Blame sysdeps/ieee754/ldbl-128/e_remainderl.c

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/* e_fmodl.c -- long double version of e_fmod.c.
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 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
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 */
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/*
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 * ====================================================
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 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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 *
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 * Developed at SunPro, a Sun Microsystems, Inc. business.
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 * Permission to use, copy, modify, and distribute this
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 * software is freely granted, provided that this notice
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 * is preserved.
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 * ====================================================
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 */
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/* __ieee754_remainderl(x,p)
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 * Return :
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 *	returns  x REM p  =  x - [x/p]*p as if in infinite
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 *	precise arithmetic, where [x/p] is the (infinite bit)
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 *	integer nearest x/p (in half way case choose the even one).
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 * Method :
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 *	Based on fmodl() return x-[x/p]chopped*p exactlp.
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 */
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#include <math.h>
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#include <math_private.h>
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static const _Float128 zero = 0;
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_Float128
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__ieee754_remainderl(_Float128 x, _Float128 p)
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{
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	int64_t hx,hp;
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	uint64_t sx,lx,lp;
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	_Float128 p_half;
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	GET_LDOUBLE_WORDS64(hx,lx,x);
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	GET_LDOUBLE_WORDS64(hp,lp,p);
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	sx = hx&0x8000000000000000ULL;
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	hp &= 0x7fffffffffffffffLL;
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	hx &= 0x7fffffffffffffffLL;
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    /* purge off exception values */
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	if((hp|lp)==0) return (x*p)/(x*p);	/* p = 0 */
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	if((hx>=0x7fff000000000000LL)||			/* x not finite */
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	  ((hp>=0x7fff000000000000LL)&&			/* p is NaN */
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	  (((hp-0x7fff000000000000LL)|lp)!=0)))
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	    return (x*p)/(x*p);
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	if (hp<=0x7ffdffffffffffffLL) x = __ieee754_fmodl(x,p+p);	/* now x < 2p */
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	if (((hx-hp)|(lx-lp))==0) return zero*x;
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	x  = fabsl(x);
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	p  = fabsl(p);
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	if (hp<0x0002000000000000LL) {
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	    if(x+x>p) {
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		x-=p;
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		if(x+x>=p) x -= p;
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	    }
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	} else {
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	    p_half = L(0.5)*p;
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	    if(x>p_half) {
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		x-=p;
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		if(x>=p_half) x -= p;
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	    }
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	}
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	GET_LDOUBLE_MSW64(hx,x);
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	SET_LDOUBLE_MSW64(x,hx^sx);
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	return x;
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}
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strong_alias (__ieee754_remainderl, __remainderl_finite)