Bochs/bochs/fpu/fpu_misc.cc
2011-04-03 10:29:19 +00:00

152 lines
3.9 KiB
C++

/////////////////////////////////////////////////////////////////////////
// $Id$
/////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2003-2009 Stanislav Shwartsman
// Written by Stanislav Shwartsman [sshwarts at sourceforge net]
//
// 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 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 "softfloatx80.h"
/* D9 C8 */
void BX_CPP_AttrRegparmN(1) BX_CPU_C::FXCH_STi(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
int st0_tag = BX_CPU_THIS_PTR the_i387.FPU_gettagi(0);
int sti_tag = BX_CPU_THIS_PTR the_i387.FPU_gettagi(i->rm());
floatx80 st0_reg = BX_READ_FPU_REG(0);
floatx80 sti_reg = BX_READ_FPU_REG(i->rm());
clear_C1();
if (st0_tag == FPU_Tag_Empty || sti_tag == FPU_Tag_Empty)
{
FPU_exception(FPU_EX_Stack_Underflow);
if(BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
/* Masked response */
if (st0_tag == FPU_Tag_Empty)
st0_reg = floatx80_default_nan;
if (sti_tag == FPU_Tag_Empty)
sti_reg = floatx80_default_nan;
}
else {
return;
}
}
BX_WRITE_FPU_REG(st0_reg, i->rm());
BX_WRITE_FPU_REG(sti_reg, 0);
}
/* D9 E0 */
void BX_CPP_AttrRegparmN(1) BX_CPU_C::FCHS(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
if (IS_TAG_EMPTY(0)) {
FPU_stack_underflow(0);
}
else {
clear_C1();
floatx80 st0_reg = BX_READ_FPU_REG(0);
BX_WRITE_FPU_REG(floatx80_chs(st0_reg), 0);
}
}
/* D9 E1 */
void BX_CPP_AttrRegparmN(1) BX_CPU_C::FABS(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
if (IS_TAG_EMPTY(0)) {
FPU_stack_underflow(0);
}
else {
clear_C1();
floatx80 st0_reg = BX_READ_FPU_REG(0);
BX_WRITE_FPU_REG(floatx80_abs(st0_reg), 0);
}
}
/* D9 F6 */
void BX_CPP_AttrRegparmN(1) BX_CPU_C::FDECSTP(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
clear_C1();
BX_CPU_THIS_PTR the_i387.tos = (BX_CPU_THIS_PTR the_i387.tos-1) & 7;
}
/* D9 F7 */
void BX_CPP_AttrRegparmN(1) BX_CPU_C::FINCSTP(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
clear_C1();
BX_CPU_THIS_PTR the_i387.tos = (BX_CPU_THIS_PTR the_i387.tos+1) & 7;
}
/* DD C0 */
void BX_CPP_AttrRegparmN(1) BX_CPU_C::FFREE_STi(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
clear_C1();
BX_CPU_THIS_PTR the_i387.FPU_settagi(FPU_Tag_Empty, i->rm());
}
/*
* Free the st(0) register and pop it from the FPU stack.
* "Undocumented" by Intel & AMD but mentioned in AMDs Athlon Docs.
*/
/* DF C0 */
void BX_CPP_AttrRegparmN(1) BX_CPU_C::FFREEP_STi(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
clear_C1();
BX_CPU_THIS_PTR the_i387.FPU_settagi(FPU_Tag_Empty, i->rm());
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
#endif