1/* Copyright (C) 1992-2026 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 /* 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
114union ieee854_long_double
115 {
116 long double d;
117
118 /* This is the IEEE 854 quad-precision format. */
119 struct
120 {
121#if __BYTE_ORDER == __BIG_ENDIAN
122 unsigned int negative:1;
123 unsigned int exponent:15;
124 /* Together these comprise the mantissa. */
125 unsigned int mantissa0:16;
126 unsigned int mantissa1:32;
127 unsigned int mantissa2:32;
128 unsigned int mantissa3:32;
129#endif /* Big endian. */
130#if __BYTE_ORDER == __LITTLE_ENDIAN
131 /* Together these comprise the mantissa. */
132 unsigned int mantissa3:32;
133 unsigned int mantissa2:32;
134 unsigned int mantissa1:32;
135 unsigned int mantissa0:16;
136 unsigned int exponent:15;
137 unsigned int negative:1;
138#endif /* Little endian. */
139 } ieee;
140
141 /* This format makes it easier to see if a NaN is a signalling NaN. */
142 struct
143 {
144#if __BYTE_ORDER == __BIG_ENDIAN
145 unsigned int negative:1;
146 unsigned int exponent:15;
147 unsigned int quiet_nan:1;
148 /* Together these comprise the mantissa. */
149 unsigned int mantissa0:15;
150 unsigned int mantissa1:32;
151 unsigned int mantissa2:32;
152 unsigned int mantissa3:32;
153#else
154 /* Together these comprise the mantissa. */
155 unsigned int mantissa3:32;
156 unsigned int mantissa2:32;
157 unsigned int mantissa1:32;
158 unsigned int mantissa0:15;
159 unsigned int quiet_nan:1;
160 unsigned int exponent:15;
161 unsigned int negative:1;
162#endif
163 } ieee_nan;
164 };
165
166#define IEEE854_LONG_DOUBLE_BIAS 0x3fff /* Added to exponent. */
167
168__END_DECLS
169
170#endif /* ieee754.h */