155 lines
3.8 KiB
C
155 lines
3.8 KiB
C
// 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);
|
|
}
|