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/////////////////////////////////////////////////////////////////////////
// $Id: ferr.cc,v 1.7 2006/03/06 22:03:04 sshwarts Exp $
/////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2003 Stanislav Shwartsman
// Written by Stanislav Shwartsman <stl at fidonet.org.il>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
/////////////////////////////////////////////////////////////////////////
#define NEED_CPU_REG_SHORTCUTS 1
#include "bochs.h"
#include "cpu/cpu.h"
#define LOG_THIS BX_CPU_THIS_PTR
#if BX_SUPPORT_FPU
#include "softfloat-specialize.h"
void BX_CPU_C::FPU_stack_overflow(void)
{
/* The masked response */
if (BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
BX_CPU_THIS_PTR the_i387.FPU_push();
BX_WRITE_FPU_REGISTER_AND_TAG(floatx80_default_nan, FPU_Tag_Special, 0);
}
FPU_exception(FPU_EX_Stack_Overflow);
}
void BX_CPU_C::FPU_stack_underflow(int stnr, int pop_stack)
{
/* The masked response */
if (BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
BX_WRITE_FPU_REGISTER_AND_TAG(floatx80_default_nan, FPU_Tag_Special, stnr);
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
FPU_exception(FPU_EX_Stack_Underflow);
}
/* Returns 1 if unmasked exception occured */
int BX_CPU_C::FPU_exception(int exception)
{
int unmasked = 0;
/* Extract only the bits which we use to set the status word */
exception &= (FPU_SW_Exceptions_Mask);
/* Set the corresponding exception bits */
FPU_PARTIAL_STATUS |= exception;
/* Set summary bits iff exception isn't masked */
if (FPU_PARTIAL_STATUS & ~FPU_CONTROL_WORD & FPU_CW_Exceptions_Mask)
{
FPU_PARTIAL_STATUS |= (FPU_SW_Summary | FPU_SW_Backward);
unmasked = 1;
}
if (exception & (FPU_SW_Stack_Fault | FPU_EX_Precision))
{
if (! (exception & FPU_SW_C1))
/* This bit distinguishes over- from underflow for a stack fault,
and roundup from round-down for precision loss. */
FPU_PARTIAL_STATUS &= ~FPU_SW_C1;
}
return unmasked;
}
#endif
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