56a6473339
Previously math-emu was using the IEEE-754 constants internally. These were differing by having the constants for rounding to +/- infinity switched, so a conversion was necessary. This would be entirely avoidable if the MIPS constants were used throughout, so get rid of the bloat. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
/* IEEE754 floating point arithmetic
|
|
* single precision
|
|
*/
|
|
/*
|
|
* 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 "ieee754sp.h"
|
|
#include "ieee754dp.h"
|
|
|
|
union ieee754sp ieee754sp_fdp(union ieee754dp x)
|
|
{
|
|
u32 rm;
|
|
|
|
COMPXDP;
|
|
union ieee754sp nan;
|
|
|
|
EXPLODEXDP;
|
|
|
|
ieee754_clearcx();
|
|
|
|
FLUSHXDP;
|
|
|
|
switch (xc) {
|
|
case IEEE754_CLASS_SNAN:
|
|
ieee754_setcx(IEEE754_INVALID_OPERATION);
|
|
return ieee754sp_nanxcpt(ieee754sp_indef());
|
|
|
|
case IEEE754_CLASS_QNAN:
|
|
nan = buildsp(xs, SP_EMAX + 1 + SP_EBIAS, (u32)
|
|
(xm >> (DP_FBITS - SP_FBITS)));
|
|
if (!ieee754sp_isnan(nan))
|
|
nan = ieee754sp_indef();
|
|
return ieee754sp_nanxcpt(nan);
|
|
|
|
case IEEE754_CLASS_INF:
|
|
return ieee754sp_inf(xs);
|
|
|
|
case IEEE754_CLASS_ZERO:
|
|
return ieee754sp_zero(xs);
|
|
|
|
case IEEE754_CLASS_DNORM:
|
|
/* can't possibly be sp representable */
|
|
ieee754_setcx(IEEE754_UNDERFLOW);
|
|
ieee754_setcx(IEEE754_INEXACT);
|
|
if ((ieee754_csr.rm == FPU_CSR_RU && !xs) ||
|
|
(ieee754_csr.rm == FPU_CSR_RD && xs))
|
|
return ieee754sp_mind(xs);
|
|
return ieee754sp_zero(xs);
|
|
|
|
case IEEE754_CLASS_NORM:
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Convert from DP_FBITS to SP_FBITS+3 with sticky right shift.
|
|
*/
|
|
rm = (xm >> (DP_FBITS - (SP_FBITS + 3))) |
|
|
((xm << (64 - (DP_FBITS - (SP_FBITS + 3)))) != 0);
|
|
|
|
return ieee754sp_format(xs, xe, rm);
|
|
}
|