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84 lines
1.9 KiB
C
84 lines
1.9 KiB
C
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/* e_remainderl.c -- long double version of e_remainder.c.
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* Conversion to long double by Ulrich Drepper,
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* Cygnus Support, drepper@cygnus.com.
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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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#if defined(LIBM_SCCS) && !defined(lint)
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static char rcsid[] = "$NetBSD: $";
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#endif
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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 fmod() 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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#ifdef __STDC__
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static const long double zero = 0.0;
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#else
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static long double zero = 0.0;
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#endif
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#ifdef __STDC__
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long double __ieee754_remainderl(long double x, long double p)
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#else
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long double __ieee754_remainderl(x,p)
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long double x,p;
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#endif
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{
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u_int32_t sx,sex,sep,x0,x1,p0,p1;
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long double p_half;
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EXTRACT_LDOUBLE_WORDS(sex,x0,x1,x);
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EXTRACT_LDOUBLE_WORDS(sep,p0,p1,p);
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sx = sex&0x8000;
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sep &= 0x7fff;
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sex &= 0x7fff;
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/* purge off exception values */
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if((sep|p0|p1)==0) return (x*p)/(x*p); /* p = 0 */
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if((sex==0x7fff)|| /* x not finite */
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((sep==0x7fff)&& /* p is NaN */
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((p0|p1)!=0)))
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return (x*p)/(x*p);
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if (sep<0x7ffe) x = __ieee754_fmodl(x,p+p); /* now x < 2p */
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if (((sex-sep)|(x0-p0)|(x1-p1))==0) return zero*x;
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x = fabsl(x);
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p = fabsl(p);
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if (sep<0x0002) {
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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 = 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_EXP(sex,x);
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SET_LDOUBLE_EXP(x,sex^sx);
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return x;
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}
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