Mesen/Core/Txc22211A.h

#pragma once
#include "stdafx.h"
#include "BaseMapper.h"

class Txc22211A : public BaseMapper
{
protected:
	TxcChip _txc = TxcChip(false);

	uint16_t GetPRGPageSize() override { return 0x8000; }
	uint16_t GetCHRPageSize() override { return 0x2000; }
	uint16_t RegisterStartAddress() override { return 0x8000; }
	uint16_t RegisterEndAddress() override { return 0xFFFF; }
	bool AllowRegisterRead() override { return true; }

	void InitMapper() override
	{
		AddRegisterRange(0x4020, 0x5FFF, MemoryOperation::Any);
		RemoveRegisterRange(0x8000, 0xFFFF, MemoryOperation::Read);

		SelectPRGPage(0, 0);
		SelectCHRPage(0, 0);
	}
	
	void StreamState(bool saving) override
	{
		BaseMapper::StreamState(saving);
		Stream(&_txc);
	}

	virtual void UpdateState()
	{
		SelectPRGPage(0, (_txc.GetOutput() >> 2) & 0x01);
		SelectCHRPage(0, _txc.GetOutput() & 0x03);
	}

	uint8_t ReadRegister(uint16_t addr) override
	{
		uint8_t openBus = _console->GetMemoryManager()->GetOpenBus();
		uint8_t value = openBus;
		if((addr & 0x103) == 0x100) {
			value = (openBus & 0xF0) | (_txc.Read() & 0x0F);
		}
		UpdateState();
		return value;
	}

	void WriteRegister(uint16_t addr, uint8_t value) override
	{
		_txc.Write(addr, value & 0x0F);
		UpdateState();
	}
};