bsnes/fc/cartridge/board/bandai-fcg.cpp

118 lines
2.5 KiB
C++

//BANDAI-FCG
struct BandaiFCG : Board {
uint8 chr_bank[8];
uint8 prg_bank;
uint2 mirror;
bool irq_counter_enable;
uint16 irq_counter;
uint16 irq_latch;
void main() {
while(true) {
if(scheduler.sync == Scheduler::SynchronizeMode::All) {
scheduler.exit(Scheduler::ExitReason::SynchronizeEvent);
}
if(irq_counter_enable) {
if(--irq_counter == 0xffff) {
cpu.set_irq_line(1);
irq_counter_enable = false;
}
}
tick();
}
}
unsigned ciram_addr(unsigned addr) const {
switch(mirror) {
case 0: return ((addr & 0x0400) >> 0) | (addr & 0x03ff);
case 1: return ((addr & 0x0800) >> 1) | (addr & 0x03ff);
case 2: return 0x0000 | (addr & 0x03ff);
case 3: return 0x0400 | (addr & 0x03ff);
}
}
uint8 prg_read(unsigned addr) {
if(addr & 0x8000) {
bool region = addr & 0x4000;
unsigned bank = (region == 0 ? prg_bank : 0x0f);
return prgrom.read((bank << 14) | (addr & 0x3fff));
}
return cpu.mdr();
}
void prg_write(unsigned addr, uint8 data) {
if(addr >= 0x6000) {
switch(addr & 15) {
case 0x00: case 0x01: case 0x02: case 0x03:
case 0x04: case 0x05: case 0x06: case 0x07:
chr_bank[addr & 7] = data;
break;
case 0x08:
prg_bank = data & 0x0f;
break;
case 0x09:
mirror = data & 0x03;
break;
case 0x0a:
cpu.set_irq_line(0);
irq_counter_enable = data & 0x01;
irq_counter = irq_latch;
break;
case 0x0b:
irq_latch = (irq_latch & 0xff00) | (data << 0);
break;
case 0x0c:
irq_latch = (irq_latch & 0x00ff) | (data << 8);
break;
case 0x0d:
//TODO: serial EEPROM support
break;
}
}
}
uint8 chr_read(unsigned addr) {
if(addr & 0x2000) return ppu.ciram_read(ciram_addr(addr));
addr = (chr_bank[addr >> 10] << 10) | (addr & 0x03ff);
return Board::chr_read(addr);
}
void chr_write(unsigned addr, uint8 data) {
if(addr & 0x2000) return ppu.ciram_write(ciram_addr(addr), data);
addr = (chr_bank[addr >> 10] << 10) | (addr & 0x03ff);
return Board::chr_write(addr, data);
}
void power() {
reset();
}
void reset() {
for(auto &n : chr_bank) n = 0;
prg_bank = 0;
mirror = 0;
irq_counter_enable = 0;
irq_counter = 0;
irq_latch = 0;
}
void serialize(serializer& s) {
Board::serialize(s);
s.array(chr_bank);
s.integer(prg_bank);
s.integer(mirror);
s.integer(irq_counter_enable);
s.integer(irq_counter);
s.integer(irq_latch);
}
BandaiFCG(Markup::Node& document) : Board(document) {
}
};