bsnes-plus/bsnes/snes/alt/cpu/timing.cpp

112 lines
3.1 KiB
C++

#ifdef CPU_CPP
void CPU::queue_event(unsigned id) {
switch(id) {
case QueueEvent::DramRefresh: return add_clocks(40);
case QueueEvent::HdmaRun: return hdma_run();
case QueueEvent::ControllerLatch: return ppu.latch_counters();
}
}
void CPU::last_cycle() {
if(status.irq_lock) {
status.irq_lock = false;
return;
}
if(status.nmi_transition) {
regs.wai = false;
status.nmi_transition = false;
status.nmi_pending = true;
}
if(status.irq_transition || regs.irq) {
regs.wai = false;
status.irq_transition = false;
status.irq_pending = !regs.p.i;
}
}
void CPU::add_clocks(unsigned clocks) {
if(status.hirq_enabled) {
if(status.virq_enabled) {
unsigned cpu_time = vcounter() * 1364 + hcounter();
unsigned irq_time = status.virq_pos * 1364 + status.hirq_pos * 4;
if(cpu_time > irq_time) irq_time += fieldlines() * 1364;
bool irq_valid = status.irq_valid;
status.irq_valid = cpu_time <= irq_time && cpu_time + clocks > irq_time;
if(!irq_valid && status.irq_valid) status.irq_line = true;
} else {
unsigned irq_time = status.hirq_pos * 4;
if(hcounter() > irq_time) irq_time += 1364;
bool irq_valid = status.irq_valid;
status.irq_valid = hcounter() <= irq_time && hcounter() + clocks > irq_time;
if(!irq_valid && status.irq_valid) status.irq_line = true;
}
if(status.irq_line) status.irq_transition = true;
} else if(status.virq_enabled) {
bool irq_valid = status.irq_valid;
status.irq_valid = vcounter() == status.virq_pos;
if(!irq_valid && status.irq_valid) status.irq_line = true;
if(status.irq_line) status.irq_transition = true;
} else {
status.irq_valid = false;
}
tick(clocks);
queue.tick(clocks);
step(clocks);
}
void CPU::scanline() {
synchronize_smp();
synchronize_ppu();
synchronize_coprocessor();
system.scanline();
if(vcounter() == 0) hdma_init();
queue.enqueue(534, QueueEvent::DramRefresh);
if(vcounter() <= (ppu.overscan() == false ? 224 : 239)) {
queue.enqueue(1104 + 8, QueueEvent::HdmaRun);
}
if(vcounter() == input.latchy) {
queue.enqueue(input.latchx, QueueEvent::ControllerLatch);
}
bool nmi_valid = status.nmi_valid;
status.nmi_valid = vcounter() >= (ppu.overscan() == false ? 225 : 240);
if(!nmi_valid && status.nmi_valid) {
status.nmi_line = true;
if(status.nmi_enabled) status.nmi_transition = true;
} else if(nmi_valid && !status.nmi_valid) {
status.nmi_line = false;
}
if(status.auto_joypad_poll && vcounter() == (ppu.overscan() == false ? 227 : 242)) {
input.poll();
run_auto_joypad_poll();
}
}
void CPU::run_auto_joypad_poll() {
uint16 joy1 = 0, joy2 = 0, joy3 = 0, joy4 = 0;
for(unsigned i = 0; i < 16; i++) {
uint8 port0 = input.port_read(0);
uint8 port1 = input.port_read(1);
joy1 |= (port0 & 1) ? (0x8000 >> i) : 0;
joy2 |= (port1 & 1) ? (0x8000 >> i) : 0;
joy3 |= (port0 & 2) ? (0x8000 >> i) : 0;
joy4 |= (port1 & 2) ? (0x8000 >> i) : 0;
}
status.joy1 = joy1;
status.joy2 = joy2;
status.joy3 = joy3;
status.joy4 = joy4;
}
#endif