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
24static const _Float128 one = 1.0, Zero[] = {0.0, -0.0,};
25
26_Float128
27__ieee754_fmodl (_Float128 x, _Float128 y)
28{
29 int64_t n,hx,hy,hz,ix,iy,sx,i;
30 u_int64_t lx,ly,lz;
31
32 GET_LDOUBLE_WORDS64(hx,lx,x);
33 GET_LDOUBLE_WORDS64(hy,ly,y);
34 sx = hx&0x8000000000000000ULL; /* sign of x */
35 hx ^=sx; /* |x| */
36 hy &= 0x7fffffffffffffffLL; /* |y| */
37
38 /* purge off exception values */
39 if((hy|ly)==0||(hx>=0x7fff000000000000LL)|| /* y=0,or x not finite */
40 ((hy|((ly|-ly)>>63))>0x7fff000000000000LL)) /* or y is NaN */
41 return (x*y)/(x*y);
42 if(hx<=hy) {
43 if((hx<hy)||(lx<ly)) return x; /* |x|<|y| return x */
44 if(lx==ly)
45 return Zero[(u_int64_t)sx>>63]; /* |x|=|y| return x*0*/
46 }
47
48 /* determine ix = ilogb(x) */
49 if(hx<0x0001000000000000LL) { /* subnormal x */
50 if(hx==0) {
51 for (ix = -16431, i=lx; i>0; i<<=1) ix -=1;
52 } else {
53 for (ix = -16382, i=hx<<15; i>0; i<<=1) ix -=1;
54 }
55 } else ix = (hx>>48)-0x3fff;
56
57 /* determine iy = ilogb(y) */
58 if(hy<0x0001000000000000LL) { /* subnormal y */
59 if(hy==0) {
60 for (iy = -16431, i=ly; i>0; i<<=1) iy -=1;
61 } else {
62 for (iy = -16382, i=hy<<15; i>0; i<<=1) iy -=1;
63 }
64 } else iy = (hy>>48)-0x3fff;
65
66 /* set up {hx,lx}, {hy,ly} and align y to x */
67 if(ix >= -16382)
68 hx = 0x0001000000000000LL|(0x0000ffffffffffffLL&hx);
69 else { /* subnormal x, shift x to normal */
70 n = -16382-ix;
71 if(n<=63) {
72 hx = (hx<<n)|(lx>>(64-n));
73 lx <<= n;
74 } else {
75 hx = lx<<(n-64);
76 lx = 0;
77 }
78 }
79 if(iy >= -16382)
80 hy = 0x0001000000000000LL|(0x0000ffffffffffffLL&hy);
81 else { /* subnormal y, shift y to normal */
82 n = -16382-iy;
83 if(n<=63) {
84 hy = (hy<<n)|(ly>>(64-n));
85 ly <<= n;
86 } else {
87 hy = ly<<(n-64);
88 ly = 0;
89 }
90 }
91
92 /* fix point fmod */
93 n = ix - iy;
94 while(n--) {
95 hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1;
96 if(hz<0){hx = hx+hx+(lx>>63); lx = lx+lx;}
97 else {
98 if((hz|lz)==0) /* return sign(x)*0 */
99 return Zero[(u_int64_t)sx>>63];
100 hx = hz+hz+(lz>>63); lx = lz+lz;
101 }
102 }
103 hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1;
104 if(hz>=0) {hx=hz;lx=lz;}
105
106 /* convert back to floating value and restore the sign */
107 if((hx|lx)==0) /* return sign(x)*0 */
108 return Zero[(u_int64_t)sx>>63];
109 while(hx<0x0001000000000000LL) { /* normalize x */
110 hx = hx+hx+(lx>>63); lx = lx+lx;
111 iy -= 1;
112 }
113 if(iy>= -16382) { /* normalize output */
114 hx = ((hx-0x0001000000000000LL)|((iy+16383)<<48));
115 SET_LDOUBLE_WORDS64(x,hx|sx,lx);
116 } else { /* subnormal output */
117 n = -16382 - iy;
118 if(n<=48) {
119 lx = (lx>>n)|((u_int64_t)hx<<(64-n));
120 hx >>= n;
121 } else if (n<=63) {
122 lx = (hx<<(64-n))|(lx>>n); hx = sx;
123 } else {
124 lx = hx>>(n-64); hx = sx;
125 }
126 SET_LDOUBLE_WORDS64(x,hx|sx,lx);
127 x *= one; /* create necessary signal */
128 }
129 return x; /* exact output */
130}
131strong_alias (__ieee754_fmodl, __fmodl_finite)
132