bsnes/gba/cartridge/flashrom.cpp

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//Dev.ID Size Blocks Manufacturer
//====== ===== ======== ============
//0xd4bf 64KB 16x4096 SST
//0x1cc2 64KB 16x4096 Macronix
//0x1b32 64KB 16x4096 Panasonic
//0x3d1f 64KB 512x 128 Atmel
//0x1362 128KB 32x4096 Sanyo
//0x09c2 128KB 32x4096 Macronix
uint8 Cartridge::FlashROM::read(uint16 addr) {
if(idmode) {
if(addr == 0x0000) return id >> 0;
if(addr == 0x0001) return id >> 8;
return 0u;
}
return data[bank << 16 | addr];
}
void Cartridge::FlashROM::write(uint16 addr, uint8 byte) {
if(bankselect) {
bankselect = false;
//bank select is only applicable on 128KB chips
if(addr == 0x0000) bank = byte & (size > 64 * 1024);
return;
}
if(writeselect) {
//Atmel writes 128 bytes per command; all others write 1 byte per command
if(id != 0x3d1f || (addr & 0x007f) == 0x007f) writeselect = false;
data[bank << 16 | addr] = byte;
return;
}
if(byte == 0xaa && addr == 0x5555) { unlockhi = true; return; }
if(byte == 0x55 && addr == 0x2aaa) { unlocklo = true; return; }
if(unlockhi && unlocklo) {
unlockhi = false;
unlocklo = false;
if(byte == 0x10 && addr == 0x5555) {
if(erasemode) {
erasemode = false;
for(unsigned n = 0; n < size; n++) data[n] = 0xff;
}
}
if(byte == 0x30 && (addr & 0x0fff) == 0x0000) {
//command only valid for non-Atmel chips
if(erasemode && id != 0x3d1f) {
erasemode = false;
unsigned offset = bank << 16 | (addr & ~4095);
for(unsigned n = 0; n < 4096; n++) data[offset++] = 0xff;
}
}
if(byte == 0x80 && addr == 0x5555) {
erasemode = true;
}
if(byte == 0x90 && addr == 0x5555) {
idmode = true;
}
if(byte == 0xa0 && addr == 0x5555) {
writeselect = true;
}
if(byte == 0xb0 && addr == 0x5555) {
bankselect = true;
}
if(byte == 0xf0 && addr == 0x5555) {
idmode = false;
}
}
}
void Cartridge::FlashROM::power() {
unlockhi = false;
unlocklo = false;
idmode = false;
bankselect = false;
writeselect = false;
bank = 0;
}
void Cartridge::FlashROM::serialize(serializer& s) {
s.array(data, size);
s.integer(size);
s.integer(id);
s.integer(unlockhi);
s.integer(unlocklo);
s.integer(idmode);
s.integer(erasemode);
s.integer(bankselect);
s.integer(writeselect);
s.integer(bank);
}