sysdeps/ieee754/flt-32/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 #if defined(LIBM_SCCS) && !defined(lint)
  17 static char rcsid[] = "$NetBSD: e_remainderf.c,v 1.4 1995/05/10 20:46:08 jtc Exp $";
  18 #endif
  19
  20 #include "math.h"
  21 #include "math_private.h"
  22
  23 #ifdef __STDC__
  24 static const float zero = 0.0;
  25 #else
  26 static float zero = 0.0;
  27 #endif
  28
  29
  30 #ifdef __STDC__
  31         float __ieee754_remainderf(float x, float p)
  32 #else
  33         float __ieee754_remainderf(x,p)
  34         float x,p;
  35 #endif
  36 {
  37         int32_t hx,hp;
  38         u_int32_t sx;
  39         float p_half;
  40
  41         GET_FLOAT_WORD(hx,x);
  42         GET_FLOAT_WORD(hp,p);
  43         sx = hx&0x80000000;
  44         hp &= 0x7fffffff;
  45         hx &= 0x7fffffff;
  46
  47     /* purge off exception values */
  48         if(hp==0) return (x*p)/(x*p);           /* p = 0 */
  49         if((hx>=0x7f800000)||                   /* x not finite */
  50           ((hp>0x7f800000)))                    /* p is NaN */
  51             return (x*p)/(x*p);
  52
  53
  54         if (hp<=0x7effffff) x = __ieee754_fmodf(x,p+p); /* now x < 2p */
  55         if ((hx-hp)==0) return zero*x;
  56         x  = fabsf(x);
  57         p  = fabsf(p);
  58         if (hp<0x01000000) {
  59             if(x+x>p) {
  60                 x-=p;
  61                 if(x+x>=p) x -= p;
  62             }
  63         } else {
  64             p_half = (float)0.5*p;
  65             if(x>p_half) {
  66                 x-=p;
  67                 if(x>=p_half) x -= p;
  68             }
  69         }
  70         GET_FLOAT_WORD(hx,x);
  71         SET_FLOAT_WORD(x,hx^sx);
  72         return x;
  73 }