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◆ main openmsx / src / memory / RomNettouYakyuu.cc
3.7 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
// Based on information from hap/enen, published here:
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// http://www.msx.org/forumtopicl8552.html
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// and his implementation in blueMSX
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//
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// Jaleco - Moero!! Nettou Yakyuu '88, 256KB ROM, CRC32 68745C64
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// NEC D7756C 146 sample player with internal 256Kbit ROM, undumped. Same
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// samples as Famicom Moero!! Pro Yakyuu (Black/Red), recording available at
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// http://home.planet.nl/~haps/segali_archive/
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// 4*8KB pages at $4000-$BFFF, initialized to 0.
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// Mapper chip is exactly the same as ASCII8, except for data bit 7:
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// a:011ppxxx xxxxxxxx d:sxxbbbbb
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// a:address, d:data, p: page, b:bank, x:don't care
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// s:if set, page reads/writes redirect to sample player via a 74HC174, eg.
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// write $80 to $7800 -> $A000-$BFFF = sample player I/O
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// Sample player (datasheet, 690KB one on
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// http://www.datasheetarchive.com/search.php?t=0&q=uPD7756 ):
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// reads: always $FF (/BUSY not used)
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// writes: d:rsxxiiii
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// i:I0-I3 (sample number, latched on /ST rising edge when not playing)
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// s:/ST (start), r:1=enable continuous rising edges to /ST (ORed with s),
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// 0=falling edge to /RESET
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// As I'm unable to measure, s and r bits pin setups are guessed from knowing
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// the behaviour (examples underneath).
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// examples:
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// - $C0: nothing
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// - $80: "strike, strike, strike, strike, ..."
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// - $80, $C0: "strike"
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// - $80, short delay, $00/$40: "stri"
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// - $80, short delay, $81: "strike, ball, ball, ball, ball, ..."
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// note: writes to sample player are ignored if on page $6000-$7FFF, possibly
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// due to conflict with mapper chip, reads still return $FF though.
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// regarding this implementation: part of the above behaviour is put in the
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// sample player. It may be a good idea to move this behaviour to a more
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// specialized class some time in the future.
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#include "RomNettouYakyuu.hh"
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#include "FileOperations.hh"
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#include "serialize.hh"
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#include "xrange.hh"
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#include <algorithm>
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namespace openmsx {
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RomNettouYakyuu::RomNettouYakyuu(const DeviceConfig& config, Rom&& rom_)
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	: Rom8kBBlocks(config, std::move(rom_))
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	, samplePlayer(
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		"Nettou Yakyuu-DAC",
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		"Jaleco Moero!! Nettou Yakuu '88 DAC", config,
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		strCat(FileOperations::stripExtension(rom.getFilename()), '_'),
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		16, "nettou_yakyuu/nettou_yakyuu_")
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{
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	reset(EmuTime::dummy());
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}
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void RomNettouYakyuu::reset(EmuTime /*time*/)
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{
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	// ASCII8 behaviour
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	setUnmapped(0);
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	setUnmapped(1);
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	for (auto i : xrange(2, 6)) {
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		setRom(i, 0);
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	}
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	setUnmapped(6);
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	setUnmapped(7);
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	std::ranges::fill(redirectToSamplePlayer, false);
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	samplePlayer.reset();
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}
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void RomNettouYakyuu::writeMem(uint16_t address, byte value, EmuTime /*time*/)
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{
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	if ((address < 0x4000) || (0xC000 <= address)) return;
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	// mapper stuff, like ASCII8
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	if ((0x6000 <= address) && (address < 0x8000)) {
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		// calculate region in switch zone
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		byte region = (address >> 11) & 3;
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		redirectToSamplePlayer[region] = (value & 0x80) != 0;
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		if (redirectToSamplePlayer[region]) {
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			setUnmapped(region + 2);
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		} else {
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			setRom(region + 2, value);
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		}
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		return;
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	}
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	// sample player stuff
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	if (!redirectToSamplePlayer[(address >> 13) - 2]) {
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		// region not redirected to sample player
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		return;
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	}
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	// bit 7==0: reset
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	if (!(value & 0x80)) {
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		samplePlayer.reset();
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		return;
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	}
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	// bit 6==1: set no retrigger, don't alter playing sample
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	if (value & 0x40) {
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		samplePlayer.stopRepeat();
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		return;
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	}
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	samplePlayer.repeat(value & 0xF);
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}
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byte* RomNettouYakyuu::getWriteCacheLine(uint16_t /*address*/)
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{
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	return nullptr;
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}
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template<typename Archive>
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void RomNettouYakyuu::serialize(Archive& ar, unsigned /*version*/)
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{
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	ar.template serializeBase<Rom8kBBlocks>(*this);
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	ar.serialize("SamplePlayer",           samplePlayer,
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	             "redirectToSamplePlayer", redirectToSamplePlayer);
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}
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INSTANTIATE_SERIALIZE_METHODS(RomNettouYakyuu);
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REGISTER_MSXDEVICE(RomNettouYakyuu, "RomNettouYakyuu");
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} // namespace openmsx