mirror of https://github.com/bsnes-emu/bsnes.git
101 lines
2.1 KiB
C++
Executable File
101 lines
2.1 KiB
C++
Executable File
struct VRC3 : Chip {
|
|
|
|
uint4 prg_bank;
|
|
bool irq_mode;
|
|
bool irq_enable;
|
|
bool irq_acknowledge;
|
|
uint16 irq_latch;
|
|
struct {
|
|
union {
|
|
uint16 w;
|
|
struct { uint8 order_lsb2(l, h); };
|
|
};
|
|
} irq_counter;
|
|
bool irq_line;
|
|
|
|
void main() {
|
|
while(true) {
|
|
if(scheduler.sync == Scheduler::SynchronizeMode::All) {
|
|
scheduler.exit(Scheduler::ExitReason::SynchronizeEvent);
|
|
}
|
|
|
|
if(irq_enable) {
|
|
if(irq_mode == 0) { //16-bit
|
|
if(++irq_counter.w == 0) {
|
|
irq_line = 1;
|
|
irq_enable = irq_acknowledge;
|
|
irq_counter.w = irq_latch;
|
|
}
|
|
}
|
|
if(irq_mode == 1) { //8-bit
|
|
if(++irq_counter.l == 0) {
|
|
irq_line = 1;
|
|
irq_enable = irq_acknowledge;
|
|
irq_counter.l = irq_latch;
|
|
}
|
|
}
|
|
}
|
|
|
|
cpu.set_irq_line(irq_line);
|
|
tick();
|
|
}
|
|
}
|
|
|
|
unsigned prg_addr(unsigned addr) const {
|
|
unsigned bank = (addr < 0xc000 ? (unsigned)prg_bank : 0x0f);
|
|
return (bank * 0x4000) + (addr & 0x3fff);
|
|
}
|
|
|
|
void reg_write(unsigned addr, uint8 data) {
|
|
switch(addr & 0xf000) {
|
|
case 0x8000: irq_latch = (irq_latch & 0xfff0) | ((data & 0x0f) << 0); break;
|
|
case 0x9000: irq_latch = (irq_latch & 0xff0f) | ((data & 0x0f) << 4); break;
|
|
case 0xa000: irq_latch = (irq_latch & 0xf0ff) | ((data & 0x0f) << 8); break;
|
|
case 0xb000: irq_latch = (irq_latch & 0x0fff) | ((data & 0x0f) << 12); break;
|
|
|
|
case 0xc000:
|
|
irq_mode = data & 0x04;
|
|
irq_enable = data & 0x02;
|
|
irq_acknowledge = data & 0x01;
|
|
if(irq_enable) irq_counter.w = irq_latch;
|
|
break;
|
|
|
|
case 0xd000:
|
|
irq_line = 0;
|
|
irq_enable = irq_acknowledge;
|
|
break;
|
|
|
|
case 0xf000:
|
|
prg_bank = data & 0x0f;
|
|
break;
|
|
}
|
|
}
|
|
|
|
void power() {
|
|
}
|
|
|
|
void reset() {
|
|
prg_bank = 0;
|
|
irq_mode = 0;
|
|
irq_enable = 0;
|
|
irq_acknowledge = 0;
|
|
irq_latch = 0;
|
|
irq_counter.w = 0;
|
|
irq_line = 0;
|
|
}
|
|
|
|
void serialize(serializer &s) {
|
|
s.integer(prg_bank);
|
|
s.integer(irq_mode);
|
|
s.integer(irq_enable);
|
|
s.integer(irq_acknowledge);
|
|
s.integer(irq_latch);
|
|
s.integer(irq_counter.w);
|
|
s.integer(irq_line);
|
|
}
|
|
|
|
VRC3(Board &board) : Chip(board) {
|
|
}
|
|
|
|
};
|