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/* IEEE754 floating point arithmetic
* double precision: common utilities
*/
/*
* 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 "ieee754dp.h"
long long ieee754dp_tlong(ieee754dp x)
{
COMPXDP;
CLEARCX;
EXPLODEXDP;
switch (xc) {
case IEEE754_CLASS_SNAN:
case IEEE754_CLASS_QNAN:
SETCX(IEEE754_INVALID_OPERATION);
return ieee754di_xcpt(ieee754di_indef(), "dp_tlong", x);
case IEEE754_CLASS_INF:
SETCX(IEEE754_OVERFLOW);
return ieee754di_xcpt(ieee754di_indef(), "dp_tlong", x);
case IEEE754_CLASS_ZERO:
return 0;
case IEEE754_CLASS_DNORM: /* much too small */
SETCX(IEEE754_UNDERFLOW);
return ieee754di_xcpt(0, "dp_tlong", x);
case IEEE754_CLASS_NORM:
break;
}
if (xe >= 63) {
SETCX(IEEE754_OVERFLOW);
return ieee754di_xcpt(ieee754di_indef(), "dp_tlong", x);
}
if (xe < 0) {
if (ieee754_csr.rm == IEEE754_RU) {
if (xs) { /* Negative */
return 0x0000000000000000LL;
} else { /* Positive */
return 0x0000000000000001LL;
}
} else if (ieee754_csr.rm == IEEE754_RD) {
if (xs) { /* Negative , return -1 */
return 0xffffffffffffffffLL;
} else { /* Positive */
return 0x0000000000000000LL;
}
} else {
SETCX(IEEE754_UNDERFLOW);
return ieee754di_xcpt(0, "dp_tlong", x);
}
}
/* oh gawd */
if (xe > DP_MBITS) {
xm <<= xe - DP_MBITS;
} else if (xe < DP_MBITS) {
unsigned long long residue;
unsigned long long mask = 0;
int i;
int round;
int sticky;
int odd;
/* compute mask */
for (i = 0; i < DP_MBITS - xe; i++) {
mask = mask << 1;
mask = mask | 0x1;
}
residue = (xm & mask) << (64 - (DP_MBITS - xe));
round =
((0x8000000000000000LL & residue) !=
0x0000000000000000LL);
sticky =
((0x7fffffffffffffffLL & residue) !=
0x0000000000000000LL);
xm >>= DP_MBITS - xe;
odd = ((xm & 0x1) != 0x0000000000000000LL);
/* Do the rounding */
if (!round && sticky) {
if ((ieee754_csr.rm == IEEE754_RU && !xs)
|| (ieee754_csr.rm == IEEE754_RD && xs)) {
xm++;
}
} else if (round && !sticky) {
if ((ieee754_csr.rm == IEEE754_RU && !xs)
|| (ieee754_csr.rm == IEEE754_RD && xs)
|| (ieee754_csr.rm == IEEE754_RN && odd)) {
xm++;
}
} else if (round && sticky) {
if ((ieee754_csr.rm == IEEE754_RU && !xs)
|| (ieee754_csr.rm == IEEE754_RD && xs)
|| (ieee754_csr.rm == IEEE754_RN)) {
xm++;
}
}
}
if (xs)
return -xm;
else
return xm;
}
unsigned long long ieee754dp_tulong(ieee754dp x)
{
ieee754dp hb = ieee754dp_1e63();
/* what if x < 0 ?? */
if (ieee754dp_lt(x, hb))
return (unsigned long long) ieee754dp_tlong(x);
return (unsigned long long) ieee754dp_tlong(ieee754dp_sub(x, hb)) |
(1ULL << 63);
}
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