Bochs/bochs/cpu/shift8.cc
2001-04-10 01:04:59 +00:00

387 lines
7.3 KiB
C++

// Copyright (C) 2000 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
#include "bochs.h"
void
BX_CPU_C::ROL_Eb(BxInstruction_t *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 &= 0x07; // use only lowest 3 bits
/* op1 is a register or memory reference */
if (i->mod == 0xc0) {
op1_8 = BX_READ_8BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg, i->rm_addr, &op1_8);
}
if (count) {
result_8 = (op1_8 << count) | (op1_8 >> (8 - count));
/* now write result back to destination */
if (i->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, result_8);
}
else {
write_RMW_virtual_byte(result_8);
}
/* set eflags:
* ROL count affects the following flags: C
*/
set_CF(result_8 & 0x01);
if (count == 1)
set_OF(((op1_8 ^ result_8) & 0x80) > 0);
}
}
void
BX_CPU_C::ROR_Eb(BxInstruction_t *i)
{
Bit8u op1_8, result_8;
Bit8u result_b7;
unsigned count;
if (i->b1 == 0xc0)
count = i->Ib;
else if (i->b1 == 0xd0)
count = 1;
else // 0xd2
count = CL;
count &= 0x07; /* use only bottom 3 bits */
/* op1 is a register or memory reference */
if (i->mod == 0xc0) {
op1_8 = BX_READ_8BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg, i->rm_addr, &op1_8);
}
if (count) {
result_8 = (op1_8 >> count) | (op1_8 << (8 - count));
/* now write result back to destination */
if (i->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, result_8);
}
else {
write_RMW_virtual_byte(result_8);
}
/* set eflags:
* ROR count affects the following flags: C
*/
result_b7 = result_8 & 0x80;
set_CF(result_b7 != 0);
if (count == 1)
set_OF(((op1_8 ^ result_8) & 0x80) > 0);
}
}
void
BX_CPU_C::RCL_Eb(BxInstruction_t *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->mod == 0xc0) {
op1_8 = BX_READ_8BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg, i->rm_addr, &op1_8);
}
if (count) {
result_8 = (op1_8 << count) |
(get_CF() << (count - 1)) |
(op1_8 >> (9 - count));
/* now write result back to destination */
if (i->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, result_8);
}
else {
write_RMW_virtual_byte(result_8);
}
/* set eflags:
* RCL count affects the following flags: C
*/
if (count == 1)
set_OF(((op1_8 ^ result_8) & 0x80) > 0);
set_CF((op1_8 >> (8 - count)) & 0x01);
}
}
void
BX_CPU_C::RCR_Eb(BxInstruction_t *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->mod == 0xc0) {
op1_8 = BX_READ_8BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg, i->rm_addr, &op1_8);
}
if (count) {
result_8 = (op1_8 >> count) |
(get_CF() << (8 - count)) |
(op1_8 << (9 - count));
/* now write result back to destination */
if (i->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, result_8);
}
else {
write_RMW_virtual_byte(result_8);
}
/* set eflags:
* RCR count affects the following flags: C
*/
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_t *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->mod == 0xc0) {
op1_8 = BX_READ_8BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg, i->rm_addr, &op1_8);
}
if (!count) return;
result_8 = (op1_8 << count);
/* now write result back to destination */
if (i->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, 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_t *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->mod == 0xc0) {
op1_8 = BX_READ_8BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg, i->rm_addr, &op1_8);
}
if (!count) return;
result_8 = (op1_8 >> count);
/* now write result back to destination */
if (i->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, 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_t *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->mod == 0xc0) {
op1_8 = BX_READ_8BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg, i->rm_addr, &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->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, result_8);
}
else {
write_RMW_virtual_byte(result_8);
}
/* set eflags:
* SAR count affects the following flags: S,Z,P,C
*/
if (count < 8) {
set_CF((op1_8 >> (count - 1)) & 0x01);
}
else {
if (op1_8 & 0x80) {
set_CF(1);
}
else {
set_CF(0);
}
}
set_ZF(result_8 == 0);
set_SF(result_8 >> 7);
if (count == 1)
set_OF(0);
set_PF_base(result_8);
}