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0dfdbbdd9b
This seems to be incorrect despite the test rom's results - Card Captor's intro sequence freezes for a few seconds because of this
56 lines
1.1 KiB
C++
56 lines
1.1 KiB
C++
#pragma once
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#include "pch.h"
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#include "WS/APU/WsApu.h"
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#include "WS/WsTypes.h"
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class WsApuCh4
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{
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private:
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WsApu* _apu = nullptr;
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WsApuCh4State* _state = nullptr;
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public:
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WsApuCh4(WsApu* apu, WsApuCh4State& state)
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{
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_state = &state;
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_apu = apu;
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}
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void Exec()
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{
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if(!_state->Enabled) {
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return;
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}
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if(_state->Timer == 0) {
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_state->Timer = 2047 - _state->Frequency;
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_state->SamplePosition = (_state->SamplePosition + 1) & 0x1F; //todows does this happen even when lfsr is enabled?
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if(_state->LfsrEnabled) {
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uint8_t newBit = ((_state->Lfsr >> 7) ^ (_state->Lfsr >> _state->TapShift) ^ 0x01) & 0x01;
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_state->Lfsr = ((_state->Lfsr << 1) | newBit) & 0x7FFF;
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}
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} else {
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_state->Timer--;
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}
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}
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void UpdateOutput()
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{
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if(!_state->Enabled) {
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_state->LeftOutput = 0;
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_state->RightOutput = 0;
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return;
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}
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uint8_t sample;
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if(_state->NoiseEnabled) {
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sample = (_state->Lfsr & 0x01) ? 0x0F : 0;
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} else {
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sample = _apu->ReadSample(3, _state->SamplePosition);
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}
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_state->LeftOutput = _state->LeftVolume * sample;
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_state->RightOutput = _state->RightVolume * sample;
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}
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};
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