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◆ main openmsx / src / memory / RomDooly.cc
2.5 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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//
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// Agigongnyong Dooly
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//
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#include "RomDooly.hh"
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#include "CacheLine.hh"
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#include "MSXException.hh"
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#include "serialize.hh"
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namespace openmsx {
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RomDooly::RomDooly(const DeviceConfig& config, Rom&& rom_)
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	: MSXRom(config, std::move(rom_))
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	, romBlockDebug(*this, std::span{&conversion, 1}, 0x4000, 0x8000, 15)
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{
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	if (rom.size() != 0x8000) {
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		throw MSXException("Dooly ROM-size must be exactly 32kB");
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	}
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	reset(EmuTime::dummy());
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}
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void RomDooly::reset(EmuTime /*time*/)
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{
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	conversion = 0;
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}
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byte RomDooly::peekMem(uint16_t address, EmuTime /*time*/) const
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{
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	if ((0x4000 <= address) && (address < 0xc000)) {
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		byte value = rom[address - 0x4000];
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		switch (conversion) {
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		case 0:
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			return value;
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		case 1:
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			return (value & 0xf8) | (value << 2 & 0x04) | (value >> 1 & 0x03);
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		case 4:
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			return (value & 0xf8) | (value >> 2 & 0x01) | (value << 1 & 0x06);
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		case 2:
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		case 5:
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		case 6:
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			switch (value & 0x07) {
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			case 1:
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			case 2:
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			case 4:
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				return value & 0xf8;
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			case 3:
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			case 5:
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			case 6:
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				if (conversion == 2) return (value & 0xf8) | (((value << 2 & 0x04) | (value >> 1 & 0x03)) ^ 0x07);
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				if (conversion == 5) return value ^ 0x07;
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				if (conversion == 6) return (value & 0xf8) | (((value >> 2 & 0x01) | (value << 1 & 0x06)) ^ 0x07);
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				[[fallthrough]];
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			default:
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				return value;
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			}
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		default:
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			return value | 0x07;
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		}
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	}
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	return 0xff;
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}
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byte RomDooly::readMem(uint16_t address, EmuTime time)
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{
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	return peekMem(address, time);
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}
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void RomDooly::writeMem(uint16_t address, byte value, EmuTime /*time*/)
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{
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	// TODO: To what region does the real cartridge react?
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	// * Using the full region [0x4000,0xc000) interferes with the
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	//   RAM-check routine of many MSX machines (game doesn't boot)
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	// * The game seems to write at many different addresses. The min/max
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	//   I've seen is 0x8780/0x8f86. So my best *guess* is to extend this
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	//   region to [0x8000,0x9000).
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	// * This smaller region seems to make the game work (on the above
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	//   machines that failed before).
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	if ((0x8000 <= address) && (address < 0x9000)) {
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		conversion = value & 0x07;
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	}
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}
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byte* RomDooly::getWriteCacheLine(uint16_t address)
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{
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	if (((0x4000 & CacheLine::HIGH) <= address) && (address < (0xc000 & CacheLine::HIGH))) {
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		return nullptr;
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	} else {
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		return unmappedWrite.data();
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	}
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}
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template<typename Archive>
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void RomDooly::serialize(Archive& ar, unsigned /*version*/)
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{
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	ar.template serializeBase<MSXDevice>(*this);
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	ar.serialize("conversion", conversion);
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}
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INSTANTIATE_SERIALIZE_METHODS(RomDooly);
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REGISTER_MSXDEVICE(RomDooly, "RomDooly");
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} // namespace openmsx