bsnes/higan/ms/cpu/bus.cpp

111 lines
2.9 KiB
C++

auto CPU::read(uint16 addr) -> uint8 {
uint8 data;
if(auto result = cartridge.read(addr)) {
data = result();
} else if(addr >= 0xc000) {
data = ram[addr & 0x1fff];
}
if(auto result = cheat.find(addr, data)) {
data = result();
}
return data;
}
auto CPU::write(uint16 addr, uint8 data) -> void {
if(cartridge.write(addr, data)) {
} else if(addr >= 0xc000) {
ram[addr & 0x1fff] = data;
}
}
auto CPU::in(uint8 addr) -> uint8 {
switch(addr >> 6) {
case 0: {
if(Model::GameGear()) {
bool start = !platform->inputPoll(ID::Port::Hardware, ID::Device::GameGearControls, 6);
return start << 7 | 0x7f;
}
return 0xff; //SMS1 = MDR, SMS2 = 0xff
}
case 1: {
return !addr.bit(0) ? vdp.vcounter() : vdp.hcounter();
}
case 2: {
return !addr.bit(0) ? vdp.data() : vdp.status();
}
case 3: {
if(Model::SG1000() || Model::SC3000()) {
auto port1 = controllerPort1.device->readData();
auto port2 = controllerPort2.device->readData();
if(addr.bit(0) == 0) {
return port1.bits(0,5) << 0 | port2.bits(0,1) << 6;
} else {
return port2.bits(2,5) << 0 | 1 << 4 | 1 << 5 | port1.bit(6) << 6 | port2.bit(6) << 7;
}
}
if(Model::MasterSystem()) {
bool reset = !platform->inputPoll(ID::Port::Hardware, ID::Device::MasterSystemControls, 0);
auto port1 = controllerPort1.device->readData();
auto port2 = controllerPort2.device->readData();
if(addr.bit(0) == 0) {
return port1.bits(0,5) << 0 | port2.bits(0,1) << 6;
} else {
return port2.bits(2,5) << 0 | reset << 4 | 1 << 5 | port1.bit(6) << 6 | port2.bit(6) << 7;
}
}
if(Model::GameGear()) {
bool up = !platform->inputPoll(ID::Port::Hardware, ID::Device::GameGearControls, 0);
bool down = !platform->inputPoll(ID::Port::Hardware, ID::Device::GameGearControls, 1);
bool left = !platform->inputPoll(ID::Port::Hardware, ID::Device::GameGearControls, 2);
bool right = !platform->inputPoll(ID::Port::Hardware, ID::Device::GameGearControls, 3);
bool one = !platform->inputPoll(ID::Port::Hardware, ID::Device::GameGearControls, 4);
bool two = !platform->inputPoll(ID::Port::Hardware, ID::Device::GameGearControls, 5);
if(!up && !down) up = 1, down = 1;
if(!left && !right) left = 1, right = 1;
if(addr.bit(0) == 0) {
return up << 0 | down << 1 | left << 2 | right << 3 | one << 4 | two << 5 | 1 << 6 | 1 << 7;
} else {
return 0xff;
}
}
return 0xff;
}
}
return 0xff;
}
auto CPU::out(uint8 addr, uint8 data) -> void {
if(addr == 0x06) {
if(Model::GameGear()) return psg.balance(data);
}
switch(addr >> 6) {
case 1: {
return psg.write(data);
}
case 2: {
return !addr.bit(0) ? vdp.data(data) : vdp.control(data);
}
case 3: {
return; //unmapped
}
}
}