OXYGENHUB
◆ main openmsx / src / memory / RomDooly.cc
2.5 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
//
2 
// Agigongnyong Dooly
3 
//
4
5 
#include "RomDooly.hh"
6 
#include "CacheLine.hh"
7 
#include "MSXException.hh"
8 
#include "serialize.hh"
9
10 
namespace openmsx {
11
12 
RomDooly::RomDooly(const DeviceConfig& config, Rom&& rom_)
13 
	: MSXRom(config, std::move(rom_))
14 
	, romBlockDebug(*this, std::span{&conversion, 1}, 0x4000, 0x8000, 15)
15 
{
16 
	if (rom.size() != 0x8000) {
17 
		throw MSXException("Dooly ROM-size must be exactly 32kB");
18 
	}
19 
	reset(EmuTime::dummy());
20 
}
21
22 
void RomDooly::reset(EmuTime /*time*/)
23 
{
24 
	conversion = 0;
25 
}
26
27 
byte RomDooly::peekMem(uint16_t address, EmuTime /*time*/) const
28 
{
29 
	if ((0x4000 <= address) && (address < 0xc000)) {
30 
		byte value = rom[address - 0x4000];
31 
		switch (conversion) {
32 
		case 0:
33 
			return value;
34 
		case 1:
35 
			return (value & 0xf8) | (value << 2 & 0x04) | (value >> 1 & 0x03);
36 
		case 4:
37 
			return (value & 0xf8) | (value >> 2 & 0x01) | (value << 1 & 0x06);
38 
		case 2:
39 
		case 5:
40 
		case 6:
41 
			switch (value & 0x07) {
42 
			case 1:
43 
			case 2:
44 
			case 4:
45 
				return value & 0xf8;
46 
			case 3:
47 
			case 5:
48 
			case 6:
49 
				if (conversion == 2) return (value & 0xf8) | (((value << 2 & 0x04) | (value >> 1 & 0x03)) ^ 0x07);
50 
				if (conversion == 5) return value ^ 0x07;
51 
				if (conversion == 6) return (value & 0xf8) | (((value >> 2 & 0x01) | (value << 1 & 0x06)) ^ 0x07);
52 
				[[fallthrough]];
53 
			default:
54 
				return value;
55 
			}
56 
		default:
57 
			return value | 0x07;
58 
		}
59 
	}
60 
	return 0xff;
61 
}
62
63 
byte RomDooly::readMem(uint16_t address, EmuTime time)
64 
{
65 
	return peekMem(address, time);
66 
}
67
68 
void RomDooly::writeMem(uint16_t address, byte value, EmuTime /*time*/)
69 
{
70 
	// TODO: To what region does the real cartridge react?
71 
	// * Using the full region [0x4000,0xc000) interferes with the
72 
	//   RAM-check routine of many MSX machines (game doesn't boot)
73 
	// * The game seems to write at many different addresses. The min/max
74 
	//   I've seen is 0x8780/0x8f86. So my best *guess* is to extend this
75 
	//   region to [0x8000,0x9000).
76 
	// * This smaller region seems to make the game work (on the above
77 
	//   machines that failed before).
78 
	if ((0x8000 <= address) && (address < 0x9000)) {
79 
		conversion = value & 0x07;
80 
	}
81 
}
82
83 
byte* RomDooly::getWriteCacheLine(uint16_t address)
84 
{
85 
	if (((0x4000 & CacheLine::HIGH) <= address) && (address < (0xc000 & CacheLine::HIGH))) {
86 
		return nullptr;
87 
	} else {
88 
		return unmappedWrite.data();
89 
	}
90 
}
91
92 
template<typename Archive>
93 
void RomDooly::serialize(Archive& ar, unsigned /*version*/)
94 
{
95 
	ar.template serializeBase<MSXDevice>(*this);
96 
	ar.serialize("conversion", conversion);
97 
}
98 
INSTANTIATE_SERIALIZE_METHODS(RomDooly);
99 
REGISTER_MSXDEVICE(RomDooly, "RomDooly");
100
101 
} // namespace openmsx