Bochs/bochs/cpu/shift16.cc
Kevin Lawton b8d7f5c88e Moved the asm() statements from the arithmetic instruction emulation
into inline functions with asm() statements in cpu.h.  This cleans
  up the *.cc code (which now doesn't have any asm()s in it), and
  centralizes the asm() code so constraints can be modified in one
  place.  This also makes it easier to cover more instructions
  with asm()s for more efficient eflags handling.
2002-10-07 22:51:58 +00:00

534 lines
12 KiB
C++

/////////////////////////////////////////////////////////////////////////
// $Id: shift16.cc,v 1.14 2002-10-07 22:51:58 kevinlawton 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::SHLD_EwGw(bxInstruction_c *i)
{
Bit16u op1_16, op2_16, result_16;
Bit32u temp_32, result_32;
unsigned count;
/* op1:op2 << count. result stored in op1 */
if (i->b1() == 0x1a4)
count = i->Ib();
else // 0x1a5
count = CL;
count &= 0x1f; // use only 5 LSB's
if (!count) return; /* NOP */
// count is 1..31
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_16 = BX_READ_16BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
}
op2_16 = BX_READ_16BIT_REG(i->nnn());
temp_32 = (op1_16 << 16) | (op2_16); // double formed by op1:op2
result_32 = temp_32 << count;
if (count > 16) {
// hack to act like x86 SHLD when count > 16
// actually shifting op1:op2:op2 << count
result_32 |= (op2_16 << (count - 16));
}
result_16 = result_32 >> 16;
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_16BIT_REG(i->rm(), result_16);
}
else {
Write_RMW_virtual_word(result_16);
}
/* set eflags:
* SHLD count affects the following flags: S,Z,P,C,O
*/
set_CF( (temp_32 >> (32 - count)) & 0x01 );
if (count == 1)
set_OF(((op1_16 ^ result_16) & 0x8000) > 0);
set_ZF(result_16 == 0);
set_SF(result_16 >> 15);
set_PF_base((Bit8u) result_16);
}
void
BX_CPU_C::SHRD_EwGw(bxInstruction_c *i)
{
#if BX_CPU_LEVEL < 3
BX_PANIC(("shrd_evgvib: not supported on < 386"));
#else
Bit16u op1_16, op2_16, result_16;
Bit32u temp_32, result_32;
unsigned count;
if (i->b1() == 0x1ac)
count = i->Ib();
else // 0x1ad
count = CL;
count &= 0x1F; /* use only 5 LSB's */
if (!count) return; /* NOP */
// count is 1..31
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_16 = BX_READ_16BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
}
op2_16 = BX_READ_16BIT_REG(i->nnn());
temp_32 = (op2_16 << 16) | op1_16; // double formed by op2:op1
result_32 = temp_32 >> count;
if (count > 16) {
// hack to act like x86 SHLD when count > 16
// actually shifting op2:op2:op1 >> count
result_32 |= (op2_16 << (32 - count));
}
result_16 = result_32;
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_16BIT_REG(i->rm(), result_16);
}
else {
Write_RMW_virtual_word(result_16);
}
/* set eflags:
* SHRD count affects the following flags: S,Z,P,C,O
*/
set_CF((temp_32 >> (count - 1)) & 0x01);
set_ZF(result_16 == 0);
set_SF(result_16 >> 15);
/* for shift of 1, OF set if sign change occurred. */
if (count == 1)
set_OF(((op1_16 ^ result_16) & 0x8000) > 0);
set_PF_base((Bit8u) result_16);
#endif /* BX_CPU_LEVEL >= 3 */
}
void
BX_CPU_C::ROL_Ew(bxInstruction_c *i)
{
Bit16u op1_16, result_16;
unsigned count;
if ( i->b1() == 0xc1 )
count = i->Ib();
else if ( i->b1() == 0xd1 )
count = 1;
else // 0xd3
count = CL;
count &= 0x0f; // only use bottom 4 bits
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_16 = BX_READ_16BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
}
if (count) {
result_16 = (op1_16 << count) | (op1_16 >> (16 - count));
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_16BIT_REG(i->rm(), result_16);
}
else {
Write_RMW_virtual_word(result_16);
}
/* set eflags:
* ROL count affects the following flags: C
*/
set_CF(result_16 & 0x01);
if (count == 1)
set_OF(((op1_16 ^ result_16) & 0x8000) > 0);
}
}
void
BX_CPU_C::ROR_Ew(bxInstruction_c *i)
{
Bit16u op1_16, result_16, result_b15;
unsigned count;
if ( i->b1() == 0xc1 )
count = i->Ib();
else if ( i->b1() == 0xd1 )
count = 1;
else // 0xd3
count = CL;
count &= 0x0f; // use only 4 LSB's
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_16 = BX_READ_16BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
}
if (count) {
result_16 = (op1_16 >> count) | (op1_16 << (16 - count));
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_16BIT_REG(i->rm(), result_16);
}
else {
Write_RMW_virtual_word(result_16);
}
/* set eflags:
* ROR count affects the following flags: C
*/
result_b15 = result_16 & 0x8000;
set_CF(result_b15 != 0);
if (count == 1)
set_OF(((op1_16 ^ result_16) & 0x8000) > 0);
}
}
void
BX_CPU_C::RCL_Ew(bxInstruction_c *i)
{
Bit16u op1_16, result_16;
unsigned count;
if ( i->b1() == 0xc1 )
count = i->Ib();
else if ( i->b1() == 0xd1 )
count = 1;
else // 0xd3
count = CL;
count &= 0x1F;
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_16 = BX_READ_16BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
}
count %= 17;
if (!count) return;
if (count==1) {
result_16 = (op1_16 << 1) | getB_CF();
}
else if (count==16) {
result_16 = (getB_CF() << 15) |
(op1_16 >> 1);
}
else { // 2..15
result_16 = (op1_16 << count) |
(getB_CF() << (count - 1)) |
(op1_16 >> (17 - count));
}
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_16BIT_REG(i->rm(), result_16);
}
else {
Write_RMW_virtual_word(result_16);
}
/* set eflags:
* RCL count affects the following flags: C
*/
if (count == 1)
set_OF(((op1_16 ^ result_16) & 0x8000) > 0);
set_CF((op1_16 >> (16 - count)) & 0x01);
}
void
BX_CPU_C::RCR_Ew(bxInstruction_c *i)
{
Bit16u op1_16, result_16;
unsigned count;
if ( i->b1() == 0xc1 )
count = i->Ib();
else if ( i->b1() == 0xd1 )
count = 1;
else // 0xd3
count = CL;
count = count & 0x1F;
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_16 = BX_READ_16BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
}
count %= 17;
if (count) {
result_16 = (op1_16 >> count) |
(getB_CF() << (16 - count)) |
(op1_16 << (17 - count));
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_16BIT_REG(i->rm(), result_16);
}
else {
Write_RMW_virtual_word(result_16);
}
/* set eflags:
* RCR count affects the following flags: C
*/
set_CF((op1_16 >> (count - 1)) & 0x01);
if (count == 1)
set_OF(((op1_16 ^ result_16) & 0x8000) > 0);
}
}
void
BX_CPU_C::SHL_Ew(bxInstruction_c *i)
{
Bit16u op1_16, result_16;
unsigned count;
if ( i->b1() == 0xc1 )
count = i->Ib();
else if ( i->b1() == 0xd1 )
count = 1;
else // 0xd3
count = CL;
count &= 0x1F; /* use only 5 LSB's */
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_16 = BX_READ_16BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
}
if (!count) return;
result_16 = (op1_16 << count);
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_16BIT_REG(i->rm(), result_16);
}
else {
Write_RMW_virtual_word(result_16);
}
SET_FLAGS_OSZAPC_16(op1_16, count, result_16, BX_INSTR_SHL16);
}
void
BX_CPU_C::SHR_Ew(bxInstruction_c *i)
{
Bit16u op1_16, result_16;
unsigned count;
if ( i->b1() == 0xc1 )
count = i->Ib();
else if ( i->b1() == 0xd1 )
count = 1;
else // 0xd3
count = CL;
count &= 0x1F; /* use only 5 LSB's */
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_16 = BX_READ_16BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
}
if (!count) return;
#if (defined(__i386__) && defined(__GNUC__) && BX_SupportHostAsms)
Bit32u flags32;
asmShr16(result_16, op1_16, count, flags32);
setEFlagsOSZAPC(flags32);
#else
result_16 = (op1_16 >> count);
#endif
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_16BIT_REG(i->rm(), result_16);
}
else {
Write_RMW_virtual_word(result_16);
}
#if !(defined(__i386__) && defined(__GNUC__) && BX_SupportHostAsms)
SET_FLAGS_OSZAPC_16(op1_16, count, result_16, BX_INSTR_SHR16);
#endif
}
void
BX_CPU_C::SAR_Ew(bxInstruction_c *i)
{
Bit16u op1_16, result_16;
unsigned count;
if ( i->b1() == 0xc1 )
count = i->Ib();
else if ( i->b1() == 0xd1 )
count = 1;
else // 0xd3
count = CL;
count &= 0x1F; /* use only 5 LSB's */
/* op1 is a register or memory reference */
if (i->modC0()) {
op1_16 = BX_READ_16BIT_REG(i->rm());
}
else {
/* pointer, segment address pair */
read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
}
if (!count) return;
if (count < 16) {
if (op1_16 & 0x8000) {
result_16 = (op1_16 >> count) | (0xffff << (16 - count));
}
else {
result_16 = (op1_16 >> count);
}
}
else {
if (op1_16 & 0x8000) {
result_16 = 0xffff;
}
else {
result_16 = 0;
}
}
/* now write result back to destination */
if (i->modC0()) {
BX_WRITE_16BIT_REG(i->rm(), result_16);
}
else {
Write_RMW_virtual_word(result_16);
}
/* set eflags:
* SAR count affects the following flags: S,Z,P,C
*/
if (count < 16) {
set_CF((op1_16 >> (count - 1)) & 0x01);
}
else {
if (op1_16 & 0x8000) {
set_CF(1);
}
else {
set_CF(0);
}
}
set_ZF(result_16 == 0);
set_SF(result_16 >> 15);
if (count == 1)
set_OF(0);
set_PF_base((Bit8u) result_16);
}