soft-fp/soft-fp.h

   1 /* Software floating-point emulation.
   2    Copyright (C) 1997-2013 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
  34
  35 #ifdef _LIBC
  36 # include <sfp-machine.h>
  37 #else
  38 # include "sfp-machine.h"
  39 #endif
  40
  41 /* Allow sfp-machine to have its own byte order definitions. */
  42 #ifndef __BYTE_ORDER
  43 # ifdef _LIBC
  44 #  include <endian.h>
  45 # else
  46 #  error "endianness not defined by sfp-machine.h"
  47 # endif
  48 #endif
  49
  50 #define _FP_WORKBITS            3
  51 #define _FP_WORK_LSB            ((_FP_W_TYPE) 1 << 3)
  52 #define _FP_WORK_ROUND          ((_FP_W_TYPE) 1 << 2)
  53 #define _FP_WORK_GUARD          ((_FP_W_TYPE) 1 << 1)
  54 #define _FP_WORK_STICKY         ((_FP_W_TYPE) 1 << 0)
  55
  56 #ifndef FP_RND_NEAREST
  57 # define FP_RND_NEAREST         0
  58 # define FP_RND_ZERO            1
  59 # define FP_RND_PINF            2
  60 # define FP_RND_MINF            3
  61 #endif
  62 #ifndef FP_ROUNDMODE
  63 # define FP_ROUNDMODE           FP_RND_NEAREST
  64 #endif
  65
  66 /* By default don't care about exceptions. */
  67 #ifndef FP_EX_INVALID
  68 # define FP_EX_INVALID          0
  69 #endif
  70 #ifndef FP_EX_OVERFLOW
  71 # define FP_EX_OVERFLOW         0
  72 #endif
  73 #ifndef FP_EX_UNDERFLOW
  74 # define FP_EX_UNDERFLOW        0
  75 #endif
  76 #ifndef FP_EX_DIVZERO
  77 # define FP_EX_DIVZERO          0
  78 #endif
  79 #ifndef FP_EX_INEXACT
  80 # define FP_EX_INEXACT          0
  81 #endif
  82 #ifndef FP_EX_DENORM
  83 # define FP_EX_DENORM           0
  84 #endif
  85
  86 /* _FP_STRUCT_LAYOUT may be defined as an attribute to determine the
  87    struct layout variant used for structures where bit-fields are used
  88    to access specific parts of binary floating-point numbers.  This is
  89    required for systems where the default ABI uses struct layout with
  90    differences in how consecutive bit-fields are laid out from the
  91    default expected by soft-fp.  */
  92 #ifndef _FP_STRUCT_LAYOUT
  93 # define _FP_STRUCT_LAYOUT
  94 #endif
  95
  96 #ifdef _FP_DECL_EX
  97 # define FP_DECL_EX                                     \
  98   int _fex = 0;                                         \
  99   _FP_DECL_EX
 100 #else
 101 # define FP_DECL_EX int _fex = 0
 102 #endif
 103
 104 /* Initialize any machine-specific state used in FP_ROUNDMODE,
 105    FP_TRAPPING_EXCEPTIONS or FP_HANDLE_EXCEPTIONS.  */
 106 #ifndef FP_INIT_ROUNDMODE
 107 # define FP_INIT_ROUNDMODE do {} while (0)
 108 #endif
 109
 110 /* Initialize any machine-specific state used in
 111    FP_HANDLE_EXCEPTIONS.  */
 112 #ifndef FP_INIT_EXCEPTIONS
 113 # define FP_INIT_EXCEPTIONS FP_INIT_ROUNDMODE
 114 #endif
 115
 116 #ifndef FP_HANDLE_EXCEPTIONS
 117 # define FP_HANDLE_EXCEPTIONS do {} while (0)
 118 #endif
 119
 120 #ifndef FP_INHIBIT_RESULTS
 121 /* By default we write the results always.
 122  * sfp-machine may override this and e.g.
 123  * check if some exceptions are unmasked
 124  * and inhibit it in such a case.
 125  */
 126 # define FP_INHIBIT_RESULTS 0
 127 #endif
 128
 129 #define FP_SET_EXCEPTION(ex)                            \
 130   _fex |= (ex)
 131
 132 #define FP_CLEAR_EXCEPTIONS                             \
 133   _fex = 0
 134
 135 #define FP_CUR_EXCEPTIONS                               \
 136   (_fex)
 137
 138 #ifndef FP_TRAPPING_EXCEPTIONS
 139 # define FP_TRAPPING_EXCEPTIONS 0
 140 #endif
 141
 142 /* A file using soft-fp may define FP_NO_EXCEPTIONS before including
 143    soft-fp.h to indicate that, although a macro used there could raise
 144    exceptions, or do rounding and potentially thereby raise
 145    exceptions, for some arguments, for the particular arguments used
 146    in that file no exceptions or rounding can occur.  Such a file
 147    should not itself use macros relating to handling exceptions and
 148    rounding modes; this is only for indirect uses (in particular, in
 149    _FP_FROM_INT and the macros it calls).  */
 150 #ifdef FP_NO_EXCEPTIONS
 151
 152 # undef FP_SET_EXCEPTION
 153 # define FP_SET_EXCEPTION(ex) do {} while (0)
 154
 155 # undef FP_CUR_EXCEPTIONS
 156 # define FP_CUR_EXCEPTIONS 0
 157
 158 # undef FP_TRAPPING_EXCEPTIONS
 159 # define FP_TRAPPING_EXCEPTIONS 0
 160
 161 # undef FP_ROUNDMODE
 162 # define FP_ROUNDMODE FP_RND_ZERO
 163
 164 #endif
 165
 166 #define _FP_ROUND_NEAREST(wc, X)                                \
 167   do                                                            \
 168     {                                                           \
 169       if ((_FP_FRAC_LOW_##wc (X) & 15) != _FP_WORK_ROUND)       \
 170         _FP_FRAC_ADDI_##wc (X, _FP_WORK_ROUND);                 \
 171     }                                                           \
 172   while (0)
 173
 174 #define _FP_ROUND_ZERO(wc, X)           (void) 0
 175
 176 #define _FP_ROUND_PINF(wc, X)                           \
 177   do                                                    \
 178     {                                                   \
 179       if (!X##_s && (_FP_FRAC_LOW_##wc (X) & 7))        \
 180         _FP_FRAC_ADDI_##wc (X, _FP_WORK_LSB);           \
 181     }                                                   \
 182   while (0)
 183
 184 #define _FP_ROUND_MINF(wc, X)                   \
 185   do                                            \
 186     {                                           \
 187       if (X##_s && (_FP_FRAC_LOW_##wc (X) & 7)) \
 188         _FP_FRAC_ADDI_##wc (X, _FP_WORK_LSB);   \
 189     }                                           \
 190   while (0)
 191
 192 #define _FP_ROUND(wc, X)                        \
 193   do                                            \
 194     {                                           \
 195       if (_FP_FRAC_LOW_##wc (X) & 7)            \
 196         {                                       \
 197           FP_SET_EXCEPTION (FP_EX_INEXACT);     \
 198           switch (FP_ROUNDMODE)                 \
 199             {                                   \
 200             case FP_RND_NEAREST:                \
 201               _FP_ROUND_NEAREST (wc, X);        \
 202               break;                            \
 203             case FP_RND_ZERO:                   \
 204               _FP_ROUND_ZERO (wc, X);           \
 205               break;                            \
 206             case FP_RND_PINF:                   \
 207               _FP_ROUND_PINF (wc, X);           \
 208               break;                            \
 209             case FP_RND_MINF:                   \
 210               _FP_ROUND_MINF (wc, X);           \
 211               break;                            \
 212             }                                   \
 213         }                                       \
 214     }                                           \
 215   while (0)
 216
 217 #define FP_CLS_NORMAL           0
 218 #define FP_CLS_ZERO             1
 219 #define FP_CLS_INF              2
 220 #define FP_CLS_NAN              3
 221
 222 #define _FP_CLS_COMBINE(x, y)   (((x) << 2) | (y))
 223
 224 #include "op-1.h"
 225 #include "op-2.h"
 226 #include "op-4.h"
 227 #include "op-8.h"
 228 #include "op-common.h"
 229
 230 /* Sigh.  Silly things longlong.h needs.  */
 231 #define UWtype          _FP_W_TYPE
 232 #define W_TYPE_SIZE     _FP_W_TYPE_SIZE
 233
 234 typedef int QItype __attribute__ ((mode (QI)));
 235 typedef int SItype __attribute__ ((mode (SI)));
 236 typedef int DItype __attribute__ ((mode (DI)));
 237 typedef unsigned int UQItype __attribute__ ((mode (QI)));
 238 typedef unsigned int USItype __attribute__ ((mode (SI)));
 239 typedef unsigned int UDItype __attribute__ ((mode (DI)));
 240 #if _FP_W_TYPE_SIZE == 32
 241 typedef unsigned int UHWtype __attribute__ ((mode (HI)));
 242 #elif _FP_W_TYPE_SIZE == 64
 243 typedef USItype UHWtype;
 244 #endif
 245
 246 #ifndef CMPtype
 247 # define CMPtype        int
 248 #endif
 249
 250 #define SI_BITS         (__CHAR_BIT__ * (int) sizeof (SItype))
 251 #define DI_BITS         (__CHAR_BIT__ * (int) sizeof (DItype))
 252
 253 #ifndef umul_ppmm
 254 # ifdef _LIBC
 255 #  include <stdlib/longlong.h>
 256 # else
 257 #  include "longlong.h"
 258 # endif
 259 #endif
 260
 261 #ifdef _LIBC
 262 # include <stdlib.h>
 263 #else
 264 extern void abort (void);
 265 #endif
 266
 267 #endif