Atari 2600 - start Supercharger emulation (and mapper AR)
This commit is contained in:
adelikat
parent
f04210c5c9
commit
d1e7ed9d91
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@ -17,8 +17,17 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
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public MOS6502X Cpu { get; private set; }
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public M6532 M6532 { get; private set; }
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public int LastAddress;
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public int NumberOfDistinctAddresses;
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public byte BaseReadMemory(ushort addr)
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{
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if (addr != LastAddress)
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{
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NumberOfDistinctAddresses++;
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LastAddress = addr;
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}
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addr = (ushort)(addr & 0x1FFF);
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if ((addr & 0x1080) == 0)
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{
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@ -51,6 +60,12 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
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public void BaseWriteMemory(ushort addr, byte value)
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{
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if (addr != LastAddress)
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{
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NumberOfDistinctAddresses++;
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LastAddress = addr;
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}
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addr = (ushort)(addr & 0x1FFF);
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if ((addr & 0x1080) == 0)
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{
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@ -129,7 +144,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
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_mapper = SetMultiCartMapper(Rom.Length, 32);
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break;
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case "AR":
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_mapper = new mAR();
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_mapper = new mAR(this); // This mapper has to set up configurations in the contructor.
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break;
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case "4K":
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_mapper = new m4K();
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@ -31,17 +31,34 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
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{
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internal class mAR : MapperBase
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{
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public mAR()
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// TODO: can we set the defaults instead of do it in the constructor?
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// TODO: fastscbios setting
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// TODO: var names, savestates, hard reset, dispose, cart ram
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public mAR(Atari2600 core)
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{
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throw new NotImplementedException();
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Core = core;
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InitializeRom();
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BankConfiguration(0);
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}
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private int _bank2k;
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private ByteBuffer _ram = new ByteBuffer(6144);
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private IntBuffer _offsets = new IntBuffer(2);
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//private ByteBuffer _ram = new ByteBuffer(6144);
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ByteBuffer myImage = new ByteBuffer(8192);
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private IntBuffer _imageOffsets = new IntBuffer(2);
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private bool _writePending = false;
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int myNumberOfDistinctAccesses = 0;
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bool myWriteEnabled = false;
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byte myDataHoldRegister;
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private readonly byte[] _RomCode = {
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// Indicates if the ROM's power is on or off
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private bool myPower;
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// Indicates when the power was last turned on
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int myPowerRomCycle;
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private ulong _elapsedCycles;
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private readonly byte[] DummyRomCode = {
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0xa5, 0xfa, 0x85, 0x80, 0x4c, 0x18, 0xf8, 0xff,
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0xff, 0xff, 0x78, 0xd8, 0xa0, 0x00, 0xa2, 0x00,
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0x94, 0x00, 0xe8, 0xd0, 0xfb, 0x4c, 0x50, 0xf8,
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@ -81,7 +98,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
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0xfa, 0x00, 0xcd, 0xf8, 0xff, 0x4c
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};
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private readonly byte[] RomHeader = {
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private readonly byte[] DefaultHeader = {
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0xac, 0xfa, 0x0f, 0x18, 0x62, 0x00, 0x24, 0x02,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0x00, 0x04, 0x08, 0x0c, 0x10, 0x14, 0x18, 0x1c,
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@ -116,34 +133,10 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00
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};
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public override bool HasCartRam
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public override void ClockCpu()
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{
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get { return true; }
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}
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public override ByteBuffer CartRam
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{
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get { return _ram; }
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}
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public override void SyncState(Serializer ser)
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{
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base.SyncState(ser);
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ser.Sync("bank4k", ref _bank2k);
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ser.Sync("ram", ref _ram);
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}
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public override void HardReset()
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{
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_bank2k = 0;
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_ram = new ByteBuffer(6144);
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base.HardReset();
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}
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public override void Dispose()
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{
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base.Dispose();
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_ram.Dispose();
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_elapsedCycles++;
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}
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private byte ReadMem(ushort addr, bool peek)
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@ -158,22 +151,57 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
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return base.ReadMemory(addr);
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}
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if (addr == 0x1850 && _offsets[1] == (3 << 11))
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if (addr == 0x1850 && _imageOffsets[1] == (3 << 11))
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{
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/// TODO: weird stuff goes here
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///
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return Core.Rom[(addr & 0x7FF) + _offsets[1]];
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return myImage[(addr & 0x7FF) + _imageOffsets[1]];
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}
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// TODO: cancel pending writes
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if (addr == 0x1FF8)
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// Cancel any pending write if more than 5 distinct accesses have occurred
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// TODO: Modify to handle when the distinct counter wraps around...
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if (_writePending &&
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(Core.NumberOfDistinctAddresses > myNumberOfDistinctAccesses + 5))
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{
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_writePending = false;
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}
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if (!((addr & 0x0F00) > 0) && (!myWriteEnabled || !_writePending))
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{
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myDataHoldRegister = (byte)addr;
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myNumberOfDistinctAccesses = Core.NumberOfDistinctAddresses;
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_writePending = true;
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}
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// Is the bank configuration hotspot being accessed?
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else if (addr == 0x1FF8)
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{
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// Yes, so handle the bank configuration
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_writePending = false;
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BankConfiguration(myDataHoldRegister);
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return Core.Rom[(_bank2k << 12) + (addr & 0xFFF)];
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}
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else if (myWriteEnabled &&
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_writePending &&
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Core.NumberOfDistinctAddresses == (myNumberOfDistinctAccesses + 5))
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{
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if ((addr & 0x800) == 0)
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{
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// TODO
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}
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else if (_imageOffsets[1] != (3 << 11)) // Don't poke Rom
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{
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// TODO
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}
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_writePending = false;
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}
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var tempVal = (addr & 0x07FF) + _imageOffsets[((addr & 0x800) > 0) ? 1 : 0];
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return myImage[(addr & 0x07FF) + _imageOffsets[((addr & 0x800) > 0) ? 1 : 0]];
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}
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public override byte ReadMemory(ushort addr)
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@ -197,5 +225,105 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
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_bank2k = 1;
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}
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}
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private void InitializeRom()
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{
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/* scrom.asm data borrowed from Stella:
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// Note that the following offsets depend on the 'scrom.asm' file
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// in src/emucore/misc. If that file is ever recompiled (and its
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// contents placed in the ourDummyROMCode array), the offsets will
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// almost definitely change
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*/
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// The scrom.asm code checks a value at offset 109 as follows:
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// 0xFF -> do a complete jump over the SC BIOS progress bars code
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// 0x00 -> show SC BIOS progress bars as normal
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DummyRomCode[109] = 0x00; // TODO: fastscbios setting
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// Stella does this, but randomness is bad for determinacy! Hopefully we don't really need it
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//ourDummyROMCode[281] = mySystem->randGenerator().next();
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// Initialize ROM with illegal 6502 opcode that causes a real 6502 to jam
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for (int i = 0; i < 2048; i++)
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{
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myImage[(3 << 11) + i] = 0x02;
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}
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// Copy the "dummy" Supercharger BIOS code into the ROM area
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for (int i = 0; i < DummyRomCode.Length; i++)
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{
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myImage[(3 << 11) + i] = DummyRomCode[i];
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}
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// Finally set 6502 vectors to point to initial load code at 0xF80A of BIOS
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myImage[(3 << 11) + 2044] = 0x0A;
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myImage[(3 << 11) + 2045] = 0xF8;
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myImage[(3 << 11) + 2046] = 0x0A;
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myImage[(3 << 11) + 2047] = 0xF8;
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}
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private void BankConfiguration(byte configuration)
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{
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// D7-D5 of this byte: Write Pulse Delay (n/a for emulator)
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//
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// D4-D0: RAM/ROM configuration:
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// $F000-F7FF $F800-FFFF Address range that banks map into
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// 000wp 2 ROM
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// 001wp 0 ROM
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// 010wp 2 0 as used in Commie Mutants and many others
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// 011wp 0 2 as used in Suicide Mission
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// 100wp 2 ROM
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// 101wp 1 ROM
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// 110wp 2 1 as used in Killer Satellites
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// 111wp 1 2 as we use for 2k/4k ROM cloning
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//
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// w = Write Enable (1 = enabled; accesses to $F000-$F0FF cause writes
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// to happen. 0 = disabled, and the cart acts like ROM.)
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// p = ROM Power (0 = enabled, 1 = off.) Only power the ROM if you're
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// wanting to access the ROM for multiloads. Otherwise set to 1.
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_bank2k = configuration & 0x1F; // remember for the bank() method
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myPower = !((configuration & 0x01) > 0);
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if (myPower)
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{
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myPowerRomCycle = (int)_elapsedCycles;
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}
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switch ((configuration >> 2) & 0x07)
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{
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case 0x00:
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_imageOffsets[0] = 2 << 11;
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_imageOffsets[1] = 3 << 11;
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break;
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case 0x01:
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_imageOffsets[0] = 0;
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_imageOffsets[1] = 3 << 11;
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break;
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case 0x02:
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_imageOffsets[0] = 2 << 11;
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_imageOffsets[1] = 0;
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break;
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case 0x03:
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_imageOffsets[0] = 0;
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_imageOffsets[1] = 2 << 11;
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break;
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case 0x04:
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_imageOffsets[0] = 2 << 11;
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_imageOffsets[1] = 3 << 11;
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break;
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case 0x05:
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_imageOffsets[0] = 1 << 11;
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_imageOffsets[1] = 3 << 11;
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break;
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case 0x06:
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_imageOffsets[0] = 2 << 11;
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_imageOffsets[1] = 1 << 11;
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break;
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case 0x07:
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_imageOffsets[0] = 1 << 11;
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_imageOffsets[1] = 2 << 11;
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break;
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}
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}
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}
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}
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@ -0,0 +1,252 @@
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;;============================================================================
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;;
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;; SSSS tt lll lll
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;; SS SS tt ll ll
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;; SS tttttt eeee ll ll aaaa
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;; SSSS tt ee ee ll ll aa
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;; SS tt eeeeee ll ll aaaaa -- "An Atari 2600 VCS Emulator"
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;; SS SS tt ee ll ll aa aa
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;; SSSS ttt eeeee llll llll aaaaa
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;;
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;; Copyright (c) 1995-2012 by Bradford W. Mott, Stephen Anthony
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;; and the Stella Team
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;;
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;; See the file "License.txt" for information on usage and redistribution of
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;; this file, and for a DISCLAIMER OF ALL WARRANTIES.
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;;
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;; $Id: scrom.asm,v 1.3 2005-06-16 01:11:29 stephena Exp $
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;;============================================================================
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;;
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;; This file contains a "dummy" Supercharger BIOS for Stella. It is based
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;; on routines developed by Eckhard Stolberg.
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;;
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;;============================================================================
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processor 6502
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VSYNC equ $00
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VBLANK equ $01
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WSYNC equ $02
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COLUPF equ $08
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COLUBK equ $09
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CTRLPF equ $0a
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PF0 equ $0d
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PF1 equ $0e
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PF2 equ $0f
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RESP0 equ $10
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RESP1 equ $11
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AUDC0 equ $15
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AUDF0 equ $17
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AUDV0 equ $19
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AUDV1 equ $1a
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GRP0 equ $1b
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GRP1 equ $1c
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ENAM0 equ $1d
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ENAM1 equ $1e
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ENABL equ $1f
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HMP0 equ $20
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HMP1 equ $21
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HMOVE equ $2a
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;;
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;; Entry point for multi-load reading
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;;
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org $F800
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LDA $FA ; Grab the load number and store it in $80 where the
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STA $80 ; emulator will grab it when it does the loading
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JMP clrp7 ; Go clear page 7 of RAM bank 1 like the real SC
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;;
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;; Entry point for initial load (invoked when the system is reset)
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;;
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org $F80A
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start SEI
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CLD
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;;
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;; Clear page zero routine for initial load (e.g., RAM and TIA registers)
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;;
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LDY #$00
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LDX #$00
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ilclr STY $00,X
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INX
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BNE ilclr
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JMP load
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;;
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;; Clear page 7 of RAM bank 1 (used for stars in the real SC)
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;;
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clrp7 LDX #$00
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LDA $F006,X
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LDA $FFF8
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LDX #$00
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mlclr3 LDA $F000
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NOP
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LDA $F700,X
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DEX
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BNE mlclr3
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JMP load
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;;
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;; NOTE: The emulator does the actual reading of the new load when the
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;; next instruction is accessed. The emulator expects the load number to
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;; to be stored in location $80. As a side-effect the emulator sets $80
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;; to contain the bank selection byte from the load's header and sets
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;; $FE and $FF to contain the starting address from the load's header.
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;;
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load org $F850
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;;
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;; Copy code into page zero to do the bank switching
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;;
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LDX #$03
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copy LDY code,X
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STY $FA,X
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DEX
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BPL copy
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;;
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;; Clear some of the 2600's RAM and TIA registers like the real SC BIOS does
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;;
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LDY #$00
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LDX #$28
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mlclr1 STY $04,X
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DEX
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BPL mlclr1
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LDX #$1C
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mlclr2 STY $81,X
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DEX
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BPL mlclr2
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;;
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;; Display the "emulated" Supercharger loading progress bar
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;;
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;; Check if we should skip the loading progress bar
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;; Note that the following code seems to never do a jump
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;; However, the comparison value can be patched outside this code
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;;
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LDA #$FF
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CMP #$00 ; patch this value to $FF outside ROM to do a jump
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BNE startbars
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JMP skipbars
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;; Otherwise we display them
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startbars:
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LDA #$00
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STA GRP0
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STA GRP1
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STA ENAM0
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STA ENAM1
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STA ENABL
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STA AUDV0
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STA AUDV1
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STA COLUPF
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STA VBLANK
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LDA #$10
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STA HMP1
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STA WSYNC
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LDX #$07
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DEX
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pos DEX
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BNE pos
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LDA #$00
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STA HMP0
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STA RESP0
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STA RESP1
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STA WSYNC
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STA HMOVE
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LDA #%00000101
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STA CTRLPF
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LDA #$FF
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STA PF0
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STA PF1
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STA PF2
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STA $84
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STA $85
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LDA #$F0
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STA $83
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LDA #$74
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STA COLUBK
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LDA #$0C
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STA AUDC0
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LDA #$1F
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STA AUDF0
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STA $82
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LDA #$07
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STA AUDV0
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a1
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LDX #$08
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LDY #$00
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a2
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STA WSYNC
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DEY
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BNE a2
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STA WSYNC
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STA WSYNC
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LDA #$02
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STA WSYNC
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STA VSYNC
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STA WSYNC
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STA WSYNC
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STA WSYNC
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LDA #$00
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STA VSYNC
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DEX
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BPL a2
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ASL $83
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ROR $84
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ROL $85
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LDA $83
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STA PF0
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LDA $84
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STA PF1
|
||||
LDA $85
|
||||
STA PF2
|
||||
LDX $82
|
||||
DEX
|
||||
STX $82
|
||||
STX AUDF0
|
||||
CPX #$0A
|
||||
BNE a1
|
||||
|
||||
LDA #%00000010
|
||||
STA VBLANK
|
||||
|
||||
LDX #$1C
|
||||
LDY #$00
|
||||
STY AUDV0
|
||||
STY COLUBK
|
||||
clear:
|
||||
STY $81,x
|
||||
DEX
|
||||
BPL clear
|
||||
skipbars:
|
||||
|
||||
;;
|
||||
;; Setup value to be stored in the bank switching control register
|
||||
;;
|
||||
LDX $80
|
||||
CMP $F000,X
|
||||
|
||||
;;
|
||||
;; Initialize A, X, Y, and SP registers
|
||||
;;
|
||||
LDA #$9a ;; This is patched outside the ROM to a random value
|
||||
LDX #$FF
|
||||
LDY #$00
|
||||
TXS
|
||||
|
||||
;;
|
||||
;; Execute the code to do bank switch and start running cartridge code
|
||||
;;
|
||||
JMP $FA
|
||||
|
||||
code dc.b $cd, $f8, $ff ;; CMP $fff8
|
||||
dc.b $4c ;; JMP $????
|
||||
|
||||
Loading…
Reference in New Issue