OXYGENHUB
◆ main openmsx / src / cpu / VDPIODelay.cc
1.9 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
#include "VDPIODelay.hh"
2
3 
#include "DummyDevice.hh"
4 
#include "MSXCPU.hh"
5 
#include "MSXCPUInterface.hh"
6 
#include "serialize.hh"
7
8 
#include "xrange.hh"
9
10 
#include <cassert>
11
12 
namespace openmsx {
13
14 
VDPIODelay::VDPIODelay(const DeviceConfig& config, MSXCPUInterface& cpuInterface)
15 
	: MSXDevice(config)
16 
	, cpu(getCPU()) // used frequently, so cache it
17 
{
18 
	for (auto port : xrange(uint8_t(0x98), uint8_t(0x9c))) {
19 
		getInDevicePtr (port) = &cpuInterface.getDummyDevice();
20 
		getOutDevicePtr(port) = &cpuInterface.getDummyDevice();
21 
	}
22 
}
23
24 
const MSXDevice& VDPIODelay::getInDevice(uint8_t port) const
25 
{
26 
	assert((0x98 <= port) && (port <= 0x9B));
27 
	return *inDevices[port - 0x98];
28 
}
29
30 
MSXDevice*& VDPIODelay::getInDevicePtr(uint8_t port)
31 
{
32 
	assert((0x98 <= port) && (port <= 0x9B));
33 
	return inDevices[port - 0x98];
34 
}
35
36 
MSXDevice*& VDPIODelay::getOutDevicePtr(uint8_t port)
37 
{
38 
	assert((0x98 <= port) && (port <= 0x9B));
39 
	return outDevices[port - 0x98];
40 
}
41
42 
uint8_t VDPIODelay::readIO(uint16_t port, EmuTime time)
43 
{
44 
	delay(time);
45 
	return getInDevicePtr(uint8_t(port))->readIO(uint8_t(port), lastTime.getTime());
46 
}
47
48 
uint8_t VDPIODelay::peekIO(uint16_t port, EmuTime time) const
49 
{
50 
	return getInDevice(uint8_t(port)).peekIO(uint8_t(port), time);
51 
}
52
53 
void VDPIODelay::writeIO(uint16_t port, uint8_t value, EmuTime time)
54 
{
55 
	delay(time);
56 
	getOutDevicePtr(uint8_t(port))->writeIO(uint8_t(port), value, lastTime.getTime());
57 
}
58
59 
void VDPIODelay::delay(EmuTime time)
60 
{
61 
	if (cpu.isR800Active()) {
62 
		// Number of cycles based on measurements on real HW.
63 
		// See doc/turbor-vdp-io-timing.ods for details.
64 
		lastTime += 62; // 8us
65 
		if (time < lastTime.getTime()) {
66 
			cpu.wait(lastTime.getTime());
67 
			return;
68 
		}
69 
	}
70 
	lastTime.advance(time);
71 
}
72
73 
template<typename Archive>
74 
void VDPIODelay::serialize(Archive& ar, unsigned /*version*/)
75 
{
76 
	ar.serialize("lastTime", lastTime);
77 
}
78 
INSTANTIATE_SERIALIZE_METHODS(VDPIODelay);
79
80 
} // namespace openmsx