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◆ main openmsx / src / MSXKanji.cc
3.6 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
#include "MSXKanji.hh"
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#include "MSXException.hh"
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#include "TclObject.hh"
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#include "serialize.hh"
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#include "one_of.hh"
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namespace openmsx {
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MSXKanji::MSXKanji(DeviceConfig& config)
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	: MSXDevice(config)
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	, rom(getName(), "Kanji ROM", config)
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	, highAddressMask(config.getChildData("type", {}) == "hangul" ? 0x7F : 0x3F)
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{
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	auto level2ViaStr = config.getChildData("level_2_via", "read"); // default 'read' for bw compat
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	if (level2ViaStr == "read") {
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		level2Via = Level2Via::Read;
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		portMask = 3;
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	} else if (level2ViaStr == "write") {
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		level2Via = Level2Via::Write;
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		portMask = 3;
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	} else if (level2ViaStr == "interlocked_write_read") {
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		level2Via = Level2Via::InterlockedWriteRead;
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		portMask = 3;
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	} else if (level2ViaStr == "only_level_1") {
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		level2Via = Level2Via::Read;
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		portMask = 1; // implemented by redirecting level2 ports to level1
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	} else {
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		throw MSXException("MSXKanji: invalid value for 'level_2_via'");
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	}
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	auto size = rom.size();
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	if (size != one_of(0x20000u, 0x40000u)) {
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		throw MSXException("MSXKanji: wrong kanji ROM, it should be either 128kB or 256kB.");
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	}
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	if ((highAddressMask == 0x7F) && (size != 0x40000)) {
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		throw MSXException("MSXKanji: for hangul type, the font ROM must be 256kB.");
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	}
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	reset(EmuTime::dummy());
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}
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void MSXKanji::reset(EmuTime /*time*/)
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{
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	adr = 0; // TODO check inital value
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	writeLevel = 0;
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}
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void MSXKanji::writeIO(uint16_t port, uint8_t value, EmuTime /*time*/)
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{
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	port &= portMask;
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	writeLevel = (port & 2) ? 1 : 0;
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	switch (port & 1) {
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	case 0:
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		adr = (adr & 0x3f800) | ((value & 0x3f) << 5); // 6 bit column
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		break;
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	case 1:
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		adr = (adr & 0x007e0) | ((value & highAddressMask) << 11); // 6 or 7 (for 'hangul') bit row
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		break;
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	}
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	// note: write to either row/column resets the counter
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}
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MSXKanji::ReadImplResult MSXKanji::readImpl(uint16_t port) const
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{
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	uint8_t readLevel = (port & portMask & 2) ? 1 : 0;
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	unsigned address = 0;
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	switch (level2Via) {
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	case Level2Via::Read:
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		address = adr | (readLevel << 17);
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		break;
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	case Level2Via::InterlockedWriteRead:
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		if (readLevel != writeLevel) return {.valid = false, .value = 0xFF};
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		[[fallthrough]];
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	case Level2Via::Write:
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		address = adr | (writeLevel << 17);
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		break;
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	}
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	auto value = (address < rom.size()) ? rom[address] : uint8_t(0xff);
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	return {.valid = true, .value = value};
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}
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uint8_t MSXKanji::peekIO(uint16_t port, EmuTime /*time*/) const
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{
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	return readImpl(port).value;
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}
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uint8_t MSXKanji::readIO(uint16_t port, EmuTime /*time*/)
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{
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	auto [valid, value] = readImpl(port);
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	if (valid) {
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		adr = (adr & ~0x1f) | ((adr + 1) & 0x1f);
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	}
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	return value;
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}
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void MSXKanji::getExtraDeviceInfo(TclObject& result) const
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{
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	rom.getInfo(result);
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}
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// version 1 : initial version
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// version 2 : replaced adr1/adr2 with a single shared adr, added writeLevel
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template<typename Archive>
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void MSXKanji::serialize(Archive& ar, unsigned version)
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{
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	ar.template serializeBase<MSXDevice>(*this);
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	if (ar.versionBelow(version, 2)) {
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		assert(Archive::IS_LOADER);
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		ar.serialize("adr1", adr);
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		//ar.serialize("adr2", adr); // ignored
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		writeLevel = 0;
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	} else {
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		ar.serialize("adr",        adr,
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		             "writeLevel", writeLevel);
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	}
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}
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INSTANTIATE_SERIALIZE_METHODS(MSXKanji);
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REGISTER_MSXDEVICE(MSXKanji, "Kanji");
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/*
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This really works!
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10 DIM A(32)
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20 FOR I=0 TO 4095
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30 OUT &HD8, I MOD 64: OUT &HD9, I\64
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40 FOR J=0 TO 31: A(J)=INP(&HD9): NEXT
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50 FOR J=0 TO 7
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60 PRINT RIGHT$("0000000"+BIN$(A(J)), 8);
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70 PRINT RIGHT$("0000000"+BIN$(A(J+8)), 8)
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80 NEXT
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90 FOR J=16 TO 23
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100 PRINT RIGHT$("0000000"+BIN$(A(J)), 8);
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110 PRINT RIGHT$("0000000"+BIN$(A(J+8)), 8)
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120 NEXT
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130 PRINT
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140 NEXT
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*/
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} // namespace openmsx