1  /* e_fmodl.c -- long double version of e_fmod.c.
       2   * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
       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  /* remainderq(x,p)
      16   * Return :
      17   *	returns  x REM p  =  x - [x/p]*p as if in infinite
      18   *	precise arithmetic, where [x/p] is the (infinite bit)
      19   *	integer nearest x/p (in half way case choose the even one).
      20   * Method :
      21   *	Based on fmodl() return x-[x/p]chopped*p exactlp.
      22   */
      23  
      24  #include "quadmath-imp.h"
      25  
      26  static const __float128 zero = 0;
      27  
      28  
      29  __float128
      30  remainderq(__float128 x, __float128 p)
      31  {
      32  	int64_t hx,hp;
      33  	uint64_t sx,lx,lp;
      34  	__float128 p_half;
      35  
      36  	GET_FLT128_WORDS64(hx,lx,x);
      37  	GET_FLT128_WORDS64(hp,lp,p);
      38  	sx = hx&0x8000000000000000ULL;
      39  	hp &= 0x7fffffffffffffffLL;
      40  	hx &= 0x7fffffffffffffffLL;
      41  
      42      /* purge off exception values */
      43  	if((hp|lp)==0) return (x*p)/(x*p);	/* p = 0 */
      44  	if((hx>=0x7fff000000000000LL)||			/* x not finite */
      45  	  ((hp>=0x7fff000000000000LL)&&			/* p is NaN */
      46  	  (((hp-0x7fff000000000000LL)|lp)!=0)))
      47  	    return (x*p)/(x*p);
      48  
      49  
      50  	if (hp<=0x7ffdffffffffffffLL) x = fmodq(x,p+p);	/* now x < 2p */
      51  	if (((hx-hp)|(lx-lp))==0) return zero*x;
      52  	x  = fabsq(x);
      53  	p  = fabsq(p);
      54  	if (hp<0x0002000000000000LL) {
      55  	    if(x+x>p) {
      56  		x-=p;
      57  		if(x+x>=p) x -= p;
      58  	    }
      59  	} else {
      60  	    p_half = 0.5Q*p;
      61  	    if(x>p_half) {
      62  		x-=p;
      63  		if(x>=p_half) x -= p;
      64  	    }
      65  	}
      66  	GET_FLT128_MSW64(hx,x);
      67  	SET_FLT128_MSW64(x,hx^sx);
      68  	return x;
      69  }