bsnes/gameboy/cpu/mmio/mmio.cpp

130 lines
3.4 KiB
C++
Executable File

#ifdef CPU_CPP
void CPU::mmio_joyp_poll() {
unsigned button = 0, dpad = 0;
button |= system.interface->input_poll((unsigned)Input::Start) << 3;
button |= system.interface->input_poll((unsigned)Input::Select) << 2;
button |= system.interface->input_poll((unsigned)Input::B) << 1;
button |= system.interface->input_poll((unsigned)Input::A) << 0;
dpad |= system.interface->input_poll((unsigned)Input::Down) << 3;
dpad |= system.interface->input_poll((unsigned)Input::Up) << 2;
dpad |= system.interface->input_poll((unsigned)Input::Left) << 1;
dpad |= system.interface->input_poll((unsigned)Input::Right) << 0;
status.joyp = 0x0f;
if(status.p15 == 0) status.joyp &= button ^ 0x0f;
if(status.p14 == 0) status.joyp &= dpad ^ 0x0f;
if(status.joyp != 0x0f) interrupt_raise(Interrupt::Joypad);
}
uint8 CPU::mmio_read(uint16 addr) {
if(addr >= 0xc000 && addr <= 0xdfff) return wram[addr & 0x1fff];
if(addr >= 0xe000 && addr <= 0xfdff) return wram[addr & 0x1fff];
if(addr >= 0xff80 && addr <= 0xfffe) return hram[addr & 0x7f];
if(addr == 0xff00) { //JOYP
return (status.p15 << 5)
| (status.p14 << 4)
| (status.joyp << 0);
}
if(addr == 0xff04) { //DIV
return status.div;
}
if(addr == 0xff05) { //TIMA
return status.tima;
}
if(addr == 0xff06) { //TMA
return status.tma;
}
if(addr == 0xff07) { //TAC
return (status.timer_enable << 2)
| (status.timer_clock << 0);
}
if(addr == 0xff0f) { //IF
return (status.interrupt_request_joypad << 4)
| (status.interrupt_request_serial << 3)
| (status.interrupt_request_timer << 2)
| (status.interrupt_request_stat << 1)
| (status.interrupt_request_vblank << 0);
}
if(addr == 0xffff) { //IE
return (status.interrupt_enable_joypad << 4)
| (status.interrupt_enable_serial << 3)
| (status.interrupt_enable_timer << 2)
| (status.interrupt_enable_stat << 1)
| (status.interrupt_enable_vblank << 0);
}
return 0x00;
}
void CPU::mmio_write(uint16 addr, uint8 data) {
if(addr >= 0xc000 && addr <= 0xdfff) { wram[addr & 0x1fff] = data; return; }
if(addr >= 0xe000 && addr <= 0xfdff) { wram[addr & 0x1fff] = data; return; }
if(addr >= 0xff80 && addr <= 0xfffe) { hram[addr & 0x7f] = data; return; }
if(addr == 0xff00) { //JOYP
status.p15 = data & 0x20;
status.p14 = data & 0x10;
mmio_joyp_poll();
return;
}
if(addr == 0xff01) { //SB
return;
}
if(addr == 0xff02) { //SC
return;
}
if(addr == 0xff04) { //DIV
status.div = 0;
return;
}
if(addr == 0xff05) { //TIMA
status.tima = data;
return;
}
if(addr == 0xff06) { //TMA
status.tma = data;
return;
}
if(addr == 0xff07) { //TAC
status.timer_enable = data & 0x04;
status.timer_clock = data & 0x03;
return;
}
if(addr == 0xff0f) { //IF
status.interrupt_request_joypad = data & 0x10;
status.interrupt_request_serial = data & 0x08;
status.interrupt_request_timer = data & 0x04;
status.interrupt_request_stat = data & 0x02;
status.interrupt_request_vblank = data & 0x01;
return;
}
if(addr == 0xffff) { //IE
status.interrupt_enable_joypad = data & 0x10;
status.interrupt_enable_serial = data & 0x08;
status.interrupt_enable_timer = data & 0x04;
status.interrupt_enable_stat = data & 0x02;
status.interrupt_enable_vblank = data & 0x01;
return;
}
}
#endif