mirror of https://github.com/bsnes-emu/bsnes.git
86 lines
2.0 KiB
C++
86 lines
2.0 KiB
C++
//70224 clocks/frame
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// 456 clocks/scanline
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// 154 scanlines/frame
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auto CPU::step(uint clocks) -> void {
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for(auto n : range(clocks)) {
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if(++status.clock == 0) {
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cartridge.mbc3.second();
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}
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//4MHz / N(hz) - 1 = mask
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status.div++;
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if((status.div & 15) == 0) timer262144hz();
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if((status.div & 63) == 0) timer65536hz();
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if((status.div & 255) == 0) timer16384hz();
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if((status.div & 511) == 0) timer8192hz();
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if((status.div & 1023) == 0) timer4096hz();
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ppu.clock -= ppu.frequency;
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if(ppu.clock < 0) co_switch(ppu.thread);
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apu.clock -= apu.frequency;
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if(apu.clock < 0) co_switch(apu.thread);
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}
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if(system.sgb()) {
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system._clocksExecuted += clocks;
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scheduler.exit(Scheduler::Event::Step);
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}
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}
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auto CPU::timer262144hz() -> void {
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if(status.timerEnable && status.timerClock == 1) {
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if(++status.tima == 0) {
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status.tima = status.tma;
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raise(Interrupt::Timer);
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}
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}
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}
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auto CPU::timer65536hz() -> void {
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if(status.timerEnable && status.timerClock == 2) {
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if(++status.tima == 0) {
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status.tima = status.tma;
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raise(Interrupt::Timer);
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}
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}
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}
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auto CPU::timer16384hz() -> void {
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if(status.timerEnable && status.timerClock == 3) {
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if(++status.tima == 0) {
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status.tima = status.tma;
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raise(Interrupt::Timer);
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}
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}
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}
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auto CPU::timer8192hz() -> void {
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if(status.serialTransfer && status.serialClock) {
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if(--status.serialBits == 0) {
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status.serialTransfer = 0;
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raise(Interrupt::Serial);
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}
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}
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}
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auto CPU::timer4096hz() -> void {
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if(status.timerEnable && status.timerClock == 0) {
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if(++status.tima == 0) {
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status.tima = status.tma;
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raise(Interrupt::Timer);
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}
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}
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}
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auto CPU::hblank() -> void {
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if(status.dmaMode == 1 && status.dmaLength && ppu.status.ly < 144) {
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for(auto n : range(16)) {
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writeDMA(status.dmaTarget++, readDMA(status.dmaSource++));
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}
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step(8 << status.speedDouble);
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status.dmaLength -= 16;
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}
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}
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