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fix(cartridge): put a bit more detail into the MBC3 RTC stub
continuous-integration/drone/push Build is failing Details

This commit is contained in:
Rekai Nyangadzayi Musuka 2021-08-03 15:18:52 -05:00
parent dd8339e8de
commit de0d147685
1 changed files with 19 additions and 8 deletions
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27
src/cartridge.rs
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@ -305,6 +305,9 @@ struct MBC3 {
currently_mapped: Option<MBC3Device>,
ram_size: RamSize,
ram: Vec<u8>,
// RTC Data Latch Previous Write
prev_latch_write: Option<u8>,
}
impl MBCIo for MBC3 {
@ -319,7 +322,7 @@ impl MBCIo for MBC3 {
Value(self.ram[0x2000 * self.ram_bank as usize + (addr as usize - 0xA000)])
}
Some(MBC3Device::RealTimeClock) if self.devices_enabled => {
unimplemented!("Reading from MBC3 RTC is currently unsupported")
todo!("Return Latched value of register")
}
_ => Value(0xFF),
},
@ -332,10 +335,12 @@ impl MBCIo for MBC3 {
fn handle_write(&mut self, addr: u16, byte: u8) {
match addr {
0x000..=0x1FFF => self.devices_enabled = (byte & 0x0F) == 0x0A, // Enable External RAM and Access to RTC if there is one
0x2000..=0x3FFF => match byte {
0x00 => self.rom_bank = 0x01,
byte => self.rom_bank = byte & 0x7F,
},
0x2000..=0x3FFF => {
self.rom_bank = match byte {
0x00 => 0x01,
byte => byte & 0x7F,
}
}
0x4000..=0x5FFF => match byte {
0x00 | 0x01 | 0x02 | 0x03 => {
self.ram_bank = byte & 0x03;
@ -343,17 +348,23 @@ impl MBCIo for MBC3 {
}
0x08 | 0x09 | 0x0A | 0x0B | 0x0C => {
self.currently_mapped = Some(MBC3Device::RealTimeClock);
unimplemented!("RTC in MBC3 is currently unimplemented")
}
_ => {}
},
0x6000..=0x7FFF => unimplemented!("RTC Data Latch is currently unimplemented"),
0x6000..=0x7FFF => {
if let Some(0x00) = self.prev_latch_write {
if byte == 0x01 {
todo!("Perform Data Latch")
}
}
self.prev_latch_write = Some(byte);
}
0xA000..=0xBFFF => match self.currently_mapped {
Some(MBC3Device::ExternalRam) if self.devices_enabled => {
self.ram[0x2000 * self.ram_bank as usize + (addr as usize - 0xA000)] = byte
}
Some(MBC3Device::RealTimeClock) if self.devices_enabled => {
unimplemented!("Writing to MBC3 RTC is currently unsupported")
todo!("Write to RTC")
}
_ => {}
},