linux/arch/arm/nwfpe/fpa11_cpdo.c
Richard Purdie f148af2593 [PATCH] ARM: 2837/2: Re: ARM: Make NWFPE preempt safe
Patch from Richard Purdie

NWFPE used global variables which meant it wasn't safe for use with
preemptive kernels. This patch removes them and communicates the
information between functions in a preempt safe manner. Generation
of some exceptions was broken and this has also been corrected.
Tests with glibc's maths test suite show no change in the results
before/after this patch.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-08-03 19:49:17 +01:00

139 lines
3.8 KiB
C

/*
NetWinder Floating Point Emulator
(c) Rebel.COM, 1998,1999
(c) Philip Blundell, 2001
Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/config.h>
#include "fpa11.h"
#include "fpopcode.h"
unsigned int SingleCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd);
unsigned int DoubleCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd);
unsigned int ExtendedCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd);
unsigned int EmulateCPDO(const unsigned int opcode)
{
FPA11 *fpa11 = GET_FPA11();
FPREG *rFd;
unsigned int nType, nDest, nRc;
struct roundingData roundData;
/* Get the destination size. If not valid let Linux perform
an invalid instruction trap. */
nDest = getDestinationSize(opcode);
if (typeNone == nDest)
return 0;
roundData.mode = SetRoundingMode(opcode);
roundData.precision = SetRoundingPrecision(opcode);
roundData.exception = 0;
/* Compare the size of the operands in Fn and Fm.
Choose the largest size and perform operations in that size,
in order to make use of all the precision of the operands.
If Fm is a constant, we just grab a constant of a size
matching the size of the operand in Fn. */
if (MONADIC_INSTRUCTION(opcode))
nType = nDest;
else
nType = fpa11->fType[getFn(opcode)];
if (!CONSTANT_FM(opcode)) {
register unsigned int Fm = getFm(opcode);
if (nType < fpa11->fType[Fm]) {
nType = fpa11->fType[Fm];
}
}
rFd = &fpa11->fpreg[getFd(opcode)];
switch (nType) {
case typeSingle:
nRc = SingleCPDO(&roundData, opcode, rFd);
break;
case typeDouble:
nRc = DoubleCPDO(&roundData, opcode, rFd);
break;
#ifdef CONFIG_FPE_NWFPE_XP
case typeExtended:
nRc = ExtendedCPDO(&roundData, opcode, rFd);
break;
#endif
default:
nRc = 0;
}
/* The CPDO functions used to always set the destination type
to be the same as their working size. */
if (nRc != 0) {
/* If the operation succeeded, check to see if the result in the
destination register is the correct size. If not force it
to be. */
fpa11->fType[getFd(opcode)] = nDest;
#ifdef CONFIG_FPE_NWFPE_XP
if (nDest != nType) {
switch (nDest) {
case typeSingle:
{
if (typeDouble == nType)
rFd->fSingle = float64_to_float32(&roundData, rFd->fDouble);
else
rFd->fSingle = floatx80_to_float32(&roundData, rFd->fExtended);
}
break;
case typeDouble:
{
if (typeSingle == nType)
rFd->fDouble = float32_to_float64(rFd->fSingle);
else
rFd->fDouble = floatx80_to_float64(&roundData, rFd->fExtended);
}
break;
case typeExtended:
{
if (typeSingle == nType)
rFd->fExtended = float32_to_floatx80(rFd->fSingle);
else
rFd->fExtended = float64_to_floatx80(rFd->fDouble);
}
break;
}
}
#else
if (nDest != nType) {
if (nDest == typeSingle)
rFd->fSingle = float64_to_float32(&roundData, rFd->fDouble);
else
rFd->fDouble = float32_to_float64(rFd->fSingle);
}
#endif
}
if (roundData.exception)
float_raise(roundData.exception);
return nRc;
}