text: 
  /* @(#)e_remainder.c 5.1 93/09/24 */
  /*
   * ====================================================
   * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   *
   * Developed at SunPro, a Sun Microsystems, Inc. business.
   * Permission to use, copy, modify, and distribute this
   * software is freely granted, provided that this notice 
   * is preserved.
   * ====================================================
   */
  
  /*
  FUNCTION
  <<remainder>>, <<remainderf>>---round and  remainder
  INDEX
          remainder
  INDEX
          remainderf
  
  SYNOPSIS
          #include <math.h>
          double remainder(double <[x]>, double <[y]>);
          float remainderf(float <[x]>, float <[y]>);
  
  DESCRIPTION
  <<remainder>> and <<remainderf>> find the remainder of
  <[x]>/<[y]>; this value is in the range -<[y]>/2 .. +<[y]>/2.
  
  RETURNS
  <<remainder>> returns the integer result as a double.
  
  PORTABILITY
  <<remainder>> is a System V release 4.
  <<remainderf>> is an extension.
  
  */
  
  /* remainder(x,p)
   * Return :                  
   * 	returns  x REM p  =  x - [x/p]*p as if in infinite 
   * 	precise arithmetic, where [x/p] is the (infinite bit) 
   *	integer nearest x/p (in half way case choose the even one).
   * Method : 
   *	Based on fmod() return x-[x/p]chopped*p exactlp.
   */
  
  #include "fdlibm.h"
  
  #ifndef _DOUBLE_IS_32BITS
  
  #ifdef __STDC__
  static const double zero = 0.0;
  #else
  static double zero = 0.0;
  #endif
  
  
  #ifdef __STDC__
  	double remainder(double x, double p)
  #else
  	double remainder(x,p)
  	double x,p;
  #endif
  {
  	__int32_t hx,hp;
  	__uint32_t sx,lx,lp;
  	double p_half;
  
  	EXTRACT_WORDS(hx,lx,x);
  	EXTRACT_WORDS(hp,lp,p);
  	sx = hx&0x80000000;
  	hp &= 0x7fffffff;
  	hx &= 0x7fffffff;
  
      /* purge off exception values */
  	if((hp|lp)==0) return (x*p)/(x*p); 	/* p = 0 */
  	if((hx>=0x7ff00000)||			/* x not finite */
  	  ((hp>=0x7ff00000)&&			/* p is NaN */
  	  (((hp-0x7ff00000)|lp)!=0)))
  	    return (x*p)/(x*p);
  
  
  	if (hp<=0x7fdfffff) x = fmod(x,p+p);	/* now x < 2p */
  	if (((hx-hp)|(lx-lp))==0) return zero*x;
  	x  = fabs(x);
  	p  = fabs(p);
  	if (hp<0x00200000) {
  	    if(x+x>p) {
  		x-=p;
  		if(x+x>=p) x -= p;
  	    }
  	} else {
  	    p_half = 0.5*p;
  	    if(x>p_half) {
  		x-=p;
  		if(x>=p_half) x -= p;
  	    }
  	}
  	GET_HIGH_WORD(hx,x);
  	SET_HIGH_WORD(x,hx^sx);
  	return x;
  }
  
  #endif /* defined(_DOUBLE_IS_32BITS) */
  