rounding can occur.  Such a file
 216    should not itself use macros relating to handling exceptions and
 217    rounding modes; this is only for indirect uses (in particular, in
 218    _FP_FROM_INT and the macros it calls).  */
 219 #ifdef FP_NO_EXCEPTIONS
 220
 221 # undef FP_SET_EXCEPTION
 222 # define FP_SET_EXCEPTION(ex) do {} while (0)
 223
 224 # undef FP_CUR_EXCEPTIONS
 225 # define FP_CUR_EXCEPTIONS 0
 226
 227 # undef FP_TRAPPING_EXCEPTIONS
 228 # define FP_TRAPPING_EXCEPTIONS 0
 229
 230 # undef FP_ROUNDMODE
 231 # define FP_ROUNDMODE FP_RND_ZERO
 232
 233 # undef _FP_TININESS_AFTER_ROUNDING
 234 # define _FP_TININESS_AFTER_ROUNDING 0
 235
 236 #endif
 237
 238 /* A file using soft-fp may define FP_NO_EXACT_UNDERFLOW before
 239    including soft-fp.h to indicate that, although a macro used there
 240    could allow for the case of exact underflow requiring the underflow
 241    exception to be raised if traps are enabled, for the particular
 242    arguments used in that file no exact underflow can occur.  */
 243 #ifdef FP_NO_EXACT_UNDERFLOW
 244 # undef FP_TRAPPING_EXCEPTIONS
 245 # define FP_TRAPPING_EXCEPTIONS 0
 246 #endif
 247
 248 #define _FP_ROUND_NEAREST(wc, X)                                \
 249   do                                                            \
 250     {                                                           \
 251       if ((_FP_FRAC_LOW_##wc (X) & 15) != _FP_WORK_ROUND)       \
 252         _FP_FRAC_ADDI_##wc (X, _FP_WORK_ROUND);                 \
 253     }                                                           \
 254   while (0)
 255
 256 #define _FP_ROUND_ZERO(wc, X)           (void) 0
 257
 258 #define _FP_ROUND_PINF(wc, X)                           \
 259   do                                                    \
 260     {                                                   \
 261       if (!X##_s && (_FP_FRAC_LOW_##wc (X) & 7))        \
 262         _FP_FRAC_ADDI_##wc (X, _FP_WORK_LSB);           \
 263     }                                                   \
 264   while (0)
 265
 266 #define _FP_ROUND_MINF(wc, X)                   \
 267   do                                            \
 268     {                                           \
 269       if (X##_s && (_FP_FRAC_LOW_##wc (X) & 7)) \
 270         _FP_FRAC_ADDI_##wc (X, _FP_WORK_LSB);   \
 271     }                                           \
 272   while (0)
 273
 274 #define _FP_ROUND(wc, X)                        \
 275   do                                            \
 276     {                                           \
 277       if (_FP_FRAC_LOW_##wc (X) & 7)            \
 278         {                                       \
 279           FP_SET_EXCEPTION (FP_EX_INEXACT);     \
 280           switch (FP_ROUNDMODE)                 \
 281             {                                   \
 282             case FP_RND_NEAREST:                \
 283               _FP_ROUND_NEAREST (wc, X);        \
 284               break;                            \
 285             case FP_RND_ZERO:                   \
 286               _FP_ROUND_ZERO (wc, X);           \
 287               break;                            \
 288             case FP_RND_PINF:                   \
 289               _FP_ROUND_PINF (wc, X);           \
 290               break;                            \
 291             case FP_RND_MINF:                   \
 292               _FP_ROUND_MINF (wc, X);           \
 293               break;                            \
 294             }                                   \
 295         }                                       \
 296     }                                           \
 297   while (0)
 298
 299 #define FP_CLS_NORMAL           0
 300 #define FP_CLS_ZERO             1
 301 #define FP_CLS_INF              2
 302 #define FP_CLS_NAN              3
 303
 304 #define _FP_CLS_COMBINE(x, y)   (((x) << 2) | (y))
 305
 306 #include "op-1.h"
 307 #include "op-2.h"
 308 #include "op-4.h"
 309 #include "op-8.h"
 310 #include "op-common.h"
 311
 312 /* Sigh.  Silly things longlong.h needs.  */
 313 #define UWtype          _FP_W_TYPE
 314 #define W_TYPE_SIZE     _FP_W_TYPE_SIZE
 315
 316 typedef int QItype __attribute__ ((mode (QI)));
 317 typedef int SItype __attribute__ ((mode (SI)));
 318 typedef int DItype __attribute__ ((mode (DI)));
 319 typedef unsigned int UQItype __attribute__ ((mode (QI)));
 320 typedef unsigned int USItype __attribute__ ((mode (SI)));
 321 typedef unsigned int UDItype __attribute__ ((mode (DI)));
 322 #if _FP_W_TYPE_SIZE == 32
 323 typedef unsigned int UHWtype __attribute__ ((mode (HI)));
 324 #elif _FP_W_TYPE_SIZE == 64
 325 typedef USItype UHWtype;
 326 #endif
 327
 328 #ifndef CMPtype
 329 # define CMPtype        int
 330 #endif
 331
 332 #define SI_BITS         (__CHAR_BIT__ * (int) sizeof (SItype))
 333 #define DI_BITS         (__CHAR_BIT__ * (int) sizeof (DItype))
 334
 335 #ifndef umul_ppmm
 336 # ifdef _LIBC
 337 #  include <stdlib/longlong.h>
 338 # else
 339 #  include "longlong.h"
 340 # endif
 341 #endif
 342
 343 #ifdef _LIBC
 344 # include <stdlib.h>
 345 #else
 346 extern void abort (void);
 347 #endif
 348
 349 #endif /* !SOFT_FP_H */