/* IEEE754 floating point arithmetic
* double precision: common utilities
*/
/*
* MIPS floating point support
* Copyright (C) 1994-2000 Algorithmics Ltd.
* http://www.algor.co.uk
*
* ########################################################################
*
* This program is free software; you can distribute it and/or modify it
* under the terms of the GNU General Public License (Version 2) as
* published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
*
* ########################################################################
*/
#include "ieee754dp.h"
ieee754dp ieee754dp_mul(ieee754dp x, ieee754dp y)
{
COMPXDP;
COMPYDP;
EXPLODEXDP;
EXPLODEYDP;
CLEARCX;
FLUSHXDP;
FLUSHYDP;
switch (CLPAIR(xc, yc)) {
case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
SETCX(IEEE754_INVALID_OPERATION);
return ieee754dp_nanxcpt(ieee754dp_indef(), "mul", x, y);
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
return y;
case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
return x;
/* Infinity handling */
case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
SETCX(IEEE754_INVALID_OPERATION);
return ieee754dp_xcpt(ieee754dp_indef(), "mul", x, y);
case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
return ieee754dp_inf(xs ^ ys);
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
return ieee754dp_zero(xs ^ ys);
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
DPDNORMX;
case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
DPDNORMY;
break;
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
DPDNORMX;
break;
case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
break;
}
/* rm = xm * ym, re = xe+ye basicly */
assert(xm & DP_HIDDEN_BIT);
assert(ym & DP_HIDDEN_BIT);
{
int re = xe + ye;
int rs = xs ^ ys;
u64 rm;
/* shunt to top of word */
xm <<= 64 - (DP_MBITS + 1);
ym <<= 64 - (DP_MBITS + 1);
/* multiply 32bits xm,ym to give high 32bits rm with stickness
*/
/* 32 * 32 => 64 */
#define DPXMULT(x,y) ((u64)(x) * (u64)y)
{
unsigned lxm = xm;
unsigned hxm = xm >> 32;
unsigned lym = ym;
unsigned hym = ym >> 32;
u64 lrm;
u64 hrm;
lrm = DPXMULT(lxm, lym);
hrm = DPXMULT(hxm, hym);
{
u64 t = DPXMULT(lxm, hym);
{
u64 at =
lrm + (t << 32);
hrm += at < lrm;
lrm = at;
}
hrm = hrm + (t >> 32);
}
{
u64 t = DPXMULT(hxm, lym);
{
u64 at =
lrm + (t << 32);
hrm += at < lrm;
lrm = at;
}
hrm = hrm + (t >> 32);
}
rm = hrm | (lrm != 0);
}
/*
* sticky shift down to normal rounding precision
*/
if ((s64) rm < 0) {
rm =
(rm >> (64 - (DP_MBITS + 1 + 3))) |
((rm << (DP_MBITS + 1 + 3)) != 0);
re++;
} else {
rm =
(rm >> (64 - (DP_MBITS + 1 + 3 + 1))) |
((rm << (DP_MBITS + 1 + 3 + 1)) != 0);
}
assert(rm & (DP_HIDDEN_BIT << 3));
DPNORMRET2(rs, re, rm, "mul", x, y);
}
}
