// $Id: RomPanasonic.cc 5751 2006-10-05 19:34:54Z m9710797 $

#include "RomPanasonic.hh"
#include "PanasonicMemory.hh"
#include "MSXMotherBoard.hh"
#include "XMLElement.hh"
#include "SRAM.hh"
#include "CacheLine.hh"
#include "Rom.hh"

namespace openmsx {

const int SRAM_BASE = 0x80;
const int RAM_BASE  = 0x180;


RomPanasonic::RomPanasonic(
	MSXMotherBoard& motherBoard, const XMLElement& config,
	const EmuTime& time, std::auto_ptr<Rom> rom_)
	: Rom8kBBlocks(motherBoard, config, time, rom_)
{
	int sramSize = config.getChildDataAsInt("sramsize", 0);
	if (sramSize) {
		sram.reset(new SRAM(motherBoard, getName() + " SRAM",
		                    sramSize * 1024, config));
	}

	if (config.getChildDataAsBool("sram-mirrored", false)) {
		maxSRAMBank = SRAM_BASE + 8;
	} else {
		maxSRAMBank = SRAM_BASE + (sramSize / 8);
	}

	reset(time);
}

RomPanasonic::~RomPanasonic()
{
}

void RomPanasonic::reset(const EmuTime& /*time*/)
{
	control = 0;
	for (int region = 0; region < 8; ++region) {
		bankSelect[region] = 0;
		setRom(region, 0);
	}
}

byte RomPanasonic::peekMem(word address, const EmuTime& time) const
{
	byte result;
	if ((control & 0x04) && (0x7FF0 <= address) && (address < 0x7FF8)) {
		// read mapper state (lower 8 bit)
		result = bankSelect[address & 7] & 0xFF;
	} else if ((control & 0x10) && (address == 0x7FF8)) {
		// read mapper state (9th bit)
		result = 0;
		for (int i = 7; i >= 0; i--) {
			result <<= 1;
			if (bankSelect[i] & 0x100) {
				result++;
			}
		}
	} else if ((control & 0x08) && (address == 0x7FF9)) {
		// read control byte
		result = control;
	} else {
		result = Rom8kBBlocks::peekMem(address, time);
	}
	//PRT_DEBUG("DEBUG read "<<hex<<(int)address<<" "<<
	//          (int)result<<dec);
	return result;
}

byte RomPanasonic::readMem(word address, const EmuTime& time)
{
	return peekMem(address, time);
}

const byte* RomPanasonic::getReadCacheLine(word address) const
{
	if ((0x7FF0 & CacheLine::HIGH) == address) {
		// TODO check mirrored
		return NULL;
	} else {
		return Rom8kBBlocks::getReadCacheLine(address);
	}
}

void RomPanasonic::writeMem(word address, byte value, const EmuTime& /*time*/)
{
	//PRT_DEBUG("DEBUG write "<<hex<<(int)address<<
	//          " "<<(int)value<<dec);
	if ((0x6000 <= address) && (address < 0x7FF0)) {
		// set mapper state (lower 8 bits)
		int region = (address & 0x1C00) >> 10;
		if ((region == 5) || (region == 6)) region ^= 3;
		int selectedBank = bankSelect[region];
		int newBank = (selectedBank & ~0xFF) | value;
		changeBank(region, newBank);
	} else if (address == 0x7FF8) {
		// set mapper state (9th bit)
		for (int region = 0; region < 8; region++) {
			if (value & 1) {
				changeBank(region, bankSelect[region] |  0x100);
			} else {
				changeBank(region, bankSelect[region] & ~0x100);
			}
			value >>= 1;
		}
	} else if (address == 0x7FF9) {
		// write control byte
		control = value;
	} else if ((0x8000 <= address) && (address < 0xC000)) {
		int region = address >> 13;
		int selectedBank = bankSelect[region];
		if (sram.get() && (SRAM_BASE <= selectedBank) &&
			    (selectedBank < maxSRAMBank)) {
			// SRAM
			int block = selectedBank - SRAM_BASE;
			sram->write((block * 0x2000) | (address & 0x1FFF), value);
		} else if (RAM_BASE <= selectedBank) {
			// RAM
			const_cast<byte*>(bank[region])[address & 0x1FFF] = value;
		}
	}
}

byte* RomPanasonic::getWriteCacheLine(word address) const
{
	//return NULL;
	if ((0x6000 <= address) && (address < 0x7FF0)) {
		return NULL;
	} else if (address == (0x7FF8 & CacheLine::HIGH)) {
		return NULL;
	} else if ((0x8000 <= address) && (address < 0xC000)) {
		int region = address >> 13;
		int selectedBank = bankSelect[region];
		if (sram.get() && (SRAM_BASE <= selectedBank) &&
			     (selectedBank < maxSRAMBank)) {
			// SRAM
			return NULL;
		} else if (RAM_BASE <= selectedBank) {
			// RAM
			return const_cast<byte*>(&bank[region][address & 0x1FFF]);
		} else {
			return unmappedWrite;
		}
	} else {
		return unmappedWrite;
	}
}

void RomPanasonic::changeBank(byte region, int bank)
{
	if (bank == bankSelect[region]) {
		return;
	}
	bankSelect[region] = bank;
	if (sram.get() && (SRAM_BASE <= bank) && (bank < maxSRAMBank)) {
		// SRAM
		int offset = (bank - SRAM_BASE) * 0x2000;
		int sramSize = sram->getSize();
		if (offset >= sramSize) {
			offset &= (sramSize - 1);
		}
		setBank(region, &sram->operator[](offset));
	} else if (RAM_BASE <= bank) {
		// RAM
		setBank(region, getMotherBoard().getPanasonicMemory().
			getRamBlock(bank - RAM_BASE));
	} else {
		// ROM
		setRom(region, bank);
	}
}

} // namespace openmsx