libgcc-math/include/ieee754.h

   1 /* Copyright (C) 1992, 1995, 1996, 1999, 2006 Free Software Foundation, Inc.
   2
   3 This file is part of GCC.
   4
   5 GCC is free software; you can redistribute it and/or modify it under
   6 the terms of the GNU General Public License as published by the Free
   7 Software Foundation; either version 2, or (at your option) any later
   8 version.
   9
  10 In addition to the permissions in the GNU General Public License, the
  11 Free Software Foundation gives you unlimited permission to link the
  12 compiled version of this file into combinations with other programs,
  13 and to distribute those combinations without any restriction coming
  14 from the use of this file.  (The General Public License restrictions
  15 do apply in other respects; for example, they cover modification of
  16 the file, and distribution when not linked into a combine
  17 executable.)
  18
  19 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  20 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  21 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  22 for more details.
  23
  24 You should have received a copy of the GNU General Public License
  25 along with GCC; see the file COPYING.  If not, write to the Free
  26 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  27 02110-1301, USA.  */
  28
  29 #ifndef _IEEE754_H
  30
  31 #define _IEEE754_H 1
  32 #include <endian.h>
  33
  34 union ieee754_float
  35   {
  36     float f;
  37
  38     /* This is the IEEE 754 single-precision format.  */
  39     struct
  40       {
  41 #if     __BYTE_ORDER == __BIG_ENDIAN
  42         unsigned int negative:1;
  43         unsigned int exponent:8;
  44         unsigned int mantissa:23;
  45 #endif                          /* Big endian.  */
  46 #if     __BYTE_ORDER == __LITTLE_ENDIAN
  47         unsigned int mantissa:23;
  48         unsigned int exponent:8;
  49         unsigned int negative:1;
  50 #endif                          /* Little endian.  */
  51       } ieee;
  52
  53     /* This format makes it easier to see if a NaN is a signalling NaN.  */
  54     struct
  55       {
  56 #if     __BYTE_ORDER == __BIG_ENDIAN
  57         unsigned int negative:1;
  58         unsigned int exponent:8;
  59         unsigned int quiet_nan:1;
  60         unsigned int mantissa:22;
  61 #endif                          /* Big endian.  */
  62 #if     __BYTE_ORDER == __LITTLE_ENDIAN
  63         unsigned int mantissa:22;
  64         unsigned int quiet_nan:1;
  65         unsigned int exponent:8;
  66         unsigned int negative:1;
  67 #endif                          /* Little endian.  */
  68       } ieee_nan;
  69   };
  70
  71 #define IEEE754_FLOAT_BIAS      0x7f /* Added to exponent.  */
  72
  73
  74 union ieee754_double
  75   {
  76     double d;
  77
  78     /* This is the IEEE 754 double-precision format.  */
  79     struct
  80       {
  81 #if     __BYTE_ORDER == __BIG_ENDIAN
  82         unsigned int negative:1;
  83         unsigned int exponent:11;
  84         /* Together these comprise the mantissa.  */
  85         unsigned int mantissa0:20;
  86         unsigned int mantissa1:32;
  87 #endif                          /* Big endian.  */
  88 #if     __BYTE_ORDER == __LITTLE_ENDIAN
  89 # if    __FLOAT_WORD_ORDER == BIG_ENDIAN
  90         unsigned int mantissa0:20;
  91         unsigned int exponent:11;
  92         unsigned int negative:1;
  93         unsigned int mantissa1:32;
  94 # else
  95         /* Together these comprise the mantissa.  */
  96         unsigned int mantissa1:32;
  97         unsigned int mantissa0:20;
  98         unsigned int exponent:11;
  99         unsigned int negative:1;
 100 # endif
 101 #endif                          /* Little endian.  */
 102       } ieee;
 103
 104     /* This format makes it easier to see if a NaN is a signalling NaN.  */
 105     struct
 106       {
 107 #if     __BYTE_ORDER == __BIG_ENDIAN
 108         unsigned int negative:1;
 109         unsigned int exponent:11;
 110         unsigned int quiet_nan:1;
 111         /* Together these comprise the mantissa.  */
 112         unsigned int mantissa0:19;
 113         unsigned int mantissa1:32;
 114 #else
 115 # if    __FLOAT_WORD_ORDER == BIG_ENDIAN
 116         unsigned int mantissa0:19;
 117         unsigned int quiet_nan:1;
 118         unsigned int exponent:11;
 119         unsigned int negative:1;
 120         unsigned int mantissa1:32;
 121 # else
 122         /* Together these comprise the mantissa.  */
 123         unsigned int mantissa1:32;
 124         unsigned int mantissa0:19;
 125         unsigned int quiet_nan:1;
 126         unsigned int exponent:11;
 127         unsigned int negative:1;
 128 # endif
 129 #endif
 130       } ieee_nan;
 131   };
 132
 133 #define IEEE754_DOUBLE_BIAS     0x3ff /* Added to exponent.  */
 134
 135
 136 #endif /* ieee754.h */