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, 2011 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/*
16 * __ieee754_fmodl(x,y)
17 * Return x mod y in exact arithmetic
18 * Method: shift and subtract
19 */
20
21#include <math.h>
22#include <math_private.h>
23#include <libm-alias-finite.h>
24
25static const _Float128 one = 1.0, Zero[] = {0.0, -0.0,};
26
27_Float128
28__ieee754_fmodl (_Float128 x, _Float128 y)
29{
30 int64_t n,hx,hy,hz,ix,iy,sx,i;
31 uint64_t lx,ly,lz;
32
33 GET_LDOUBLE_WORDS64(hx,lx,x);
34 GET_LDOUBLE_WORDS64(hy,ly,y);
35 sx = hx&0x8000000000000000ULL; /* sign of x */
36 hx ^=sx; /* |x| */
37 hy &= 0x7fffffffffffffffLL; /* |y| */
38
39 /* purge off exception values */
40 if((hy|ly)==0||(hx>=0x7fff000000000000LL)|| /* y=0,or x not finite */
41 ((hy|((ly|-ly)>>63))>0x7fff000000000000LL)) /* or y is NaN */
42 return (x*y)/(x*y);
43 if(hx<=hy) {
44 if((hx<hy)||(lx<ly)) return x; /* |x|<|y| return x */
45 if(lx==ly)
46 return Zero[(uint64_t)sx>>63]; /* |x|=|y| return x*0*/
47 }
48
49 /* determine ix = ilogb(x) */
50 if(hx<0x0001000000000000LL) { /* subnormal x */
51 if(hx==0) {
52 for (ix = -16431, i=lx; i>0; i<<=1) ix -=1;
53 } else {
54 for (ix = -16382, i=hx<<15; i>0; i<<=1) ix -=1;
55 }
56 } else ix = (hx>>48)-0x3fff;
57
58 /* determine iy = ilogb(y) */
59 if(hy<0x0001000000000000LL) { /* subnormal y */
60 if(hy==0) {
61 for (iy = -16431, i=ly; i>0; i<<=1) iy -=1;
62 } else {
63 for (iy = -16382, i=hy<<15; i>0; i<<=1) iy -=1;
64 }
65 } else iy = (hy>>48)-0x3fff;
66
67 /* set up {hx,lx}, {hy,ly} and align y to x */
68 if(ix >= -16382)
69 hx = 0x0001000000000000LL|(0x0000ffffffffffffLL&hx);
70 else { /* subnormal x, shift x to normal */
71 n = -16382-ix;
72 if(n<=63) {
73 hx = (hx<<n)|(lx>>(64-n));
74 lx <<= n;
75 } else {
76 hx = lx<<(n-64);
77 lx = 0;
78 }
79 }
80 if(iy >= -16382)
81 hy = 0x0001000000000000LL|(0x0000ffffffffffffLL&hy);
82 else { /* subnormal y, shift y to normal */
83 n = -16382-iy;
84 if(n<=63) {
85 hy = (hy<<n)|(ly>>(64-n));
86 ly <<= n;
87 } else {
88 hy = ly<<(n-64);
89 ly = 0;
90 }
91 }
92
93 /* fix point fmod */
94 n = ix - iy;
95 while(n--) {
96 hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1;
97 if(hz<0){hx = hx+hx+(lx>>63); lx = lx+lx;}
98 else {
99 if((hz|lz)==0) /* return sign(x)*0 */
100 return Zero[(uint64_t)sx>>63];
101 hx = hz+hz+(lz>>63); lx = lz+lz;
102 }
103 }
104 hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1;
105 if(hz>=0) {hx=hz;lx=lz;}
106
107 /* convert back to floating value and restore the sign */
108 if((hx|lx)==0) /* return sign(x)*0 */
109 return Zero[(uint64_t)sx>>63];
110 while(hx<0x0001000000000000LL) { /* normalize x */
111 hx = hx+hx+(lx>>63); lx = lx+lx;
112 iy -= 1;
113 }
114 if(iy>= -16382) { /* normalize output */
115 hx = ((hx-0x0001000000000000LL)|((iy+16383)<<48));
116 SET_LDOUBLE_WORDS64(x,hx|sx,lx);
117 } else { /* subnormal output */
118 n = -16382 - iy;
119 if(n<=48) {
120 lx = (lx>>n)|((uint64_t)hx<<(64-n));
121 hx >>= n;
122 } else if (n<=63) {
123 lx = (hx<<(64-n))|(lx>>n); hx = sx;
124 } else {
125 lx = hx>>(n-64); hx = sx;
126 }
127 SET_LDOUBLE_WORDS64(x,hx|sx,lx);
128 x *= one; /* create necessary signal */
129 }
130 return x; /* exact output */
131}
132libm_alias_finite (__ieee754_fmodl, __fmodl)
133