mirror of https://github.com/bsnes-emu/bsnes.git
107 lines
3.0 KiB
C++
107 lines
3.0 KiB
C++
#include <gb/gb.hpp>
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namespace GameBoy {
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#include "sequencer/sequencer.cpp"
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#include "square1/square1.cpp"
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#include "square2/square2.cpp"
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#include "wave/wave.cpp"
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#include "noise/noise.cpp"
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#include "serialization.cpp"
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APU apu;
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auto APU::Enter() -> void {
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while(true) scheduler.synchronize(), apu.main();
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}
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auto APU::main() -> void {
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square1.run();
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square2.run();
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wave.run();
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noise.run();
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sequencer.run();
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hipass(sequencer.center, sequencer.centerBias);
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hipass(sequencer.left, sequencer.leftBias);
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hipass(sequencer.right, sequencer.rightBias);
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interface->audioSample(sequencer.left, sequencer.right);
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if(cycle == 0) { //512hz
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if(phase == 0 || phase == 2 || phase == 4 || phase == 6) { //256hz
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square1.clockLength();
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square2.clockLength();
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wave.clockLength();
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noise.clockLength();
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}
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if(phase == 2 || phase == 6) { //128hz
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square1.clockSweep();
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}
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if(phase == 7) { //64hz
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square1.clockEnvelope();
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square2.clockEnvelope();
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noise.clockEnvelope();
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}
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phase++;
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}
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cycle++;
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clock += cpu.frequency;
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if(clock >= 0 && !scheduler.synchronizing()) co_switch(cpu.thread);
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}
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//filter to remove DC bias
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auto APU::hipass(int16& sample, int64& bias) -> void {
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bias += ((((int64)sample << 16) - (bias >> 16)) * 57593) >> 16;
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sample = sclamp<16>(sample - (bias >> 32));
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}
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auto APU::power() -> void {
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create(Enter, 2 * 1024 * 1024);
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for(uint n = 0xff10; n <= 0xff3f; n++) bus.mmio[n] = this;
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square1.power();
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square2.power();
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wave.power();
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noise.power();
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sequencer.power();
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phase = 0;
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cycle = 0;
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LinearFeedbackShiftRegisterGenerator r;
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for(auto& n : wave.pattern) n = r();
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}
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auto APU::mmio_read(uint16 addr) -> uint8 {
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if(addr >= 0xff10 && addr <= 0xff14) return square1.read(addr);
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if(addr >= 0xff15 && addr <= 0xff19) return square2.read(addr);
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if(addr >= 0xff1a && addr <= 0xff1e) return wave.read(addr);
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if(addr >= 0xff1f && addr <= 0xff23) return noise.read(addr);
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if(addr >= 0xff24 && addr <= 0xff26) return sequencer.read(addr);
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if(addr >= 0xff30 && addr <= 0xff3f) return wave.read(addr);
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return 0xff;
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}
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auto APU::mmio_write(uint16 addr, uint8 data) -> void {
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if(!sequencer.enable) {
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bool valid = addr == 0xff26; //NR52
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if(!system.cgb()) {
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//NRx1 length is writable only on DMG,SGB; not on CGB
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if(addr == 0xff11) valid = true, data &= 0x3f; //NR11; duty is not writable (remains 0)
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if(addr == 0xff16) valid = true, data &= 0x3f; //NR21; duty is not writable (remains 0)
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if(addr == 0xff1b) valid = true; //NR31
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if(addr == 0xff20) valid = true; //NR41
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}
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if(!valid) return;
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}
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if(addr >= 0xff10 && addr <= 0xff14) return square1.write(addr, data);
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if(addr >= 0xff15 && addr <= 0xff19) return square2.write(addr, data);
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if(addr >= 0xff1a && addr <= 0xff1e) return wave.write(addr, data);
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if(addr >= 0xff1f && addr <= 0xff23) return noise.write(addr, data);
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if(addr >= 0xff24 && addr <= 0xff26) return sequencer.write(addr, data);
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if(addr >= 0xff30 && addr <= 0xff3f) return wave.write(addr, data);
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}
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}
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