summaryrefslogtreecommitdiff
path: root/libm/src/s_isnan.c
blob: a68f8ef76556b837aae8307ecf557e719a2a8e75 (plain)
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

/* @(#)s_isnan.c 1.3 95/01/18 */
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunSoft, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice 
 * is preserved.
 * ====================================================
 */

/*
 * isnan(x) returns 1 is x is nan, else 0;
 * no branching!
 */

#include "fdlibm.h"

#ifdef __STDC__
	int isnan(double x)
#else
	int isnan(x)
	double x;
#endif
{
	int hx,lx;
	hx = (__HI(x)&0x7fffffff);
	lx = __LO(x);
	hx |= (unsigned)(lx|(-lx))>>31;	
	hx = 0x7ff00000 - hx;
	return ((unsigned)(hx))>>31;
}