Bochs/bochs/cpu/shift8.cc
2005-02-16 21:27:21 +00:00

359 lines
7.8 KiB
C++

/////////////////////////////////////////////////////////////////////////
// $Id: shift8.cc,v 1.21 2005-02-16 21:27:20 sshwarts Exp $
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001 MandrakeSoft S.A.
//
// MandrakeSoft S.A.
// 43, rue d'Aboukir
// 75002 Paris - France
// http://www.linux-mandrake.com/
// http://www.mandrakesoft.com/
//
// 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"
#define LOG_THIS BX_CPU_THIS_PTR
void BX_CPU_C::ROL_Eb(bxInstruction_c *i)
{
Bit8u op1_8, result_8;
unsigned count;
if (i->b1() == 0xc0)
count = i->Ib();
else if (i->b1() == 0xd0)
count = 1;
else // 0xd2
count = CL;
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
}
if ( (count & 0x07) == 0 ) {
if ( count & 0x18 ) {
unsigned bit0 = op1_8 & 1;
set_CF(bit0);
set_OF(bit0 ^ (op1_8 >> 7));
}
return;
}
count &= 0x07; // use only lowest 3 bits
result_8 = (op1_8 << count) | (op1_8 >> (8 - count));
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), result_8);
}
else {
Write_RMW_virtual_byte(result_8);
}
/* set eflags:
* ROL count affects the following flags: C, O
*/
bx_bool temp_CF = (result_8 & 0x01);
set_CF(temp_CF);
set_OF(temp_CF ^ (result_8 >> 7));
}
void BX_CPU_C::ROR_Eb(bxInstruction_c *i)
{
Bit8u op1_8, result_8;
unsigned count;
if (i->b1() == 0xc0)
count = i->Ib();
else if (i->b1() == 0xd0)
count = 1;
else // 0xd2
count = CL;
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
}
if ( (count & 0x07) == 0 ) {
if ( count & 0x18 ) {
unsigned bit6 = (op1_8 >> 6) & 1;
unsigned bit7 = (op1_8 >> 7);
set_CF(bit7);
set_OF(bit7 ^ bit6);
}
return;
}
count &= 0x07; /* use only bottom 3 bits */
result_8 = (op1_8 >> count) | (op1_8 << (8 - count));
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), result_8);
}
else {
Write_RMW_virtual_byte(result_8);
}
/* set eflags:
* ROR count affects the following flags: C, O
*/
bx_bool result_b7 = (result_8 & 0x80) != 0;
set_CF(result_b7);
if (count == 1)
set_OF(((op1_8 ^ result_8) & 0x80) > 0);
}
void BX_CPU_C::RCL_Eb(bxInstruction_c *i)
{
Bit8u op1_8, result_8;
unsigned count;
if (i->b1() == 0xc0)
count = i->Ib();
else if (i->b1() == 0xd0)
count = 1;
else // 0xd2
count = CL;
count = (count & 0x1f) % 9;
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
}
if (! count) return;
if (count==1) {
result_8 = (op1_8 << 1) | getB_CF();
}
else {
result_8 = (op1_8 << count) | (getB_CF() << (count - 1)) |
(op1_8 >> (9 - count));
}
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), result_8);
}
else {
Write_RMW_virtual_byte(result_8);
}
/* set eflags:
* RCL count affects the following flags: C, O
*/
bx_bool temp_CF = (op1_8 >> (8 - count)) & 0x01;
set_CF(temp_CF);
set_OF(temp_CF ^ (result_8 >> 7));
}
void BX_CPU_C::RCR_Eb(bxInstruction_c *i)
{
Bit8u op1_8, result_8;
unsigned count;
if (i->b1() == 0xc0)
count = i->Ib();
else if (i->b1() == 0xd0)
count = 1;
else // 0xd2
count = CL;
count = (count & 0x1f) % 9;
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
}
if (! count) return;
result_8 = (op1_8 >> count) | (getB_CF() << (8 - count)) |
(op1_8 << (9 - count));
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), result_8);
}
else {
Write_RMW_virtual_byte(result_8);
}
/* set eflags:
* RCR count affects the following flags: C, O
*/
set_CF((op1_8 >> (count - 1)) & 0x01);
if (count == 1)
set_OF(((op1_8 ^ result_8) & 0x80) > 0);
}
void BX_CPU_C::SHL_Eb(bxInstruction_c *i)
{
Bit8u op1_8, result_8;
unsigned count;
if (i->b1() == 0xc0)
count = i->Ib();
else if (i->b1() == 0xd0)
count = 1;
else // 0xd2
count = CL;
count &= 0x1f;
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
}
if (!count) return;
result_8 = (op1_8 << count);
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), result_8);
}
else {
Write_RMW_virtual_byte(result_8);
}
SET_FLAGS_OSZAPC_8(op1_8, count, result_8, BX_INSTR_SHL8);
}
void BX_CPU_C::SHR_Eb(bxInstruction_c *i)
{
Bit8u op1_8, result_8;
unsigned count;
if (i->b1() == 0xc0)
count = i->Ib();
else if (i->b1() == 0xd0)
count = 1;
else // 0xd2
count = CL;
count &= 0x1f;
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
}
if (!count) return;
result_8 = (op1_8 >> count);
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), result_8);
}
else {
Write_RMW_virtual_byte(result_8);
}
SET_FLAGS_OSZAPC_8(op1_8, count, result_8, BX_INSTR_SHR8);
}
void BX_CPU_C::SAR_Eb(bxInstruction_c *i)
{
Bit8u op1_8, result_8;
unsigned count;
if (i->b1() == 0xc0)
count = i->Ib();
else if (i->b1() == 0xd0)
count = 1;
else // 0xd2
count = CL;
count &= 0x1f;
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_8 = BX_READ_8BIT_REGx(i->rm(),i->extend8bitL());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1_8);
}
if (!count) return;
if (count < 8) {
if (op1_8 & 0x80) {
result_8 = (op1_8 >> count) | (0xff << (8 - count));
}
else {
result_8 = (op1_8 >> count);
}
}
else {
if (op1_8 & 0x80) {
result_8 = 0xff;
}
else {
result_8 = 0;
}
}
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), result_8);
}
else {
Write_RMW_virtual_byte(result_8);
}
SET_FLAGS_OSZAPC_8(op1_8, count, result_8, BX_INSTR_SAR8);
}