s_isnan.c revision 110769 
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/* For binary compat; to be removed in FreeBSD 6.0. */
14
15#ifndef lint
16static char rcsid[] = "$FreeBSD: head/lib/msun/src/s_isnan.c 110769 2003-02-12 20:03:41Z mike $";
17#endif
18
19/*
20 * isnan(x) returns 1 is x is nan, else 0;
21 * no branching!
22 */
23
24#include "math.h"
25#include "math_private.h"
26
27#undef isnan
28
29	int isnan(double x)
30{
31	int32_t hx,lx;
32	EXTRACT_WORDS(hx,lx,x);
33	hx &= 0x7fffffff;
34	hx |= (u_int32_t)(lx|(-lx))>>31;
35	hx = 0x7ff00000 - hx;
36	return (int)((u_int32_t)(hx))>>31;
37}
38