mirror of
git://gcc.gnu.org/git/gcc.git
synced 2024-12-19 01:39:15 +08:00
81 lines
1.7 KiB
C
81 lines
1.7 KiB
C
|
|
/* @(#)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.
|
|
* ====================================================
|
|
*/
|
|
|
|
/* __ieee754_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 __ieee754_remainder(double x, double p)
|
|
#else
|
|
double __ieee754_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 = __ieee754_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) */
|