sysdeps/ieee754/ieee754.h

   1 /* Copyright (C) 1992, 1995, 1996, 1999 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #ifndef _IEEE754_H
  20
  21 #define _IEEE754_H 1
  22 #include <features.h>
  23
  24 #include <endian.h>
  25
  26 __BEGIN_DECLS
  27
  28 union ieee754_float
  29   {
  30     float f;
  31
  32     /* This is the IEEE 754 single-precision format.  */
  33     struct
  34       {
  35 #if     __BYTE_ORDER == __BIG_ENDIAN
  36         unsigned int negative:1;
  37         unsigned int exponent:8;
  38         unsigned int mantissa:23;
  39 #endif                          /* Big endian.  */
  40 #if     __BYTE_ORDER == __LITTLE_ENDIAN
  41         unsigned int mantissa:23;
  42         unsigned int exponent:8;
  43         unsigned int negative:1;
  44 #endif                          /* Little endian.  */
  45       } ieee;
  46
  47     /* This format makes it easier to see if a NaN is a signalling NaN.  */
  48     struct
  49       {
  50 #if     __BYTE_ORDER == __BIG_ENDIAN
  51         unsigned int negative:1;
  52         unsigned int exponent:8;
  53         unsigned int quiet_nan:1;
  54         unsigned int mantissa:22;
  55 #endif                          /* Big endian.  */
  56 #if     __BYTE_ORDER == __LITTLE_ENDIAN
  57         unsigned int mantissa:22;
  58         unsigned int quiet_nan:1;
  59         unsigned int exponent:8;
  60         unsigned int negative:1;
  61 #endif                          /* Little endian.  */
  62       } ieee_nan;
  63   };
  64
  65 #define IEEE754_FLOAT_BIAS      0x7f /* Added to exponent.  */
  66
  67
  68 union ieee754_double
  69   {
  70     double d;
  71
  72     /* This is the IEEE 754 double-precision format.  */
  73     struct
  74       {
  75 #if     __BYTE_ORDER == __BIG_ENDIAN
  76         unsigned int negative:1;
  77         unsigned int exponent:11;
  78         /* Together these comprise the mantissa.  */
  79         unsigned int mantissa0:20;
  80         unsigned int mantissa1:32;
  81 #endif                          /* Big endian.  */
  82 #if     __BYTE_ORDER == __LITTLE_ENDIAN
  83 # if    __FLOAT_WORD_ORDER == __BIG_ENDIAN
  84         unsigned int mantissa0:20;
  85         unsigned int exponent:11;
  86         unsigned int negative:1;
  87         unsigned int mantissa1:32;
  88 # else
  89         /* Together these comprise the mantissa.  */
  90         unsigned int mantissa1:32;
  91         unsigned int mantissa0:20;
  92         unsigned int exponent:11;
  93         unsigned int negative:1;
  94 # endif
  95 #endif                          /* Little endian.  */
  96       } ieee;
  97
  98     /* This format makes it easier to see if a NaN is a signalling NaN.  */
  99     struct
 100       {
 101 #if     __BYTE_ORDER == __BIG_ENDIAN
 102         unsigned int negative:1;
 103         unsigned int exponent:11;
 104         unsigned int quiet_nan:1;
 105         /* Together these comprise the mantissa.  */
 106         unsigned int mantissa0:19;
 107         unsigned int mantissa1:32;
 108 #else
 109 # if    __FLOAT_WORD_ORDER == __BIG_ENDIAN
 110         unsigned int mantissa0:19;
 111         unsigned int quiet_nan:1;
 112         unsigned int exponent:11;
 113         unsigned int negative:1;
 114         unsigned int mantissa1:32;
 115 # else
 116         /* Together these comprise the mantissa.  */
 117         unsigned int mantissa1:32;
 118         unsigned int mantissa0:19;
 119         unsigned int quiet_nan:1;
 120         unsigned int exponent:11;
 121         unsigned int negative:1;
 122 # endif
 123 #endif
 124       } ieee_nan;
 125   };
 126
 127 #define IEEE754_DOUBLE_BIAS     0x3ff /* Added to exponent.  */
 128
 129
 130 union ieee854_long_double
 131   {
 132     long double d;
 133
 134     /* This is the IEEE 854 double-extended-precision format.  */
 135     struct
 136       {
 137 #if     __BYTE_ORDER == __BIG_ENDIAN
 138         unsigned int negative:1;
 139         unsigned int exponent:15;
 140         unsigned int empty:16;
 141         unsigned int mantissa0:32;
 142         unsigned int mantissa1:32;
 143 #endif
 144 #if     __BYTE_ORDER == __LITTLE_ENDIAN
 145 # if    __FLOAT_WORD_ORDER == __BIG_ENDIAN
 146         unsigned int exponent:15;
 147         unsigned int negative:1;
 148         unsigned int empty:16;
 149         unsigned int mantissa0:32;
 150         unsigned int mantissa1:32;
 151 # else
 152         unsigned int mantissa1:32;
 153         unsigned int mantissa0:32;
 154         unsigned int exponent:15;
 155         unsigned int negative:1;
 156         unsigned int empty:16;
 157 # endif
 158 #endif
 159       } ieee;
 160
 161     /* This is for NaNs in the IEEE 854 double-extended-precision format.  */
 162     struct
 163       {
 164 #if     __BYTE_ORDER == __BIG_ENDIAN
 165         unsigned int negative:1;
 166         unsigned int exponent:15;
 167         unsigned int empty:16;
 168         unsigned int one:1;
 169         unsigned int quiet_nan:1;
 170         unsigned int mantissa0:30;
 171         unsigned int mantissa1:32;
 172 #endif
 173 #if     __BYTE_ORDER == __LITTLE_ENDIAN
 174 # if    __FLOAT_WORD_ORDER == __BIG_ENDIAN
 175         unsigned int exponent:15;
 176         unsigned int negative:1;
 177         unsigned int empty:16;
 178         unsigned int mantissa0:30;
 179         unsigned int quiet_nan:1;
 180         unsigned int one:1;
 181         unsigned int mantissa1:32;
 182 # else
 183         unsigned int mantissa1:32;
 184         unsigned int mantissa0:30;
 185         unsigned int quiet_nan:1;
 186         unsigned int one:1;
 187         unsigned int exponent:15;
 188         unsigned int negative:1;
 189         unsigned int empty:16;
 190 # endif
 191 #endif
 192       } ieee_nan;
 193   };
 194
 195 #define IEEE854_LONG_DOUBLE_BIAS 0x3fff
 196
 197 __END_DECLS
 198
 199 #endif /* ieee754.h */