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
134
135
136
137
138
|
/* Macros for quiet not-a-number.
Copyright (C) 2023-2025 Free Software Foundation, Inc.
This file 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.
This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */
#ifndef _SIGNED_NAN_H
#define _SIGNED_NAN_H
#include <math.h>
#include "nan.h"
#ifdef __cplusplus
extern "C" {
#endif
/* Returns - x, implemented by inverting the sign bit,
so that it works also on 'float' NaN values. */
_GL_UNUSED static float
minus_NaNf (float x)
{
#if defined __mips__
/* The mips instruction neg.s may have no effect on NaNs.
Therefore, invert the sign bit using integer operations. */
union { unsigned int i; float value; } u;
u.value = x;
u.i ^= 1U << 31;
return u.value;
#else
return - x;
#endif
}
/* Returns a quiet 'float' NaN with sign bit == 0. */
_GL_UNUSED static float
positive_NaNf ()
{
/* 'volatile' works around a GCC bug:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655> */
float volatile nan = NaNf ();
return (signbit (nan) ? minus_NaNf (nan) : nan);
}
/* Returns a quiet 'float' NaN with sign bit == 1. */
_GL_UNUSED static float
negative_NaNf ()
{
/* 'volatile' works around a GCC bug:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655> */
float volatile nan = NaNf ();
return (signbit (nan) ? nan : minus_NaNf (nan));
}
/* Returns - x, implemented by inverting the sign bit,
so that it works also on 'double' NaN values. */
_GL_UNUSED static double
minus_NaNd (double x)
{
#if defined __mips__
/* The mips instruction neg.d may have no effect on NaNs.
Therefore, invert the sign bit using integer operations. */
union { unsigned long long i; double value; } u;
u.value = x;
u.i ^= 1ULL << 63;
return u.value;
#else
return - x;
#endif
}
/* Returns a quiet 'double' NaN with sign bit == 0. */
_GL_UNUSED static double
positive_NaNd ()
{
/* 'volatile' works around a GCC bug:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655> */
double volatile nan = NaNd ();
return (signbit (nan) ? minus_NaNd (nan) : nan);
}
/* Returns a quiet 'double' NaN with sign bit == 1. */
_GL_UNUSED static double
negative_NaNd ()
{
/* 'volatile' works around a GCC bug:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655> */
double volatile nan = NaNd ();
return (signbit (nan) ? nan : minus_NaNd (nan));
}
/* Returns - x, implemented by inverting the sign bit,
so that it works also on 'long double' NaN values. */
_GL_UNUSED static long double
minus_NaNl (long double x)
{
return - x;
}
/* Returns a quiet 'long double' NaN with sign bit == 0. */
_GL_UNUSED static long double
positive_NaNl ()
{
/* 'volatile' works around a GCC bug:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655> */
long double volatile nan = NaNl ();
return (signbit (nan) ? minus_NaNl (nan) : nan);
}
/* Returns a quiet 'long double' NaN with sign bit == 1. */
_GL_UNUSED static long double
negative_NaNl ()
{
/* 'volatile' works around a GCC bug:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655> */
long double volatile nan = NaNl ();
return (signbit (nan) ? nan : minus_NaNl (nan));
}
#ifdef __cplusplus
}
#endif
#endif /* _SIGNED_NAN_H */
|
