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◆ main openmsx / src / cpu / VDPIODelay.cc
1.9 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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#include "VDPIODelay.hh"
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#include "DummyDevice.hh"
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#include "MSXCPU.hh"
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#include "MSXCPUInterface.hh"
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#include "serialize.hh"
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#include "xrange.hh"
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#include <cassert>
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namespace openmsx {
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VDPIODelay::VDPIODelay(const DeviceConfig& config, MSXCPUInterface& cpuInterface)
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	: MSXDevice(config)
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	, cpu(getCPU()) // used frequently, so cache it
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{
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	for (auto port : xrange(uint8_t(0x98), uint8_t(0x9c))) {
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		getInDevicePtr (port) = &cpuInterface.getDummyDevice();
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		getOutDevicePtr(port) = &cpuInterface.getDummyDevice();
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	}
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}
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const MSXDevice& VDPIODelay::getInDevice(uint8_t port) const
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{
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	assert((0x98 <= port) && (port <= 0x9B));
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	return *inDevices[port - 0x98];
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}
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MSXDevice*& VDPIODelay::getInDevicePtr(uint8_t port)
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{
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	assert((0x98 <= port) && (port <= 0x9B));
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	return inDevices[port - 0x98];
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}
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MSXDevice*& VDPIODelay::getOutDevicePtr(uint8_t port)
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{
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	assert((0x98 <= port) && (port <= 0x9B));
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	return outDevices[port - 0x98];
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}
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uint8_t VDPIODelay::readIO(uint16_t port, EmuTime time)
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{
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	delay(time);
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	return getInDevicePtr(uint8_t(port))->readIO(uint8_t(port), lastTime.getTime());
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}
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uint8_t VDPIODelay::peekIO(uint16_t port, EmuTime time) const
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{
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	return getInDevice(uint8_t(port)).peekIO(uint8_t(port), time);
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}
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void VDPIODelay::writeIO(uint16_t port, uint8_t value, EmuTime time)
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{
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	delay(time);
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	getOutDevicePtr(uint8_t(port))->writeIO(uint8_t(port), value, lastTime.getTime());
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}
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void VDPIODelay::delay(EmuTime time)
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{
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	if (cpu.isR800Active()) {
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		// Number of cycles based on measurements on real HW.
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		// See doc/turbor-vdp-io-timing.ods for details.
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		lastTime += 62; // 8us
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		if (time < lastTime.getTime()) {
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			cpu.wait(lastTime.getTime());
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			return;
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		}
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	}
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	lastTime.advance(time);
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}
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template<typename Archive>
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void VDPIODelay::serialize(Archive& ar, unsigned /*version*/)
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{
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	ar.serialize("lastTime", lastTime);
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}
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INSTANTIATE_SERIALIZE_METHODS(VDPIODelay);
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} // namespace openmsx