sysdeps/ieee754/ieee754.h

   1 /* Copyright (C) 1992-2018 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _IEEE754_H
  19
  20 #define _IEEE754_H 1
  21 #include <features.h>
  22
  23 #include <endian.h>
  24
  25 __BEGIN_DECLS
  26
  27 union ieee754_float
  28   {
  29     float f;
  30
  31     /* This is the IEEE 754 single-precision format.  */
  32     struct
  33       {
  34 #if     __BYTE_ORDER == __BIG_ENDIAN
  35         unsigned int negative:1;
  36         unsigned int exponent:8;
  37         unsigned int mantissa:23;
  38 #endif                          /* Big endian.  */
  39 #if     __BYTE_ORDER == __LITTLE_ENDIAN
  40         unsigned int mantissa:23;
  41         unsigned int exponent:8;
  42         unsigned int negative:1;
  43 #endif                          /* Little endian.  */
  44       } ieee;
  45
  46     /* This format makes it easier to see if a NaN is a signalling NaN.  */
  47     struct
  48       {
  49 #if     __BYTE_ORDER == __BIG_ENDIAN
  50         unsigned int negative:1;
  51         unsigned int exponent:8;
  52         unsigned int quiet_nan:1;
  53         unsigned int mantissa:22;
  54 #endif                          /* Big endian.  */
  55 #if     __BYTE_ORDER == __LITTLE_ENDIAN
  56         unsigned int mantissa:22;
  57         unsigned int quiet_nan:1;
  58         unsigned int exponent:8;
  59         unsigned int negative:1;
  60 #endif                          /* Little endian.  */
  61       } ieee_nan;
  62   };
  63
  64 #define IEEE754_FLOAT_BIAS      0x7f /* Added to exponent.  */
  65
  66
  67 union ieee754_double
  68   {
  69     double d;
  70
  71     /* This is the IEEE 754 double-precision format.  */
  72     struct
  73       {
  74 #if     __BYTE_ORDER == __BIG_ENDIAN
  75         unsigned int negative:1;
  76         unsigned int exponent:11;
  77         /* Together these comprise the mantissa.  */
  78         unsigned int mantissa0:20;
  79         unsigned int mantissa1:32;
  80 #endif                          /* Big endian.  */
  81 #if     __BYTE_ORDER == __LITTLE_ENDIAN
  82 # if    __FLOAT_WORD_ORDER == __BIG_ENDIAN
  83         unsigned int mantissa0:20;
  84         unsigned int exponent:11;
  85         unsigned int negative:1;
  86         unsigned int mantissa1:32;
  87 # else
  88         /* Together these comprise the mantissa.  */
  89         unsigned int mantissa1:32;
  90         unsigned int mantissa0:20;
  91         unsigned int exponent:11;
  92         unsigned int negative:1;
  93 # endif
  94 #endif                          /* Little endian.  */
  95       } ieee;
  96
  97     /* This format makes it easier to see if a NaN is a signalling NaN.  */
  98     struct
  99       {
 100 #if     __BYTE_ORDER == __BIG_ENDIAN
 101         unsigned int negative:1;
 102         unsigned int exponent:11;
 103         unsigned int quiet_nan:1;
 104         /* Together these comprise the mantissa.  */
 105         unsigned int mantissa0:19;
 106         unsigned int mantissa1:32;
 107 #else
 108 # if    __FLOAT_WORD_ORDER == __BIG_ENDIAN
 109         unsigned int mantissa0:19;
 110         unsigned int quiet_nan:1;
 111         unsigned int exponent:11;
 112         unsigned int negative:1;
 113         unsigned int mantissa1:32;
 114 # else
 115         /* Together these comprise the mantissa.  */
 116         unsigned int mantissa1:32;
 117         unsigned int mantissa0:19;
 118         unsigned int quiet_nan:1;
 119         unsigned int exponent:11;
 120         unsigned int negative:1;
 121 # endif
 122 #endif
 123       } ieee_nan;
 124   };
 125
 126 #define IEEE754_DOUBLE_BIAS     0x3ff /* Added to exponent.  */
 127
 128
 129 union ieee854_long_double
 130   {
 131     long double d;
 132
 133     /* This is the IEEE 854 double-extended-precision format.  */
 134     struct
 135       {
 136 #if     __BYTE_ORDER == __BIG_ENDIAN
 137         unsigned int negative:1;
 138         unsigned int exponent:15;
 139         unsigned int empty:16;
 140         unsigned int mantissa0:32;
 141         unsigned int mantissa1:32;
 142 #endif
 143 #if     __BYTE_ORDER == __LITTLE_ENDIAN
 144 # if    __FLOAT_WORD_ORDER == __BIG_ENDIAN
 145         unsigned int exponent:15;
 146         unsigned int negative:1;
 147         unsigned int empty:16;
 148         unsigned int mantissa0:32;
 149         unsigned int mantissa1:32;
 150 # else
 151         unsigned int mantissa1:32;
 152         unsigned int mantissa0:32;
 153         unsigned int exponent:15;
 154         unsigned int negative:1;
 155         unsigned int empty:16;
 156 # endif
 157 #endif
 158       } ieee;
 159
 160     /* This is for NaNs in the IEEE 854 double-extended-precision format.  */
 161     struct
 162       {
 163 #if     __BYTE_ORDER == __BIG_ENDIAN
 164         unsigned int negative:1;
 165         unsigned int exponent:15;
 166         unsigned int empty:16;
 167         unsigned int one:1;
 168         unsigned int quiet_nan:1;
 169         unsigned int mantissa0:30;
 170         unsigned int mantissa1:32;
 171 #endif
 172 #if     __BYTE_ORDER == __LITTLE_ENDIAN
 173 # if    __FLOAT_WORD_ORDER == __BIG_ENDIAN
 174         unsigned int exponent:15;
 175         unsigned int negative:1;
 176         unsigned int empty:16;
 177         unsigned int mantissa0:30;
 178         unsigned int quiet_nan:1;
 179         unsigned int one:1;
 180         unsigned int mantissa1:32;
 181 # else
 182         unsigned int mantissa1:32;
 183         unsigned int mantissa0:30;
 184         unsigned int quiet_nan:1;
 185         unsigned int one:1;
 186         unsigned int exponent:15;
 187         unsigned int negative:1;
 188         unsigned int empty:16;
 189 # endif
 190 #endif
 191       } ieee_nan;
 192   };
 193
 194 #define IEEE854_LONG_DOUBLE_BIAS 0x3fff
 195
 196 __END_DECLS
 197
 198 #endif /* ieee754.h */