bsnes/higan/sfc/cpu/memory.cpp

44 lines
905 B
C++

auto CPU::readPort(uint2 port) const -> uint8 {
return io.port[port];
}
auto CPU::writePort(uint2 port, uint8 data) -> void {
io.port[port] = data;
}
auto CPU::idle() -> void {
status.clockCount = 6;
dmaEdge();
step(6);
aluEdge();
}
auto CPU::read(uint24 addr) -> uint8 {
status.clockCount = speed(addr);
dmaEdge();
step(status.clockCount - 4);
r.mdr = bus.read(addr, r.mdr);
step(4);
aluEdge();
return r.mdr;
}
auto CPU::write(uint24 addr, uint8 data) -> void {
aluEdge();
status.clockCount = speed(addr);
dmaEdge();
step(status.clockCount);
bus.write(addr, r.mdr = data);
}
auto CPU::speed(uint24 addr) const -> uint {
if(addr & 0x408000) return addr & 0x800000 ? io.romSpeed : 8;
if(addr + 0x6000 & 0x4000) return 8;
if(addr - 0x4000 & 0x7e00) return 6;
return 12;
}
auto CPU::readDisassembler(uint24 addr) -> uint8 {
return bus.read(addr, r.mdr);
}