sysdeps/ieee754/ieee754.h

   1 /* Copyright (C) 1992, 1995, 1996 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 not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 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         /* Together these comprise the mantissa.  */
  84         unsigned int mantissa1:32;
  85         unsigned int mantissa0:20;
  86         unsigned int exponent:11;
  87         unsigned int negative:1;
  88 #endif                          /* Little endian.  */
  89       } ieee;
  90
  91     /* This format makes it easier to see if a NaN is a signalling NaN.  */
  92     struct
  93       {
  94 #if     __BYTE_ORDER == __BIG_ENDIAN
  95         unsigned int negative:1;
  96         unsigned int exponent:11;
  97         unsigned int quiet_nan:1;
  98         /* Together these comprise the mantissa.  */
  99         unsigned int mantissa0:19;
 100         unsigned int mantissa1:32;
 101 #else
 102         /* Together these comprise the mantissa.  */
 103         unsigned int mantissa1:32;
 104         unsigned int mantissa0:19;
 105         unsigned int quiet_nan:1;
 106         unsigned int exponent:11;
 107         unsigned int negative:1;
 108 #endif
 109       } ieee_nan;
 110   };
 111
 112 #define IEEE754_DOUBLE_BIAS     0x3ff /* Added to exponent.  */
 113
 114
 115 union ieee854_long_double
 116   {
 117     long double d;
 118
 119     /* This is the IEEE 854 double-extended-precision format.  */
 120     struct
 121       {
 122 #if     __BYTE_ORDER == __BIG_ENDIAN
 123         unsigned int negative:1;
 124         unsigned int exponent:15;
 125         unsigned int empty:16;
 126         unsigned int mantissa0:32;
 127         unsigned int mantissa1:32;
 128 #endif
 129 #if     __BYTE_ORDER == __LITTLE_ENDIAN
 130         unsigned int mantissa1:32;
 131         unsigned int mantissa0:32;
 132         unsigned int exponent:15;
 133         unsigned int negative:1;
 134         unsigned int empty:16;
 135 #endif
 136       } ieee;
 137
 138     /* This is for NaNs in the IEEE 854 double-extended-precision format.  */
 139     struct
 140       {
 141 #if     __BYTE_ORDER == __BIG_ENDIAN
 142         unsigned int negative:1;
 143         unsigned int exponent:15;
 144         unsigned int empty:16;
 145         unsigned int one:1;
 146         unsigned int quiet_nan:1;
 147         unsigned int mantissa0:30;
 148         unsigned int mantissa1:32;
 149 #endif
 150 #if     __BYTE_ORDER == __LITTLE_ENDIAN
 151         unsigned int mantissa1:32;
 152         unsigned int mantissa0:30;
 153         unsigned int quiet_nan:1;
 154         unsigned int one:1;
 155         unsigned int exponent:15;
 156         unsigned int negative:1;
 157         unsigned int empty:16;
 158 #endif
 159       } ieee_nan;
 160   };
 161
 162 #define IEEE854_LONG_DOUBLE_BIAS 0x3fff
 163
 164 __END_DECLS
 165
 166 #endif /* ieee754.h */