sysdeps/ieee754/ieee754.h

   1 /* Copyright (C) 1992, 1995 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 Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 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 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <endian.h>
  20
  21 union ieee754_float
  22   {
  23     float f;
  24
  25     /* This is the IEEE 754 single-precision format.  */
  26     struct
  27       {
  28 #if     __BYTE_ORDER == __BIG_ENDIAN
  29         unsigned int negative:1;
  30         unsigned int exponent:8;
  31         unsigned int mantissa:23;
  32 #endif                          /* Big endian.  */
  33 #if     __BYTE_ORDER == __LITTLE_ENDIAN
  34         unsigned int mantissa:23;
  35         unsigned int exponent:8;
  36         unsigned int negative:1;
  37 #endif                          /* Little endian.  */
  38       } ieee;
  39
  40     /* This format makes it easier to see if a NaN is a signalling NaN.  */
  41     struct
  42       {
  43 #if     __BYTE_ORDER == __BIG_ENDIAN
  44         unsigned int negative:1;
  45         unsigned int exponent:8;
  46         unsigned int quiet_nan:1;
  47         unsigned int mantissa:22;
  48 #endif                          /* Big endian.  */
  49 #if     __BYTE_ORDER == __LITTLE_ENDIAN
  50         unsigned int mantissa:22;
  51         unsigned int quiet_nan:1;
  52         unsigned int exponent:8;
  53         unsigned int negative:1;
  54 #endif                          /* Little endian.  */
  55       } ieee_nan;
  56   };
  57
  58 #define IEEE754_FLOAT_BIAS      0x7f /* Added to exponent.  */
  59
  60
  61 union ieee754_double
  62   {
  63     double d;
  64
  65     /* This is the IEEE 754 double-precision format.  */
  66     struct
  67       {
  68 #if     __BYTE_ORDER == __BIG_ENDIAN
  69         unsigned int negative:1;
  70         unsigned int exponent:11;
  71         /* Together these comprise the mantissa.  */
  72         unsigned int mantissa0:20;
  73         unsigned int mantissa1:32;
  74 #endif                          /* Big endian.  */
  75 #if     __BYTE_ORDER == __LITTLE_ENDIAN
  76         /* Together these comprise the mantissa.  */
  77         unsigned int mantissa1:32;
  78         unsigned int mantissa0:20;
  79         unsigned int exponent:11;
  80         unsigned int negative:1;
  81 #endif                          /* Little endian.  */
  82       } ieee;
  83
  84     /* This format makes it easier to see if a NaN is a signalling NaN.  */
  85     struct
  86       {
  87 #if     __BYTE_ORDER == __BIG_ENDIAN
  88         unsigned int negative:1;
  89         unsigned int exponent:11;
  90         unsigned int quiet_nan:1;
  91         /* Together these conprise the mantissa.  */
  92         unsigned int mantissa0:19;
  93         unsigned int mantissa1:32;
  94 #else
  95         /* Together these conprise the mantissa.  */
  96         unsigned int mantissa1:32;
  97         unsigned int mantissa0:19;
  98         unsigned int quiet_nan:1;
  99         unsigned int exponent:11;
 100         unsigned int negative:1;
 101 #endif
 102       } ieee_nan;
 103   };
 104
 105 #define IEEE754_DOUBLE_BIAS     0x3ff /* Added to exponent.  */
 106
 107
 108 union ieee854_long_double
 109   {
 110     long double d;
 111
 112     /* This is the IEEE 854 double-extended-precision format.  */
 113     struct
 114       {
 115 #if     __BYTE_ORDER == __BIG_ENDIAN
 116         unsigned int negative:1;
 117         unsigned int exponent:15;
 118         unsigned int empty:16;
 119         unsigned int mantissa0:32;
 120         unsigned int mantissa1:32;
 121 #endif
 122 #if     __BYTE_ORDER == __LITTLE_ENDIAN
 123         unsigned int mantissa1:32;
 124         unsigned int mantissa0:32;
 125         unsigned int exponent:15;
 126         unsigned int negative:1;
 127         unsigned int empty:16;
 128 #endif
 129       } ieee;
 130
 131     /* This is for NaNs in the IEEE 854 double-extended-precision format.  */
 132     struct
 133       {
 134 #if     __BYTE_ORDER == __BIG_ENDIAN
 135         unsigned int negative:1;
 136         unsigned int exponent:15;
 137         unsigned int empty:16;
 138         unsigned int quiet_nan:1;
 139         unsigned int mantissa0:31;
 140         unsigned int mantissa1:32;
 141 #endif
 142 #if     __BYTE_ORDER == __LITTLE_ENDIAN
 143         unsigned int mantissa1:32;
 144         unsigned int mantissa0:31;
 145         unsigned int quiet_nan:1;
 146         unsigned int exponent:15;
 147         unsigned int negative:1;
 148         unsigned int empty:16;
 149 #endif
 150       } ieee_nan;
 151   };
 152
 153 #define IEEE854_LONG_DOUBLE_BIAS 0x3fff