1 /* Copyright (C) 2000-2023 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 empty0:32;
138 unsigned int negative:1;
139 unsigned int exponent:15;
140 unsigned int empty1:16;
141 unsigned int mantissa0:32;
142 unsigned int mantissa1:32;
143 #endif
144 #if __BYTE_ORDER == __LITTLE_ENDIAN
145 # if __FLOAT_WORD_ORDER == __BIG_ENDIAN
146 unsigned int empty0:32;
147 unsigned int exponent:15;
148 unsigned int negative:1;
149 unsigned int empty1:16;
150 unsigned int mantissa0:32;
151 unsigned int mantissa1:32;
152 # else
153 unsigned int mantissa1:32;
154 unsigned int mantissa0:32;
155 unsigned int exponent:15;
156 unsigned int negative:1;
157 unsigned int empty1:16;
158 unsigned int empty0:32;
159 # endif
160 #endif
161 } ieee;
162
163 /* This is for NaNs in the IEEE 854 double-extended-precision format. */
164 struct
165 {
166 #if __BYTE_ORDER == __BIG_ENDIAN
167 unsigned int empty0:32;
168 unsigned int negative:1;
169 unsigned int exponent:15;
170 unsigned int empty1:16;
171 unsigned int one:1;
172 unsigned int quiet_nan:1;
173 unsigned int mantissa0:30;
174 unsigned int mantissa1:32;
175 #endif
176 #if __BYTE_ORDER == __LITTLE_ENDIAN
177 # if __FLOAT_WORD_ORDER == __BIG_ENDIAN
178 unsigned int empty0:32;
179 unsigned int exponent:15;
180 unsigned int negative:1;
181 unsigned int empty1:16;
182 unsigned int mantissa0:30;
183 unsigned int quiet_nan:1;
184 unsigned int one:1;
185 unsigned int mantissa1:32;
186 # else
187 unsigned int mantissa1:32;
188 unsigned int mantissa0:30;
189 unsigned int quiet_nan:1;
190 unsigned int one:1;
191 unsigned int exponent:15;
192 unsigned int negative:1;
193 unsigned int empty1:16;
194 unsigned int empty0:32;
195 # endif
196 #endif
197 } ieee_nan;
198 };
199
200 #define IEEE854_LONG_DOUBLE_BIAS 0x3fff
201
202 __END_DECLS
203
204 #endif /* ieee754.h */