mirror of https://github.com/bsnes-emu/bsnes.git
38 lines
1.1 KiB
C++
38 lines
1.1 KiB
C++
auto CPU::prefetch_sync(uint32 addr) -> void {
|
|
if(addr == prefetch.addr) return;
|
|
|
|
prefetch.addr = addr;
|
|
prefetch.load = addr;
|
|
prefetch.wait = bus_wait(Half | Nonsequential, prefetch.load);
|
|
}
|
|
|
|
auto CPU::prefetch_step(uint clocks) -> void {
|
|
step(clocks);
|
|
if(!regs.wait.control.prefetch || active.dma) return;
|
|
|
|
while(!prefetch.full() && clocks--) {
|
|
if(--prefetch.wait) continue;
|
|
prefetch.slot[prefetch.load >> 1 & 7] = cartridge.read(Half, prefetch.load);
|
|
prefetch.load += 2;
|
|
prefetch.wait = bus_wait(Half | Sequential, prefetch.load);
|
|
}
|
|
}
|
|
|
|
auto CPU::prefetch_wait() -> void {
|
|
if(!regs.wait.control.prefetch || active.dma || prefetch.full()) return;
|
|
|
|
prefetch_step(prefetch.wait);
|
|
prefetch.wait = bus_wait(Half | Nonsequential, prefetch.load);
|
|
}
|
|
|
|
auto CPU::prefetch_read() -> uint16 {
|
|
if(prefetch.empty()) prefetch_step(prefetch.wait);
|
|
else prefetch_step(1);
|
|
|
|
if(prefetch.full()) prefetch.wait = bus_wait(Half | Sequential, prefetch.load);
|
|
|
|
uint16 half = prefetch.slot[prefetch.addr >> 1 & 7];
|
|
prefetch.addr += 2;
|
|
return half;
|
|
}
|