blob: 52dbe8be9cc23cbb546cbee6ce03e16f247a8e6b (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
/* Copyright (C) 1992-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _IEEE754_H
#define _IEEE754_H 1
#include <features.h>
#include <endian.h>
__BEGIN_DECLS
union ieee754_float
{
float f;
/* This is the IEEE 754 single-precision format. */
struct
{
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned int negative:1;
unsigned int exponent:8;
unsigned int mantissa:23;
#endif /* Big endian. */
#if __BYTE_ORDER == __LITTLE_ENDIAN
unsigned int mantissa:23;
unsigned int exponent:8;
unsigned int negative:1;
#endif /* Little endian. */
} ieee;
/* This format makes it easier to see if a NaN is a signalling NaN. */
struct
{
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned int negative:1;
unsigned int exponent:8;
unsigned int quiet_nan:1;
unsigned int mantissa:22;
#endif /* Big endian. */
#if __BYTE_ORDER == __LITTLE_ENDIAN
unsigned int mantissa:22;
unsigned int quiet_nan:1;
unsigned int exponent:8;
unsigned int negative:1;
#endif /* Little endian. */
} ieee_nan;
};
#define IEEE754_FLOAT_BIAS 0x7f /* Added to exponent. */
union ieee754_double
{
double d;
/* This is the IEEE 754 double-precision format. */
struct
{
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned int negative:1;
unsigned int exponent:11;
/* Together these comprise the mantissa. */
unsigned int mantissa0:20;
unsigned int mantissa1:32;
#endif /* Big endian. */
#if __BYTE_ORDER == __LITTLE_ENDIAN
/* Together these comprise the mantissa. */
unsigned int mantissa1:32;
unsigned int mantissa0:20;
unsigned int exponent:11;
unsigned int negative:1;
#endif /* Little endian. */
} ieee;
/* This format makes it easier to see if a NaN is a signalling NaN. */
struct
{
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned int negative:1;
unsigned int exponent:11;
unsigned int quiet_nan:1;
/* Together these comprise the mantissa. */
unsigned int mantissa0:19;
unsigned int mantissa1:32;
#else
/* Together these comprise the mantissa. */
unsigned int mantissa1:32;
unsigned int mantissa0:19;
unsigned int quiet_nan:1;
unsigned int exponent:11;
unsigned int negative:1;
#endif
} ieee_nan;
};
#define IEEE754_DOUBLE_BIAS 0x3ff /* Added to exponent. */
/* IBM extended format for long double.
Each long double is made up of two IEEE doubles. The value of the
long double is the sum of the values of the two parts. The most
significant part is required to be the value of the long double
rounded to the nearest double, as specified by IEEE. For Inf
values, the least significant part is required to be one of +0.0 or
-0.0. No other requirements are made; so, for example, 1.0 may be
represented as (1.0, +0.0) or (1.0, -0.0), and the low part of a
NaN is don't-care. */
union ibm_extended_long_double
{
long double ld;
union ieee754_double d[2];
};
__END_DECLS
#endif /* ieee754.h */
|
