bsnes/higan/gb/cartridge/mbc3/mbc3.cpp

119 lines
2.8 KiB
C++

auto Cartridge::MBC3::second() -> void {
if(!rtc.halt) {
if(++rtc.second >= 60) {
rtc.second = 0;
if(++rtc.minute >= 60) {
rtc.minute = 0;
if(++rtc.hour >= 24) {
rtc.hour = 0;
if(++rtc.day >= 512) {
rtc.day = 0;
rtc.dayCarry = true;
}
}
}
}
}
}
auto Cartridge::MBC3::readIO(uint16 addr) -> uint8 {
if((addr & 0xc000) == 0x0000) { //$0000-3fff
return cartridge.readROM(addr);
}
if((addr & 0xc000) == 0x4000) { //$4000-7fff
return cartridge.readROM(rom.select<< 14 | (uint14)addr);
}
if((addr & 0xe000) == 0xa000) { //$a000-bfff
if(ram.enable) {
if(ram.select <= 0x03) {
return cartridge.readRAM(ram.select << 13 | (uint13)addr);
}
if(ram.select == 0x08) return rtc.latchSecond;
if(ram.select == 0x09) return rtc.latchMinute;
if(ram.select == 0x0a) return rtc.latchHour;
if(ram.select == 0x0b) return rtc.latchDay;
if(ram.select == 0x0c) return rtc.latchDayCarry << 7 | rtc.latchDay >> 8;
}
return 0xff;
}
return 0xff;
}
auto Cartridge::MBC3::writeIO(uint16 addr, uint8 data) -> void {
if((addr & 0xe000) == 0x0000) { //$0000-1fff
ram.enable = (data & 0x0f) == 0x0a;
return;
}
if((addr & 0xe000) == 0x2000) { //$2000-3fff
rom.select = (data & 0x7f) + ((data & 0x7f) == 0);
return;
}
if((addr & 0xe000) == 0x4000) { //$4000-5fff
ram.select = data;
return;
}
if((addr & 0xe000) == 0x6000) { //$6000-7fff
if(rtc.latch == 0 && data == 1) {
rtc.latchSecond = rtc.second;
rtc.latchMinute = rtc.minute;
rtc.latchHour = rtc.hour;
rtc.latchDay = rtc.day;
rtc.latchDayCarry = rtc.dayCarry;
}
rtc.latch = data;
return;
}
if((addr & 0xe000) == 0xa000) { //$a000-bfff
if(ram.enable) {
if(ram.select <= 0x03) {
cartridge.writeRAM(ram.select << 13 | (uint13)addr, data);
} else if(ram.select == 0x08) {
if(data >= 60) data = 0;
rtc.second = data;
} else if(ram.select == 0x09) {
if(data >= 60) data = 0;
rtc.minute = data;
} else if(ram.select == 0x0a) {
if(data >= 24) data = 0;
rtc.hour = data;
} else if(ram.select == 0x0b) {
rtc.day = (rtc.day & 0x0100) | data;
} else if(ram.select == 0x0c) {
rtc.day = ((data & 1) << 8) | (rtc.day & 0xff);
rtc.halt = data & 0x40;
rtc.dayCarry = data & 0x80;
}
}
return;
}
}
auto Cartridge::MBC3::power() -> void {
rom.select = 0x01;
ram.enable = false;
ram.select = 0x00;
rtc.latch = 0;
rtc.halt = true;
rtc.second = 0;
rtc.minute = 0;
rtc.hour = 0;
rtc.day = 0;
rtc.dayCarry = false;
rtc.latchSecond = 0;
rtc.latchMinute = 0;
rtc.latchHour = 0;
rtc.latchDay = 0;
rtc.latchDayCarry = false;
}