125 lines
3 KiB
C
125 lines
3 KiB
C
|
/* 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 <linux/kernel.h>
|
||
|
|
#include "ieee754dp.h"
|
||
|
|
|
||
|
|
int ieee754dp_tint(ieee754dp x)
|
||
|
|
{
|
||
|
|
COMPXDP;
|
||
|
|
|
||
|
|
CLEARCX;
|
||
|
|
|
||
|
|
EXPLODEXDP;
|
||
|
|
FLUSHXDP;
|
||
|
|
|
||
|
|
switch (xc) {
|
||
|
|
case IEEE754_CLASS_SNAN:
|
||
|
|
case IEEE754_CLASS_QNAN:
|
||
|
|
case IEEE754_CLASS_INF:
|
||
|
|
SETCX(IEEE754_INVALID_OPERATION);
|
||
|
|
return ieee754si_xcpt(ieee754si_indef(), "dp_tint", x);
|
||
|
|
case IEEE754_CLASS_ZERO:
|
||
|
|
return 0;
|
||
|
|
case IEEE754_CLASS_DNORM:
|
||
|
|
case IEEE754_CLASS_NORM:
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
if (xe > 31) {
|
||
|
|
/* Set invalid. We will only use overflow for floating
|
||
|
|
point overflow */
|
||
|
|
SETCX(IEEE754_INVALID_OPERATION);
|
||
|
|
return ieee754si_xcpt(ieee754si_indef(), "dp_tint", x);
|
||
|
|
}
|
||
|
|
/* oh gawd */
|
||
|
|
if (xe > DP_MBITS) {
|
||
|
|
xm <<= xe - DP_MBITS;
|
||
|
|
} else if (xe < DP_MBITS) {
|
||
|
|
u64 residue;
|
||
|
|
int round;
|
||
|
|
int sticky;
|
||
|
|
int odd;
|
||
|
|
|
||
|
|
if (xe < -1) {
|
||
|
|
residue = xm;
|
||
|
|
round = 0;
|
||
|
|
sticky = residue != 0;
|
||
|
|
xm = 0;
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
residue = xm << (64 - DP_MBITS + xe);
|
||
|
|
round = (residue >> 63) != 0;
|
||
|
|
sticky = (residue << 1) != 0;
|
||
|
|
xm >>= DP_MBITS - xe;
|
||
|
|
}
|
||
|
|
/* Note: At this point upper 32 bits of xm are guaranteed
|
||
|
|
to be zero */
|
||
|
|
odd = (xm & 0x1) != 0x0;
|
||
|
|
switch (ieee754_csr.rm) {
|
||
|
|
case IEEE754_RN:
|
||
|
|
if (round && (sticky || odd))
|
||
|
|
xm++;
|
||
|
|
break;
|
||
|
|
case IEEE754_RZ:
|
||
|
|
break;
|
||
|
|
case IEEE754_RU: /* toward +Infinity */
|
||
|
|
if ((round || sticky) && !xs)
|
||
|
|
xm++;
|
||
|
|
break;
|
||
|
|
case IEEE754_RD: /* toward -Infinity */
|
||
|
|
if ((round || sticky) && xs)
|
||
|
|
xm++;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
/* look for valid corner case 0x80000000 */
|
||
|
|
if ((xm >> 31) != 0 && (xs == 0 || xm != 0x80000000)) {
|
||
|
|
/* This can happen after rounding */
|
||
|
|
SETCX(IEEE754_INVALID_OPERATION);
|
||
|
|
return ieee754si_xcpt(ieee754si_indef(), "dp_tint", x);
|
||
|
|
}
|
||
|
|
if (round || sticky)
|
||
|
|
SETCX(IEEE754_INEXACT);
|
||
|
|
}
|
||
|
|
if (xs)
|
||
|
|
return -xm;
|
||
|
|
else
|
||
|
|
return xm;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
unsigned int ieee754dp_tuns(ieee754dp x)
|
||
|
|
{
|
||
|
|
ieee754dp hb = ieee754dp_1e31();
|
||
|
|
|
||
|
|
/* what if x < 0 ?? */
|
||
|
|
if (ieee754dp_lt(x, hb))
|
||
|
|
return (unsigned) ieee754dp_tint(x);
|
||
|
|
|
||
|
|
return (unsigned) ieee754dp_tint(ieee754dp_sub(x, hb)) |
|
||
|
|
((unsigned) 1 << 31);
|
||
|
|
}
|