bsnes/higan/sfc/alt/cpu/timing.cpp

120 lines
3.2 KiB
C++
Executable File

#ifdef CPU_CPP
void CPU::queue_event(unsigned id) {
switch(id) {
case QueueEvent::DramRefresh: return add_clocks(40);
case QueueEvent::HdmaRun: return hdma_run();
}
}
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.vtime * 1364 + status.htime * 4;
unsigned framelines = (system.region() == System::Region::NTSC ? 262 : 312) + field();
if(cpu_time > irq_time) irq_time += framelines * 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.htime * 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.vtime;
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_coprocessors();
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);
}
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_enabled && vcounter() == (ppu.overscan() == false ? 227 : 242)) {
run_auto_joypad_poll();
}
}
void CPU::run_auto_joypad_poll() {
input.port1->latch(1);
input.port2->latch(1);
input.port1->latch(0);
input.port2->latch(0);
uint16 joy1 = 0, joy2 = 0, joy3 = 0, joy4 = 0;
for(unsigned i = 0; i < 16; i++) {
uint8 port0 = input.port1->data();
uint8 port1 = input.port2->data();
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.joy1l = joy1;
status.joy1h = joy1 >> 8;
status.joy2l = joy2;
status.joy2h = joy2 >> 8;
status.joy3l = joy3;
status.joy3h = joy3 >> 8;
status.joy4l = joy4;
status.joy4h = joy4 >> 8;
}
#endif