void
bx_cpu_c::SUB_EbIb(BxInstruction_t *i)
{
Bit8u op2_8, op1_8, diff_8;
op2_8 = i->Ib;
/* op1_8 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);
}
diff_8 = op1_8 - op2_8;
/* now write diff back to destination */
if (i->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, diff_8);
}
else {
write_RMW_virtual_byte(diff_8);
}
SET_FLAGS_OSZAPC_8(op1_8, op2_8, diff_8, BX_INSTR_SUB8);
}
void
bx_cpu_c::DEC_Eb(BxInstruction_t *i)
{
Bit8u op1_8;
/* op1_8 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);
}
op1_8--;
/* now write sum back to destination */
if (i->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, op1_8);
}
else {
write_RMW_virtual_byte(op1_8);
}
SET_FLAGS_OSZAP_8(0, 0, op1_8, BX_INSTR_DEC8);
}
void
bx_cpu_c::SBB_EbGb(BxInstruction_t *i)
{
Bit8u op2_8, op1_8, diff_8;
Boolean temp_CF;
temp_CF = get_CF();
/* op2 is a register, i->rm_addr is an index of a register */
op2_8 = BX_READ_8BIT_REG(i->nnn);
/* op1_8 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);
}
diff_8 = op1_8 - (op2_8 + temp_CF);
/* now write diff back to destination */
if (i->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, diff_8);
}
else {
write_RMW_virtual_byte(diff_8);
}
SET_FLAGS_OSZAPC_8_CF(op1_8, op2_8, diff_8, BX_INSTR_SBB8,
temp_CF);
}
void
bx_cpu_c::ADC_EbIb(BxInstruction_t *i)
{
Bit8u op2, op1, sum;
Boolean temp_CF;
temp_CF = get_CF();
op2 = i->Ib;
/* op1 is a register or memory reference */
if (i->mod == 0xc0) {
op1 = BX_READ_8BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg, i->rm_addr, &op1);
}
sum = op1 + op2 + temp_CF;
/* now write sum back to destination */
if (i->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, sum);
}
else {
write_RMW_virtual_byte(sum);
}
SET_FLAGS_OSZAPC_8_CF(op1, op2, sum, BX_INSTR_ADC8,
temp_CF);
}
void
bx_cpu_c::ADD_EbGb(BxInstruction_t *i)
{
Bit8u op2, op1, sum;
/* op2 is a register, i->rm_addr is an index of a register */
op2 = BX_READ_8BIT_REG(i->nnn);
/* op1 is a register or memory reference */
if (i->mod == 0xc0) {
op1 = BX_READ_8BIT_REG(i->rm);
}
else {
read_RMW_virtual_byte(i->seg, i->rm_addr, &op1);
}
sum = op1 + op2;
/* now write sum back to destination */
if (i->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, sum);
}
else {
write_RMW_virtual_byte(sum);
}
SET_FLAGS_OSZAPC_8(op1, op2, sum, BX_INSTR_ADD8);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::DEC_EbM(bxInstruction_c *i)
{
bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
Bit32u op1_8 = read_RMW_virtual_byte(i->seg(), eaddr);
op1_8--;
write_RMW_virtual_byte(op1_8);
SET_FLAGS_OSZAP_SUB_8(op1_8 + 1, 0, op1_8);
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::SBB_EbIbM(bxInstruction_c *i)
{
bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
Bit32u op1_8 = read_RMW_virtual_byte(i->seg(), eaddr);
Bit32u op2_8 = i->Ib();
Bit32u diff_8 = op1_8 - (op2_8 + getB_CF());
write_RMW_virtual_byte(diff_8);
SET_FLAGS_OSZAPC_SUB_8(op1_8, op2_8, diff_8);
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::ADC_EbGbM(bxInstruction_c *i)
{
bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
Bit32u op1 = read_RMW_virtual_byte(i->seg(), eaddr);
Bit32u op2 = BX_READ_8BIT_REGx(i->nnn(), i->extend8bitL());
Bit32u sum = op1 + op2 + getB_CF();
write_RMW_virtual_byte(sum);
SET_FLAGS_OSZAPC_ADD_8(op1, op2, sum);
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::ADD_EbIbM(bxInstruction_c *i)
{
bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
Bit32u op1 = read_RMW_virtual_byte(i->seg(), eaddr);
Bit32u op2 = i->Ib();
Bit32u sum = op1 + op2;
write_RMW_virtual_byte(sum);
SET_FLAGS_OSZAPC_ADD_8(op1, op2, sum);
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::SUB_EbGbM(bxInstruction_c *i)
{
bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
Bit32u op1_8 = read_RMW_virtual_byte(i->seg(), eaddr);
Bit32u op2_8 = BX_READ_8BIT_REGx(i->nnn(), i->extend8bitL());
Bit32u diff_8 = op1_8 - op2_8;
write_RMW_virtual_byte(diff_8);
SET_FLAGS_OSZAPC_SUB_8(op1_8, op2_8, diff_8);
BX_NEXT_INSTR(i);
}
void
bx_cpu_c::XADD_EbGb(BxInstruction_t *i)
{
#if (BX_CPU_LEVEL >= 4) || (BX_CPU_LEVEL_HACKED >= 4)
Bit8u op2, op1, sum;
/* XADD dst(r/m8), src(r8)
* temp <-- src + dst | sum = op2 + op1
* src <-- dst | op2 = op1
* dst <-- tmp | op1 = sum
*/
/* op2 is a register, i->rm_addr is an index of a register */
op2 = BX_READ_8BIT_REG(i->nnn);
/* op1 is a register or memory reference */
if (i->mod == 0xc0) {
op1 = BX_READ_8BIT_REG(i->rm);
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg, i->rm_addr, &op1);
}
sum = op1 + op2;
/* now write sum back to destination */
if (i->mod == 0xc0) {
// and write destination into source
// Note: if both op1 & op2 are registers, the last one written
// should be the sum, as op1 & op2 may be the same register.
// For example: XADD AL, AL
BX_WRITE_8BIT_REG(i->nnn, op1);
BX_WRITE_8BIT_REG(i->rm, sum);
}
else {
write_RMW_virtual_byte(sum);
/* and write destination into source */
BX_WRITE_8BIT_REG(i->nnn, op1);
}
SET_FLAGS_OSZAPC_8(op1, op2, sum, BX_INSTR_XADD8);
#else
BX_PANIC(("XADD_EbGb: not supported on < 80486"));
#endif
}
void
bx_cpu_c::CMPXCHG_EbGb(BxInstruction_t *i)
{
#if (BX_CPU_LEVEL >= 4) || (BX_CPU_LEVEL_HACKED >= 4)
Bit8u op2_8, op1_8, diff_8;
/* op1_8 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);
}
diff_8 = AL - op1_8;
SET_FLAGS_OSZAPC_8(AL, op1_8, diff_8, BX_INSTR_CMP8);
if (diff_8 == 0) { // if accumulator == dest
// ZF = 1
set_ZF(1);
// dest <-- src
op2_8 = BX_READ_8BIT_REG(i->nnn);
if (i->mod == 0xc0) {
BX_WRITE_8BIT_REG(i->rm, op2_8);
}
else {
write_RMW_virtual_byte(op2_8);
}
}
else {
// ZF = 0
set_ZF(0);
// accumulator <-- dest
AL = op1_8;
}
#else
BX_PANIC(("CMPXCHG_EbGb:"));
#endif
}
void BX_CPU_C::XCHG_EbGb(bxInstruction_c *i)
{
Bit8u op2, op1;
op2 = BX_READ_8BIT_REGx(i->nnn(), i->extend8bitL());
/* op1 is a register or memory reference */
if (i->modC0()) {
op1 = BX_READ_8BIT_REGx(i->rm(), i->extend8bitL());
BX_WRITE_8BIT_REGx(i->rm(), i->extend8bitL(), op2);
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg(), RMAddr(i), &op1);
write_RMW_virtual_byte(op2);
}
BX_WRITE_8BIT_REGx(i->nnn(), i->extend8bitL(), op1);
}
void
bx_cpu_c::XCHG_EbGb(BxInstruction_t *i)
{
Bit8u op2, op1;
/* op2 is a register, op2_addr is an index of a register */
op2 = BX_READ_8BIT_REG(i->nnn);
/* op1 is a register or memory reference */
if (i->mod == 0xc0) {
op1 = BX_READ_8BIT_REG(i->rm);
BX_WRITE_8BIT_REG(i->rm, op2);
}
else {
/* pointer, segment address pair */
read_RMW_virtual_byte(i->seg, i->rm_addr, &op1);
write_RMW_virtual_byte(op2);
}
BX_WRITE_8BIT_REG(i->nnn, op1);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::CMPXCHG_EbGbM(bxInstruction_c *i)
{
bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
Bit32u op1_8 = read_RMW_virtual_byte(i->seg(), eaddr);
Bit32u diff_8 = AL - op1_8;
SET_FLAGS_OSZAPC_SUB_8(AL, op1_8, diff_8);
if (diff_8 == 0) { // if accumulator == dest
// dest <-- src
Bit32u op2_8 = BX_READ_8BIT_REGx(i->nnn(), i->extend8bitL());
write_RMW_virtual_byte(op2_8);
}
else {
// accumulator <-- dest
AL = op1_8;
}
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::XADD_EbGbM(bxInstruction_c *i)
{
/* XADD dst(r/m8), src(r8)
* temp <-- src + dst | sum = op2 + op1
* src <-- dst | op2 = op1
* dst <-- tmp | op1 = sum
*/
bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
Bit32u op1 = read_RMW_virtual_byte(i->seg(), eaddr);
Bit32u op2 = BX_READ_8BIT_REGx(i->nnn(), i->extend8bitL());
Bit32u sum = op1 + op2;
write_RMW_virtual_byte(sum);
/* and write destination into source */
BX_WRITE_8BIT_REGx(i->nnn(), i->extend8bitL(), op1);
SET_FLAGS_OSZAPC_ADD_8(op1, op2, sum);
BX_NEXT_INSTR(i);
}