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https://github.com/bsnes-emu/bsnes.git
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ff3750de4f
byuu says:
Changelog:
- fc/apu: $4003,$4007 writes initialize duty counter to 0 instead of 7
- fc/apu: corrected duty table entries for use with decrementing duty
counter
- processor/spc700: emulated the behavior of cycle 3 of (x)+
instructions to not read I/O registers
- specifically, this prevents reads from $fd-ff from resetting the
timers, as observed on real hardware
- sfc/controller: added ControllerPort class to match Mega Drive
design
- sfc/expansion: added ExpansionPort class to match Mega Drive design
- sfc/system: removed Peripherals class
- sfc/system: changed `colorburst()` to `cpuFrequency()`; added
`apuFrequency()`
- sfc: replaced calls to `system.region == System::Region::*` with
`Region::*()`
- sfc/expansion: remove thread from scheduler when device is destroyed
- sfc/smp: `{read,write}Port` now use a separate 4x8-bit buffer instead
of underlying APU RAM [hex\_usr]
39 lines
839 B
C++
39 lines
839 B
C++
auto APU::Pulse::clockLength() -> void {
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if(envelope.loopMode == 0) {
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if(lengthCounter) lengthCounter--;
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}
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}
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auto APU::Pulse::clock() -> uint8 {
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if(!sweep.checkPeriod()) return 0;
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if(lengthCounter == 0) return 0;
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static const uint dutyTable[4][8] = {
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{0, 0, 0, 0, 0, 0, 0, 1}, //12.5%
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{0, 0, 0, 0, 0, 0, 1, 1}, //25.0%
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{0, 0, 0, 0, 1, 1, 1, 1}, //50.0%
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{1, 1, 1, 1, 1, 1, 0, 0}, //25.0% (negated)
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};
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uint8 result = dutyTable[duty][dutyCounter] ? envelope.volume() : 0;
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if(sweep.pulsePeriod < 0x008) result = 0;
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if(--periodCounter == 0) {
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periodCounter = (sweep.pulsePeriod + 1) * 2;
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dutyCounter--;
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}
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return result;
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}
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auto APU::Pulse::power() -> void {
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envelope.power();
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sweep.power();
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lengthCounter = 0;
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duty = 0;
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dutyCounter = 0;
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period = 0;
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periodCounter = 1;
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}
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