Bochs/bochs/cpu/mult16.cc
Bryce Denney 49664f7503 - parts of the SMP merge apparantly broke the debugger and this revision
tries to fix it.  The shortcuts to register names such as AX and DL are
  #defines in cpu/cpu.h, and they are defined in terms of BX_CPU_THIS_PTR.
  When BX_USE_CPU_SMF=1, this works fine.  (This is what bochs used for
  a long time, and nobody used the SMF=0 mode at all.)  To make SMP bochs
  work, I had to get SMF=0 mode working for the CPU so that there could
  be an array of cpus.

  When SMF=0 for the CPU, BX_CPU_THIS_PTR is defined to be "this->" which
  only works within methods of BX_CPU_C.  Code outside of BX_CPU_C must
  reference BX_CPU(num) instead.
- to try to enforce the correct use of AL/AX/DL/etc. shortcuts, they are
  now only #defined when "NEED_CPU_REG_SHORTCUTS" is #defined.  This is
  only done in the cpu/*.cc code.
2001-05-24 18:46:34 +00:00

293 lines
6.5 KiB
C++

// 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::MUL_AXEw(BxInstruction_t *i)
{
Bit16u op1_16, op2_16, product_16h, product_16l;
Bit32u product_32;
Boolean temp_flag;
op1_16 = AX;
/* op2 is a register or memory reference */
if (i->mod == 0xc0) {
op2_16 = BX_READ_16BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_virtual_word(i->seg, i->rm_addr, &op2_16);
}
product_32 = ((Bit32u) op1_16) * ((Bit32u) op2_16);
product_16l = (product_32 & 0xFFFF);
product_16h = product_32 >> 16;
/* now write product back to destination */
AX = product_16l;
DX = product_16h;
/* set eflags:
* MUL affects the following flags: C,O
*/
temp_flag = (product_16h != 0);
SET_FLAGS_OxxxxC(temp_flag, temp_flag);
}
void
BX_CPU_C::IMUL_AXEw(BxInstruction_t *i)
{
Bit16s op1_16, op2_16;
Bit32s product_32;
Bit16u product_16h, product_16l;
op1_16 = AX;
/* op2 is a register or memory reference */
if (i->mod == 0xc0) {
op2_16 = BX_READ_16BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_virtual_word(i->seg, i->rm_addr, (Bit16u *) &op2_16);
}
product_32 = ((Bit32s) op1_16) * ((Bit32s) op2_16);
product_16l = (product_32 & 0xFFFF);
product_16h = product_32 >> 16;
/* now write product back to destination */
AX = product_16l;
DX = product_16h;
/* set eflags:
* IMUL affects the following flags: C,O
* IMUL r/m16: condition for clearing CF & OF:
* DX:AX = sign-extend of AX
*/
if ( (DX==0xffff) && (AX & 0x8000) ) {
SET_FLAGS_OxxxxC(0, 0);
}
else if ( (DX==0x0000) && (AX < 0x8000) ) {
SET_FLAGS_OxxxxC(0, 0);
}
else {
SET_FLAGS_OxxxxC(1, 1);
}
}
void
BX_CPU_C::DIV_AXEw(BxInstruction_t *i)
{
Bit16u op2_16, remainder_16, quotient_16l;
Bit32u op1_32, quotient_32;
op1_32 = (((Bit32u) DX) << 16) | ((Bit32u) AX);
/* op2 is a register or memory reference */
if (i->mod == 0xc0) {
op2_16 = BX_READ_16BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_virtual_word(i->seg, i->rm_addr, &op2_16);
}
if (op2_16 == 0) {
exception(BX_DE_EXCEPTION, 0, 0);
}
quotient_32 = op1_32 / op2_16;
remainder_16 = op1_32 % op2_16;
quotient_16l = quotient_32 & 0xFFFF;
if (quotient_32 != quotient_16l) {
exception(BX_DE_EXCEPTION, 0, 0);
}
/* set EFLAGS:
* DIV affects the following flags: O,S,Z,A,P,C are undefined
*/
#if INTEL_DIV_FLAG_BUG == 1
set_CF(1);
#endif
/* now write quotient back to destination */
AX = quotient_16l;
DX = remainder_16;
}
void
BX_CPU_C::IDIV_AXEw(BxInstruction_t *i)
{
Bit16s op2_16, remainder_16, quotient_16l;
Bit32s op1_32, quotient_32;
op1_32 = ((((Bit32u) DX) << 16) | ((Bit32u) AX));
/* op2 is a register or memory reference */
if (i->mod == 0xc0) {
op2_16 = BX_READ_16BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_virtual_word(i->seg, i->rm_addr, (Bit16u *) &op2_16);
}
if (op2_16 == 0) {
exception(BX_DE_EXCEPTION, 0, 0);
}
quotient_32 = op1_32 / op2_16;
remainder_16 = op1_32 % op2_16;
quotient_16l = quotient_32 & 0xFFFF;
if (quotient_32 != quotient_16l) {
exception(BX_DE_EXCEPTION, 0, 0);
}
/* set EFLAGS:
* IDIV affects the following flags: O,S,Z,A,P,C are undefined
*/
#if INTEL_DIV_FLAG_BUG == 1
set_CF(1);
#endif
/* now write quotient back to destination */
AX = quotient_16l;
DX = remainder_16;
}
void
BX_CPU_C::IMUL_GwEwIw(BxInstruction_t *i)
{
#if BX_CPU_LEVEL < 2
BX_PANIC(("IMUL_GvEvIv() unsupported on 8086!\n"));
#else
Bit16u product_16l;
Bit16s op2_16, op3_16;
Bit32s product_32;
op3_16 = i->Iw;
/* op2 is a register or memory reference */
if (i->mod == 0xc0) {
op2_16 = BX_READ_16BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_virtual_word(i->seg, i->rm_addr, (Bit16u *) &op2_16);
}
product_32 = op2_16 * op3_16;
product_16l = (product_32 & 0xFFFF);
/* now write product back to destination */
BX_WRITE_16BIT_REG(i->nnn, product_16l);
/* set eflags:
* IMUL affects the following flags: C,O
* IMUL r16,r/m16,imm16: condition for clearing CF & OF:
* result exactly fits within r16
*/
if (product_32 > -32768 && product_32 < 32767) {
SET_FLAGS_OxxxxC(0, 0);
}
else {
SET_FLAGS_OxxxxC(1, 1);
}
#endif
}
void
BX_CPU_C::IMUL_GwEw(BxInstruction_t *i)
{
#if BX_CPU_LEVEL < 3
BX_PANIC(("IMUL_GvEv() unsupported on 8086!\n"));
#else
Bit16u product_16l;
Bit16s op1_16, op2_16;
Bit32s product_32;
/* op2 is a register or memory reference */
if (i->mod == 0xc0) {
op2_16 = BX_READ_16BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_virtual_word(i->seg, i->rm_addr, (Bit16u *) &op2_16);
}
op1_16 = BX_READ_16BIT_REG(i->nnn);
product_32 = op1_16 * op2_16;
product_16l = (product_32 & 0xFFFF);
/* now write product back to destination */
BX_WRITE_16BIT_REG(i->nnn, product_16l);
/* set eflags:
* IMUL affects the following flags: C,O
* IMUL r16,r/m16,imm16: condition for clearing CF & OF:
* result exactly fits within r16
*/
if (product_32 > -32768 && product_32 < 32767) {
SET_FLAGS_OxxxxC(0, 0);
}
else {
SET_FLAGS_OxxxxC(1, 1);
}
#endif
}