Mesen-X/Core/DeltaModulationChannel.h

#pragma once
#include "stdafx.h"
#include "IMemoryHandler.h"
#include "BaseApuChannel.h"

class Console;

class DeltaModulationChannel : public BaseApuChannel
{
private:	
	const uint16_t _dmcPeriodLookupTableNtsc[16] = { 428, 380, 340, 320, 286, 254, 226, 214, 190, 160, 142, 128, 106,  84,  72,  54 };
	const uint16_t _dmcPeriodLookupTablePal[16] = { 398, 354, 316, 298, 276, 236, 210, 198, 176, 148, 132, 118,  98,  78,  66,  50 };

	uint16_t _sampleAddr = 0;
	uint16_t _sampleLength = 0;
	uint8_t _outputLevel = 0;
	bool _irqEnabled = false;
	bool _loopFlag = false;

	uint16_t _currentAddr = 0;
	uint16_t _bytesRemaining = 0;
	uint8_t _readBuffer = 0;
	bool _bufferEmpty = true;

	uint8_t _shiftRegister = 0;
	uint8_t _bitsRemaining = 0;
	bool _silenceFlag = true;
	bool _needToRun = false;
	bool _needInit = false;

	uint8_t _lastValue4011 = 0;

	void InitSample();
	
	void Clock() override;

public:
	DeltaModulationChannel(AudioChannel channel, shared_ptr<Console> console, SoundMixer* mixer);

	virtual void Reset(bool softReset) override;
	virtual void StreamState(bool saving) override;

	bool IrqPending(uint32_t cyclesToRun);
	bool NeedToRun();
	bool GetStatus() override;
	void GetMemoryRanges(MemoryRanges &ranges) override;
	void WriteRAM(uint16_t addr, uint8_t value) override;

	void SetEnabled(bool enabled);
	void StartDmcTransfer();
	uint16_t GetDmcReadAddress();
	void SetDmcReadBuffer(uint8_t value);

	ApuDmcState GetState();
};