POK
isnan.c
1 /*
2  * POK header
3  *
4  * The following file is a part of the POK project. Any modification should
5  * made according to the POK licence. You CANNOT use this file or a part of
6  * this file is this part of a file for your own project
7  *
8  * For more information on the POK licence, please see our LICENCE FILE
9  *
10  * Please follow the coding guidelines described in doc/CODING_GUIDELINES
11  *
12  * Copyright (c) 2007-2009 POK team
13  *
14  * Created by julien on Fri Jan 30 13:44:27 2009
15  */
16 
17 /* @(#)s_isnan.c 5.1 93/09/24 */
18 /*
19  * ====================================================
20  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
21  *
22  * Developed at SunPro, a Sun Microsystems, Inc. business.
23  * Permission to use, copy, modify, and distribute this
24  * software is freely granted, provided that this notice
25  * is preserved.
26  * ====================================================
27  */
28 
29 /*
30  * isnan(x) returns 1 is x is nan, else 0;
31  * no branching!
32  */
33 
34 #ifdef POK_NEEDS_LIBMATH
35 #include <types.h>
36 #include "math_private.h"
37 
38 int
39 isnan(double x)
40 {
41  int32_t hx,lx;
42  EXTRACT_WORDS(hx,lx,x);
43  hx &= 0x7fffffff;
44  hx |= (uint32_t)(lx|(-lx))>>31;
45  hx = 0x7ff00000 - hx;
46  return (int)((uint32_t)(hx))>>31;
47 }
48 #endif
49