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// SPDX-License-Identifier: GPL-2.0-only
/* IEEE754 floating point arithmetic
* single precision
*/
/*
* MIPS floating point support
* Copyright (C) 1994-2000 Algorithmics Ltd.
*/
#include "ieee754sp.h"
union ieee754sp ieee754sp_mul(union ieee754sp x, union ieee754sp y)
{
int re;
int rs;
unsigned int rm;
unsigned short lxm;
unsigned short hxm;
unsigned short lym;
unsigned short hym;
unsigned int lrm;
unsigned int hrm;
unsigned int t;
unsigned int at;
COMPXSP;
COMPYSP;
EXPLODEXSP;
EXPLODEYSP;
ieee754_clearcx();
FLUSHXSP;
FLUSHYSP;
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 ieee754sp_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 ieee754sp_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 ieee754sp_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 ieee754sp_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 ieee754sp_zero(xs ^ ys);
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
SPDNORMX;
fallthrough;
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;
}
/* rm = xm * ym, re = xe+ye basically */
assert(xm & SP_HIDDEN_BIT);
assert(ym & SP_HIDDEN_BIT);
re = xe + ye;
rs = xs ^ ys;
/* shunt to top of word */
xm <<= 32 - (SP_FBITS + 1);
ym <<= 32 - (SP_FBITS + 1);
/*
* Multiply 32 bits xm, ym to give high 32 bits rm with stickness.
*/
lxm = xm & 0xffff;
hxm = xm >> 16;
lym = ym & 0xffff;
hym = ym >> 16;
lrm = lxm * lym; /* 16 * 16 => 32 */
hrm = hxm * hym; /* 16 * 16 => 32 */
t = lxm * hym; /* 16 * 16 => 32 */
at = lrm + (t << 16);
hrm += at < lrm;
lrm = at;
hrm = hrm + (t >> 16);
t = hxm * lym; /* 16 * 16 => 32 */
at = lrm + (t << 16);
hrm += at < lrm;
lrm = at;
hrm = hrm + (t >> 16);
rm = hrm | (lrm != 0);
/*
* Sticky shift down to normal rounding precision.
*/
if ((int) rm < 0) {
rm = (rm >> (32 - (SP_FBITS + 1 + 3))) |
((rm << (SP_FBITS + 1 + 3)) != 0);
re++;
} else {
rm = (rm >> (32 - (SP_FBITS + 1 + 3 + 1))) |
((rm << (SP_FBITS + 1 + 3 + 1)) != 0);
}
assert(rm & (SP_HIDDEN_BIT << 3));
return ieee754sp_format(rs, re, rm);
}
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