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 14 static char rcsid[] = "$Id: s_isnan.c,v 1.1.1.1 1994/08/19 09:39:52 jkh Exp $"; 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 #ifdef __STDC__ 26 int isnan(double x) 27 #else 28 int isnan(x) 29 double x; 30 #endif 31 { 32 int32_t hx,lx; 33 EXTRACT_WORDS(hx,lx,x); 34 hx &= 0x7fffffff; 35 hx |= (u_int32_t)(lx|(-lx))>>31; 36 hx = 0x7ff00000 - hx; 37 return (int)((u_int32_t)(hx))>>31; 38 } 39