compiler/mlib/e_remainderf.c

   1 /* e_remainderf.c -- float version of e_remainder.c.
   2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   3  */
   4
   5 /*
   6  * ====================================================
   7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   8  *
   9  * Developed at SunPro, a Sun Microsystems, Inc. business.
  10  * Permission to use, copy, modify, and distribute this
  11  * software is freely granted, provided that this notice
  12  * is preserved.
  13  * ====================================================
  14  */
  15
  16 #ifndef lint
  17 static char rcsid[] = "$FreeBSD: src/lib/msun/src/e_remainderf.c,v 1.7 2002/05/28 18:15:04 alfred Exp $";
  18 #endif
  19
  20 #include "math.h"
  21 #include "math_private.h"
  22
  23 static const float zero = 0.0;
  24
  25
  26 float
  27 __ieee754_remainderf(float x, float p)
  28 {
  29         int32_t hx,hp;
  30         u_int32_t sx;
  31         float p_half;
  32
  33         GET_FLOAT_WORD(hx,x);
  34         GET_FLOAT_WORD(hp,p);
  35         sx = hx&0x80000000;
  36         hp &= 0x7fffffff;
  37         hx &= 0x7fffffff;
  38
  39     /* purge off exception values */
  40         if(hp==0) return (x*p)/(x*p);           /* p = 0 */
  41         if((hx>=0x7f800000)||                   /* x not finite */
  42           ((hp>0x7f800000)))                    /* p is NaN */
  43             return (x*p)/(x*p);
  44
  45
  46         if (hp<=0x7effffff) x = __ieee754_fmodf(x,p+p); /* now x < 2p */
  47         if ((hx-hp)==0) return zero*x;
  48         x  = fabsf(x);
  49         p  = fabsf(p);
  50         if (hp<0x01000000) {
  51             if(x+x>p) {
  52                 x-=p;
  53                 if(x+x>=p) x -= p;
  54             }
  55         } else {
  56             p_half = (float)0.5*p;
  57             if(x>p_half) {
  58                 x-=p;
  59                 if(x>=p_half) x -= p;
  60             }
  61         }
  62         GET_FLOAT_WORD(hx,x);
  63         SET_FLOAT_WORD(x,hx^sx);
  64         return x;
  65 }