mirror of https://github.com/bsnes-emu/bsnes.git
25 lines
499 B
C++
25 lines
499 B
C++
auto PSG::Noise::run() -> void {
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if(counter--) return;
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if(rate == 0) counter = 0x10;
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if(rate == 1) counter = 0x20;
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if(rate == 2) counter = 0x40;
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if(rate == 3) counter = pitch; //shared with tone2
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if(clock ^= 1) { //0->1 transition
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output = lfsr.bit(0);
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lfsr = (lfsr.bit(0) ^ (lfsr.bit(3) & enable)) << 15 | lfsr >> 1;
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}
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}
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auto PSG::Noise::power() -> void {
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volume = ~0;
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counter = 0;
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pitch = 0;
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enable = 0;
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rate = 0;
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lfsr = 0x8000;
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clock = 0;
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output = 0;
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}
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