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/*
* This file is part of SIS.
*
* SIS, SPARC instruction simulator. Copyright (C) 1995 Jiri Gaisler, European
* Space Agency
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
*
* This file implements the interface between the host and the simulated
* FPU. IEEE trap handling is done as follows:
* 1. In the host, all IEEE traps are masked
* 2. After each simulated FPU instruction, check if any exception occured
* by reading the exception bits from the host FPU status register
* (get_accex()).
* 3. Propagate any exceptions to the simulated FSR.
* 4. Clear host exception bits
*
*
*/
#include "config.h"
#include "sis.h"
#include <fenv.h>
/* This routine should return the accrued exceptions */
int
get_accex()
{
int fexc, accx;
fexc = fetestexcept (FE_ALL_EXCEPT);
accx = 0;
if (fexc & FE_INEXACT)
accx |= 1;
if (fexc & FE_DIVBYZERO)
accx |= 2;
if (fexc & FE_UNDERFLOW)
accx |= 4;
if (fexc & FE_OVERFLOW)
accx |= 8;
if (fexc & FE_INVALID)
accx |= 0x10;
return accx;
}
/* How to clear the accrued exceptions */
void
clear_accex()
{
feclearexcept (FE_ALL_EXCEPT);
}
/* How to map SPARC FSR onto the host */
void
set_fsr(fsr)
uint32 fsr;
{
int fround;
fsr >>= 30;
switch (fsr) {
case 0:
fround = FE_TONEAREST;
break;
case 1:
fround = FE_TOWARDZERO;
break;
case 2:
fround = FE_UPWARD;
break;
case 3:
fround = FE_DOWNWARD;
break;
}
fesetround (fround);
}
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