s_isnan.c revision 97409 
1/* @(#)s_isnan.c 5.1 93/09/24 */
2/*
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5 *
6 * Developed at SunPro, a Sun Microsystems, Inc. business.
7 * Permission to use, copy, modify, and distribute this
8 * software is freely granted, provided that this notice
9 * is preserved.
10 * ====================================================
11 */
12
13#ifndef lint
14static char rcsid[] = "$FreeBSD: head/lib/msun/src/s_isnan.c 97409 2002-05-28 17:51:46Z alfred $";
15#endif
16
17/*
18 * isnan(x) returns 1 is x is nan, else 0;
19 * no branching!
20 */
21
22#include "math.h"
23#include "math_private.h"
24
25	int isnan(double x)
26{
27	int32_t hx,lx;
28	EXTRACT_WORDS(hx,lx,x);
29	hx &= 0x7fffffff;
30	hx |= (u_int32_t)(lx|(-lx))>>31;
31	hx = 0x7ff00000 - hx;
32	return (int)((u_int32_t)(hx))>>31;
33}
34