sysdeps/ieee754/ldbl-128ibm/ieee754.h

   1 /* Copyright (C) 1992-2014 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         /* Together these comprise the mantissa.  */
  83         unsigned int mantissa1:32;
  84         unsigned int mantissa0:20;
  85         unsigned int exponent:11;
  86         unsigned int negative:1;
  87 #endif                          /* Little endian.  */
  88       } ieee;
  89
  90     /* This format makes it easier to see if a NaN is a signalling NaN.  */
  91     struct
  92       {
  93 #if     __BYTE_ORDER == __BIG_ENDIAN
  94         unsigned int negative:1;
  95         unsigned int exponent:11;
  96         unsigned int quiet_nan:1;
  97         /* Together these comprise the mantissa.  */
  98         unsigned int mantissa0:19;
  99         unsigned int mantissa1:32;
 100 #else
 101         /* Together these comprise the mantissa.  */
 102         unsigned int mantissa1:32;
 103         unsigned int mantissa0:19;
 104         unsigned int quiet_nan:1;
 105         unsigned int exponent:11;
 106         unsigned int negative:1;
 107 #endif
 108       } ieee_nan;
 109   };
 110
 111 #define IEEE754_DOUBLE_BIAS     0x3ff /* Added to exponent.  */
 112
 113
 114 /* IBM extended format for long double.
 115
 116    Each long double is made up of two IEEE doubles.  The value of the
 117    long double is the sum of the values of the two parts.  The most
 118    significant part is required to be the value of the long double
 119    rounded to the nearest double, as specified by IEEE.  For Inf
 120    values, the least significant part is required to be one of +0.0 or
 121    -0.0.  No other requirements are made; so, for example, 1.0 may be
 122    represented as (1.0, +0.0) or (1.0, -0.0), and the low part of a
 123    NaN is don't-care.  */
 124
 125 union ibm_extended_long_double
 126   {
 127     long double ld;
 128     union ieee754_double d[2];
 129    };
 130
 131 __END_DECLS
 132
 133 #endif /* ieee754.h */