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
|
/* @(#)s_isnan.c 5.1 93/09/24 */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
/*
FUNCTION
<<isnan>>, <<isnanf>>, <<isinf>>, <<isinff>>, <<finite>>, <<finitef>>---test for exceptional numbers
INDEX
isnan
INDEX
isinf
INDEX
finite
INDEX
isnanf
INDEX
isinff
INDEX
finitef
ANSI_SYNOPSIS
#include <ieeefp.h>
int isnan(double <[arg]>);
int isinf(double <[arg]>);
int finite(double <[arg]>);
int isnanf(float <[arg]>);
int isinff(float <[arg]>);
int finitef(float <[arg]>);
TRAD_SYNOPSIS
#include <ieeefp.h>
int isnan(<[arg]>)
double <[arg]>;
int isinf(<[arg]>)
double <[arg]>;
int finite(<[arg]>);
double <[arg]>;
int isnanf(<[arg]>);
float <[arg]>;
int isinff(<[arg]>);
float <[arg]>;
int finitef(<[arg]>);
float <[arg]>;
DESCRIPTION
These functions provide information on the floating-point
argument supplied.
There are five major number formats:
o+
o zero
A number which contains all zero bits.
o subnormal
A number with a zero exponent but a nonzero fraction.
o normal
A number with an exponent and a fraction.
o infinity
A number with an all 1's exponent and a zero fraction.
o NAN
A number with an all 1's exponent and a nonzero fraction.
o-
<<isnan>> returns 1 if the argument is a nan. <<isinf>>
returns 1 if the argument is infinity. <<finite>> returns 1 if the
argument is zero, subnormal or normal.
The <<isnanf>>, <<isinff>> and <<finitef>> functions perform the same
operations as their <<isnan>>, <<isinf>> and <<finite>>
counterparts, but on single-precision floating-point numbers.
It should be noted that the C99 standard dictates that <<isnan>>
and <<isinf>> are macros that operate on multiple types of
floating-point. The SUSv2 standard declares <<isnan>> as
a function taking double. Newlib has decided to declare
them both as macros in math.h and as functions in ieeefp.h.
QUICKREF
isnan - pure
QUICKREF
isinf - pure
QUICKREF
finite - pure
QUICKREF
isnan - pure
QUICKREF
isinf - pure
QUICKREF
finite - pure
*/
/*
* isnan(x) returns 1 is x is nan, else 0;
* no branching!
*
* The C99 standard dictates that isnan is a macro taking
* multiple floating-point types while the SUSv2 standard
* notes it is a function taking a double argument. Newlib
* has chosen to implement it as a macro in <math.h> and
* declare it as a function in <ieeefp.h>.
*/
#include "fdlibm.h"
#include <ieeefp.h>
#ifndef _DOUBLE_IS_32BITS
#ifdef __STDC__
int isnan(double x)
#else
int isnan(x)
double x;
#endif
{
__int32_t hx,lx;
EXTRACT_WORDS(hx,lx,x);
hx &= 0x7fffffff;
hx |= (__uint32_t)(lx|(-lx))>>31;
hx = 0x7ff00000 - hx;
return (int)(((__uint32_t)(hx))>>31);
}
#endif /* _DOUBLE_IS_32BITS */
|
