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◆ main openmsx / src / MSXE6Timer.cc
1.1 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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#include "MSXE6Timer.hh"
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#include "serialize.hh"
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namespace openmsx {
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MSXE6Timer::MSXE6Timer(const DeviceConfig& config)
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	: MSXDevice(config)
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	, reference(getCurrentTime())
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{
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}
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void MSXE6Timer::reset(EmuTime time)
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{
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	reference.reset(time);
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}
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void MSXE6Timer::writeIO(uint16_t /*port*/, byte /*value*/, EmuTime time)
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{
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	/*
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	The Clock class rounds down time to its clock resolution.
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	This is correct for the E6 timer, verified by running the following
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	program in R800 mode:
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		org &HC000
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		di
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		ld c,&HE6
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	loop:
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		out (&HE6),a
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		in d,(c)
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		jp z,loop
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		ei
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		ret
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	It returns with D=1.
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	*/
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	reference.advance(time);
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}
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byte MSXE6Timer::readIO(uint16_t port, EmuTime time)
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{
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	return peekIO(port, time);
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}
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byte MSXE6Timer::peekIO(uint16_t port, EmuTime time) const
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{
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	auto counter = reference.getTicksTill(time);
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	return (port & 1) ? ((counter >> 8) & 0xFF) : (counter & 0xFF);
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}
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template<typename Archive>
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void MSXE6Timer::serialize(Archive& ar, unsigned /*version*/)
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{
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	ar.template serializeBase<MSXDevice>(*this);
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	ar.serialize("reference", reference);
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}
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INSTANTIATE_SERIALIZE_METHODS(MSXE6Timer);
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REGISTER_MSXDEVICE(MSXE6Timer, "E6Timer");
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} // namespace openmsx