MBC2 working

src/mbc.cpp

@@ -64,6 +64,14 @@ Byte *AddressSpace::MBCRead(const Word address) {
     if (address <= 0x7FFF)
       return &romRamSelect;
   }
+  if (MBC == MBC2 || MBC == MBC2Battery) {
+    if (address <= 0x3FFF) {
+      if (address & 0x0100)
+        return &romBankRegister;
+      else
+        return &ramEnable;
+    }
+  }
   return &dummyVal;
 }
 
@@ -93,8 +101,7 @@ void AddressSpace::MBCUpdate() {
 
     loadRomBank();
     loadRamBank();
-  }
-  if (MBC == MBC1Ram || MBC == MBC1RamBattery) {
+  } else if (MBC == MBC1Ram || MBC == MBC1RamBattery) {
     // Selected ROM Bank = (Secondary Bank << 5) + ROM Bank
     romBankRegister &= 0b11111;
     twoBitBankRegister &= 0b11;
@@ -119,7 +126,9 @@ void AddressSpace::MBCUpdate() {
     loadRomBank();
     loadRamBank();
   } else if (MBC == MBC2 || MBC == MBC2Battery) {
-    // TODO
+    selectedRomBank = romBankRegister & 0x0F;
+    loadRomBank();
+    loadRamBank();
   } else if (MBC == MBC3 || MBC == MBC3TimerBattery) {
     romBankRegister &= 0b11111;
     twoBitBankRegister &= 0b11;
@@ -168,7 +177,8 @@ void AddressSpace::createRamBank() {
 }
 
 void AddressSpace::loadRamBank() {
-  if (cartridgeRam != nullptr)
+  if (cartridgeRam != nullptr) {
     memoryLayout.externalRam =
         cartridgeRam + (RAM_BANK_SIZE * selectedExternalRamBank);
+  }
 }