bsnes/higan/processor/m68k/instructions.cpp

1174 lines
33 KiB
C++

auto M68K::testCondition(uint4 condition) -> bool {
switch(condition) {
case 0: return true; //T
case 1: return false; //F
case 2: return !r.c && !r.z; //HI
case 3: return r.c || r.z; //LS
case 4: return !r.c; //CC,HS
case 5: return r.c; //CS,LO
case 6: return !r.z; //NE
case 7: return r.z; //EQ
case 8: return !r.v; //VC
case 9: return r.v; //VS
case 10: return !r.n; //PL
case 11: return r.n; //MI
case 12: return r.n == r.v; //GE
case 13: return r.n != r.v; //LT
case 14: return r.n == r.v && !r.z; //GT
case 15: return r.n != r.v || r.z; //LE
}
unreachable;
}
//
template<> auto M68K::bytes<Byte>() -> uint { return 1; }
template<> auto M68K::bytes<Word>() -> uint { return 2; }
template<> auto M68K::bytes<Long>() -> uint { return 4; }
template<> auto M68K::bits<Byte>() -> uint { return 8; }
template<> auto M68K::bits<Word>() -> uint { return 16; }
template<> auto M68K::bits<Long>() -> uint { return 32; }
template<uint Size> auto M68K::lsb() -> uint32 { return 1; }
template<> auto M68K::msb<Byte>() -> uint32 { return 0x80; }
template<> auto M68K::msb<Word>() -> uint32 { return 0x8000; }
template<> auto M68K::msb<Long>() -> uint32 { return 0x80000000; }
template<> auto M68K::mask<Byte>() -> uint32 { return 0xff; }
template<> auto M68K::mask<Word>() -> uint32 { return 0xffff; }
template<> auto M68K::mask<Long>() -> uint32 { return 0xffffffff; }
template<> auto M68K::clip<Byte>(uint32 data) -> uint32 { return data & 0xff; }
template<> auto M68K::clip<Word>(uint32 data) -> uint32 { return data & 0xffff; }
template<> auto M68K::clip<Long>(uint32 data) -> uint32 { return data & 0xffffffff; }
template<> auto M68K::sign<Byte>(uint32 data) -> int32 { return (int8)data; }
template<> auto M68K::sign<Word>(uint32 data) -> int32 { return (int16)data; }
template<> auto M68K::sign<Long>(uint32 data) -> int32 { return (int32)data; }
//
auto M68K::instructionABCD(EffectiveAddress with, EffectiveAddress from) -> void {
auto source = read<Byte>(from);
auto target = read<Byte, Hold>(with);
auto result = source + target + r.x;
bool c = false;
bool v = false;
if(((target ^ source ^ result) & 0x10) || (result & 0x0f) >= 0x0a) {
auto previous = result;
result += 0x06;
v |= ((~previous & 0x80) & (result & 0x80));
}
if(result >= 0xa0) {
auto previous = result;
result += 0x60;
c = true;
v |= ((~previous & 0x80) & (result & 0x80));
}
write<Byte>(with, result);
r.c = c;
r.v = v;
r.z = clip<Byte>(result) ? 0 : r.z;
r.n = sign<Byte>(result) < 0;
r.x = r.c;
}
template<uint Size, bool Extend> auto M68K::ADD(uint32 source, uint32 target) -> uint32 {
auto result = (uint64)source + target;
if(Extend) result += r.x;
r.c = sign<Size>(result >> 1) < 0;
r.v = sign<Size>(~(target ^ source) & (target ^ result)) < 0;
r.z = clip<Size>(result) ? 0 : (Extend ? r.z : 1);
r.n = sign<Size>(result) < 0;
r.x = r.c;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionADD(EffectiveAddress from, DataRegister with) -> void {
auto source = read<Size>(from);
auto target = read<Size>(with);
auto result = ADD<Size>(source, target);
write<Size>(with, result);
}
template<uint Size> auto M68K::instructionADD(DataRegister from, EffectiveAddress with) -> void {
auto source = read<Size>(from);
auto target = read<Size, Hold>(with);
auto result = ADD<Size>(source, target);
write<Size>(with, result);
}
template<uint Size> auto M68K::instructionADDA(AddressRegister ar, EffectiveAddress ea) -> void {
auto source = sign<Size>(read<Size>(ea));
auto target = read<Long>(ar);
write<Long>(ar, source + target);
}
template<uint Size> auto M68K::instructionADDI(EffectiveAddress modify) -> void {
auto source = readPC<Size>();
auto target = read<Size, Hold>(modify);
auto result = ADD<Size>(source, target);
write<Size>(modify, result);
}
template<uint Size> auto M68K::instructionADDQ(uint4 immediate, EffectiveAddress with) -> void {
auto source = immediate;
auto target = read<Size, Hold>(with);
auto result = ADD<Size>(source, target);
write<Size>(with, result);
}
//Size is ignored: always uses Long
template<uint Size> auto M68K::instructionADDQ(uint4 immediate, AddressRegister with) -> void {
auto result = read<Long>(with) + immediate;
write<Long>(with, result);
}
template<uint Size> auto M68K::instructionADDX(EffectiveAddress with, EffectiveAddress from) -> void {
auto source = read<Size>(from);
auto target = read<Size, Hold>(with);
auto result = ADD<Size, Extend>(source, target);
write<Size>(with, result);
}
template<uint Size> auto M68K::AND(uint32 source, uint32 target) -> uint32 {
uint32 result = target & source;
r.c = 0;
r.v = 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionAND(EffectiveAddress from, DataRegister with) -> void {
auto source = read<Size>(from);
auto target = read<Size>(with);
auto result = AND<Size>(source, target);
write<Size>(with, result);
}
template<uint Size> auto M68K::instructionAND(DataRegister from, EffectiveAddress with) -> void {
auto source = read<Size>(from);
auto target = read<Size, Hold>(with);
auto result = AND<Size>(source, target);
write<Size>(with, result);
}
template<uint Size> auto M68K::instructionANDI(EffectiveAddress with) -> void {
auto source = readPC<Size>();
auto target = read<Size, Hold>(with);
auto result = AND<Size>(source, target);
write<Size>(with, result);
}
auto M68K::instructionANDI_TO_CCR() -> void {
auto data = readPC<Word>();
writeCCR(readCCR() & data);
}
auto M68K::instructionANDI_TO_SR() -> void {
if(!supervisor()) return;
auto data = readPC<Word>();
writeSR(readSR() & data);
}
template<uint Size> auto M68K::ASL(uint32 result, uint shift) -> uint32 {
bool carry = false;
uint32 overflow = 0;
for(auto _ : range(shift)) {
carry = result & msb<Size>();
uint32 before = result;
result <<= 1;
overflow |= before ^ result;
}
r.c = carry;
r.v = sign<Size>(overflow) < 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
if(shift) r.x = r.c;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionASL(uint4 shift, DataRegister modify) -> void {
auto result = ASL<Size>(read<Size>(modify), shift);
write<Size>(modify, result);
}
template<uint Size> auto M68K::instructionASL(DataRegister shift, DataRegister modify) -> void {
auto count = read<Long>(shift) & 63;
auto result = ASL<Size>(read<Size>(modify), count);
write<Size>(modify, result);
}
auto M68K::instructionASL(EffectiveAddress modify) -> void {
auto result = ASL<Word>(read<Word, Hold>(modify), 1);
write<Word>(modify, result);
}
template<uint Size> auto M68K::ASR(uint32 result, uint shift) -> uint32 {
bool carry = false;
uint32 overflow = 0;
for(auto _ : range(shift)) {
carry = result & lsb<Size>();
uint32 before = result;
result = sign<Size>(result) >> 1;
overflow |= before ^ result;
}
r.c = carry;
r.v = sign<Size>(overflow) < 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
if(shift) r.x = r.c;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionASR(uint4 shift, DataRegister modify) -> void {
auto result = ASR<Size>(read<Size>(modify), shift);
write<Size>(modify, result);
}
template<uint Size> auto M68K::instructionASR(DataRegister shift, DataRegister modify) -> void {
auto count = read<Long>(shift) & 63;
auto result = ASR<Size>(read<Size>(modify), count);
write<Size>(modify, result);
}
auto M68K::instructionASR(EffectiveAddress modify) -> void {
auto result = ASR<Word>(read<Word, Hold>(modify), 1);
write<Word>(modify, result);
}
auto M68K::instructionBCC(uint4 condition, uint8 displacement) -> void {
auto extension = readPC<Word>();
if(displacement) r.pc -= 2;
if(condition >= 2 && !testCondition(condition)) return;
if(condition == 1) push<Long>(r.pc);
r.pc += displacement ? (int8_t)displacement : (int16_t)extension - 2;
}
template<uint Size> auto M68K::instructionBCHG(DataRegister bit, EffectiveAddress with) -> void {
auto index = read<Size>(bit) & bits<Size>() - 1;
auto test = read<Size, Hold>(with);
r.z = test.bit(index) == 0;
test.bit(index) ^= 1;
write<Size>(with, test);
}
template<uint Size> auto M68K::instructionBCHG(EffectiveAddress with) -> void {
auto index = readPC<Word>() & bits<Size>() - 1;
auto test = read<Size, Hold>(with);
r.z = test.bit(index) == 0;
test.bit(index) ^= 1;
write<Size>(with, test);
}
template<uint Size> auto M68K::instructionBCLR(DataRegister bit, EffectiveAddress with) -> void {
auto index = read<Size>(bit) & bits<Size>() - 1;
auto test = read<Size, Hold>(with);
r.z = test.bit(index) == 0;
test.bit(index) = 0;
write<Size>(with, test);
}
template<uint Size> auto M68K::instructionBCLR(EffectiveAddress with) -> void {
auto index = readPC<Word>() & bits<Size>() - 1;
auto test = read<Size, Hold>(with);
r.z = test.bit(index) == 0;
test.bit(index) = 0;
write<Size>(with, test);
}
template<uint Size> auto M68K::instructionBSET(DataRegister bit, EffectiveAddress with) -> void {
auto index = read<Size>(bit) & bits<Size>() - 1;
auto test = read<Size, Hold>(with);
r.z = test.bit(index) == 0;
test.bit(index) = 1;
write<Size>(with, test);
}
template<uint Size> auto M68K::instructionBSET(EffectiveAddress with) -> void {
auto index = readPC<Word>() & bits<Size>() - 1;
auto test = read<Size, Hold>(with);
r.z = test.bit(index) == 0;
test.bit(index) = 1;
write<Size>(with, test);
}
template<uint Size> auto M68K::instructionBTST(DataRegister bit, EffectiveAddress with) -> void {
auto index = read<Size>(bit) & bits<Size>() - 1;
auto test = read<Size>(with);
r.z = test.bit(index) == 0;
}
template<uint Size> auto M68K::instructionBTST(EffectiveAddress with) -> void {
auto index = readPC<Word>() & bits<Size>() - 1;
auto test = read<Size>(with);
r.z = test.bit(index) == 0;
}
auto M68K::instructionCHK(DataRegister compare, EffectiveAddress maximum) -> void {
auto source = read<Word>(maximum);
auto target = read<Word>(compare);
r.z = clip<Word>(target) == 0;
r.n = sign<Word>(target) < 0;
if(r.n) return exception(Exception::BoundsCheck, Vector::BoundsCheck);
auto result = (uint64)target - source;
r.c = sign<Word>(result >> 1) < 0;
r.v = sign<Word>((target ^ source) & (target ^ result)) < 0;
r.z = clip<Word>(result) == 0;
r.n = sign<Word>(result) < 0;
if(r.n == r.v && !r.z) return exception(Exception::BoundsCheck, Vector::BoundsCheck);
}
template<uint Size> auto M68K::instructionCLR(EffectiveAddress ea) -> void {
read<Size, Hold>(ea);
write<Size>(ea, 0);
r.c = 0;
r.v = 0;
r.z = 1;
r.n = 0;
}
template<uint Size> auto M68K::CMP(uint32 source, uint32 target) -> uint32 {
auto result = (uint64)target - source;
r.c = sign<Size>(result >> 1) < 0;
r.v = sign<Size>((target ^ source) & (target ^ result)) < 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionCMP(DataRegister dr, EffectiveAddress ea) -> void {
auto source = read<Size>(ea);
auto target = read<Size>(dr);
CMP<Size>(source, target);
}
template<uint Size> auto M68K::instructionCMPA(AddressRegister ar, EffectiveAddress ea) -> void {
auto source = sign<Size>(read<Size>(ea));
auto target = read<Long>(ar);
CMP<Long>(source, target);
}
template<uint Size> auto M68K::instructionCMPI(EffectiveAddress ea) -> void {
auto source = readPC<Size>();
auto target = read<Size>(ea);
CMP<Size>(source, target);
}
template<uint Size> auto M68K::instructionCMPM(EffectiveAddress ax, EffectiveAddress ay) -> void {
auto source = read<Size>(ay);
auto target = read<Size>(ax);
CMP<Size>(source, target);
}
auto M68K::instructionDBCC(uint4 condition, DataRegister dr) -> void {
auto displacement = readPC<Word>();
if(!testCondition(condition)) {
uint16 result = read<Word>(dr);
write<Word>(dr, result - 1);
if(result) r.pc -= 2, r.pc += sign<Word>(displacement);
}
}
template<bool Sign> auto M68K::DIV(uint16 divisor, DataRegister with) -> void {
auto dividend = read<Long>(with);
bool negativeQuotient = false;
bool negativeRemainder = false;
bool overflow = false;
if(divisor == 0) return exception(Exception::DivisionByZero, Vector::DivisionByZero);
if(Sign) {
negativeQuotient = (dividend >> 31) ^ (divisor >> 15);
if(dividend >> 31) dividend = -dividend, negativeRemainder = true;
if(divisor >> 15) divisor = -divisor;
}
auto result = dividend;
for(auto _ : range(16)) {
bool lb = false;
if(result >= (uint32)divisor << 15) result -= divisor << 15, lb = true;
bool ob = result >> 31;
result = result << 1 | lb;
if(ob) overflow = true;
}
if(Sign) {
if((uint16)result > 0x7fff + negativeQuotient) overflow = true;
}
if(result >> 16 >= divisor) overflow = true;
if(Sign && !overflow) {
if(negativeQuotient) result = ((-result) & 0xffff) | (result & 0xffff0000);
if(negativeRemainder) result = (((-(result >> 16)) << 16) & 0xffff0000) | (result & 0xffff);
}
if(!overflow) write<Long>(with, result);
r.c = 0;
r.v = overflow;
r.z = clip<Word>(result) == 0;
r.n = sign<Word>(result) < 0;
}
auto M68K::instructionDIVS(DataRegister with, EffectiveAddress from) -> void {
auto divisor = read<Word>(from);
DIV<1>(divisor, with);
}
auto M68K::instructionDIVU(DataRegister with, EffectiveAddress from) -> void {
auto divisor = read<Word>(from);
DIV<0>(divisor, with);
}
template<uint Size> auto M68K::EOR(uint32 source, uint32 target) -> uint32 {
uint32 result = target ^ source;
r.c = 0;
r.v = 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionEOR(DataRegister from, EffectiveAddress with) -> void {
auto source = read<Size>(from);
auto target = read<Size, Hold>(with);
auto result = EOR<Size>(source, target);
write<Size>(with, result);
}
template<uint Size> auto M68K::instructionEORI(EffectiveAddress with) -> void {
auto source = readPC<Size>();
auto target = read<Size, Hold>(with);
auto result = EOR<Size>(source, target);
write<Size>(with, result);
}
auto M68K::instructionEORI_TO_CCR() -> void {
auto data = readPC<Word>();
writeCCR(readCCR() ^ data);
}
auto M68K::instructionEORI_TO_SR() -> void {
if(!supervisor()) return;
auto data = readPC<Word>();
writeSR(readSR() ^ data);
}
auto M68K::instructionEXG(DataRegister x, DataRegister y) -> void {
auto z = read<Long>(x);
write<Long>(x, read<Long>(y));
write<Long>(y, z);
}
auto M68K::instructionEXG(AddressRegister x, AddressRegister y) -> void {
auto z = read<Long>(x);
write<Long>(x, read<Long>(y));
write<Long>(y, z);
}
auto M68K::instructionEXG(DataRegister x, AddressRegister y) -> void {
auto z = read<Long>(x);
write<Long>(x, read<Long>(y));
write<Long>(y, z);
}
template<> auto M68K::instructionEXT<Word>(DataRegister with) -> void {
auto result = (int8)read<Byte>(with);
write<Word>(with, result);
r.c = 0;
r.v = 0;
r.z = clip<Word>(result) == 0;
r.n = sign<Word>(result) < 0;
}
template<> auto M68K::instructionEXT<Long>(DataRegister with) -> void {
auto result = (int16)read<Word>(with);
write<Long>(with, result);
r.c = 0;
r.v = 0;
r.z = clip<Long>(result) == 0;
r.n = sign<Long>(result) < 0;
}
auto M68K::instructionILLEGAL() -> void {
r.pc -= 2;
if(opcode >> 12 == 0xa) return exception(Exception::Illegal, Vector::IllegalLineA);
if(opcode >> 12 == 0xf) return exception(Exception::Illegal, Vector::IllegalLineF);
return exception(Exception::Illegal, Vector::Illegal);
}
auto M68K::instructionJMP(EffectiveAddress target) -> void {
r.pc = fetch<Long>(target);
}
auto M68K::instructionJSR(EffectiveAddress target) -> void {
auto pc = fetch<Long>(target);
push<Long>(r.pc);
r.pc = pc;
}
auto M68K::instructionLEA(AddressRegister ar, EffectiveAddress ea) -> void {
write<Long>(ar, fetch<Long>(ea));
}
auto M68K::instructionLINK(AddressRegister with) -> void {
auto displacement = (int16)readPC<Word>();
auto sp = AddressRegister{7};
push<Long>(read<Long>(with));
write<Long>(with, read<Long>(sp));
write<Long>(sp, read<Long>(sp) + displacement);
}
template<uint Size> auto M68K::LSL(uint32 result, uint shift) -> uint32 {
bool carry = false;
for(auto _ : range(shift)) {
carry = result & msb<Size>();
result <<= 1;
}
r.c = carry;
r.v = 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
if(shift) r.x = r.c;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionLSL(uint4 immediate, DataRegister dr) -> void {
auto result = LSL<Size>(read<Size>(dr), immediate);
write<Size>(dr, result);
}
template<uint Size> auto M68K::instructionLSL(DataRegister sr, DataRegister dr) -> void {
auto shift = read<Long>(sr) & 63;
auto result = LSL<Size>(read<Size>(dr), shift);
write<Size>(dr, result);
}
auto M68K::instructionLSL(EffectiveAddress ea) -> void {
auto result = LSL<Word>(read<Word, Hold>(ea), 1);
write<Word>(ea, result);
}
template<uint Size> auto M68K::LSR(uint32 result, uint shift) -> uint32 {
bool carry = false;
for(auto _ : range(shift)) {
carry = result & lsb<Size>();
result >>= 1;
}
r.c = carry;
r.v = 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
if(shift) r.x = r.c;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionLSR(uint4 immediate, DataRegister dr) -> void {
auto result = LSR<Size>(read<Size>(dr), immediate);
write<Size>(dr, result);
}
template<uint Size> auto M68K::instructionLSR(DataRegister shift, DataRegister dr) -> void {
auto count = read<Long>(shift) & 63;
auto result = LSR<Size>(read<Size>(dr), count);
write<Size>(dr, result);
}
auto M68K::instructionLSR(EffectiveAddress ea) -> void {
auto result = LSR<Word>(read<Word, Hold>(ea), 1);
write<Word>(ea, result);
}
template<uint Size> auto M68K::instructionMOVE(EffectiveAddress to, EffectiveAddress from) -> void {
auto data = read<Size>(from);
write<Size>(to, data);
r.c = 0;
r.v = 0;
r.z = clip<Size>(data) == 0;
r.n = sign<Size>(data) < 0;
}
template<uint Size> auto M68K::instructionMOVEA(AddressRegister ar, EffectiveAddress ea) -> void {
auto data = sign<Size>(read<Size>(ea));
write<Long>(ar, data);
}
template<uint Size> auto M68K::instructionMOVEM_TO_MEM(EffectiveAddress to) -> void {
auto list = readPC<Word>();
auto addr = fetch<Long>(to);
for(uint n : range(16)) {
if(!list.bit(n)) continue;
//pre-decrement mode traverses registers in reverse order {A7-A0, D7-D0}
uint index = to.mode == AddressRegisterIndirectWithPreDecrement ? 15 - n : n;
if(to.mode == AddressRegisterIndirectWithPreDecrement) addr -= bytes<Size>();
auto data = index < 8 ? read<Size>(DataRegister{index}) : read<Size>(AddressRegister{index});
write<Size>(addr, data);
if(to.mode != AddressRegisterIndirectWithPreDecrement) addr += bytes<Size>();
}
AddressRegister with{to.reg};
if(to.mode == AddressRegisterIndirectWithPreDecrement ) write<Long>(with, addr);
if(to.mode == AddressRegisterIndirectWithPostIncrement) write<Long>(with, addr);
}
template<uint Size> auto M68K::instructionMOVEM_TO_REG(EffectiveAddress from) -> void {
auto list = readPC<Word>();
auto addr = fetch<Long>(from);
for(uint n : range(16)) {
if(!list.bit(n)) continue;
uint index = from.mode == AddressRegisterIndirectWithPreDecrement ? 15 - n : n;
if(from.mode == AddressRegisterIndirectWithPreDecrement) addr -= bytes<Size>();
auto data = read<Size>(addr);
data = sign<Size>(data);
index < 8 ? write<Long>(DataRegister{index}, data) : write<Long>(AddressRegister{index}, data);
if(from.mode != AddressRegisterIndirectWithPreDecrement) addr += bytes<Size>();
}
AddressRegister with{from.reg};
if(from.mode == AddressRegisterIndirectWithPreDecrement ) write<Long>(with, addr);
if(from.mode == AddressRegisterIndirectWithPostIncrement) write<Long>(with, addr);
}
template<uint Size> auto M68K::instructionMOVEP(DataRegister from, EffectiveAddress to) -> void {
auto address = fetch<Size>(to);
auto data = read<Long>(from);
uint shift = bits<Size>();
for(auto _ : range(bytes<Size>())) {
shift -= 8;
write<Byte>(address, data >> shift);
address += 2;
}
}
template<uint Size> auto M68K::instructionMOVEP(EffectiveAddress from, DataRegister to) -> void {
auto address = fetch<Size>(from);
auto data = read<Long>(to);
uint shift = bits<Size>();
for(auto _ : range(bytes<Size>())) {
shift -= 8;
data &= ~(0xff << shift);
data |= read<Byte>(address) << shift;
address += 2;
}
write<Long>(to, data);
}
auto M68K::instructionMOVEQ(DataRegister dr, uint8 immediate) -> void {
write<Long>(dr, sign<Byte>(immediate));
r.c = 0;
r.v = 0;
r.z = clip<Byte>(immediate) == 0;
r.n = sign<Byte>(immediate) < 0;
}
auto M68K::instructionMOVE_FROM_SR(EffectiveAddress ea) -> void {
auto data = readSR();
write<Word>(ea, data);
}
auto M68K::instructionMOVE_TO_CCR(EffectiveAddress ea) -> void {
auto data = read<Word>(ea);
writeCCR(data);
}
auto M68K::instructionMOVE_TO_SR(EffectiveAddress ea) -> void {
if(!supervisor()) return;
auto data = read<Word>(ea);
writeSR(data);
}
auto M68K::instructionMOVE_FROM_USP(AddressRegister to) -> void {
if(!supervisor()) return;
write<Long>(to, r.sp);
}
auto M68K::instructionMOVE_TO_USP(AddressRegister from) -> void {
if(!supervisor()) return;
r.sp = read<Long>(from);
}
auto M68K::instructionMULS(DataRegister with, EffectiveAddress from) -> void {
auto source = read<Word>(from);
auto target = read<Word>(with);
auto result = (int16)source * (int16)target;
write<Long>(with, result);
r.c = 0;
r.v = 0;
r.z = clip<Long>(result) == 0;
r.n = sign<Long>(result) < 0;
}
auto M68K::instructionMULU(DataRegister with, EffectiveAddress from) -> void {
auto source = read<Word>(from);
auto target = read<Word>(with);
auto result = source * target;
write<Long>(with, result);
r.c = 0;
r.v = 0;
r.z = clip<Long>(result) == 0;
r.n = sign<Long>(result) < 0;
}
auto M68K::instructionNBCD(EffectiveAddress with) -> void {
auto source = read<Byte, Hold>(with);
auto target = 0u;
auto result = target - source - r.x;
bool c = false;
bool v = false;
const bool adjustLo = (target ^ source ^ result) & 0x10;
const bool adjustHi = result & 0x100;
if(adjustLo) {
auto previous = result;
result -= 0x06;
c = (~previous & 0x80) & ( result & 0x80);
v |= ( previous & 0x80) & (~result & 0x80);
}
if(adjustHi) {
auto previous = result;
result -= 0x60;
c = true;
v |= (previous & 0x80) & (~result & 0x80);
}
write<Byte>(with, result);
r.c = c;
r.v = v;
r.z = clip<Byte>(result) ? 0 : r.z;
r.n = sign<Byte>(result) < 0;
r.x = r.c;
}
template<uint Size> auto M68K::instructionNEG(EffectiveAddress with) -> void {
auto result = SUB<Size>(read<Size, Hold>(with), 0);
write<Size>(with, result);
}
template<uint Size> auto M68K::instructionNEGX(EffectiveAddress with) -> void {
auto result = SUB<Size, Extend>(read<Size, Hold>(with), 0);
write<Size>(with, result);
}
auto M68K::instructionNOP() -> void {
}
template<uint Size> auto M68K::instructionNOT(EffectiveAddress with) -> void {
auto result = ~read<Size, Hold>(with);
write<Size>(with, result);
r.c = 0;
r.v = 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
}
template<uint Size> auto M68K::OR(uint32 source, uint32 target) -> uint32 {
auto result = target | source;
r.c = 0;
r.v = 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionOR(EffectiveAddress from, DataRegister with) -> void {
auto source = read<Size>(from);
auto target = read<Size>(with);
auto result = OR<Size>(source, target);
write<Size>(with, result);
}
template<uint Size> auto M68K::instructionOR(DataRegister from, EffectiveAddress with) -> void {
auto source = read<Size>(from);
auto target = read<Size, Hold>(with);
auto result = OR<Size>(source, target);
write<Size>(with, result);
}
template<uint Size> auto M68K::instructionORI(EffectiveAddress with) -> void {
auto source = readPC<Size>();
auto target = read<Size, Hold>(with);
auto result = OR<Size>(source, target);
write<Size>(with, result);
}
auto M68K::instructionORI_TO_CCR() -> void {
auto data = readPC<Word>();
writeCCR(readCCR() | data);
}
auto M68K::instructionORI_TO_SR() -> void {
if(!supervisor()) return;
auto data = readPC<Word>();
writeSR(readSR() | data);
}
auto M68K::instructionPEA(EffectiveAddress from) -> void {
auto data = fetch<Long>(from);
push<Long>(data);
}
auto M68K::instructionRESET() -> void {
if(!supervisor()) return;
r.reset = true;
}
template<uint Size> auto M68K::ROL(uint32 result, uint shift) -> uint32 {
bool carry = false;
for(auto _ : range(shift)) {
carry = result & msb<Size>();
result = result << 1 | carry;
}
r.c = carry;
r.v = 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionROL(uint4 shift, DataRegister modify) -> void {
auto result = ROL<Size>(read<Size>(modify), shift);
write<Size>(modify, result);
}
template<uint Size> auto M68K::instructionROL(DataRegister shift, DataRegister modify) -> void {
auto count = read<Long>(shift) & 63;
auto result = ROL<Size>(read<Size>(modify), count);
write<Size>(modify, result);
}
auto M68K::instructionROL(EffectiveAddress modify) -> void {
auto result = ROL<Word>(read<Word, Hold>(modify), 1);
write<Word>(modify, result);
}
template<uint Size> auto M68K::ROR(uint32 result, uint shift) -> uint32 {
bool carry = false;
for(auto _ : range(shift)) {
carry = result & lsb<Size>();
result >>= 1;
if(carry) result |= msb<Size>();
}
r.c = carry;
r.v = 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionROR(uint4 shift, DataRegister modify) -> void {
auto result = ROR<Size>(read<Size>(modify), shift);
write<Size>(modify, result);
}
template<uint Size> auto M68K::instructionROR(DataRegister shift, DataRegister modify) -> void {
auto count = read<Long>(shift) & 63;
auto result = ROR<Size>(read<Size>(modify), count);
write<Size>(modify, result);
}
auto M68K::instructionROR(EffectiveAddress modify) -> void {
auto result = ROR<Word>(read<Word, Hold>(modify), 1);
write<Word>(modify, result);
}
template<uint Size> auto M68K::ROXL(uint32 result, uint shift) -> uint32 {
bool carry = r.x;
for(auto _ : range(shift)) {
bool extend = carry;
carry = result & msb<Size>();
result = result << 1 | extend;
}
r.c = carry;
r.v = 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
r.x = r.c;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionROXL(uint4 shift, DataRegister modify) -> void {
auto result = ROXL<Size>(read<Size>(modify), shift);
write<Size>(modify, result);
}
template<uint Size> auto M68K::instructionROXL(DataRegister shift, DataRegister modify) -> void {
auto count = read<Long>(shift) & 63;
auto result = ROXL<Size>(read<Size>(modify), count);
write<Size>(modify, result);
}
auto M68K::instructionROXL(EffectiveAddress modify) -> void {
auto result = ROXL<Word>(read<Word, Hold>(modify), 1);
write<Word>(modify, result);
}
template<uint Size> auto M68K::ROXR(uint32 result, uint shift) -> uint32 {
bool carry = r.x;
for(auto _ : range(shift)) {
bool extend = carry;
carry = result & lsb<Size>();
result >>= 1;
if(extend) result |= msb<Size>();
}
r.c = carry;
r.v = 0;
r.z = clip<Size>(result) == 0;
r.n = sign<Size>(result) < 0;
r.x = r.c;
return clip<Size>(result);
}
template<uint Size> auto M68K::instructionROXR(uint4 shift, DataRegister modify) -> void {
auto result = ROXR<Size>(read<Size>(modify), shift);
write<Size>(modify, result);
}
template<uint Size> auto M68K::instructionROXR(DataRegister shift, DataRegister modify) -> void {
auto count = read<Long>(shift) & 63;
auto result = ROXR<Size>(read<Size>(modify), count);
write<Size>(modify, result);
}
auto M68K::instructionROXR(EffectiveAddress modify) -> void {
auto result = ROXR<Word>(read<Word, Hold>(modify), 1);
write<Word>(modify, result);
}
auto M68K::instructionRTE() -> void {
if(!supervisor()) return;
auto sr = pop<Word>();
r.pc = pop<Long>();
writeSR(sr);
}
auto M68K::instructionRTR() -> void {
writeCCR(pop<Word>());
r.pc = pop<Long>();
}
auto M68K::instructionRTS() -> void {
r.pc = pop<Long>();
}
auto M68K::instructionSBCD(EffectiveAddress with, EffectiveAddress from) -> void {
auto source = read<Byte>(from);
auto target = read<Byte, Hold>(with);
auto result = target - source - r.x;
bool c = false;
bool v = false;
const bool adjustLo = (target ^ source ^ result) & 0x10;
const bool adjustHi = result & 0x100;
if(adjustLo) {
auto previous = result;
result -= 0x06;
c = (~previous & 0x80) & ( result & 0x80);
v |= ( previous & 0x80) & (~result & 0x80);
}
if(adjustHi) {
auto previous = result;
result -= 0x60;
c = true;
v |= (previous & 0x80) & (~result & 0x80);
}
write<Byte>(with, result);
r.c = c;
r.v = v;
r.z = clip<Byte>(result) ? 0 : r.z;
r.n = sign<Byte>(result) < 0;
r.x = r.c;
}
auto M68K::instructionSCC(uint4 condition, EffectiveAddress to) -> void {
uint8 result = testCondition(condition) ? ~0 : 0;
write<Byte>(to, result);
}
auto M68K::instructionSTOP() -> void {
if(!supervisor()) return;
auto sr = readPC<Word>();
writeSR(sr);
r.stop = true;
}
template<uint Size, bool Extend> auto M68K::SUB(uint32 source, uint32 target) -> uint32 {
auto result = (uint64)target - source;
if(Extend) result -= r.x;
r.c = sign<Size>(result >> 1) < 0;
r.v = sign<Size>((target ^ source) & (target ^ result)) < 0;
r.z = clip<Size>(result) ? 0 : (Extend ? r.z : 1);
r.n = sign<Size>(result) < 0;
r.x = r.c;
return result;
}
template<uint Size> auto M68K::instructionSUB(EffectiveAddress source_, DataRegister target_) -> void {
auto source = read<Size>(source_);
auto target = read<Size>(target_);
auto result = SUB<Size>(source, target);
write<Size>(target_, result);
}
template<uint Size> auto M68K::instructionSUB(DataRegister source_, EffectiveAddress target_) -> void {
auto source = read<Size>(source_);
auto target = read<Size, Hold>(target_);
auto result = SUB<Size>(source, target);
write<Size>(target_, result);
}
template<uint Size> auto M68K::instructionSUBA(AddressRegister to, EffectiveAddress from) -> void {
auto source = sign<Size>(read<Size>(from));
auto target = read<Long>(to);
write<Long>(to, target - source);
}
template<uint Size> auto M68K::instructionSUBI(EffectiveAddress with) -> void {
auto source = readPC<Size>();
auto target = read<Size, Hold>(with);
auto result = SUB<Size>(source, target);
write<Size>(with, result);
}
template<uint Size> auto M68K::instructionSUBQ(uint4 immediate, EffectiveAddress with) -> void {
auto source = immediate;
auto target = read<Size, Hold>(with);
auto result = SUB<Size>(source, target);
write<Size>(with, result);
}
//Size is ignored: always uses Long
template<uint Size> auto M68K::instructionSUBQ(uint4 immediate, AddressRegister with) -> void {
auto result = read<Long>(with) - immediate;
write<Long>(with, result);
}
template<uint Size> auto M68K::instructionSUBX(EffectiveAddress with, EffectiveAddress from) -> void {
auto source = read<Size>(from);
auto target = read<Size, Hold>(with);
auto result = SUB<Size, Extend>(source, target);
write<Size>(with, result);
}
auto M68K::instructionSWAP(DataRegister with) -> void {
auto result = read<Long>(with);
result = result >> 16 | result << 16;
write<Long>(with, result);
r.c = 0;
r.v = 0;
r.z = clip<Long>(result) == 0;
r.n = sign<Long>(result) < 0;
}
auto M68K::instructionTAS(EffectiveAddress with) -> void {
uint32 data;
if(with.mode == DataRegisterDirect) {
data = read<Byte, Hold>(with);
write<Byte>(with, data | 0x80);
} else {
//Mega Drive models 1&2 have a bug that prevents TAS write from taking effect
//this bugged behavior is required for certain software to function correctly
data = read<Byte>(with);
step(4);
}
r.c = 0;
r.v = 0;
r.z = clip<Byte>(data) == 0;
r.n = sign<Byte>(data) < 0;
}
auto M68K::instructionTRAP(uint4 vector) -> void {
exception(Exception::Trap, 32 + vector, r.i);
}
auto M68K::instructionTRAPV() -> void {
if(r.v) exception(Exception::Overflow, Vector::Overflow);
}
template<uint Size> auto M68K::instructionTST(EffectiveAddress ea) -> void {
auto data = read<Size>(ea);
r.c = 0;
r.v = 0;
r.z = clip<Size>(data) == 0;
r.n = sign<Size>(data) < 0;
}
auto M68K::instructionUNLK(AddressRegister with) -> void {
auto sp = AddressRegister{7};
write<Long>(sp, read<Long>(with));
write<Long>(with, pop<Long>());
}