gonzui

    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: /*
   14:  * copysign(double x, double y)
   15:  * copysign(x,y) returns a value with the magnitude of x and
   16:  * with the sign bit of y.
   17:  */
   18: 
   19: /* LINTLIBRARY */
   20: 
   21: #include <sys/cdefs.h>
   22: #include <float.h>
   23: #include <math.h>
   24: 
   25: #include "math_private.h"
   26: 
   27: double
   28: copysign(double x, double y)
   29: {
   30:         u_int32_t hx,hy;
   31:         GET_HIGH_WORD(hx,x);
   32:         GET_HIGH_WORD(hy,y);
   33:         SET_HIGH_WORD(x,(hx&0x7fffffff)|(hy&0x80000000));
   34:         return x;
   35: }
   36: 
   37: #if     LDBL_MANT_DIG == 53
   38: #ifdef  lint
   39: /* PROTOLIB1 */
   40: long double copysignl(long double, long double);
   41: #else   /* lint */
   42: __weak_alias(copysignl, copysign);
   43: #endif  /* lint */
   44: #endif  /* LDBL_MANT_DIG == 53 */