mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-11 07:40:05 +00:00
72 lines
1.8 KiB
C
72 lines
1.8 KiB
C
/* e_fmodl.c -- long double version of e_fmod.c.
|
|
* Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
|
|
*/
|
|
/*
|
|
* ====================================================
|
|
* 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_remainderl(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 fmodl() return x-[x/p]chopped*p exactlp.
|
|
*/
|
|
|
|
#include <math.h>
|
|
#include <math_private.h>
|
|
|
|
static const long double zero = 0.0L;
|
|
|
|
|
|
long double
|
|
__ieee754_remainderl(long double x, long double p)
|
|
{
|
|
int64_t hx,hp;
|
|
u_int64_t sx,lx,lp;
|
|
long double p_half;
|
|
|
|
GET_LDOUBLE_WORDS64(hx,lx,x);
|
|
GET_LDOUBLE_WORDS64(hp,lp,p);
|
|
sx = hx&0x8000000000000000ULL;
|
|
hp &= 0x7fffffffffffffffLL;
|
|
hx &= 0x7fffffffffffffffLL;
|
|
|
|
/* purge off exception values */
|
|
if((hp|(lp&0x7fffffffffffffff))==0) return (x*p)/(x*p); /* p = 0 */
|
|
if((hx>=0x7ff0000000000000LL)|| /* x not finite */
|
|
((hp>=0x7ff0000000000000LL)&& /* p is NaN */
|
|
(((hp-0x7ff0000000000000LL)|lp)!=0)))
|
|
return (x*p)/(x*p);
|
|
|
|
|
|
if (hp<=0x7fdfffffffffffffLL) x = __ieee754_fmodl(x,p+p); /* now x < 2p */
|
|
if (((hx-hp)|(lx-lp))==0) return zero*x;
|
|
x = fabsl(x);
|
|
p = fabsl(p);
|
|
if (hp<0x0020000000000000LL) {
|
|
if(x+x>p) {
|
|
x-=p;
|
|
if(x+x>=p) x -= p;
|
|
}
|
|
} else {
|
|
p_half = 0.5L*p;
|
|
if(x>p_half) {
|
|
x-=p;
|
|
if(x>=p_half) x -= p;
|
|
}
|
|
}
|
|
GET_LDOUBLE_MSW64(hx,x);
|
|
SET_LDOUBLE_MSW64(x,hx^sx);
|
|
return x;
|
|
}
|
|
strong_alias (__ieee754_remainderl, __remainderl_finite)
|