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      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 #include <sys/cdefs.h>
     14 #if defined(LIBM_SCCS) && !defined(lint)
     15 __RCSID("$NetBSD: s_isnan.c,v 1.11 2002/05/26 22:01:56 wiz Exp $");
     16 #endif
     17 
     18 /*
     19  * isnan(x) returns 1 is x is nan, else 0;
     20  * no branching!
     21  */
     22 
     23 #include "math.h"
     24 #include "math_private.h"
     25 
     26 int
     27 isnan(double x)
     28 {
     29 	int32_t hx,lx;
     30 	EXTRACT_WORDS(hx,lx,x);
     31 	hx &= 0x7fffffff;
     32 	hx |= (u_int32_t)(lx|(-lx))>>31;
     33 	hx = 0x7ff00000 - hx;
     34 	return (int)((u_int32_t)(hx))>>31;
     35 }
     36