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◆ main openmsx / src / memory / RomKonami.cc
2.2 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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// KONAMI 8kB cartridges (without SCC)
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//
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// this type is used by Konami cartridges without SCC and some others
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// examples of cartridges: Nemesis, Penguin Adventure, Usas, Metal Gear, Shalom,
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// The Maze of Galious, Aleste 1, 1942, Heaven, Mystery World, ...
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// (the latter four are hacked ROM images with modified mappers)
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//
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// page at 4000 is fixed, other banks are switched by writing at
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// 0x6000, 0x8000 and 0xA000 (those addresses are used by the games, but any
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// other address in a page switches that page as well)
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#include "RomKonami.hh"
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#include "MSXCliComm.hh"
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#include "MSXMotherBoard.hh"
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#include "serialize.hh"
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#include "xrange.hh"
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namespace openmsx {
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RomKonami::RomKonami(const DeviceConfig& config, Rom&& rom_)
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	: Rom8kBBlocks(config, std::move(rom_))
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{
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	// Konami mapper is 256kB in size, even if ROM is smaller.
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	setBlockMask(31);
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	// warn if a ROM is used that would not work on a real Konami mapper
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	if (rom.size() > 256 * 1024) {
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		getMotherBoard().getMSXCliComm().printWarning(
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			"The size of this ROM image is larger than 256kB, "
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			"which is not supported on real Konami mapper chips!");
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	}
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	reset(EmuTime::dummy());
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}
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void RomKonami::bankSwitch(unsigned page, unsigned block)
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{
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	setRom(page, block);
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	// Note: the mirror behavior is different from RomKonamiSCC !
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	if (page == 2 || page == 3) {
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		// [0x4000-0x8000), mirrored in [0x0000-0x4000)
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		setRom(page - 2, block);
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	} else if (page == 4 || page == 5) {
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		// [0x8000-0xC000), mirrored in [0xC000-0x10000)
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		setRom(page + 2, block);
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	} else {
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		assert(false);
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	}
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}
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void RomKonami::reset(EmuTime /*time*/)
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{
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	for (auto i : xrange(2, 6)) {
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		bankSwitch(i, i - 2);
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	}
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}
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void RomKonami::writeMem(uint16_t address, byte value, EmuTime /*time*/)
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{
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	// Note: [0x4000..0x6000) is fixed at segment 0.
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	if (0x6000 <= address && address < 0xC000) {
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		bankSwitch(address >> 13, value);
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	}
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}
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byte* RomKonami::getWriteCacheLine(uint16_t address)
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{
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	return (0x6000 <= address && address < 0xC000) ? nullptr : unmappedWrite.data();
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}
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template<typename Archive>
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void RomKonami::serialize(Archive& ar, unsigned /*version*/)
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{
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	ar.template serializeBase<Rom8kBBlocks>(*this);
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}
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INSTANTIATE_SERIALIZE_METHODS(RomKonami);
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REGISTER_MSXDEVICE(RomKonami, "RomKonami");
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} // namespace openmsx