remquol.c revision 25c28e83beb90e7c80452a7c818c5e6f73a07dc8
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma weak remquol = __remquol
#include "libm.h"
#include "libm_synonyms.h"
#if defined(__SUNPRO_C)
#include <sunmath.h> /* fabsl */
#endif
/* INDENT OFF */
static const int
is = -0x7fffffff - 1,
im = 0x0000ffff,
iu = 0x00010000;
static const long double zero = 0.0L, one = 1.0L;
/* INDENT ON */
#if defined(__sparc)
#define __H0(x) ((int *) &x)[0]
#define __H1(x) ((int *) &x)[1]
#define __H2(x) ((int *) &x)[2]
#define __H3(x) ((int *) &x)[3]
#else
#error Unsupported architecture
#endif
/*
* On entrance: *quo is initialized to 0, x finite and y non-zero & ordered
*/
static long double
fmodquol(long double x, long double y, int *quo) {
long double a, b;
int n, ix, iy, k, sx, sq, m;
int hx;
int x0, y0, z0, carry;
unsigned x1, x2, x3, y1, y2, y3, z1, z2, z3;
hx = __H0(x);
x1 = __H1(x);
x2 = __H2(x);
x3 = __H3(x);
y0 = __H0(y);
y1 = __H1(y);
y2 = __H2(y);
y3 = __H3(y);
sx = hx & is;
sq = (hx ^ y0) & is;
x0 = hx ^ sx;
y0 &= ~0x80000000;
a = fabsl(x);
b = fabsl(y);
if (a <= b) {
if (a < b)
return (x);
else {
*quo = 1 + (sq >> 30);
return (zero * x);
}
}
/* determine ix = ilogbl(x) */
if (x0 < iu) { /* subnormal x */
ix = 0;
ix = -16382;
while (x0 == 0) {
ix -= 16;
x0 = x1 >> 16;
x1 = (x1 << 16) | (x2 >> 16);
x2 = (x2 << 16) | (x3 >> 16);
x3 = (x3 << 16);
}
while (x0 < iu) {
ix -= 1;
x0 = (x0 << 1) | (x1 >> 31);
x1 = (x1 << 1) | (x2 >> 31);
x2 = (x2 << 1) | (x3 >> 31);
x3 <<= 1;
}
} else {
ix = (x0 >> 16) - 16383;
x0 = iu | (x0 & im);
}
/* determine iy = ilogbl(y) */
if (y0 < iu) { /* subnormal y */
iy = -16382;
while (y0 == 0) {
iy -= 16;
y0 = y1 >> 16;
y1 = (y1 << 16) | (y2 >> 16);
y2 = (y2 << 16) | (y3 >> 16);
y3 = (y3 << 16);
}
while (y0 < iu) {
iy -= 1;
y0 = (y0 << 1) | (y1 >> 31);
y1 = (y1 << 1) | (y2 >> 31);
y2 = (y2 << 1) | (y3 >> 31);
y3 <<= 1;
}
} else {
iy = (y0 >> 16) - 16383;
y0 = iu | (y0 & im);
}
/* fix point fmod */
n = ix - iy;
m = 0;
while (n--) {
while (x0 == 0 && n >= 16) {
m <<= 16;
n -= 16;
x0 = x1 >> 16;
x1 = (x1 << 16) | (x2 >> 16);
x2 = (x2 << 16) | (x3 >> 16);
x3 = (x3 << 16);
}
while (x0 < iu && n >= 1) {
m += m;
n -= 1;
x0 = (x0 << 1) | (x1 >> 31);
x1 = (x1 << 1) | (x2 >> 31);
x2 = (x2 << 1) | (x3 >> 31);
x3 = (x3 << 1);
}
carry = 0;
z3 = x3 - y3;
carry = z3 > x3;
if (carry == 0) {
z2 = x2 - y2;
carry = z2 > x2;
} else {
z2 = x2 - y2 - 1;
carry = z2 >= x2;
}
if (carry == 0) {
z1 = x1 - y1;
carry = z1 > x1;
} else {
z1 = x1 - y1 - 1;
carry = z1 >= x1;
}
z0 = x0 - y0 - carry;
if (z0 < 0) { /* double x */
x0 = x0 + x0 + ((x1 & is) != 0);
x1 = x1 + x1 + ((x2 & is) != 0);
x2 = x2 + x2 + ((x3 & is) != 0);
x3 = x3 + x3;
m += m;
} else {
m += 1;
if (z0 == 0) {
if ((z1 | z2 | z3) == 0) {
/* 0: we are done */
if (n < 31)
m <<= (1 + n);
else
m = 0;
m &= ~0x80000000;
*quo = sq >= 0 ? m : -m;
__H0(a) = hx & is;
__H1(a) = __H2(a) = __H3(a) = 0;
return (a);
}
}
/* x = z << 1 */
z0 = z0 + z0 + ((z1 & is) != 0);
z1 = z1 + z1 + ((z2 & is) != 0);
z2 = z2 + z2 + ((z3 & is) != 0);
z3 = z3 + z3;
x0 = z0;
x1 = z1;
x2 = z2;
x3 = z3;
m += m;
}
}
carry = 0;
z3 = x3 - y3;
carry = z3 > x3;
if (carry == 0) {
z2 = x2 - y2;
carry = z2 > x2;
} else {
z2 = x2 - y2 - 1;
carry = z2 >= x2;
}
if (carry == 0) {
z1 = x1 - y1;
carry = z1 > x1;
} else {
z1 = x1 - y1 - 1;
carry = z1 >= x1;
}
z0 = x0 - y0 - carry;
if (z0 >= 0) {
x0 = z0;
x1 = z1;
x2 = z2;
x3 = z3;
m += 1;
}
m &= ~0x80000000;
*quo = sq >= 0 ? m : -m;
/* convert back to floating value and restore the sign */
if ((x0 | x1 | x2 | x3) == 0) {
__H0(a) = hx & is;
__H1(a) = __H2(a) = __H3(a) = 0;
return (a);
}
while (x0 < iu) {
if (x0 == 0) {
iy -= 16;
x0 = x1 >> 16;
x1 = (x1 << 16) | (x2 >> 16);
x2 = (x2 << 16) | (x3 >> 16);
x3 = (x3 << 16);
} else {
x0 = x0 + x0 + ((x1 & is) != 0);
x1 = x1 + x1 + ((x2 & is) != 0);
x2 = x2 + x2 + ((x3 & is) != 0);
x3 = x3 + x3;
iy -= 1;
}
}
/* normalize output */
if (iy >= -16382) {
__H0(a) = sx | (x0 - iu) | ((iy + 16383) << 16);
__H1(a) = x1;
__H2(a) = x2;
__H3(a) = x3;
} else { /* subnormal output */
n = -16382 - iy;
k = n & 31;
if (k <= 16) {
x3 = (x2 << (32 - k)) | (x3 >> k);
x2 = (x1 << (32 - k)) | (x2 >> k);
x1 = (x0 << (32 - k)) | (x1 >> k);
x0 >>= k;
} else {
x3 = (x2 << (32 - k)) | (x3 >> k);
x2 = (x1 << (32 - k)) | (x2 >> k);
x1 = (x0 << (32 - k)) | (x1 >> k);
x0 = 0;
}
while (n >= 32) {
n -= 32;
x3 = x2;
x2 = x1;
x1 = x0;
x0 = 0;
}
__H0(a) = x0 | sx;
__H1(a) = x1;
__H2(a) = x2;
__H3(a) = x3;
a *= one;
}
return (a);
}
long double
remquol(long double x, long double y, int *quo) {
int hx, hy, sx, sq;
long double v;
hx = __H0(x); /* high word of x */
hy = __H0(y); /* high word of y */
sx = hx & is; /* sign of x */
sq = (hx ^ hy) & is; /* sign of x/y */
hx ^= sx; /* |x| */
hy &= ~0x80000000;
/* purge off exception values */
*quo = 0;
/* y=0, y is NaN, x is NaN or inf */
if (y == 0.0L || y != y || hx >= 0x7fff0000)
return ((x * y) / (x * y));
y = fabsl(y);
x = fabsl(x);
if (hy <= 0x7ffdffff) {
x = fmodquol(x, y + y, quo);
*quo = ((*quo) & 0x3fffffff) << 1;
}
if (hy < 0x00020000) {
if (x + x > y) {
*quo += 1;
if (x == y)
x = zero;
else
x -= y;
if (x + x >= y) {
x -= y;
*quo += 1;
}
}
} else {
v = 0.5L * y;
if (x > v) {
*quo += 1;
if (x == y)
x = zero;
else
x -= y;
if (x >= v) {
x -= y;
*quo += 1;
}
}
}
if (sq != 0)
*quo = -(*quo);
return (sx == 0 ? x : -x);
}