mirror of
https://github.com/bsnes-emu/bsnes.git
synced 2025-02-23 22:52:34 +01:00
78d49d3873
byuu says: Changelog: - int_t<bits> replaced with Integer<bits> - uint_t<bits> replaced with Natural<bits> - fixed "Synchronize Audio" menu option that broke recently - all of sfc/performance ported to "auto function() -> return;" syntax With this WIP, all of higan is finally ported over to the new function declaration syntax. Thank the gods. There's still going to be periodic disruption for diffs from porting over signed->int, unsigned->uint, and whatever we come up with for the new Natural<> and Integer<> classes. But the worst of it's behind us now.
94 lines
2.0 KiB
C++
94 lines
2.0 KiB
C++
auto APU::Noise::divider() const -> uint {
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if(divisor == 0) return 4;
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return divisor * 8;
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}
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auto APU::Noise::run() -> void {
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if(period && --period == 0) {
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period = divider() << frequency;
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if(frequency < 14) {
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bool bit = (lfsr ^ (lfsr >> 1)) & 1;
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lfsr = (lfsr >> 1) ^ (bit << (narrowlfsr ? 6 : 14));
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}
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}
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output = volume;
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if(enable == false || (lfsr & 1)) output = 0;
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}
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auto APU::Noise::clocklength() -> void {
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if(enable && counter) {
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if(++length == 0) enable = false;
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}
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}
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auto APU::Noise::clockenvelope() -> void {
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if(enable && envelope.frequency && --envelope.period == 0) {
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envelope.period = envelope.frequency;
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if(envelope.direction == 0 && volume > 0) volume--;
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if(envelope.direction == 1 && volume < 15) volume++;
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}
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}
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auto APU::Noise::read(uint addr) const -> uint8 {
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switch(addr) {
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case 1: return 0;
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case 2: return (envelope.frequency << 0) | (envelope.direction << 3) | (envelope.volume << 4);
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case 3: return (divisor << 0) | (narrowlfsr << 3) | (frequency << 4);
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case 4: return (counter << 6);
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}
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}
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auto APU::Noise::write(uint addr, uint8 byte) -> void {
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switch(addr) {
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case 1: //NR41
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length = byte >> 0;
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break;
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case 2: //NR42
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envelope.frequency = byte >> 0;
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envelope.direction = byte >> 3;
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envelope.volume = byte >> 4;
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if(!envelope.dacEnable()) enable = false;
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break;
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case 3: //NR43
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divisor = byte >> 0;
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narrowlfsr = byte >> 3;
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frequency = byte >> 4;
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period = divider() << frequency;
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break;
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case 4: //NR44
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counter = byte >> 6;
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initialize = byte >> 7;
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if(initialize) {
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enable = envelope.dacEnable();
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lfsr = -1;
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envelope.period = envelope.frequency;
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volume = envelope.volume;
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}
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break;
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}
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}
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auto APU::Noise::power() -> void {
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envelope.frequency = 0;
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envelope.direction = 0;
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envelope.volume = 0;
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envelope.period = 0;
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length = 0;
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divisor = 0;
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narrowlfsr = 0;
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frequency = 0;
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counter = 0;
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initialize = 0;
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enable = 0;
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lfsr = 0;
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output = 0;
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period = 0;
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volume = 0;
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}
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