mirror of
https://github.com/fluencelabs/musl
synced 2025-06-01 17:11:53 +00:00
67 lines
1.6 KiB
C
67 lines
1.6 KiB
C
/* origin: FreeBSD /usr/src/lib/msun/src/e_remainder.c */
|
|
/*
|
|
* ====================================================
|
|
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
|
*
|
|
* Developed at SunSoft, a Sun Microsystems, Inc. business.
|
|
* Permission to use, copy, modify, and distribute this
|
|
* software is freely granted, provided that this notice
|
|
* is preserved.
|
|
* ====================================================
|
|
*/
|
|
/* 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 "libm.h"
|
|
|
|
double remainder(double x, double p)
|
|
{
|
|
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 || /* p = 0 */
|
|
hx >= 0x7ff00000 || /* x not finite */
|
|
(hp >= 0x7ff00000 && (hp-0x7ff00000 | lp) != 0)) /* p is NaN */
|
|
return (x*p)/(x*p);
|
|
|
|
if (hp <= 0x7fdfffff)
|
|
x = fmod(x, p+p); /* now x < 2p */
|
|
if (((hx-hp)|(lx-lp)) == 0)
|
|
return 0.0*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);
|
|
if ((hx&0x7fffffff) == 0)
|
|
hx = 0;
|
|
SET_HIGH_WORD(x, hx^sx);
|
|
return x;
|
|
}
|