sysdeps/ieee754/flt-32/e_remainderf.c

   1 /* e_remainderf.c -- float version of e_remainder.c.
   2  */
   3
   4 /*
   5  * ====================================================
   6  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   7  *
   8  * Developed at SunPro, a Sun Microsystems, Inc. business.
   9  * Permission to use, copy, modify, and distribute this
  10  * software is freely granted, provided that this notice
  11  * is preserved.
  12  * ====================================================
  13  */
  14
  15 #include <math.h>
  16 #include <math_private.h>
  17 #include <libm-alias-finite.h>
  18
  19 static const float zero = 0.0;
  20
  21
  22 float
  23 __ieee754_remainderf(float x, float p)
  24 {
  25         int32_t hx,hp;
  26         uint32_t sx;
  27         float p_half;
  28
  29         GET_FLOAT_WORD(hx,x);
  30         GET_FLOAT_WORD(hp,p);
  31         sx = hx&0x80000000;
  32         hp &= 0x7fffffff;
  33         hx &= 0x7fffffff;
  34
  35     /* purge off exception values */
  36         if(hp==0) return (x*p)/(x*p);           /* p = 0 */
  37         if((hx>=0x7f800000)||                   /* x not finite */
  38           ((hp>0x7f800000)))                    /* p is NaN */
  39             return (x*p)/(x*p);
  40
  41
  42         if (hp<=0x7effffff) x = __ieee754_fmodf(x,p+p); /* now x < 2p */
  43         if ((hx-hp)==0) return zero*x;
  44         x  = fabsf(x);
  45         p  = fabsf(p);
  46         if (hp<0x01000000) {
  47             if(x+x>p) {
  48                 x-=p;
  49                 if(x+x>=p) x -= p;
  50             }
  51         } else {
  52             p_half = (float)0.5*p;
  53             if(x>p_half) {
  54                 x-=p;
  55                 if(x>=p_half) x -= p;
  56             }
  57         }
  58         GET_FLOAT_WORD(hx,x);
  59         SET_FLOAT_WORD(x,hx^sx);
  60         return x;
  61 }
  62 libm_alias_finite (__ieee754_remainderf, __remainderf)