mirror of https://github.com/bsnes-emu/bsnes.git
95 lines
2.4 KiB
C++
95 lines
2.4 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::add_clocks(uint clocks) -> void {
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if(oamdma.active) {
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for(uint n = 0; n < 4 * clocks; n++) {
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bus.write(0xfe00 + oamdma.offset, bus.read((oamdma.bank << 8) + oamdma.offset));
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if(++oamdma.offset == 160) {
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oamdma.active = false;
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break;
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}
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}
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}
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system.clocks_executed += clocks;
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if(system.sgb()) scheduler.exit(Scheduler::ExitReason::StepEvent);
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status.clock += clocks;
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if(status.clock >= 4 * 1024 * 1024) {
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status.clock -= 4 * 1024 * 1024;
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cartridge.mbc3.second();
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}
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//4MHz / N(hz) - 1 = mask
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if((status.clock & 15) == 0) timer_262144hz();
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if((status.clock & 63) == 0) timer_65536hz();
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if((status.clock & 255) == 0) timer_16384hz();
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if((status.clock & 511) == 0) timer_8192hz();
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if((status.clock & 1023) == 0) timer_4096hz();
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ppu.clock -= clocks * ppu.frequency;
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if(ppu.clock < 0) co_switch(scheduler.active_thread = ppu.thread);
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apu.clock -= clocks * apu.frequency;
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if(apu.clock < 0) co_switch(scheduler.active_thread = apu.thread);
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}
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auto CPU::timer_262144hz() -> void {
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if(status.timer_enable && status.timer_clock == 1) {
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if(++status.tima == 0) {
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status.tima = status.tma;
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interrupt_raise(Interrupt::Timer);
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}
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}
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}
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auto CPU::timer_65536hz() -> void {
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if(status.timer_enable && status.timer_clock == 2) {
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if(++status.tima == 0) {
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status.tima = status.tma;
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interrupt_raise(Interrupt::Timer);
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}
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}
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}
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auto CPU::timer_16384hz() -> void {
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if(status.timer_enable && status.timer_clock == 3) {
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if(++status.tima == 0) {
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status.tima = status.tma;
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interrupt_raise(Interrupt::Timer);
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}
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}
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status.div++;
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}
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auto CPU::timer_8192hz() -> void {
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if(status.serial_transfer && status.serial_clock) {
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if(--status.serial_bits == 0) {
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status.serial_transfer = 0;
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interrupt_raise(Interrupt::Serial);
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}
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}
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}
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auto CPU::timer_4096hz() -> void {
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if(status.timer_enable && status.timer_clock == 0) {
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if(++status.tima == 0) {
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status.tima = status.tma;
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interrupt_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.dma_mode == 1 && status.dma_length && ppu.status.ly < 144) {
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for(auto n : range(16)) {
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dma_write(status.dma_target++, dma_read(status.dma_source++));
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}
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add_clocks(8 << status.speed_double);
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status.dma_length -= 16;
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}
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}
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