_Q_sub.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (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 2003 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include "quad.h"
#ifdef __sparcv9
/*
* _Qp_sub(pz, ox, oy) sets *pz = *ox - *oy.
*/
void
_Qp_sub(union longdouble *pz, const union longdouble *ox,
const union longdouble *oy)
#else
/*
* _Q_sub(ox, oy) returns *ox - *oy.
*/
union longdouble
_Q_sub(const union longdouble *ox, const union longdouble *oy)
#endif /* __sparcv9 */
{
union longdouble z;
const union longdouble *x, *y;
unsigned int xm, ym, tm, fsr;
int flip;
/* sort so |x| >= |y| */
xm = ox->l.msw & 0x7fffffff;
ym = oy->l.msw & 0x7fffffff;
if (ym > xm || ym == xm && (oy->l.frac2 > ox->l.frac2 ||
oy->l.frac2 == ox->l.frac2 && (oy->l.frac3 > ox->l.frac3 ||
oy->l.frac3 == ox->l.frac3 && oy->l.frac4 > ox->l.frac4))) {
y = ox;
x = oy;
tm = xm;
xm = ym;
ym = tm;
flip = 0x80000000;
} else {
x = ox;
y = oy;
flip = 0;
}
/* get the fsr */
__quad_getfsrp(&fsr);
/* handle nan and inf cases */
if (xm >= 0x7fff0000) {
/* x is nan or inf */
if (ym >= 0x7fff0000) {
/* y is nan or inf */
if ((ym & 0xffff) | y->l.frac2 | y->l.frac3 |
y->l.frac4) {
/* y is nan; x must be nan too */
/* the following logic implements V9 app. B */
if (!(ym & 0x8000)) {
/* y is snan, signal invalid */
if (fsr & FSR_NVM) {
__quad_fsubq(ox, oy, &Z);
} else {
Z = (xm & 0x8000)? *y : *oy;
Z.l.msw |= 0x8000;
fsr = (fsr & ~FSR_CEXC) |
FSR_NVA | FSR_NVC;
__quad_setfsrp(&fsr);
}
QUAD_RETURN(Z);
}
/* x and y are both qnan */
Z = *oy;
QUAD_RETURN(Z);
}
if (!((xm & 0xffff) | x->l.frac2 | x->l.frac3 |
x->l.frac4)) {
/* x and y are both inf */
if (!((x->l.msw ^ y->l.msw) & 0x80000000)) {
/* inf - inf, signal invalid */
if (fsr & FSR_NVM) {
__quad_fsubq(ox, oy, &Z);
} else {
Z.l.msw = 0x7fffffff;
Z.l.frac2 = Z.l.frac3 =
Z.l.frac4 = 0xffffffff;
fsr = (fsr & ~FSR_CEXC) |
FSR_NVA | FSR_NVC;
__quad_setfsrp(&fsr);
}
QUAD_RETURN(Z);
}
/* inf + inf, return inf */
Z = *x;
Z.l.msw ^= flip;
QUAD_RETURN(Z);
}
}
if ((xm & 0xffff) | x->l.frac2 | x->l.frac3 | x->l.frac4) {
/* x is nan */
if (!(xm & 0x8000)) {
/* snan, signal invalid */
if (fsr & FSR_NVM) {
__quad_fsubq(ox, oy, &Z);
} else {
Z = *x;
Z.l.msw |= 0x8000;
fsr = (fsr & ~FSR_CEXC) | FSR_NVA |
FSR_NVC;
__quad_setfsrp(&fsr);
}
QUAD_RETURN(Z);
}
Z = *x;
QUAD_RETURN(Z);
}
/* x is inf */
Z = *x;
Z.l.msw ^= flip;
QUAD_RETURN(Z);
}
/* now x and y are finite and |x| >= |y| */
fsr &= ~FSR_CEXC;
z.l.msw = (x->l.msw & 0x80000000) ^ flip;
if ((x->l.msw ^ y->l.msw) & 0x80000000)
__quad_mag_add(x, y, &z, &fsr);
else
__quad_mag_sub(x, y, &z, &fsr);
if ((fsr & FSR_CEXC) & (fsr >> 23)) {
__quad_setfsrp(&fsr);
__quad_fsubq(ox, oy, &Z);
} else {
Z = z;
fsr |= (fsr & 0x1f) << 5;
__quad_setfsrp(&fsr);
}
QUAD_RETURN(Z);
}