OXYGENHUB
◆ main openmsx / src / memory / RomKorean128in1.cc
1.5 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
// Korean 128-in-1 cartridge for Sega/MSX, see
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// https://www.smspower.org/forums/17902-DumpingKorean128128In1CartridgeLikelyPirateMissingOriginalLabel
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//
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// Reverse engineered by bsittler.
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//
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//    ... the unusual MSX mapper this dump normally would require, where writing
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//    byte Y to address 0x6000 would map 0x4000-0x5FFF to Y, 0x6000-0x7FFF to Y
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//    XOR 1, 0x8000-0x9FFF to Y XOR 2, and 0xA000-0xBFFF to Y XOR 3.
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//
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// Those are 8KB page numbers, naturally. And yes, it really is XOR and not
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// addition - sometimes two games share a page and map it differently in a way
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// that only works when the operation is XOR.
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#include "RomKorean128in1.hh"
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#include "CacheLine.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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RomKorean128in1::RomKorean128in1(const DeviceConfig& config, Rom&& rom_)
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	: Rom8kBBlocks(config, std::move(rom_))
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{
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	reset(EmuTime::dummy());
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}
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void RomKorean128in1::reset(EmuTime /*time*/)
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{
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	setUnmapped(0);
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	setUnmapped(1);
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	// TODO: initial mapping not known (?)
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	for (auto i : xrange(2, 6)) {
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		setRom(i, i - 2);
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	}
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	setUnmapped(6);
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	setUnmapped(7);
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}
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void RomKorean128in1::writeMem(uint16_t address, byte value, EmuTime /*time*/)
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{
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	if (address == 0x6000) {
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		for (auto i : xrange(2, 6)) {
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			setRom(i, value ^ (i - 2));
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		}
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	}
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}
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byte* RomKorean128in1::getWriteCacheLine(uint16_t address)
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{
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	if (address == (0x6000 & 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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REGISTER_MSXDEVICE(RomKorean128in1, "RomKorean128in1");
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} // namespace openmsx