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/* IEEE754 floating point arithmetic
* single precision
*/
/*
* MIPS floating point support
* Copyright (C) 1994-2000 Algorithmics Ltd. All rights reserved.
* 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 "ieee754sp.h"
ieee754sp ieee754sp_div(ieee754sp x, ieee754sp y)
{
COMPXSP;
COMPYSP;
CLEARCX;
EXPLODEXSP;
EXPLODEYSP;
switch (CLPAIR(xc, yc)) {
case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
return ieee754sp_nanxcpt(ieee754sp_bestnan(x, y), "div", x,
y);
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 ieee754sp_nanxcpt(y, "div", x, y);
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 ieee754sp_nanxcpt(x, "div", x, y);
case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
return ieee754sp_bestnan(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_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 handeling
*/
case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
SETCX(IEEE754_INVALID_OPERATION);
return ieee754sp_xcpt(ieee754sp_indef(), "div", x, y);
case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
return ieee754sp_zero(xs ^ ys);
case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
return ieee754sp_inf(xs ^ ys);
/* Zero handeling
*/
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
SETCX(IEEE754_INVALID_OPERATION);
return ieee754sp_xcpt(ieee754sp_indef(), "div", x, y);
case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
SETCX(IEEE754_ZERO_DIVIDE);
return ieee754sp_xcpt(ieee754sp_inf(xs ^ ys), "div", x, y);
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
return ieee754sp_zero(xs == ys ? 0 : 1);
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
SPDNORMX;
case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
SPDNORMY;
break;
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
SPDNORMX;
break;
case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
break;
}
assert(xm & SP_HIDDEN_BIT);
assert(ym & SP_HIDDEN_BIT);
/* provide rounding space */
xm <<= 3;
ym <<= 3;
{
/* now the dirty work */
unsigned rm = 0;
int re = xe - ye;
unsigned bm;
for (bm = SP_MBIT(SP_MBITS + 2); bm; bm >>= 1) {
if (xm >= ym) {
xm -= ym;
rm |= bm;
if (xm == 0)
break;
}
xm <<= 1;
}
rm <<= 1;
if (xm)
rm |= 1; /* have remainder, set sticky */
assert(rm);
/* normalise rm to rounding precision ?
*/
while ((rm >> (SP_MBITS + 3)) == 0) {
rm <<= 1;
re--;
}
SPNORMRET2(xs == ys ? 0 : 1, re, rm, "div", x, y);
}
}
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