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1/* Copyright (C) 1992-2025 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
27union 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
67union 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
129union 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 */