openMSX
RomMatraCompilation.cc
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1 #include "RomMatraCompilation.hh"
2 #include "one_of.hh"
3 #include "serialize.hh"
4 #include "xrange.hh"
5 
6 // This is basically a generic 8kB mapper (Konami like, but without fixed page
7 // at 0x4000), with an extra offset register accessible at 0xBA00.
8 // The software only writes to 0x5000, 0x6000, 0x8000, 0xA000 to switch mapper
9 // page. I took these as unique switching addresses, as some of the compilation
10 // software would write to others, causing crashes.
11 // It seems that a write of 1 (and probably 0, but the software doesn't do
12 // that) to the offset register should be ignored and will disable the mapper
13 // switch addresses. Values of 2 or larger written there must be lowered by 2
14 // to get the actual offset to use.
15 
16 namespace openmsx {
17 
19  : Rom8kBBlocks(config, std::move(rom_))
20 {
21  reset(EmuTime::dummy());
22 }
23 
24 void RomMatraCompilation::reset(EmuTime::param /*time*/)
25 {
26  setUnmapped(0);
27  setUnmapped(1);
28  for (auto i : xrange(2, 6)) {
29  setRom(i, i - 2);
30  }
31  setUnmapped(6);
32  setUnmapped(7);
33 
34  blockOffset = 2;
35 }
36 
37 void RomMatraCompilation::writeMem(word address, byte value, EmuTime::param /*time*/)
38 {
39  if (address == 0xBA00) {
40  // write of block offset
41  blockOffset = value;
42  // retro-actively select the blocks for this offset
43  if (blockOffset >= 2) {
44  for (auto i : xrange(2, 6)) {
45  setRom(i, blockNr[i] + blockOffset - 2);
46  }
47  }
48  } else if ((blockOffset >= 2) &&
49  (address == one_of(0x5000, 0x6000, 0x8000, 0xA000))) {
50  setRom(address >> 13, value + blockOffset - 2);
51  }
52 }
53 
55 {
56  if ((0x5000 <= address) && (address < 0xC000)) {
57  return nullptr;
58  } else {
59  return unmappedWrite;
60  }
61 }
62 
63 template<typename Archive>
64 void RomMatraCompilation::serialize(Archive& ar, unsigned /*version*/)
65 {
66  ar.template serializeBase<Rom8kBBlocks>(*this);
67 
68  ar.serialize("blockOffset", blockOffset);
69 }
71 REGISTER_MSXDEVICE(RomMatraCompilation, "RomMatraCompilation");
72 
73 } // namespace openmsx
Definition: one_of.hh:7
static byte unmappedWrite[0x10000]
Definition: MSXDevice.hh:302
byte blockNr[NUM_BANKS]
Definition: RomBlocks.hh:85
void setRom(byte region, unsigned block)
Selects a block of the ROM image for reading in a certain region.
Definition: RomBlocks.cc:105
void setUnmapped(byte region)
Select 'unmapped' memory for this region.
Definition: RomBlocks.cc:92
void serialize(Archive &ar, unsigned version)
void writeMem(word address, byte value, EmuTime::param time) override
Write a given byte to a given location at a certain time to this device.
byte * getWriteCacheLine(word address) const override
Test that the memory in the interval [start, start + CacheLine::SIZE) is cacheable for writing.
void reset(EmuTime::param time) override
This method is called on reset.
RomMatraCompilation(const DeviceConfig &config, Rom &&rom)
This file implemented 3 utility functions:
Definition: Autofire.cc:9
REGISTER_MSXDEVICE(ChakkariCopy, "ChakkariCopy")
uint16_t word
16 bit unsigned integer
Definition: openmsx.hh:29
#define INSTANTIATE_SERIALIZE_METHODS(CLASS)
Definition: serialize.hh:998
constexpr auto xrange(T e)
Definition: xrange.hh:155