dp_flong.c
1.54 KB
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/* IEEE754 floating point arithmetic
* double precision: common utilities
*/
/*
* MIPS floating point support
* Copyright (C) 1994-2000 Algorithmics Ltd.
*
* 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.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "ieee754dp.h"
union ieee754dp ieee754dp_flong(s64 x)
{
u64 xm;
int xe;
int xs;
ieee754_clearcx();
if (x == 0)
return ieee754dp_zero(0);
if (x == 1 || x == -1)
return ieee754dp_one(x < 0);
if (x == 10 || x == -10)
return ieee754dp_ten(x < 0);
xs = (x < 0);
if (xs) {
if (x == (1ULL << 63))
xm = (1ULL << 63); /* max neg can't be safely negated */
else
xm = -x;
} else {
xm = x;
}
/* normalize */
xe = DP_FBITS + 3;
if (xm >> (DP_FBITS + 1 + 3)) {
/* shunt out overflow bits */
while (xm >> (DP_FBITS + 1 + 3)) {
XDPSRSX1();
}
} else {
/* normalize in grs extended double precision */
while ((xm >> (DP_FBITS + 3)) == 0) {
xm <<= 1;
xe--;
}
}
return ieee754dp_format(xs, xe, xm);
}