/* Extracted from the Fake86 project and heavily modified to run within

/* Extracted from the Fake86 project and heavily modified to run within
the Collapse OS project with its simple needs.
*/
/*
Fake86: A portable, open-source 8086 PC emulator.
Copyright (C)2010-2013 Mike Chambers

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program 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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/

#include <stdint.h>
#include <stdio.h>
#include "cpu.h"

#define StepIP(x) ip += x
#define signext(value) (int16_t)(int8_t)(value)
#define signext32(value) (int32_t)(int16_t)(value)
#define getsegreg(regid) segregs[regid]
#define putsegreg(regid, writeval) segregs[regid] = writeval
// Warning: those macros below *can't* be called with reg*l and reg*h
#define getreg8(regid) regs.byteregs[byteregtable[regid]]
#define putreg8(regid, writeval) regs.byteregs[byteregtable[regid]] = writeval

uint8_t byteregtable[8] = { regal, regcl, regdl, regbl, regah, regch, regdh, regbh };

static const uint8_t parity[0x100] = {
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1
};

uint8_t RAM[0x100000];
INTHOOK INTHOOKS[0x100] = {0};
uint8_t opcode, segoverride, reptype, hltstate = 0;
uint16_t segregs[4], ip, useseg, oldsp;
uint8_t tempcf, cf, pf, af, zf, sf, tf, ifl, df, of, mode, reg, rm;
uint16_t oper1, oper2, res16, disp16, temp16, stacksize, frametemp;
uint8_t oper1b, oper2b, res8, disp8, nestlev, addrbyte;
uint32_t temp1, temp2, temp3, ea;

union _bytewordregs_ regs;

uint8_t portram[0x10000];

void intcall86(uint8_t intnum);

static void portout (uint16_t portnum, uint8_t value) {}
static void portout16 (uint16_t portnum, uint16_t value) {}
static uint8_t portin (uint16_t portnum) { return 0; }
static uint16_t portin16 (uint16_t portnum) { return 0; }

void write86 (uint32_t addr32, uint8_t value) {
RAM[addr32 & 0xFFFFF] = value;
}

void writew86 (uint32_t addr32, uint16_t value) {
write86(addr32, (uint8_t) value);
write86(addr32 + 1, (uint8_t) (value >> 8) );
}

uint8_t read86 (uint32_t addr32) {
addr32 &= 0xFFFFF;
return (RAM[addr32]);
}

uint16_t readw86 (uint32_t addr32) {
return ( (uint16_t) read86 (addr32) | (uint16_t) (read86 (addr32 + 1) << 8) );
}

static void flag_szp8 (uint8_t value) {
if (!value) {
zf = 1;
}
else {
zf = 0; /* set or clear zero flag */
}

if (value & 0x80) {
sf = 1;
}
else {
sf = 0; /* set or clear sign flag */
}

pf = parity[value]; /* retrieve parity state from lookup table */
}

static void flag_szp16 (uint16_t value) {
if (!value) {
zf = 1;
}
else {
zf = 0; /* set or clear zero flag */
}

if (value & 0x8000) {
sf = 1;
}
else {
sf = 0; /* set or clear sign flag */
}

pf = parity[value & 255]; /* retrieve parity state from lookup table */
}

static void flag_log8 (uint8_t value) {
flag_szp8 (value);
cf = 0;
of = 0; /* bitwise logic ops always clear carry and overflow */
}

static void flag_log16 (uint16_t value) {
flag_szp16 (value);
cf = 0;
of = 0; /* bitwise logic ops always clear carry and overflow */
}

static void flag_adc8 (uint8_t v1, uint8_t v2, uint8_t v3) {

/* v1 = destination operand, v2 = source operand, v3 = carry flag */
uint16_t dst;

dst = (uint16_t) v1 + (uint16_t) v2 + (uint16_t) v3;
flag_szp8 ( (uint8_t) dst);
if ( ( (dst ^ v1) & (dst ^ v2) & 0x80) == 0x80) {
of = 1;
}
else {
of = 0; /* set or clear overflow flag */
}

if (dst & 0xFF00) {
cf = 1;
}
else {
cf = 0; /* set or clear carry flag */
}

if ( ( (v1 ^ v2 ^ dst) & 0x10) == 0x10) {
af = 1;
}
else {
af = 0; /* set or clear auxilliary flag */
}
}

static void flag_adc16 (uint16_t v1, uint16_t v2, uint16_t v3) {

uint32_t dst;

dst = (uint32_t) v1 + (uint32_t) v2 + (uint32_t) v3;
flag_szp16 ( (uint16_t) dst);
if ( ( ( (dst ^ v1) & (dst ^ v2) ) & 0x8000) == 0x8000) {
of = 1;
}
else {
of = 0;
}

if (dst & 0xFFFF0000) {
cf = 1;
}
else {
cf = 0;
}

if ( ( (v1 ^ v2 ^ dst) & 0x10) == 0x10) {
af = 1;
}
else {
af = 0;
}
}

static void flag_add8 (uint8_t v1, uint8_t v2) {
/* v1 = destination operand, v2 = source operand */
uint16_t dst;

dst = (uint16_t) v1 + (uint16_t) v2;
flag_szp8 ( (uint8_t) dst);
if (dst & 0xFF00) {
cf = 1;
}
else {
cf = 0;
}

if ( ( (dst ^ v1) & (dst ^ v2) & 0x80) == 0x80) {
of = 1;
}
else {
of = 0;
}

if ( ( (v1 ^ v2 ^ dst) & 0x10) == 0x10) {
af = 1;
}
else {
af = 0;
}
}

static void flag_add16 (uint16_t v1, uint16_t v2) {
/* v1 = destination operand, v2 = source operand */
uint32_t dst;

dst = (uint32_t) v1 + (uint32_t) v2;
flag_szp16 ( (uint16_t) dst);
if (dst & 0xFFFF0000) {
cf = 1;
}
else {
cf = 0;
}

if ( ( (dst ^ v1) & (dst ^ v2) & 0x8000) == 0x8000) {
of = 1;
}
else {
of = 0;
}

if ( ( (v1 ^ v2 ^ dst) & 0x10) == 0x10) {
af = 1;
}
else {
af = 0;
}
}

static void flag_sbb8 (uint8_t v1, uint8_t v2, uint8_t v3) {

/* v1 = destination operand, v2 = source operand, v3 = carry flag */
uint16_t dst;

v2 += v3;
dst = (uint16_t) v1 - (uint16_t) v2;
flag_szp8 ( (uint8_t) dst);
if (dst & 0xFF00) {
cf = 1;
}
else {
cf = 0;
}

if ( (dst ^ v1) & (v1 ^ v2) & 0x80) {
of = 1;
}
else {
of = 0;
}

if ( (v1 ^ v2 ^ dst) & 0x10) {
af = 1;
}
else {
af = 0;
}
}

static void flag_sbb16 (uint16_t v1, uint16_t v2, uint16_t v3) {

/* v1 = destination operand, v2 = source operand, v3 = carry flag */
uint32_t dst;

v2 += v3;
dst = (uint32_t) v1 - (uint32_t) v2;
flag_szp16 ( (uint16_t) dst);
if (dst & 0xFFFF0000) {
cf = 1;
}
else {
cf = 0;
}

if ( (dst ^ v1) & (v1 ^ v2) & 0x8000) {
of = 1;
}
else {
of = 0;
}

if ( (v1 ^ v2 ^ dst) & 0x10) {
af = 1;
}
else {
af = 0;
}
}

static void flag_sub8 (uint8_t v1, uint8_t v2) {

/* v1 = destination operand, v2 = source operand */
uint16_t dst;

dst = (uint16_t) v1 - (uint16_t) v2;
flag_szp8 ( (uint8_t) dst);
if (dst & 0xFF00) {
cf = 1;
}
else {
cf = 0;
}

if ( (dst ^ v1) & (v1 ^ v2) & 0x80) {
of = 1;
}
else {
of = 0;
}

if ( (v1 ^ v2 ^ dst) & 0x10) {
af = 1;
}
else {
af = 0;
}
}

static void flag_sub16 (uint16_t v1, uint16_t v2) {

/* v1 = destination operand, v2 = source operand */
uint32_t dst;

dst = (uint32_t) v1 - (uint32_t) v2;
flag_szp16 ( (uint16_t) dst);
if (dst & 0xFFFF0000) {
cf = 1;
}
else {
cf = 0;
}

if ( (dst ^ v1) & (v1 ^ v2) & 0x8000) {
of = 1;
}
else {
of = 0;
}

if ( (v1 ^ v2 ^ dst) & 0x10) {
af = 1;
}
else {
af = 0;
}
}

static void op_adc8() {
res8 = oper1b + oper2b + cf;
flag_adc8 (oper1b, oper2b, cf);
}

static void op_adc16() {
res16 = oper1 + oper2 + cf;
flag_adc16 (oper1, oper2, cf);
}

static void op_add8() {
res8 = oper1b + oper2b;
flag_add8 (oper1b, oper2b);
}

static void op_add16() {
res16 = oper1 + oper2;
flag_add16 (oper1, oper2);
}

static void op_and8() {
res8 = oper1b & oper2b;
flag_log8 (res8);
}

static void op_and16() {
res16 = oper1 & oper2;
flag_log16 (res16);
}

static void op_or8() {
res8 = oper1b | oper2b;
flag_log8 (res8);
}

static void op_or16() {
res16 = oper1 | oper2;
flag_log16 (res16);
}

static void op_xor8() {
res8 = oper1b ^ oper2b;
flag_log8 (res8);
}

static void op_xor16() {
res16 = oper1 ^ oper2;
flag_log16 (res16);
}

static void op_sub8() {
res8 = oper1b - oper2b;
flag_sub8 (oper1b, oper2b);
}

static void op_sub16() {
res16 = oper1 - oper2;
flag_sub16 (oper1, oper2);
}

static void op_sbb8() {
res8 = oper1b - (oper2b + cf);
flag_sbb8 (oper1b, oper2b, cf);
}

static void op_sbb16() {
res16 = oper1 - (oper2 + cf);
flag_sbb16 (oper1, oper2, cf);
}

static void getea (uint8_t rmval) {
uint32_t tempea;

tempea = 0;
switch (mode) {
case 0:
switch (rmval) {
case 0:
tempea = regs.wordregs[regbx] + regs.wordregs[regsi];
break;
case 1:
tempea = regs.wordregs[regbx] + regs.wordregs[regdi];
break;
case 2:
tempea = regs.wordregs[regbp] + regs.wordregs[regsi];
break;
case 3:
tempea = regs.wordregs[regbp] + regs.wordregs[regdi];
break;
case 4:
tempea = regs.wordregs[regsi];
break;
case 5:
tempea = regs.wordregs[regdi];
break;
case 6:
tempea = disp16;
break;
case 7:
tempea = regs.wordregs[regbx];
break;
}
break;

case 1:
case 2:
switch (rmval) {
case 0:
tempea = regs.wordregs[regbx] + regs.wordregs[regsi] + disp16;
break;
case 1:
tempea = regs.wordregs[regbx] + regs.wordregs[regdi] + disp16;
break;
case 2:
tempea = regs.wordregs[regbp] + regs.wordregs[regsi] + disp16;
break;
case 3:
tempea = regs.wordregs[regbp] + regs.wordregs[regdi] + disp16;
break;
case 4:
tempea = regs.wordregs[regsi] + disp16;
break;
case 5:
tempea = regs.wordregs[regdi] + disp16;
break;
case 6:
tempea = regs.wordregs[regbp] + disp16;
break;
case 7:
tempea = regs.wordregs[regbx] + disp16;
break;
}
break;
}

ea = (tempea & 0xFFFF) + (useseg << 4);
}

static void push (uint16_t pushval) {
regs.wordregs[regsp] = regs.wordregs[regsp] - 2;
putmem16 (segregs[regss], regs.wordregs[regsp], pushval);
}

static uint16_t pop() {

uint16_t tempval;

tempval = getmem16 (segregs[regss], regs.wordregs[regsp]);
regs.wordregs[regsp] = regs.wordregs[regsp] + 2;
return tempval;
}

static uint16_t readrm16 (uint8_t rmval) {
if (mode < 3) {
getea (rmval);
return read86 (ea) | ( (uint16_t) read86 (ea + 1) << 8);
}
else {
return getreg16 (rmval);
}
}

static uint8_t readrm8 (uint8_t rmval) {
if (mode < 3) {
getea (rmval);
return read86 (ea);
}
else {
return getreg8 (rmval);
}
}

static void writerm16 (uint8_t rmval, uint16_t value) {
if (mode < 3) {
getea (rmval);
write86 (ea, value & 0xFF);
write86 (ea + 1, value >> 8);
}
else {
putreg16 (rmval, value);
}
}

static void writerm8 (uint8_t rmval, uint8_t value) {
if (mode < 3) {
getea (rmval);
write86 (ea, value);
}
else {
putreg8 (rmval, value);
}
}

static uint8_t op_grp2_8 (uint8_t cnt) {

uint16_t s;
uint16_t shift;
uint16_t oldcf;
uint16_t msb;

s = oper1b;
oldcf = cf;
cnt &= 0x1F;
switch (reg) {
case 0: /* ROL r/m8 */
for (shift = 1; shift <= cnt; shift++) {
if (s & 0x80) {
cf = 1;
}
else {
cf = 0;
}

s = s << 1;
s = s | cf;
}

if (cnt == 1) {
//of = cf ^ ( (s >> 7) & 1);
if ((s & 0x80) && cf) of = 1; else of = 0;
} else of = 0;
break;

case 1: /* ROR r/m8 */
for (shift = 1; shift <= cnt; shift++) {
cf = s & 1;
s = (s >> 1) | (cf << 7);
}

if (cnt == 1) {
of = (s >> 7) ^ ( (s >> 6) & 1);
}
break;

case 2: /* RCL r/m8 */
for (shift = 1; shift <= cnt; shift++) {
oldcf = cf;
if (s & 0x80) {
cf = 1;
}
else {
cf = 0;
}

s = s << 1;
s = s | oldcf;
}

if (cnt == 1) {
of = cf ^ ( (s >> 7) & 1);
}
break;

case 3: /* RCR r/m8 */
for (shift = 1; shift <= cnt; shift++) {
oldcf = cf;
cf = s & 1;
s = (s >> 1) | (oldcf << 7);
}

if (cnt == 1) {
of = (s >> 7) ^ ( (s >> 6) & 1);
}
break;

case 4:
case 6: /* SHL r/m8 */
for (shift = 1; shift <= cnt; shift++) {
if (s & 0x80) {
cf = 1;
}
else {
cf = 0;
}

s = (s << 1) & 0xFF;
}

if ( (cnt == 1) && (cf == (s >> 7) ) ) {
of = 0;
}
else {
of = 1;
}

flag_szp8 ( (uint8_t) s);
break;

case 5: /* SHR r/m8 */
if ( (cnt == 1) && (s & 0x80) ) {
of = 1;
}
else {
of = 0;
}

for (shift = 1; shift <= cnt; shift++) {
cf = s & 1;
s = s >> 1;
}

flag_szp8 ( (uint8_t) s);
break;

case 7: /* SAR r/m8 */
for (shift = 1; shift <= cnt; shift++) {
msb = s & 0x80;
cf = s & 1;
s = (s >> 1) | msb;
}

of = 0;
flag_szp8 ( (uint8_t) s);
break;
}

return s & 0xFF;
}

static uint16_t op_grp2_16 (uint8_t cnt) {

uint32_t s;
uint32_t shift;
uint32_t oldcf;
uint32_t msb;

s = oper1;
oldcf = cf;
cnt &= 0x1F;
switch (reg) {
case 0: /* ROL r/m8 */
for (shift = 1; shift <= cnt; shift++) {
if (s & 0x8000) {
cf = 1;
}
else {
cf = 0;
}

s = s << 1;
s = s | cf;
}

if (cnt == 1) {
of = cf ^ ( (s >> 15) & 1);
}
break;

case 1: /* ROR r/m8 */
for (shift = 1; shift <= cnt; shift++) {
cf = s & 1;
s = (s >> 1) | (cf << 15);
}

if (cnt == 1) {
of = (s >> 15) ^ ( (s >> 14) & 1);
}
break;

case 2: /* RCL r/m8 */
for (shift = 1; shift <= cnt; shift++) {
oldcf = cf;
if (s & 0x8000) {
cf = 1;
}
else {
cf = 0;
}

s = s << 1;
s = s | oldcf;
}

if (cnt == 1) {
of = cf ^ ( (s >> 15) & 1);
}
break;

case 3: /* RCR r/m8 */
for (shift = 1; shift <= cnt; shift++) {
oldcf = cf;
cf = s & 1;
s = (s >> 1) | (oldcf << 15);
}

if (cnt == 1) {
of = (s >> 15) ^ ( (s >> 14) & 1);
}
break;

case 4:
case 6: /* SHL r/m8 */
for (shift = 1; shift <= cnt; shift++) {
if (s & 0x8000) {
cf = 1;
}
else {
cf = 0;
}

s = (s << 1) & 0xFFFF;
}

if ( (cnt == 1) && (cf == (s >> 15) ) ) {
of = 0;
}
else {
of = 1;
}

flag_szp16 ( (uint16_t) s);
break;

case 5: /* SHR r/m8 */
if ( (cnt == 1) && (s & 0x8000) ) {
of = 1;
}
else {
of = 0;
}

for (shift = 1; shift <= cnt; shift++) {
cf = s & 1;
s = s >> 1;
}

flag_szp16 ( (uint16_t) s);
break;

case 7: /* SAR r/m8 */
for (shift = 1; shift <= cnt; shift++) {
msb = s & 0x8000;
cf = s & 1;
s = (s >> 1) | msb;
}

of = 0;
flag_szp16 ( (uint16_t) s);
break;
}

return (uint16_t) s & 0xFFFF;
}

static void op_div8 (uint16_t valdiv, uint8_t divisor) {
if (divisor == 0) {
intcall86 (0);
return;
}

if ( (valdiv / (uint16_t) divisor) > 0xFF) {
intcall86 (0);
return;
}

regs.byteregs[regah] = valdiv % (uint16_t) divisor;
regs.byteregs[regal] = valdiv / (uint16_t) divisor;
}

static void op_idiv8 (uint16_t valdiv, uint8_t divisor) {

uint16_t s1;
uint16_t s2;
uint16_t d1;
uint16_t d2;
int sign;

if (divisor == 0) {
intcall86 (0);
return;
}

s1 = valdiv;
s2 = divisor;
sign = ( ( (s1 ^ s2) & 0x8000) != 0);
s1 = (s1 < 0x8000) ? s1 : ( (~s1 + 1) & 0xffff);
s2 = (s2 < 0x8000) ? s2 : ( (~s2 + 1) & 0xffff);
d1 = s1 / s2;
d2 = s1 % s2;
if (d1 & 0xFF00) {
intcall86 (0);
return;
}

if (sign) {
d1 = (~d1 + 1) & 0xff;
d2 = (~d2 + 1) & 0xff;
}

regs.byteregs[regah] = (uint8_t) d2;
regs.byteregs[regal] = (uint8_t) d1;
}

static void op_grp3_8() {
oper1 = signext (oper1b);
oper2 = signext (oper2b);
switch (reg) {
case 0:
case 1: /* TEST */
flag_log8 (oper1b & getmem8 (segregs[regcs], ip) );
StepIP (1);
break;

case 2: /* NOT */
res8 = ~oper1b;
break;

case 3: /* NEG */
res8 = (~oper1b) + 1;
flag_sub8 (0, oper1b);
if (res8 == 0) {
cf = 0;
}
else {
cf = 1;
}
break;

case 4: /* MUL */
temp1 = (uint32_t) oper1b * (uint32_t) regs.byteregs[regal];
regs.wordregs[regax] = temp1 & 0xFFFF;
flag_szp8 ( (uint8_t) temp1);
if (regs.byteregs[regah]) {
cf = 1;
of = 1;
}
else {
cf = 0;
of = 0;
}
break;

case 5: /* IMUL */
oper1 = signext (oper1b);
temp1 = signext (regs.byteregs[regal]);
temp2 = oper1;
if ( (temp1 & 0x80) == 0x80) {
temp1 = temp1 | 0xFFFFFF00;
}

if ( (temp2 & 0x80) == 0x80) {
temp2 = temp2 | 0xFFFFFF00;
}

temp3 = (temp1 * temp2) & 0xFFFF;
regs.wordregs[regax] = temp3 & 0xFFFF;
if (regs.byteregs[regah]) {
cf = 1;
of = 1;
}
else {
cf = 0;
of = 0;
}
break;

case 6: /* DIV */
op_div8 (regs.wordregs[regax], oper1b);
break;

case 7: /* IDIV */
op_idiv8 (regs.wordregs[regax], oper1b);
break;
}
}

static void op_div16 (uint32_t valdiv, uint16_t divisor) {
if (divisor == 0) {
intcall86 (0);
return;
}

if ( (valdiv / (uint32_t) divisor) > 0xFFFF) {
intcall86 (0);
return;
}

regs.wordregs[regdx] = valdiv % (uint32_t) divisor;
regs.wordregs[regax] = valdiv / (uint32_t) divisor;
}

static void op_idiv16 (uint32_t valdiv, uint16_t divisor) {

uint32_t d1;
uint32_t d2;
uint32_t s1;
uint32_t s2;
int sign;

if (divisor == 0) {
intcall86 (0);
return;
}

s1 = valdiv;
s2 = divisor;
s2 = (s2 & 0x8000) ? (s2 | 0xffff0000) : s2;
sign = ( ( (s1 ^ s2) & 0x80000000) != 0);
s1 = (s1 < 0x80000000) ? s1 : ( (~s1 + 1) & 0xffffffff);
s2 = (s2 < 0x80000000) ? s2 : ( (~s2 + 1) & 0xffffffff);
d1 = s1 / s2;
d2 = s1 % s2;
if (d1 & 0xFFFF0000) {
intcall86 (0);
return;
}

if (sign) {
d1 = (~d1 + 1) & 0xffff;
d2 = (~d2 + 1) & 0xffff;
}

regs.wordregs[regax] = d1;
regs.wordregs[regdx] = d2;
}

static void op_grp3_16() {
switch (reg) {
case 0:
case 1: /* TEST */
flag_log16 (oper1 & getmem16 (segregs[regcs], ip) );
StepIP (2);
break;

case 2: /* NOT */
res16 = ~oper1;
break;

case 3: /* NEG */
res16 = (~oper1) + 1;
flag_sub16 (0, oper1);
if (res16) {
cf = 1;
}
else {
cf = 0;
}
break;

case 4: /* MUL */
temp1 = (uint32_t) oper1 * (uint32_t) regs.wordregs[regax];
regs.wordregs[regax] = temp1 & 0xFFFF;
regs.wordregs[regdx] = temp1 >> 16;
flag_szp16 ( (uint16_t) temp1);
if (regs.wordregs[regdx]) {
cf = 1;
of = 1;
}
else {
cf = 0;
of = 0;
}
break;

case 5: /* IMUL */
temp1 = regs.wordregs[regax];
temp2 = oper1;
if (temp1 & 0x8000) {
temp1 |= 0xFFFF0000;
}

if (temp2 & 0x8000) {
temp2 |= 0xFFFF0000;
}

temp3 = temp1 * temp2;
regs.wordregs[regax] = temp3 & 0xFFFF; /* into register ax */
regs.wordregs[regdx] = temp3 >> 16; /* into register dx */
if (regs.wordregs[regdx]) {
cf = 1;
of = 1;
}
else {
cf = 0;
of = 0;
}
break;

case 6: /* DIV */
op_div16 ( ( (uint32_t) regs.wordregs[regdx] << 16) + regs.wordregs[regax], oper1);
break;

case 7: /* DIV */
op_idiv16 ( ( (uint32_t) regs.wordregs[regdx] << 16) + regs.wordregs[regax], oper1);
break;
}
}

static void op_grp5() {
switch (reg) {
case 0: /* INC Ev */
oper2 = 1;
tempcf = cf;
op_add16();
cf = tempcf;
writerm16 (rm, res16);
break;

case 1: /* DEC Ev */
oper2 = 1;
tempcf = cf;
op_sub16();
cf = tempcf;
writerm16 (rm, res16);
break;

case 2: /* CALL Ev */
push (ip);
ip = oper1;
break;

case 3: /* CALL Mp */
push (segregs[regcs]);
push (ip);
getea (rm);
ip = (uint16_t) read86 (ea) + (uint16_t) read86 (ea + 1) * 256;
segregs[regcs] = (uint16_t) read86 (ea + 2) + (uint16_t) read86 (ea + 3) * 256;
break;

case 4: /* JMP Ev */
ip = oper1;
break;

case 5: /* JMP Mp */
getea (rm);
ip = (uint16_t) read86 (ea) + (uint16_t) read86 (ea + 1) * 256;
segregs[regcs] = (uint16_t) read86 (ea + 2) + (uint16_t) read86 (ea + 3) * 256;
break;

case 6: /* PUSH Ev */
push (oper1);
break;
}
}

void intcall86(uint8_t intnum) {
if (intnum == 0) {
fprintf(stderr, "INT 0 called, halting\n");
hltstate = 1;
return;
}
if (INTHOOKS[intnum] != NULL) {
INTHOOKS[intnum]();
return;
}
fprintf(stderr, "Unknown INT called: %x\n", intnum);
}

uint16_t makeflagsword() {
return 2 | (uint16_t) cf | ((uint16_t) pf << 2) | ((uint16_t) af << 4) | \
((uint16_t) zf << 6) | ((uint16_t) sf << 7) | ((uint16_t) tf << 8) | \
((uint16_t) ifl << 9) | ((uint16_t) df << 10) | ((uint16_t) of << 11);
}

void decodeflagsword(uint16_t x) {
cf = x & 1;
pf = (x >> 2) & 1;
af = (x >> 4) & 1;
zf = (x >> 6) & 1;
sf = (x >> 7) & 1;
tf = (x >> 8) & 1;
ifl = (x >> 9) & 1;
df = (x >> 10) & 1;
of = (x >> 11) & 1;
}

static void modregrm() {
addrbyte = getmem8(segregs[regcs], ip);
StepIP(1);
mode = addrbyte >> 6;
reg = (addrbyte >> 3) & 7;
rm = addrbyte & 7;
switch(mode)
{
case 0:
if (rm == 6) {
disp16 = getmem16(segregs[regcs], ip);
StepIP(2);
}
if (((rm == 2) || (rm == 3)) && !segoverride) {
useseg = segregs[regss];
}
break;

case 1:
disp16 = signext(getmem8(segregs[regcs], ip));
StepIP(1);
if (((rm == 2) || (rm == 3) || (rm == 6)) && !segoverride) {
useseg = segregs[regss];
}
break;

case 2:
disp16 = getmem16(segregs[regcs], ip);
StepIP(2);
if (((rm == 2) || (rm == 3) || (rm == 6)) && !segoverride) {
useseg = segregs[regss];
}
break;

default:
disp8 = 0;
disp16 = 0;
}
}

int exec86(int execloops) {
int loopcount;
uint8_t docontinue;
static uint16_t firstip;
uint16_t oldcf;

for (loopcount = 0; loopcount < execloops; loopcount++) {
if (hltstate) return 0;

reptype = 0;
segoverride = 0;
useseg = segregs[regds];
docontinue = 0;
firstip = ip;

while (!docontinue) {
segregs[regcs] = segregs[regcs] & 0xFFFF;
ip = ip & 0xFFFF;
opcode = getmem8 (segregs[regcs], ip);
StepIP (1);

switch (opcode) {
/* segment prefix check */
case 0x2E: /* segment segregs[regcs] */
useseg = segregs[regcs];
segoverride = 1;
break;

case 0x3E: /* segment segregs[regds] */
useseg = segregs[regds];
segoverride = 1;
break;

case 0x26: /* segment segregs[reges] */
useseg = segregs[reges];
segoverride = 1;
break;

case 0x36: /* segment segregs[regss] */
useseg = segregs[regss];
segoverride = 1;
break;

/* repetition prefix check */
case 0xF3: /* REP/REPE/REPZ */
reptype = 1;
break;

case 0xF2: /* REPNE/REPNZ */
reptype = 2;
break;

default:
docontinue = 1;
break;
}
}

switch (opcode) {
case 0x0: /* 00 ADD Eb Gb */
modregrm();
oper1b = readrm8 (rm);
oper2b = getreg8 (reg);
op_add8();
writerm8 (rm, res8);
break;

case 0x1: /* 01 ADD Ev Gv */
modregrm();
oper1 = readrm16 (rm);
oper2 = getreg16 (reg);
op_add16();
writerm16 (rm, res16);
break;

case 0x2: /* 02 ADD Gb Eb */
modregrm();
oper1b = getreg8 (reg);
oper2b = readrm8 (rm);
op_add8();
putreg8 (reg, res8);
break;

case 0x3: /* 03 ADD Gv Ev */
modregrm();
oper1 = getreg16 (reg);
oper2 = readrm16 (rm);
op_add16();
putreg16 (reg, res16);
break;

case 0x4: /* 04 ADD regs.byteregs[regal] Ib */
oper1b = regs.byteregs[regal];
oper2b = getmem8 (segregs[regcs], ip);
StepIP (1);
op_add8();
regs.byteregs[regal] = res8;
break;

case 0x5: /* 05 ADD eAX Iv */
oper1 = regs.wordregs[regax];
oper2 = getmem16 (segregs[regcs], ip);
StepIP (2);
op_add16();
regs.wordregs[regax] = res16;
break;

case 0x6: /* 06 PUSH segregs[reges] */
push (segregs[reges]);
break;

case 0x7: /* 07 POP segregs[reges] */
segregs[reges] = pop();
break;

case 0x8: /* 08 OR Eb Gb */
modregrm();
oper1b = readrm8 (rm);
oper2b = getreg8 (reg);
op_or8();
writerm8 (rm, res8);
break;

case 0x9: /* 09 OR Ev Gv */
modregrm();
oper1 = readrm16 (rm);
oper2 = getreg16 (reg);
op_or16();
writerm16 (rm, res16);
break;

case 0xA: /* 0A OR Gb Eb */
modregrm();
oper1b = getreg8 (reg);
oper2b = readrm8 (rm);
op_or8();
putreg8 (reg, res8);
break;

case 0xB: /* 0B OR Gv Ev */
modregrm();
oper1 = getreg16 (reg);
oper2 = readrm16 (rm);
op_or16();
putreg16 (reg, res16);
break;

case 0xC: /* 0C OR regs.byteregs[regal] Ib */
oper1b = regs.byteregs[regal];
oper2b = getmem8 (segregs[regcs], ip);
StepIP (1);
op_or8();
regs.byteregs[regal] = res8;
break;

case 0xD: /* 0D OR eAX Iv */
oper1 = regs.wordregs[regax];
oper2 = getmem16 (segregs[regcs], ip);
StepIP (2);
op_or16();
regs.wordregs[regax] = res16;
break;

case 0xE: /* 0E PUSH segregs[regcs] */
push (segregs[regcs]);
break;

case 0x10: /* 10 ADC Eb Gb */
modregrm();
oper1b = readrm8 (rm);
oper2b = getreg8 (reg);
op_adc8();
writerm8 (rm, res8);
break;

case 0x11: /* 11 ADC Ev Gv */
modregrm();
oper1 = readrm16 (rm);
oper2 = getreg16 (reg);
op_adc16();
writerm16 (rm, res16);
break;

case 0x12: /* 12 ADC Gb Eb */
modregrm();
oper1b = getreg8 (reg);
oper2b = readrm8 (rm);
op_adc8();
putreg8 (reg, res8);
break;

case 0x13: /* 13 ADC Gv Ev */
modregrm();
oper1 = getreg16 (reg);
oper2 = readrm16 (rm);
op_adc16();
putreg16 (reg, res16);
break;

case 0x14: /* 14 ADC regs.byteregs[regal] Ib */
oper1b = regs.byteregs[regal];
oper2b = getmem8 (segregs[regcs], ip);
StepIP (1);
op_adc8();
regs.byteregs[regal] = res8;
break;

case 0x15: /* 15 ADC eAX Iv */
oper1 = regs.wordregs[regax];
oper2 = getmem16 (segregs[regcs], ip);
StepIP (2);
op_adc16();
regs.wordregs[regax] = res16;
break;

case 0x16: /* 16 PUSH segregs[regss] */
push (segregs[regss]);
break;

case 0x17: /* 17 POP segregs[regss] */
segregs[regss] = pop();
break;

case 0x18: /* 18 SBB Eb Gb */
modregrm();
oper1b = readrm8 (rm);
oper2b = getreg8 (reg);
op_sbb8();
writerm8 (rm, res8);
break;

case 0x19: /* 19 SBB Ev Gv */
modregrm();
oper1 = readrm16 (rm);
oper2 = getreg16 (reg);
op_sbb16();
writerm16 (rm, res16);
break;

case 0x1A: /* 1A SBB Gb Eb */
modregrm();
oper1b = getreg8 (reg);
oper2b = readrm8 (rm);
op_sbb8();
putreg8 (reg, res8);
break;

case 0x1B: /* 1B SBB Gv Ev */
modregrm();
oper1 = getreg16 (reg);
oper2 = readrm16 (rm);
op_sbb16();
putreg16 (reg, res16);
break;

case 0x1C: /* 1C SBB regs.byteregs[regal] Ib */
oper1b = regs.byteregs[regal];
oper2b = getmem8 (segregs[regcs], ip);
StepIP (1);
op_sbb8();
regs.byteregs[regal] = res8;
break;

case 0x1D: /* 1D SBB eAX Iv */
oper1 = regs.wordregs[regax];
oper2 = getmem16 (segregs[regcs], ip);
StepIP (2);
op_sbb16();
regs.wordregs[regax] = res16;
break;

case 0x1E: /* 1E PUSH segregs[regds] */
push (segregs[regds]);
break;

case 0x1F: /* 1F POP segregs[regds] */
segregs[regds] = pop();
break;

case 0x20: /* 20 AND Eb Gb */
modregrm();
oper1b = readrm8 (rm);
oper2b = getreg8 (reg);
op_and8();
writerm8 (rm, res8);
break;

case 0x21: /* 21 AND Ev Gv */
modregrm();
oper1 = readrm16 (rm);
oper2 = getreg16 (reg);
op_and16();
writerm16 (rm, res16);
break;

case 0x22: /* 22 AND Gb Eb */
modregrm();
oper1b = getreg8 (reg);
oper2b = readrm8 (rm);
op_and8();
putreg8 (reg, res8);
break;

case 0x23: /* 23 AND Gv Ev */
modregrm();
oper1 = getreg16 (reg);
oper2 = readrm16 (rm);
op_and16();
putreg16 (reg, res16);
break;

case 0x24: /* 24 AND regs.byteregs[regal] Ib */
oper1b = regs.byteregs[regal];
oper2b = getmem8 (segregs[regcs], ip);
StepIP (1);
op_and8();
regs.byteregs[regal] = res8;
break;

case 0x25: /* 25 AND eAX Iv */
oper1 = regs.wordregs[regax];
oper2 = getmem16 (segregs[regcs], ip);
StepIP (2);
op_and16();
regs.wordregs[regax] = res16;
break;

case 0x27: /* 27 DAA */
if ( ( (regs.byteregs[regal] & 0xF) > 9) || (af == 1) ) {
oper1 = regs.byteregs[regal] + 6;
regs.byteregs[regal] = oper1 & 255;
if (oper1 & 0xFF00) {
cf = 1;
}
else {
cf = 0;
}

af = 1;
}
else {
//af = 0;
}

if ( (regs.byteregs[regal] > 0x9F) || (cf == 1) ) {
regs.byteregs[regal] = regs.byteregs[regal] + 0x60;
cf = 1;
}
else {
//cf = 0;
}

regs.byteregs[regal] = regs.byteregs[regal] & 255;
flag_szp8 (regs.byteregs[regal]);
break;

case 0x28: /* 28 SUB Eb Gb */
modregrm();
oper1b = readrm8 (rm);
oper2b = getreg8 (reg);
op_sub8();
writerm8 (rm, res8);
break;

case 0x29: /* 29 SUB Ev Gv */
modregrm();
oper1 = readrm16 (rm);
oper2 = getreg16 (reg);
op_sub16();
writerm16 (rm, res16);
break;

case 0x2A: /* 2A SUB Gb Eb */
modregrm();
oper1b = getreg8 (reg);
oper2b = readrm8 (rm);
op_sub8();
putreg8 (reg, res8);
break;

case 0x2B: /* 2B SUB Gv Ev */
modregrm();
oper1 = getreg16 (reg);
oper2 = readrm16 (rm);
op_sub16();
putreg16 (reg, res16);
break;

case 0x2C: /* 2C SUB regs.byteregs[regal] Ib */
oper1b = regs.byteregs[regal];
oper2b = getmem8 (segregs[regcs], ip);
StepIP (1);
op_sub8();
regs.byteregs[regal] = res8;
break;

case 0x2D: /* 2D SUB eAX Iv */
oper1 = regs.wordregs[regax];
oper2 = getmem16 (segregs[regcs], ip);
StepIP (2);
op_sub16();
regs.wordregs[regax] = res16;
break;

case 0x2F: /* 2F DAS */
if ( ( (regs.byteregs[regal] & 15) > 9) || (af == 1) ) {
oper1 = regs.byteregs[regal] - 6;
regs.byteregs[regal] = oper1 & 255;
if (oper1 & 0xFF00) {
cf = 1;
}
else {
cf = 0;
}

af = 1;
}
else {
af = 0;
}

if ( ( (regs.byteregs[regal] & 0xF0) > 0x90) || (cf == 1) ) {
regs.byteregs[regal] = regs.byteregs[regal] - 0x60;
cf = 1;
}
else {
cf = 0;
}

flag_szp8 (regs.byteregs[regal]);
break;

case 0x30: /* 30 XOR Eb Gb */
modregrm();
oper1b = readrm8 (rm);
oper2b = getreg8 (reg);
op_xor8();
writerm8 (rm, res8);
break;

case 0x31: /* 31 XOR Ev Gv */
modregrm();
oper1 = readrm16 (rm);
oper2 = getreg16 (reg);
op_xor16();
writerm16 (rm, res16);
break;

case 0x32: /* 32 XOR Gb Eb */
modregrm();
oper1b = getreg8 (reg);
oper2b = readrm8 (rm);
op_xor8();
putreg8 (reg, res8);
break;

case 0x33: /* 33 XOR Gv Ev */
modregrm();
oper1 = getreg16 (reg);
oper2 = readrm16 (rm);
op_xor16();
putreg16 (reg, res16);
break;

case 0x34: /* 34 XOR regs.byteregs[regal] Ib */
oper1b = regs.byteregs[regal];
oper2b = getmem8 (segregs[regcs], ip);
StepIP (1);
op_xor8();
regs.byteregs[regal] = res8;
break;

case 0x35: /* 35 XOR eAX Iv */
oper1 = regs.wordregs[regax];
oper2 = getmem16 (segregs[regcs], ip);
StepIP (2);
op_xor16();
regs.wordregs[regax] = res16;
break;

case 0x37: /* 37 AAA ASCII */
if ( ( (regs.byteregs[regal] & 0xF) > 9) || (af == 1) ) {
regs.byteregs[regal] = regs.byteregs[regal] + 6;
regs.byteregs[regah] = regs.byteregs[regah] + 1;
af = 1;
cf = 1;
}
else {
af = 0;
cf = 0;
}

regs.byteregs[regal] = regs.byteregs[regal] & 0xF;
break;

case 0x38: /* 38 CMP Eb Gb */
modregrm();
oper1b = readrm8 (rm);
oper2b = getreg8 (reg);
flag_sub8 (oper1b, oper2b);
break;

case 0x39: /* 39 CMP Ev Gv */
modregrm();
oper1 = readrm16 (rm);
oper2 = getreg16 (reg);
flag_sub16 (oper1, oper2);
break;

case 0x3A: /* 3A CMP Gb Eb */
modregrm();
oper1b = getreg8 (reg);
oper2b = readrm8 (rm);
flag_sub8 (oper1b, oper2b);
break;

case 0x3B: /* 3B CMP Gv Ev */
modregrm();
oper1 = getreg16 (reg);
oper2 = readrm16 (rm);
flag_sub16 (oper1, oper2);
break;

case 0x3C: /* 3C CMP regs.byteregs[regal] Ib */
oper1b = regs.byteregs[regal];
oper2b = getmem8 (segregs[regcs], ip);
StepIP (1);
flag_sub8 (oper1b, oper2b);
break;

case 0x3D: /* 3D CMP eAX Iv */
oper1 = regs.wordregs[regax];
oper2 = getmem16 (segregs[regcs], ip);
StepIP (2);
flag_sub16 (oper1, oper2);
break;

case 0x3F: /* 3F AAS ASCII */
if ( ( (regs.byteregs[regal] & 0xF) > 9) || (af == 1) ) {
regs.byteregs[regal] = regs.byteregs[regal] - 6;
regs.byteregs[regah] = regs.byteregs[regah] - 1;
af = 1;
cf = 1;
}
else {
af = 0;
cf = 0;
}

regs.byteregs[regal] = regs.byteregs[regal] & 0xF;
break;

case 0x40: /* 40 INC eAX */
oldcf = cf;
oper1 = regs.wordregs[regax];
oper2 = 1;
op_add16();
cf = oldcf;
regs.wordregs[regax] = res16;
break;

case 0x41: /* 41 INC eCX */
oldcf = cf;
oper1 = regs.wordregs[regcx];
oper2 = 1;
op_add16();
cf = oldcf;
regs.wordregs[regcx] = res16;
break;

case 0x42: /* 42 INC eDX */
oldcf = cf;
oper1 = regs.wordregs[regdx];
oper2 = 1;
op_add16();
cf = oldcf;
regs.wordregs[regdx] = res16;
break;

case 0x43: /* 43 INC eBX */
oldcf = cf;
oper1 = regs.wordregs[regbx];
oper2 = 1;
op_add16();
cf = oldcf;
regs.wordregs[regbx] = res16;
break;

case 0x44: /* 44 INC eSP */
oldcf = cf;
oper1 = regs.wordregs[regsp];
oper2 = 1;
op_add16();
cf = oldcf;
regs.wordregs[regsp] = res16;
break;

case 0x45: /* 45 INC eBP */
oldcf = cf;
oper1 = regs.wordregs[regbp];
oper2 = 1;
op_add16();
cf = oldcf;
regs.wordregs[regbp] = res16;
break;

case 0x46: /* 46 INC eSI */
oldcf = cf;
oper1 = regs.wordregs[regsi];
oper2 = 1;
op_add16();
cf = oldcf;
regs.wordregs[regsi] = res16;
break;

case 0x47: /* 47 INC eDI */
oldcf = cf;
oper1 = regs.wordregs[regdi];
oper2 = 1;
op_add16();
cf = oldcf;
regs.wordregs[regdi] = res16;
break;

case 0x48: /* 48 DEC eAX */
oldcf = cf;
oper1 = regs.wordregs[regax];
oper2 = 1;
op_sub16();
cf = oldcf;
regs.wordregs[regax] = res16;
break;

case 0x49: /* 49 DEC eCX */
oldcf = cf;
oper1 = regs.wordregs[regcx];
oper2 = 1;
op_sub16();
cf = oldcf;
regs.wordregs[regcx] = res16;
break;

case 0x4A: /* 4A DEC eDX */
oldcf = cf;
oper1 = regs.wordregs[regdx];
oper2 = 1;
op_sub16();
cf = oldcf;
regs.wordregs[regdx] = res16;
break;

case 0x4B: /* 4B DEC eBX */
oldcf = cf;
oper1 = regs.wordregs[regbx];
oper2 = 1;
op_sub16();
cf = oldcf;
regs.wordregs[regbx] = res16;
break;

case 0x4C: /* 4C DEC eSP */
oldcf = cf;
oper1 = regs.wordregs[regsp];
oper2 = 1;
op_sub16();
cf = oldcf;
regs.wordregs[regsp] = res16;
break;

case 0x4D: /* 4D DEC eBP */
oldcf = cf;
oper1 = regs.wordregs[regbp];
oper2 = 1;
op_sub16();
cf = oldcf;
regs.wordregs[regbp] = res16;
break;

case 0x4E: /* 4E DEC eSI */
oldcf = cf;
oper1 = regs.wordregs[regsi];
oper2 = 1;
op_sub16();
cf = oldcf;
regs.wordregs[regsi] = res16;
break;

case 0x4F: /* 4F DEC eDI */
oldcf = cf;
oper1 = regs.wordregs[regdi];
oper2 = 1;
op_sub16();
cf = oldcf;
regs.wordregs[regdi] = res16;
break;

case 0x50: /* 50 PUSH eAX */
push (regs.wordregs[regax]);
break;

case 0x51: /* 51 PUSH eCX */
push (regs.wordregs[regcx]);
break;

case 0x52: /* 52 PUSH eDX */
push (regs.wordregs[regdx]);
break;

case 0x53: /* 53 PUSH eBX */
push (regs.wordregs[regbx]);
break;

case 0x54: /* 54 PUSH eSP */
#ifdef USE_286_STYLE_PUSH_SP
push (regs.wordregs[regsp]);
#else
push (regs.wordregs[regsp] - 2);
#endif
break;

case 0x55: /* 55 PUSH eBP */
push (regs.wordregs[regbp]);
break;

case 0x56: /* 56 PUSH eSI */
push (regs.wordregs[regsi]);
break;

case 0x57: /* 57 PUSH eDI */
push (regs.wordregs[regdi]);
break;

case 0x58: /* 58 POP eAX */
regs.wordregs[regax] = pop();
break;

case 0x59: /* 59 POP eCX */
regs.wordregs[regcx] = pop();
break;

case 0x5A: /* 5A POP eDX */
regs.wordregs[regdx] = pop();
break;

case 0x5B: /* 5B POP eBX */
regs.wordregs[regbx] = pop();
break;

case 0x5C: /* 5C POP eSP */
regs.wordregs[regsp] = pop();
break;

case 0x5D: /* 5D POP eBP */
regs.wordregs[regbp] = pop();
break;

case 0x5E: /* 5E POP eSI */
regs.wordregs[regsi] = pop();
break;

case 0x5F: /* 5F POP eDI */
regs.wordregs[regdi] = pop();
break;

#ifndef CPU_8086
case 0x60: /* 60 PUSHA (80186+) */
oldsp = regs.wordregs[regsp];
push (regs.wordregs[regax]);
push (regs.wordregs[regcx]);
push (regs.wordregs[regdx]);
push (regs.wordregs[regbx]);
push (oldsp);
push (regs.wordregs[regbp]);
push (regs.wordregs[regsi]);
push (regs.wordregs[regdi]);
break;

case 0x61: /* 61 POPA (80186+) */
regs.wordregs[regdi] = pop();
regs.wordregs[regsi] = pop();
regs.wordregs[regbp] = pop();
pop();
regs.wordregs[regbx] = pop();
regs.wordregs[regdx] = pop();
regs.wordregs[regcx] = pop();
regs.wordregs[regax] = pop();
break;

case 0x62: /* 62 BOUND Gv, Ev (80186+) */
modregrm();
getea (rm);
if (signext32 (getreg16 (reg) ) < signext32 ( getmem16 (ea >> 4, ea & 15) ) ) {
intcall86 (5); //bounds check exception
}
else {
ea += 2;
if (signext32 (getreg16 (reg) ) > signext32 ( getmem16 (ea >> 4, ea & 15) ) ) {
intcall86(5); //bounds check exception
}
}
break;

case 0x68: /* 68 PUSH Iv (80186+) */
push (getmem16 (segregs[regcs], ip) );
StepIP (2);
break;

case 0x69: /* 69 IMUL Gv Ev Iv (80186+) */
modregrm();
temp1 = readrm16 (rm);
temp2 = getmem16 (segregs[regcs], ip);
StepIP (2);
if ( (temp1 & 0x8000L) == 0x8000L) {
temp1 = temp1 | 0xFFFF0000L;
}

if ( (temp2 & 0x8000L) == 0x8000L) {
temp2 = temp2 | 0xFFFF0000L;
}

temp3 = temp1 * temp2;
putreg16 (reg, temp3 & 0xFFFFL);
if (temp3 & 0xFFFF0000L) {
cf = 1;
of = 1;
}
else {
cf = 0;
of = 0;
}
break;

case 0x6A: /* 6A PUSH Ib (80186+) */
push (getmem8 (segregs[regcs], ip) );
StepIP (1);
break;

case 0x6B: /* 6B IMUL Gv Eb Ib (80186+) */
modregrm();
temp1 = readrm16 (rm);
temp2 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if ( (temp1 & 0x8000L) == 0x8000L) {
temp1 = temp1 | 0xFFFF0000L;
}

if ( (temp2 & 0x8000L) == 0x8000L) {
temp2 = temp2 | 0xFFFF0000L;
}

temp3 = temp1 * temp2;
putreg16 (reg, temp3 & 0xFFFFL);
if (temp3 & 0xFFFF0000L) {
cf = 1;
of = 1;
}
else {
cf = 0;
of = 0;
}
break;

case 0x6C: /* 6E INSB */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

putmem8 (useseg, regs.wordregs[regsi], portin (regs.wordregs[regdx]) );
if (df) {
regs.wordregs[regsi] = regs.wordregs[regsi] - 1;
regs.wordregs[regdi] = regs.wordregs[regdi] - 1;
}
else {
regs.wordregs[regsi] = regs.wordregs[regsi] + 1;
regs.wordregs[regdi] = regs.wordregs[regdi] + 1;
}

if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0x6D: /* 6F INSW */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

putmem16 (useseg, regs.wordregs[regsi], portin16 (regs.wordregs[regdx]) );
if (df) {
regs.wordregs[regsi] = regs.wordregs[regsi] - 2;
regs.wordregs[regdi] = regs.wordregs[regdi] - 2;
}
else {
regs.wordregs[regsi] = regs.wordregs[regsi] + 2;
regs.wordregs[regdi] = regs.wordregs[regdi] + 2;
}

if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0x6E: /* 6E OUTSB */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

portout (regs.wordregs[regdx], getmem8 (useseg, regs.wordregs[regsi]) );
if (df) {
regs.wordregs[regsi] = regs.wordregs[regsi] - 1;
regs.wordregs[regdi] = regs.wordregs[regdi] - 1;
}
else {
regs.wordregs[regsi] = regs.wordregs[regsi] + 1;
regs.wordregs[regdi] = regs.wordregs[regdi] + 1;
}

if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0x6F: /* 6F OUTSW */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

portout16 (regs.wordregs[regdx], getmem16 (useseg, regs.wordregs[regsi]) );
if (df) {
regs.wordregs[regsi] = regs.wordregs[regsi] - 2;
regs.wordregs[regdi] = regs.wordregs[regdi] - 2;
}
else {
regs.wordregs[regsi] = regs.wordregs[regsi] + 2;
regs.wordregs[regdi] = regs.wordregs[regdi] + 2;
}

if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;
#endif

case 0x70: /* 70 JO Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (of) {
ip = ip + temp16;
}
break;

case 0x71: /* 71 JNO Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (!of) {
ip = ip + temp16;
}
break;

case 0x72: /* 72 JB Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (cf) {
ip = ip + temp16;
}
break;

case 0x73: /* 73 JNB Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (!cf) {
ip = ip + temp16;
}
break;

case 0x74: /* 74 JZ Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (zf) {
ip = ip + temp16;
}
break;

case 0x75: /* 75 JNZ Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (!zf) {
ip = ip + temp16;
}
break;

case 0x76: /* 76 JBE Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (cf || zf) {
ip = ip + temp16;
}
break;

case 0x77: /* 77 JA Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (!cf && !zf) {
ip = ip + temp16;
}
break;

case 0x78: /* 78 JS Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (sf) {
ip = ip + temp16;
}
break;

case 0x79: /* 79 JNS Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (!sf) {
ip = ip + temp16;
}
break;

case 0x7A: /* 7A JPE Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (pf) {
ip = ip + temp16;
}
break;

case 0x7B: /* 7B JPO Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (!pf) {
ip = ip + temp16;
}
break;

case 0x7C: /* 7C JL Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (sf != of) {
ip = ip + temp16;
}
break;

case 0x7D: /* 7D JGE Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (sf == of) {
ip = ip + temp16;
}
break;

case 0x7E: /* 7E JLE Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if ( (sf != of) || zf) {
ip = ip + temp16;
}
break;

case 0x7F: /* 7F JG Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (!zf && (sf == of) ) {
ip = ip + temp16;
}
break;

case 0x80:
case 0x82: /* 80/82 GRP1 Eb Ib */
modregrm();
oper1b = readrm8 (rm);
oper2b = getmem8 (segregs[regcs], ip);
StepIP (1);
switch (reg) {
case 0:
op_add8();
break;
case 1:
op_or8();
break;
case 2:
op_adc8();
break;
case 3:
op_sbb8();
break;
case 4:
op_and8();
break;
case 5:
op_sub8();
break;
case 6:
op_xor8();
break;
case 7:
flag_sub8 (oper1b, oper2b);
break;
default:
break; /* to avoid compiler warnings */
}

if (reg < 7) {
writerm8 (rm, res8);
}
break;

case 0x81: /* 81 GRP1 Ev Iv */
case 0x83: /* 83 GRP1 Ev Ib */
modregrm();
oper1 = readrm16 (rm);
if (opcode == 0x81) {
oper2 = getmem16 (segregs[regcs], ip);
StepIP (2);
}
else {
oper2 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
}

switch (reg) {
case 0:
op_add16();
break;
case 1:
op_or16();
break;
case 2:
op_adc16();
break;
case 3:
op_sbb16();
break;
case 4:
op_and16();
break;
case 5:
op_sub16();
break;
case 6:
op_xor16();
break;
case 7:
flag_sub16 (oper1, oper2);
break;
default:
break; /* to avoid compiler warnings */
}

if (reg < 7) {
writerm16 (rm, res16);
}
break;

case 0x84: /* 84 TEST Gb Eb */
modregrm();
oper1b = getreg8 (reg);
oper2b = readrm8 (rm);
flag_log8 (oper1b & oper2b);
break;

case 0x85: /* 85 TEST Gv Ev */
modregrm();
oper1 = getreg16 (reg);
oper2 = readrm16 (rm);
flag_log16 (oper1 & oper2);
break;

case 0x86: /* 86 XCHG Gb Eb */
modregrm();
oper1b = getreg8 (reg);
putreg8 (reg, readrm8 (rm) );
writerm8 (rm, oper1b);
break;

case 0x87: /* 87 XCHG Gv Ev */
modregrm();
oper1 = getreg16 (reg);
putreg16 (reg, readrm16 (rm) );
writerm16 (rm, oper1);
break;

case 0x88: /* 88 MOV Eb Gb */
modregrm();
writerm8 (rm, getreg8 (reg) );
break;

case 0x89: /* 89 MOV Ev Gv */
modregrm();
writerm16 (rm, getreg16 (reg) );
break;

case 0x8A: /* 8A MOV Gb Eb */
modregrm();
putreg8 (reg, readrm8 (rm) );
break;

case 0x8B: /* 8B MOV Gv Ev */
modregrm();
putreg16 (reg, readrm16 (rm) );
break;

case 0x8C: /* 8C MOV Ew Sw */
modregrm();
writerm16 (rm, getsegreg (reg) );
break;

case 0x8D: /* 8D LEA Gv M */
modregrm();
getea (rm);
putreg16 (reg, ea - segbase (useseg) );
break;

case 0x8E: /* 8E MOV Sw Ew */
modregrm();
putsegreg (reg, readrm16 (rm) );
break;

case 0x8F: /* 8F POP Ev */
modregrm();
writerm16 (rm, pop() );
break;

case 0x90: /* 90 NOP */
break;

case 0x91: /* 91 XCHG eCX eAX */
oper1 = regs.wordregs[regcx];
regs.wordregs[regcx] = regs.wordregs[regax];
regs.wordregs[regax] = oper1;
break;

case 0x92: /* 92 XCHG eDX eAX */
oper1 = regs.wordregs[regdx];
regs.wordregs[regdx] = regs.wordregs[regax];
regs.wordregs[regax] = oper1;
break;

case 0x93: /* 93 XCHG eBX eAX */
oper1 = regs.wordregs[regbx];
regs.wordregs[regbx] = regs.wordregs[regax];
regs.wordregs[regax] = oper1;
break;

case 0x94: /* 94 XCHG eSP eAX */
oper1 = regs.wordregs[regsp];
regs.wordregs[regsp] = regs.wordregs[regax];
regs.wordregs[regax] = oper1;
break;

case 0x95: /* 95 XCHG eBP eAX */
oper1 = regs.wordregs[regbp];
regs.wordregs[regbp] = regs.wordregs[regax];
regs.wordregs[regax] = oper1;
break;

case 0x96: /* 96 XCHG eSI eAX */
oper1 = regs.wordregs[regsi];
regs.wordregs[regsi] = regs.wordregs[regax];
regs.wordregs[regax] = oper1;
break;

case 0x97: /* 97 XCHG eDI eAX */
oper1 = regs.wordregs[regdi];
regs.wordregs[regdi] = regs.wordregs[regax];
regs.wordregs[regax] = oper1;
break;

case 0x98: /* 98 CBW */
if ( (regs.byteregs[regal] & 0x80) == 0x80) {
regs.byteregs[regah] = 0xFF;
}
else {
regs.byteregs[regah] = 0;
}
break;

case 0x99: /* 99 CWD */
if ( (regs.byteregs[regah] & 0x80) == 0x80) {
regs.wordregs[regdx] = 0xFFFF;
}
else {
regs.wordregs[regdx] = 0;
}
break;

case 0x9A: /* 9A CALL Ap */
oper1 = getmem16 (segregs[regcs], ip);
StepIP (2);
oper2 = getmem16 (segregs[regcs], ip);
StepIP (2);
push (segregs[regcs]);
push (ip);
ip = oper1;
segregs[regcs] = oper2;
break;

case 0x9B: /* 9B WAIT */
break;

case 0x9C: /* 9C PUSHF */
push (makeflagsword() | 0xF800);
break;

case 0x9D: /* 9D POPF */
decodeflagsword (pop());
break;

case 0x9E: /* 9E SAHF */
decodeflagsword ( (makeflagsword() & 0xFF00) | regs.byteregs[regah]);
break;

case 0x9F: /* 9F LAHF */
regs.byteregs[regah] = makeflagsword() & 0xFF;
break;

case 0xA0: /* A0 MOV regs.byteregs[regal] Ob */
regs.byteregs[regal] = getmem8 (useseg, getmem16 (segregs[regcs], ip) );
StepIP (2);
break;

case 0xA1: /* A1 MOV eAX Ov */
oper1 = getmem16 (useseg, getmem16 (segregs[regcs], ip) );
StepIP (2);
regs.wordregs[regax] = oper1;
break;

case 0xA2: /* A2 MOV Ob regs.byteregs[regal] */
putmem8 (useseg, getmem16 (segregs[regcs], ip), regs.byteregs[regal]);
StepIP (2);
break;

case 0xA3: /* A3 MOV Ov eAX */
putmem16 (useseg, getmem16 (segregs[regcs], ip), regs.wordregs[regax]);
StepIP (2);
break;

case 0xA4: /* A4 MOVSB */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

putmem8 (segregs[reges], regs.wordregs[regdi], getmem8 (useseg, regs.wordregs[regsi]) );
if (df) {
regs.wordregs[regsi] = regs.wordregs[regsi] - 1;
regs.wordregs[regdi] = regs.wordregs[regdi] - 1;
}
else {
regs.wordregs[regsi] = regs.wordregs[regsi] + 1;
regs.wordregs[regdi] = regs.wordregs[regdi] + 1;
}

if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0xA5: /* A5 MOVSW */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

putmem16 (segregs[reges], regs.wordregs[regdi], getmem16 (useseg, regs.wordregs[regsi]) );
if (df) {
regs.wordregs[regsi] = regs.wordregs[regsi] - 2;
regs.wordregs[regdi] = regs.wordregs[regdi] - 2;
}
else {
regs.wordregs[regsi] = regs.wordregs[regsi] + 2;
regs.wordregs[regdi] = regs.wordregs[regdi] + 2;
}

if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0xA6: /* A6 CMPSB */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

oper1b = getmem8 (useseg, regs.wordregs[regsi]);
oper2b = getmem8 (segregs[reges], regs.wordregs[regdi]);
if (df) {
regs.wordregs[regsi] = regs.wordregs[regsi] - 1;
regs.wordregs[regdi] = regs.wordregs[regdi] - 1;
}
else {
regs.wordregs[regsi] = regs.wordregs[regsi] + 1;
regs.wordregs[regdi] = regs.wordregs[regdi] + 1;
}

flag_sub8 (oper1b, oper2b);
if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

if ( (reptype == 1) && !zf) {
break;
}
else if ( (reptype == 2) && (zf == 1) ) {
break;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0xA7: /* A7 CMPSW */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

oper1 = getmem16 (useseg,regs.wordregs[regsi]);
oper2 = getmem16 (segregs[reges], regs.wordregs[regdi]);
if (df) {
regs.wordregs[regsi] = regs.wordregs[regsi] - 2;
regs.wordregs[regdi] = regs.wordregs[regdi] - 2;
}
else {
regs.wordregs[regsi] = regs.wordregs[regsi] + 2;
regs.wordregs[regdi] = regs.wordregs[regdi] + 2;
}

flag_sub16 (oper1, oper2);
if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

if ( (reptype == 1) && !zf) {
break;
}

if ( (reptype == 2) && (zf == 1) ) {
break;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0xA8: /* A8 TEST regs.byteregs[regal] Ib */
oper1b = regs.byteregs[regal];
oper2b = getmem8 (segregs[regcs], ip);
StepIP (1);
flag_log8 (oper1b & oper2b);
break;

case 0xA9: /* A9 TEST eAX Iv */
oper1 = regs.wordregs[regax];
oper2 = getmem16 (segregs[regcs], ip);
StepIP (2);
flag_log16 (oper1 & oper2);
break;

case 0xAA: /* AA STOSB */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

putmem8 (segregs[reges], regs.wordregs[regdi], regs.byteregs[regal]);
if (df) {
regs.wordregs[regdi] = regs.wordregs[regdi] - 1;
}
else {
regs.wordregs[regdi] = regs.wordregs[regdi] + 1;
}

if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0xAB: /* AB STOSW */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

putmem16 (segregs[reges], regs.wordregs[regdi], regs.wordregs[regax]);
if (df) {
regs.wordregs[regdi] = regs.wordregs[regdi] - 2;
}
else {
regs.wordregs[regdi] = regs.wordregs[regdi] + 2;
}

if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0xAC: /* AC LODSB */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

regs.byteregs[regal] = getmem8 (useseg, regs.wordregs[regsi]);
if (df) {
regs.wordregs[regsi] = regs.wordregs[regsi] - 1;
}
else {
regs.wordregs[regsi] = regs.wordregs[regsi] + 1;
}

if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0xAD: /* AD LODSW */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

oper1 = getmem16 (useseg, regs.wordregs[regsi]);
regs.wordregs[regax] = oper1;
if (df) {
regs.wordregs[regsi] = regs.wordregs[regsi] - 2;
}
else {
regs.wordregs[regsi] = regs.wordregs[regsi] + 2;
}

if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0xAE: /* AE SCASB */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

oper1b = regs.byteregs[regal];
oper2b = getmem8 (segregs[reges], regs.wordregs[regdi]);
flag_sub8 (oper1b, oper2b);
if (df) {
regs.wordregs[regdi] = regs.wordregs[regdi] - 1;
}
else {
regs.wordregs[regdi] = regs.wordregs[regdi] + 1;
}

if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

if ( (reptype == 1) && !zf) {
break;
}
else if ( (reptype == 2) && (zf == 1) ) {
break;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0xAF: /* AF SCASW */
if (reptype && (regs.wordregs[regcx] == 0) ) {
break;
}

oper1 = regs.wordregs[regax];
oper2 = getmem16 (segregs[reges], regs.wordregs[regdi]);
flag_sub16 (oper1, oper2);
if (df) {
regs.wordregs[regdi] = regs.wordregs[regdi] - 2;
}
else {
regs.wordregs[regdi] = regs.wordregs[regdi] + 2;
}

if (reptype) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
}

if ( (reptype == 1) && !zf) {
break;
}
else if ( (reptype == 2) & (zf == 1) ) {
break;
}

loopcount++;
if (!reptype) {
break;
}

ip = firstip;
break;

case 0xB0: /* B0 MOV regs.byteregs[regal] Ib */
regs.byteregs[regal] = getmem8 (segregs[regcs], ip);
StepIP (1);
break;

case 0xB1: /* B1 MOV regs.byteregs[regcl] Ib */
regs.byteregs[regcl] = getmem8 (segregs[regcs], ip);
StepIP (1);
break;

case 0xB2: /* B2 MOV regs.byteregs[regdl] Ib */
regs.byteregs[regdl] = getmem8 (segregs[regcs], ip);
StepIP (1);
break;

case 0xB3: /* B3 MOV regs.byteregs[regbl] Ib */
regs.byteregs[regbl] = getmem8 (segregs[regcs], ip);
StepIP (1);
break;

case 0xB4: /* B4 MOV regs.byteregs[regah] Ib */
regs.byteregs[regah] = getmem8 (segregs[regcs], ip);
StepIP (1);
break;

case 0xB5: /* B5 MOV regs.byteregs[regch] Ib */
regs.byteregs[regch] = getmem8 (segregs[regcs], ip);
StepIP (1);
break;

case 0xB6: /* B6 MOV regs.byteregs[regdh] Ib */
regs.byteregs[regdh] = getmem8 (segregs[regcs], ip);
StepIP (1);
break;

case 0xB7: /* B7 MOV regs.byteregs[regbh] Ib */
regs.byteregs[regbh] = getmem8 (segregs[regcs], ip);
StepIP (1);
break;

case 0xB8: /* B8 MOV eAX Iv */
oper1 = getmem16 (segregs[regcs], ip);
StepIP (2);
regs.wordregs[regax] = oper1;
break;

case 0xB9: /* B9 MOV eCX Iv */
oper1 = getmem16 (segregs[regcs], ip);
StepIP (2);
regs.wordregs[regcx] = oper1;
break;

case 0xBA: /* BA MOV eDX Iv */
oper1 = getmem16 (segregs[regcs], ip);
StepIP (2);
regs.wordregs[regdx] = oper1;
break;

case 0xBB: /* BB MOV eBX Iv */
oper1 = getmem16 (segregs[regcs], ip);
StepIP (2);
regs.wordregs[regbx] = oper1;
break;

case 0xBC: /* BC MOV eSP Iv */
regs.wordregs[regsp] = getmem16 (segregs[regcs], ip);
StepIP (2);
break;

case 0xBD: /* BD MOV eBP Iv */
regs.wordregs[regbp] = getmem16 (segregs[regcs], ip);
StepIP (2);
break;

case 0xBE: /* BE MOV eSI Iv */
regs.wordregs[regsi] = getmem16 (segregs[regcs], ip);
StepIP (2);
break;

case 0xBF: /* BF MOV eDI Iv */
regs.wordregs[regdi] = getmem16 (segregs[regcs], ip);
StepIP (2);
break;

case 0xC0: /* C0 GRP2 byte imm8 (80186+) */
modregrm();
oper1b = readrm8 (rm);
oper2b = getmem8 (segregs[regcs], ip);
StepIP (1);
writerm8 (rm, op_grp2_8 (oper2b) );
break;

case 0xC1: /* C1 GRP2 word imm8 (80186+) */
modregrm();
oper1 = readrm16 (rm);
oper2 = getmem8 (segregs[regcs], ip);
StepIP (1);
writerm16 (rm, op_grp2_16 ( (uint8_t) oper2) );
break;

case 0xC2: /* C2 RET Iw */
oper1 = getmem16 (segregs[regcs], ip);
ip = pop();
regs.wordregs[regsp] = regs.wordregs[regsp] + oper1;
break;

case 0xC3: /* C3 RET */
ip = pop();
break;

case 0xC4: /* C4 LES Gv Mp */
modregrm();
getea (rm);
putreg16 (reg, read86 (ea) + read86 (ea + 1) * 256);
segregs[reges] = read86 (ea + 2) + read86 (ea + 3) * 256;
break;

case 0xC5: /* C5 LDS Gv Mp */
modregrm();
getea (rm);
putreg16 (reg, read86 (ea) + read86 (ea + 1) * 256);
segregs[regds] = read86 (ea + 2) + read86 (ea + 3) * 256;
break;

case 0xC6: /* C6 MOV Eb Ib */
modregrm();
writerm8 (rm, getmem8 (segregs[regcs], ip) );
StepIP (1);
break;

case 0xC7: /* C7 MOV Ev Iv */
modregrm();
writerm16 (rm, getmem16 (segregs[regcs], ip) );
StepIP (2);
break;

case 0xC8: /* C8 ENTER (80186+) */
stacksize = getmem16 (segregs[regcs], ip);
StepIP (2);
nestlev = getmem8 (segregs[regcs], ip);
StepIP (1);
push (regs.wordregs[regbp]);
frametemp = regs.wordregs[regsp];
if (nestlev) {
for (temp16 = 1; temp16 < nestlev; temp16++) {
regs.wordregs[regbp] = regs.wordregs[regbp] - 2;
push (regs.wordregs[regbp]);
}

push (regs.wordregs[regsp]);
}

regs.wordregs[regbp] = frametemp;
regs.wordregs[regsp] = regs.wordregs[regbp] - stacksize;

break;

case 0xC9: /* C9 LEAVE (80186+) */
regs.wordregs[regsp] = regs.wordregs[regbp];
regs.wordregs[regbp] = pop();
break;

case 0xCA: /* CA RETF Iw */
oper1 = getmem16 (segregs[regcs], ip);
ip = pop();
segregs[regcs] = pop();
regs.wordregs[regsp] = regs.wordregs[regsp] + oper1;
break;

case 0xCB: /* CB RETF */
ip = pop();;
segregs[regcs] = pop();
break;

case 0xCC: /* CC INT 3 */
intcall86 (3);
break;

case 0xCD: /* CD INT Ib */
oper1b = getmem8 (segregs[regcs], ip);
StepIP (1);
intcall86 (oper1b);
break;

case 0xCE: /* CE INTO */
if (of) {
intcall86 (4);
}
break;

case 0xCF: /* CF IRET */
ip = pop();
segregs[regcs] = pop();
decodeflagsword (pop() );

/*
* if (net.enabled) net.canrecv = 1;
*/
break;

case 0xD0: /* D0 GRP2 Eb 1 */
modregrm();
oper1b = readrm8 (rm);
writerm8 (rm, op_grp2_8 (1) );
break;

case 0xD1: /* D1 GRP2 Ev 1 */
modregrm();
oper1 = readrm16 (rm);
writerm16 (rm, op_grp2_16 (1) );
break;

case 0xD2: /* D2 GRP2 Eb regs.byteregs[regcl] */
modregrm();
oper1b = readrm8 (rm);
writerm8 (rm, op_grp2_8 (regs.byteregs[regcl]) );
break;

case 0xD3: /* D3 GRP2 Ev regs.byteregs[regcl] */
modregrm();
oper1 = readrm16 (rm);
writerm16 (rm, op_grp2_16 (regs.byteregs[regcl]) );
break;

case 0xD4: /* D4 AAM I0 */
oper1 = getmem8 (segregs[regcs], ip);
StepIP (1);
if (!oper1) {
intcall86 (0);
break;
} /* division by zero */

regs.byteregs[regah] = (regs.byteregs[regal] / oper1) & 255;
regs.byteregs[regal] = (regs.byteregs[regal] % oper1) & 255;
flag_szp16 (regs.wordregs[regax]);
break;

case 0xD5: /* D5 AAD I0 */
oper1 = getmem8 (segregs[regcs], ip);
StepIP (1);
regs.byteregs[regal] = (regs.byteregs[regah] * oper1 + regs.byteregs[regal]) & 255;
regs.byteregs[regah] = 0;
flag_szp16 (regs.byteregs[regah] * oper1 + regs.byteregs[regal]);
sf = 0;
break;

case 0xD6: /* D6 XLAT on V20/V30, SALC on 8086/8088 */
case 0xD7: /* D7 XLAT */
regs.byteregs[regal] = read86(useseg * 16 + (regs.wordregs[regbx]) + regs.byteregs[regal]);
break;

case 0xD8:
case 0xD9:
case 0xDA:
case 0xDB:
case 0xDC:
case 0xDE:
case 0xDD:
case 0xDF: /* escape to x87 FPU (unsupported) */
modregrm();
break;

case 0xE0: /* E0 LOOPNZ Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
if ( (regs.wordregs[regcx]) && !zf) {
ip = ip + temp16;
}
break;

case 0xE1: /* E1 LOOPZ Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
if (regs.wordregs[regcx] && (zf == 1) ) {
ip = ip + temp16;
}
break;

case 0xE2: /* E2 LOOP Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
if (regs.wordregs[regcx]) {
ip = ip + temp16;
}
break;

case 0xE3: /* E3 JCXZ Jb */
temp16 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
if (!regs.wordregs[regcx]) {
ip = ip + temp16;
}
break;

case 0xE4: /* E4 IN regs.byteregs[regal] Ib */
oper1b = getmem8 (segregs[regcs], ip);
StepIP (1);
regs.byteregs[regal] = (uint8_t) portin (oper1b);
break;

case 0xE5: /* E5 IN eAX Ib */
oper1b = getmem8 (segregs[regcs], ip);
StepIP (1);
regs.wordregs[regax] = portin16 (oper1b);
break;

case 0xE6: /* E6 OUT Ib regs.byteregs[regal] */
oper1b = getmem8 (segregs[regcs], ip);
StepIP (1);
portout (oper1b, regs.byteregs[regal]);
break;

case 0xE7: /* E7 OUT Ib eAX */
oper1b = getmem8 (segregs[regcs], ip);
StepIP (1);
portout16 (oper1b, regs.wordregs[regax]);
break;

case 0xE8: /* E8 CALL Jv */
oper1 = getmem16 (segregs[regcs], ip);
StepIP (2);
push (ip);
ip = ip + oper1;
break;

case 0xE9: /* E9 JMP Jv */
oper1 = getmem16 (segregs[regcs], ip);
StepIP (2);
ip = ip + oper1;
break;

case 0xEA: /* EA JMP Ap */
oper1 = getmem16 (segregs[regcs], ip);
StepIP (2);
oper2 = getmem16 (segregs[regcs], ip);
ip = oper1;
segregs[regcs] = oper2;
break;

case 0xEB: /* EB JMP Jb */
oper1 = signext (getmem8 (segregs[regcs], ip) );
StepIP (1);
ip = ip + oper1;
break;

case 0xEC: /* EC IN regs.byteregs[regal] regdx */
oper1 = regs.wordregs[regdx];
regs.byteregs[regal] = (uint8_t) portin (oper1);
break;

case 0xED: /* ED IN eAX regdx */
oper1 = regs.wordregs[regdx];
regs.wordregs[regax] = portin16 (oper1);
break;

case 0xEE: /* EE OUT regdx regs.byteregs[regal] */
oper1 = regs.wordregs[regdx];
portout (oper1, regs.byteregs[regal]);
break;

case 0xEF: /* EF OUT regdx eAX */
oper1 = regs.wordregs[regdx];
portout16 (oper1, regs.wordregs[regax]);
break;

case 0xF0: /* F0 LOCK */
break;

case 0xF4: /* F4 HLT */
hltstate = 1;
break;

case 0xF5: /* F5 CMC */
if (!cf) {
cf = 1;
}
else {
cf = 0;
}
break;

case 0xF6: /* F6 GRP3a Eb */
modregrm();
oper1b = readrm8 (rm);
op_grp3_8();
if ( (reg > 1) && (reg < 4) ) {
writerm8 (rm, res8);
}
break;

case 0xF7: /* F7 GRP3b Ev */
modregrm();
oper1 = readrm16 (rm);
op_grp3_16();
if ( (reg > 1) && (reg < 4) ) {
writerm16 (rm, res16);
}
break;

case 0xF8: /* F8 CLC */
cf = 0;
break;

case 0xF9: /* F9 STC */
cf = 1;
break;

case 0xFA: /* FA CLI */
ifl = 0;
break;

case 0xFB: /* FB STI */
ifl = 1;
break;

case 0xFC: /* FC CLD */
df = 0;
break;

case 0xFD: /* FD STD */
df = 1;
break;

case 0xFE: /* FE GRP4 Eb */
modregrm();
oper1b = readrm8 (rm);
oper2b = 1;
if (!reg) {
tempcf = cf;
res8 = oper1b + oper2b;
flag_add8 (oper1b, oper2b);
cf = tempcf;
writerm8 (rm, res8);
}
else {
tempcf = cf;
res8 = oper1b - oper2b;
flag_sub8 (oper1b, oper2b);
cf = tempcf;
writerm8 (rm, res8);
}
break;

case 0xFF: /* FF GRP5 Ev */
modregrm();
oper1 = readrm16 (rm);
op_grp5();
break;

default:
intcall86 (6); /* trip invalid opcode exception (this occurs on the 80186+, 8086/8088 CPUs treat them as NOPs. */
/* technically they aren't exactly like NOPs in most cases, but for our pursoses, that's accurate enough. */
break;
}
}
return 1;
}

void reset86(uint16_t startip) {
segregs[regcs] = 0;
ip = startip;
hltstate = 0;
}