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MBC1 issues should be mostly fixed

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This commit is contained in:
Braiden Gent
2024-04-18 18:47:16 -07:00
parent 34ca656771
commit 056cd02375
2 changed files with 32 additions and 8 deletions
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30
src/mbc.cpp
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@@ -68,16 +68,37 @@ Byte* AddressSpace::MBCRead(const Word address) {
}
void AddressSpace::MBCUpdate() {
//TODO: multicart roms need to be able to switch the first rom bank as well
//see: https://gbdev.io/pandocs/MBC1.html
if (MBC == MBC1) {
//TODO: multicart roms need to be able to switch the first rom bank as well
//see: https://gbdev.io/pandocs/MBC1.html
//Selected ROM Bank = (Secondary Bank << 5) + ROM Bank
romBankRegister &= 0x1F;
twoBitBankRegister &= 0x3;
//512 KiB can only have 8KiB of ram
if (romSize > 524288) {
if (romSize >= 524288) {
if (romBankRegister == 0)
selectedRomBank = (twoBitBankRegister << 5) + 1;
selectedRomBank = (twoBitBankRegister << 5) + romBankRegister;
}
else {
if (romBankRegister == 0)
selectedRomBank = 1;
else
selectedRomBank = romBankRegister;
}
selectedExternalRamBank = 0;
loadRomBank();
loadRamBank();
}
if (MBC == MBC1Ram || MBC == MBC1RamBattery) {
//Selected ROM Bank = (Secondary Bank << 5) + ROM Bank
romBankRegister &= 0x1F;
twoBitBankRegister &= 0x3;
//512 KiB can only have 8KiB of ram
if (romSize >= 524288) {
if (romBankRegister == 0)
selectedRomBank = (twoBitBankRegister << 5) + 1;
selectedRomBank = (twoBitBankRegister << 5) + romBankRegister;
@@ -93,7 +114,6 @@ void AddressSpace::MBCUpdate() {
loadRomBank();
loadRamBank();
}
if (MBC == MBC1Ram || MBC == MBC1RamBattery) {}
}
void AddressSpace::loadRomBank() {