173 lines
4.4 KiB
C
173 lines
4.4 KiB
C
/* IEEE754 floating point arithmetic
|
|
* double precision: common utilities
|
|
*/
|
|
/*
|
|
* MIPS floating point support
|
|
* Copyright (C) 1994-2000 Algorithmics Ltd.
|
|
*
|
|
* 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.,
|
|
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*/
|
|
|
|
#include "ieee754dp.h"
|
|
|
|
union ieee754dp ieee754dp_mul(union ieee754dp x, union ieee754dp y)
|
|
{
|
|
int re;
|
|
int rs;
|
|
u64 rm;
|
|
unsigned int lxm;
|
|
unsigned int hxm;
|
|
unsigned int lym;
|
|
unsigned int hym;
|
|
u64 lrm;
|
|
u64 hrm;
|
|
u64 t;
|
|
u64 at;
|
|
|
|
COMPXDP;
|
|
COMPYDP;
|
|
|
|
EXPLODEXDP;
|
|
EXPLODEYDP;
|
|
|
|
ieee754_clearcx();
|
|
|
|
FLUSHXDP;
|
|
FLUSHYDP;
|
|
|
|
switch (CLPAIR(xc, yc)) {
|
|
case CLPAIR(IEEE754_CLASS_QNAN, 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):
|
|
return ieee754dp_nanxcpt(y);
|
|
|
|
case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
|
|
case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
|
|
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):
|
|
return ieee754dp_nanxcpt(x);
|
|
|
|
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):
|
|
ieee754_setcx(IEEE754_INVALID_OPERATION);
|
|
return ieee754dp_indef();
|
|
|
|
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;
|
|
/* fall through */
|
|
|
|
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 basically */
|
|
assert(xm & DP_HIDDEN_BIT);
|
|
assert(ym & DP_HIDDEN_BIT);
|
|
|
|
re = xe + ye;
|
|
rs = xs ^ ys;
|
|
|
|
/* shunt to top of word */
|
|
xm <<= 64 - (DP_FBITS + 1);
|
|
ym <<= 64 - (DP_FBITS + 1);
|
|
|
|
/*
|
|
* Multiply 64 bits xm, ym to give high 64 bits rm with stickness.
|
|
*/
|
|
|
|
lxm = xm;
|
|
hxm = xm >> 32;
|
|
lym = ym;
|
|
hym = ym >> 32;
|
|
|
|
lrm = DPXMULT(lxm, lym);
|
|
hrm = DPXMULT(hxm, hym);
|
|
|
|
t = DPXMULT(lxm, hym);
|
|
|
|
at = lrm + (t << 32);
|
|
hrm += at < lrm;
|
|
lrm = at;
|
|
|
|
hrm = hrm + (t >> 32);
|
|
|
|
t = DPXMULT(hxm, lym);
|
|
|
|
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_FBITS + 1 + 3))) |
|
|
((rm << (DP_FBITS + 1 + 3)) != 0);
|
|
re++;
|
|
} else {
|
|
rm = (rm >> (64 - (DP_FBITS + 1 + 3 + 1))) |
|
|
((rm << (DP_FBITS + 1 + 3 + 1)) != 0);
|
|
}
|
|
assert(rm & (DP_HIDDEN_BIT << 3));
|
|
|
|
return ieee754dp_format(rs, re, rm);
|
|
}
|