bsnes/sfc/cpu/memory/memory.cpp

49 lines
1.0 KiB
C++

auto CPU::portRead(uint2 port) const -> uint8 {
return status.port[port];
}
auto CPU::portWrite(uint2 port, uint8 data) -> void {
status.port[port] = data;
}
auto CPU::op_io() -> void {
status.clock_count = 6;
dma_edge();
add_clocks(6);
alu_edge();
}
auto CPU::op_read(uint32 addr) -> uint8 {
status.clock_count = speed(addr);
dma_edge();
add_clocks(status.clock_count - 4);
regs.mdr = bus.read(addr);
add_clocks(4);
alu_edge();
debugger.op_read(addr, regs.mdr);
return regs.mdr;
}
auto CPU::op_write(uint32 addr, uint8 data) -> void {
alu_edge();
status.clock_count = speed(addr);
dma_edge();
add_clocks(status.clock_count);
bus.write(addr, regs.mdr = data);
debugger.op_write(addr, regs.mdr);
}
auto CPU::speed(uint addr) const -> uint {
if(addr & 0x408000) {
if(addr & 0x800000) return status.rom_speed;
return 8;
}
if((addr + 0x6000) & 0x4000) return 8;
if((addr - 0x4000) & 0x7e00) return 6;
return 12;
}
auto CPU::disassembler_read(uint32 addr) -> uint8 {
return bus.read(addr);
}