| 1 |
740 |
jeremybenn |
/* 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 |
|
|
/*
|
| 16 |
|
|
* fmodq(x,y)
|
| 17 |
|
|
* Return x mod y in exact arithmetic
|
| 18 |
|
|
* Method: shift and subtract
|
| 19 |
|
|
*/
|
| 20 |
|
|
|
| 21 |
|
|
#include "quadmath-imp.h"
|
| 22 |
|
|
|
| 23 |
|
|
static const __float128 one = 1.0, Zero[] = {0.0, -0.0,};
|
| 24 |
|
|
|
| 25 |
|
|
__float128
|
| 26 |
|
|
fmodq (__float128 x, __float128 y)
|
| 27 |
|
|
{
|
| 28 |
|
|
int64_t n,hx,hy,hz,ix,iy,sx,i;
|
| 29 |
|
|
uint64_t lx,ly,lz;
|
| 30 |
|
|
|
| 31 |
|
|
GET_FLT128_WORDS64(hx,lx,x);
|
| 32 |
|
|
GET_FLT128_WORDS64(hy,ly,y);
|
| 33 |
|
|
sx = hx&0x8000000000000000ULL; /* sign of x */
|
| 34 |
|
|
hx ^=sx; /* |x| */
|
| 35 |
|
|
hy &= 0x7fffffffffffffffLL; /* |y| */
|
| 36 |
|
|
|
| 37 |
|
|
/* purge off exception values */
|
| 38 |
|
|
if((hy|ly)==0||(hx>=0x7fff000000000000LL)|| /* y=0,or x not finite */
|
| 39 |
|
|
((hy|((ly|-ly)>>63))>0x7fff000000000000LL)) /* or y is NaN */
|
| 40 |
|
|
return (x*y)/(x*y);
|
| 41 |
|
|
if(hx<=hy) {
|
| 42 |
|
|
if((hx<hy)||(lx<ly)) return x; /* |x|<|y| return x */
|
| 43 |
|
|
if(lx==ly)
|
| 44 |
|
|
return Zero[(uint64_t)sx>>63]; /* |x|=|y| return x*0*/
|
| 45 |
|
|
}
|
| 46 |
|
|
|
| 47 |
|
|
/* determine ix = ilogb(x) */
|
| 48 |
|
|
if(hx<0x0001000000000000LL) { /* subnormal x */
|
| 49 |
|
|
if(hx==0) {
|
| 50 |
|
|
for (ix = -16431, i=lx; i>0; i<<=1) ix -=1;
|
| 51 |
|
|
} else {
|
| 52 |
|
|
for (ix = -16382, i=hx<<15; i>0; i<<=1) ix -=1;
|
| 53 |
|
|
}
|
| 54 |
|
|
} else ix = (hx>>48)-0x3fff;
|
| 55 |
|
|
|
| 56 |
|
|
/* determine iy = ilogb(y) */
|
| 57 |
|
|
if(hy<0x0001000000000000LL) { /* subnormal y */
|
| 58 |
|
|
if(hy==0) {
|
| 59 |
|
|
for (iy = -16431, i=ly; i>0; i<<=1) iy -=1;
|
| 60 |
|
|
} else {
|
| 61 |
|
|
for (iy = -16382, i=hy<<15; i>0; i<<=1) iy -=1;
|
| 62 |
|
|
}
|
| 63 |
|
|
} else iy = (hy>>48)-0x3fff;
|
| 64 |
|
|
|
| 65 |
|
|
/* set up {hx,lx}, {hy,ly} and align y to x */
|
| 66 |
|
|
if(ix >= -16382)
|
| 67 |
|
|
hx = 0x0001000000000000LL|(0x0000ffffffffffffLL&hx);
|
| 68 |
|
|
else { /* subnormal x, shift x to normal */
|
| 69 |
|
|
n = -16382-ix;
|
| 70 |
|
|
if(n<=63) {
|
| 71 |
|
|
hx = (hx<<n)|(lx>>(64-n));
|
| 72 |
|
|
lx <<= n;
|
| 73 |
|
|
} else {
|
| 74 |
|
|
hx = lx<<(n-64);
|
| 75 |
|
|
lx = 0;
|
| 76 |
|
|
}
|
| 77 |
|
|
}
|
| 78 |
|
|
if(iy >= -16382)
|
| 79 |
|
|
hy = 0x0001000000000000LL|(0x0000ffffffffffffLL&hy);
|
| 80 |
|
|
else { /* subnormal y, shift y to normal */
|
| 81 |
|
|
n = -16382-iy;
|
| 82 |
|
|
if(n<=63) {
|
| 83 |
|
|
hy = (hy<<n)|(ly>>(64-n));
|
| 84 |
|
|
ly <<= n;
|
| 85 |
|
|
} else {
|
| 86 |
|
|
hy = ly<<(n-64);
|
| 87 |
|
|
ly = 0;
|
| 88 |
|
|
}
|
| 89 |
|
|
}
|
| 90 |
|
|
|
| 91 |
|
|
/* fix point fmod */
|
| 92 |
|
|
n = ix - iy;
|
| 93 |
|
|
while(n--) {
|
| 94 |
|
|
hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1;
|
| 95 |
|
|
if(hz<0){hx = hx+hx+(lx>>63); lx = lx+lx;}
|
| 96 |
|
|
else {
|
| 97 |
|
|
if((hz|lz)==0) /* return sign(x)*0 */
|
| 98 |
|
|
return Zero[(uint64_t)sx>>63];
|
| 99 |
|
|
hx = hz+hz+(lz>>63); lx = lz+lz;
|
| 100 |
|
|
}
|
| 101 |
|
|
}
|
| 102 |
|
|
hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1;
|
| 103 |
|
|
if(hz>=0) {hx=hz;lx=lz;}
|
| 104 |
|
|
|
| 105 |
|
|
/* convert back to floating value and restore the sign */
|
| 106 |
|
|
if((hx|lx)==0) /* return sign(x)*0 */
|
| 107 |
|
|
return Zero[(uint64_t)sx>>63];
|
| 108 |
|
|
while(hx<0x0001000000000000LL) { /* normalize x */
|
| 109 |
|
|
hx = hx+hx+(lx>>63); lx = lx+lx;
|
| 110 |
|
|
iy -= 1;
|
| 111 |
|
|
}
|
| 112 |
|
|
if(iy>= -16382) { /* normalize output */
|
| 113 |
|
|
hx = ((hx-0x0001000000000000LL)|((iy+16383)<<48));
|
| 114 |
|
|
SET_FLT128_WORDS64(x,hx|sx,lx);
|
| 115 |
|
|
} else { /* subnormal output */
|
| 116 |
|
|
n = -16382 - iy;
|
| 117 |
|
|
if(n<=48) {
|
| 118 |
|
|
lx = (lx>>n)|((uint64_t)hx<<(64-n));
|
| 119 |
|
|
hx >>= n;
|
| 120 |
|
|
} else if (n<=63) {
|
| 121 |
|
|
lx = (hx<<(64-n))|(lx>>n); hx = sx;
|
| 122 |
|
|
} else {
|
| 123 |
|
|
lx = hx>>(n-64); hx = sx;
|
| 124 |
|
|
}
|
| 125 |
|
|
SET_FLT128_WORDS64(x,hx|sx,lx);
|
| 126 |
|
|
x *= one; /* create necessary signal */
|
| 127 |
|
|
}
|
| 128 |
|
|
return x; /* exact output */
|
| 129 |
|
|
}
|
