1 2 /* @(#)s_isnan.c 1.3 95/01/18 */ 3 /* 4 * ==================================================== 5 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 6 * 7 * Developed at SunSoft, a Sun Microsystems, Inc. business. 8 * Permission to use, copy, modify, and distribute this 9 * software is freely granted, provided that this notice 10 * is preserved. 11 * ==================================================== 12 */ 13 14 /* 15 * ieee_isnan(x) returns 1 is x is nan, else 0; 16 * no branching! 17 */ 18 19 #include "fdlibm.h" 20 21 #ifdef __STDC__ 22 int ieee_isnan(double x) 23 #else 24 int ieee_isnan(x) 25 double x; 26 #endif 27 { 28 int hx,lx; 29 hx = (__HI(x)&0x7fffffff); 30 lx = __LO(x); 31 hx |= (unsigned)(lx|(-lx))>>31; 32 hx = 0x7ff00000 - hx; 33 return ((unsigned)(hx))>>31; 34 } 35
