1/* e_fmodl.c -- long double version of e_fmod.c.
2 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
3 */
4/*
5 * ====================================================
6 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
7 *
8 * Developed at SunPro, a Sun Microsystems, Inc. business.
9 * Permission to use, copy, modify, and distribute this
10 * software is freely granted, provided that this notice
11 * is preserved.
12 * ====================================================
13 */
14
15/* __ieee754_remainderl(x,p)
16 * Return :
17 * returns x REM p = x - [x/p]*p as if in infinite
18 * precise arithmetic, where [x/p] is the (infinite bit)
19 * integer nearest x/p (in half way case choose the even one).
20 * Method :
21 * Based on fmodl() return x-[x/p]chopped*p exactlp.
22 */
23
24#include <math.h>
25#include <math_private.h>
26#include <libm-alias-finite.h>
27
28static const _Float128 zero = 0;
29
30
31_Float128
32__ieee754_remainderl(_Float128 x, _Float128 p)
33{
34 int64_t hx,hp;
35 uint64_t sx,lx,lp;
36 _Float128 p_half;
37
38 GET_LDOUBLE_WORDS64(hx,lx,x);
39 GET_LDOUBLE_WORDS64(hp,lp,p);
40 sx = hx&0x8000000000000000ULL;
41 hp &= 0x7fffffffffffffffLL;
42 hx &= 0x7fffffffffffffffLL;
43
44 /* purge off exception values */
45 if((hp|lp)==0) return (x*p)/(x*p); /* p = 0 */
46 if((hx>=0x7fff000000000000LL)|| /* x not finite */
47 ((hp>=0x7fff000000000000LL)&& /* p is NaN */
48 (((hp-0x7fff000000000000LL)|lp)!=0)))
49 return (x*p)/(x*p);
50
51
52 if (hp<=0x7ffdffffffffffffLL) x = __ieee754_fmodl(x,p+p); /* now x < 2p */
53 if (((hx-hp)|(lx-lp))==0) return zero*x;
54 x = fabsl(x);
55 p = fabsl(p);
56 if (hp<0x0002000000000000LL) {
57 if(x+x>p) {
58 x-=p;
59 if(x+x>=p) x -= p;
60 }
61 } else {
62 p_half = L(0.5)*p;
63 if(x>p_half) {
64 x-=p;
65 if(x>=p_half) x -= p;
66 }
67 }
68 GET_LDOUBLE_MSW64(hx,x);
69 SET_LDOUBLE_MSW64(x,hx^sx);
70 return x;
71}
72libm_alias_finite (__ieee754_remainderl, __remainderl)
73