@Override
public final void cartWrite(final int addr, final int data) {
if (addr < 0x8000 || addr > 0xffff) {
super.cartWrite(addr, data);
return;
}
final boolean bit0 = utils.getbit(addr, registers[0]);
final boolean bit1 = utils.getbit(addr, registers[1]);
switch (addr >> 12) {
case 0x8:
// 8000-8003: prg bank 0 select
prgbank0 = data;
setbanks();
break;
case 0x9:
case 0xa:
// sound registers here
sndchip.write((addr & 0xf000) + (bit1 ? 2 : 0) + (bit0 ? 1 : 0), data);
break;
case 0xc:
// c000-c003: prg bank 1 select
prgbank1 = data;
setbanks();
break;
case 0xb:
if (bit0 && bit1) {
// mirroring select
switch ((data >> 2) & 3) {
case 0:
setmirroring(Mapper.MirrorType.V_MIRROR);
break;
case 1:
setmirroring(Mapper.MirrorType.H_MIRROR);
break;
case 2:
setmirroring(Mapper.MirrorType.SS_MIRROR0);
break;
case 3:
setmirroring(Mapper.MirrorType.SS_MIRROR1);
break;
}
} else {
// expansion sound register here as well
sndchip.write((addr & 0xf000) + (bit1 ? 2 : 0) + (bit0 ? 1 : 0), data);
}
break;
case 0xd:
// character bank selects
chrbank[(bit1 ? 2 : 0) + (bit0 ? 1 : 0)] = data;
setbanks();
break;
case 0xe:
chrbank[(bit1 ? 2 : 0) + (bit0 ? 1 : 0) + 4] = data;
setbanks();
break;
case 0xf:
// irq control
if (!bit1) {
if (!bit0) {
irqreload = data;
} else {
irqack = utils.getbit(data, 0);
irqenable = utils.getbit(data, 1);
irqmode = utils.getbit(data, 2);
if (irqenable) {
irqcounter = irqreload;
prescaler = 341;
}
if (firedinterrupt) {
--cpu.interrupt;
}
firedinterrupt = false;
}
} else {
if (!bit0) {
irqenable = irqack;
if (firedinterrupt) {
--cpu.interrupt;
}
firedinterrupt = false;
}
}
}
}
