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The C and C++ Include Header Files
/usr/include/x86_64-linux-gnu/ieee754.h
$ cat -n /usr/include/x86_64-linux-gnu/ieee754.h 1 /* Copyright (C) 1992-2024 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 <https://www.gnu.org/licenses/>. */ 17 18 #ifndef _IEEE754_H 19 #define _IEEE754_H 1 20 21 #include <features.h> 22 23 #include <bits/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 */
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