1 /* @(#)s_copysign.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_copysign.c,v 1.4 1994/03/03 17:04:30 jtc Exp $"; 15 #endif 16 17 /* 18 * copysign(double x, double y) 19 * copysign(x,y) returns a value with the magnitude of x and 20 * with the sign bit of y. 21 */ 22 23 #include <math.h> 24 #include <machine/endian.h> 25 26 #if BYTE_ORDER == LITTLE_ENDIAN 27 #define n0 1 28 #else 29 #define n0 0 30 #endif 31 32 #ifdef __STDC__ 33 double copysign(double x, double y) 34 #else 35 double copysign(x,y) 36 double x,y; 37 #endif 38 { 39 *(n0+(unsigned*)&x) = 40 (*(n0+(unsigned*)&x)&0x7fffffff)|(*(n0+(unsigned*)&y)&0x80000000); 41 return x; 42 } 43