46 lines
1.4 KiB
C
Executable File
46 lines
1.4 KiB
C
Executable File
#include "gb-impl.h"
|
|
|
|
void mbc1_changeBank(gb *cpu, WORD addr, BYTE data) {
|
|
// RAM enabling
|
|
if (addr < 0x2000) {
|
|
BYTE testData = data & 0xF;
|
|
if (testData == 0x0) {
|
|
cpu->isRAMEnable = 0;
|
|
} else {
|
|
cpu->isRAMEnable = 1;
|
|
}
|
|
}
|
|
|
|
/*Change ROM bank*/
|
|
else if ((addr >= 0x2000) && (addr < 0x4000)) {
|
|
BYTE lower5 = data & 31;
|
|
cpu->currentROMBank &= 224; // turn off the lower 5
|
|
cpu->currentROMBank |= lower5;
|
|
if (cpu->currentROMBank == 0 || cpu->currentROMBank == 0x20 ||
|
|
cpu->currentROMBank == 0x40 || cpu->currentROMBank == 0x60)
|
|
cpu->currentROMBank++;
|
|
}
|
|
|
|
/*Depending from the MBC1 type, I have to change something*/
|
|
else if ((addr >= 0x4000) && (addr < 0x6000)) {
|
|
if (cpu->ROMBankType == 1) {
|
|
cpu->currentROMBank &= 31;
|
|
data &= 0x3;
|
|
data <<= 5;
|
|
cpu->currentROMBank |= data;
|
|
if (cpu->currentROMBank == 0 || cpu->currentROMBank == 0x20 ||
|
|
cpu->currentROMBank == 0x40 || cpu->currentROMBank == 0x60)
|
|
cpu->currentROMBank++;
|
|
} else
|
|
cpu->currentRAMBank = data & 0x3;
|
|
}
|
|
|
|
/*Determine which type of MBC1 is*/
|
|
else if ((addr >= 0x6000) && (addr < 0x8000)) {
|
|
BYTE newData = data & 0x1;
|
|
cpu->ROMBankType = (newData == 0) ? 1 : 0;
|
|
if (cpu->ROMBankType == 1)
|
|
cpu->currentRAMBank = 0;
|
|
}
|
|
}
|