mirror of https://github.com/bsnes-emu/bsnes.git
59 lines
1.5 KiB
C++
59 lines
1.5 KiB
C++
auto SMP::addClocks(uint clocks) -> void {
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step(clocks);
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synchronizeDSP();
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#if defined(DEBUGGER)
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synchronizeCPU();
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#else
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//forcefully sync S-SMP to S-CPU in case chips are not communicating
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//sync if S-SMP is more than 24 samples ahead of S-CPU
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if(clock > +(768 * 24 * (int64)24000000)) synchronizeCPU();
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#endif
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}
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auto SMP::cycleEdge() -> void {
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timer0.tick();
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timer1.tick();
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timer2.tick();
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//TEST register S-SMP speed control
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//24 clocks have already been added for this cycle at this point
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switch(status.clockSpeed) {
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case 0: break; //100% speed
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case 1: addClocks(24); break; // 50% speed
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case 2: while(true) addClocks(24); // 0% speed -- locks S-SMP
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case 3: addClocks(24 * 9); break; // 10% speed
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}
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}
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template<unsigned Frequency>
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auto SMP::Timer<Frequency>::tick() -> void {
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//stage 0 increment
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stage0 += smp.status.timerStep;
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if(stage0 < Frequency) return;
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stage0 -= Frequency;
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//stage 1 increment
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stage1 ^= 1;
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synchronizeStage1();
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}
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template<unsigned Frequency>
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auto SMP::Timer<Frequency>::synchronizeStage1() -> void {
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bool newLine = stage1;
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if(smp.status.timersEnable == false) newLine = false;
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if(smp.status.timersDisable == true) newLine = false;
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bool oldLine = line;
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line = newLine;
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if(oldLine != 1 || newLine != 0) return; //only pulse on 1->0 transition
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//stage 2 increment
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if(enable == false) return;
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if(++stage2 != target) return;
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//stage 3 increment
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stage2 = 0;
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stage3++;
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}
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