libretro/Mesen-S
1
0
Fork 0
mirror of https://github.com/libretro/Mesen-S.git synced 2025-03-01 13:16:44 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

SA-1: Added variable bit length data support

Browse Source
This commit is contained in:
Sour 2019-08-09 00:04:01 -04:00
parent 22d4f58eae
commit efe157cfcb
3 changed files with 46 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
Core/Sa1.cpp
View File

@ -188,16 +188,21 @@ void Sa1::Sa1RegisterWrite(uint16_t addr, uint8_t value)
case 0x2258:
//VBD (Variable length bit processing)
_state.VariableLengthAutoIncrement = (value & 0x80) != 0;
_state.VariableLength = value & 0x0F;
if(value) {
LogDebug("Variable length");
_state.VarLenAutoInc = (value & 0x80) != 0;
_state.VarLenBitCount = value == 0 ? 16 : (value & 0x0F);
if(!_state.VarLenAutoInc) {
IncVarLenPosition();
}
break;
case 0x2259: _state.VariableLengthAddress = (_state.VariableLengthAddress & 0xFFFF00) | value; break; //VDA (Variable length data address - Low)
case 0x225A: _state.VariableLengthAddress = (_state.VariableLengthAddress & 0xFF00FF) | (value << 8); break; //VDA (Variable length data address - Mid)
case 0x225B: _state.VariableLengthAddress = (_state.VariableLengthAddress & 0x00FFFF) | (value << 16); break; //VDA (Variable length data address - High)
case 0x2259: _state.VarLenAddress = (_state.VarLenAddress & 0xFFFF00) | value; break; //VDA (Variable length data address - Low)
case 0x225A: _state.VarLenAddress = (_state.VarLenAddress & 0xFF00FF) | (value << 8); break; //VDA (Variable length data address - Mid)
case 0x225B:
//VDA (Variable length data address - High)
_state.VarLenAddress = (_state.VarLenAddress & 0x00FFFF) | (value << 16);
_state.VarLenCurrentBit = 0;
break;
}
}
@ -347,8 +352,21 @@ uint8_t Sa1::Sa1RegisterRead(uint16_t addr)
case 0x230B: return _state.MathOverflow; break; //OF (Arithmetic overflow flag)
case 0x230C: break; //VDP (Variable length data port - Low)
case 0x230D: break; //VDP (Variable length data port - High)
case 0x230C: {
//VDP (Variable length data port - Low)
uint32_t data = ReadSa1(_state.VarLenAddress) | (ReadSa1(_state.VarLenAddress + 1) << 8) | (ReadSa1(_state.VarLenAddress + 2) << 16);
return data >> _state.VarLenCurrentBit;
}
case 0x230D: {
//VDP (Variable length data port - High)
uint32_t data = ReadSa1(_state.VarLenAddress) | (ReadSa1(_state.VarLenAddress + 1) << 8) | (ReadSa1(_state.VarLenAddress + 2) << 16);
uint8_t value = data >> (_state.VarLenCurrentBit + 8);
if(_state.VarLenAutoInc) {
IncVarLenPosition();
}
return value;
}
}
LogDebug("[Debug] Read SA1 - missing register: $" + HexUtilities::ToHex(addr));
@ -588,6 +606,13 @@ void Sa1::UpdateSaveRamMappings()
}
}
void Sa1::IncVarLenPosition()
{
_state.VarLenCurrentBit += _state.VarLenBitCount;
_state.VarLenAddress += _state.VarLenCurrentBit >> 3;
_state.VarLenCurrentBit &= 0x07;
}
void Sa1::CalculateMathOpResult()
{
if((int)_state.MathOp & (int)Sa1MathOp::Sum) {
@ -754,13 +779,14 @@ void Sa1::Serialize(Serializer &s)
_state.CpuIRamWriteProtect, _state.Sa1IRamWriteProtect, _state.DmaSrcAddr, _state.DmaDestAddr, _state.DmaSize, _state.DmaEnabled, _state.DmaPriority,
_state.DmaCharConv, _state.DmaCharConvAuto, _state.DmaDestDevice, _state.DmaSrcDevice, _state.DmaRunning, _state.DmaIrqFlag, _state.HorizontalTimerEnabled,
_state.VerticalTimerEnabled, _state.UseLinearTimer, _state.HTimer, _state.VTimer, _state.LinearTimerValue, _state.MathOp, _state.MultiplicandDividend,
_state.MultiplierDivisor, _state.MathOpResult, _state.MathOverflow, _state.VariableLengthAutoIncrement, _state.VariableLength, _state.VariableLengthAddress,
_state.MultiplierDivisor, _state.MathOpResult, _state.MathOverflow, _state.VarLenAutoInc, _state.VarLenBitCount, _state.VarLenAddress,
_state.Banks[0], _state.Banks[1], _state.Banks[2], _state.Banks[3],
_state.BitmapRegister1[0], _state.BitmapRegister1[1], _state.BitmapRegister1[2], _state.BitmapRegister1[3],
_state.BitmapRegister1[4], _state.BitmapRegister1[5], _state.BitmapRegister1[6], _state.BitmapRegister1[7],
_state.BitmapRegister2[0], _state.BitmapRegister2[1], _state.BitmapRegister2[2], _state.BitmapRegister2[3],
_state.BitmapRegister2[4], _state.BitmapRegister2[5], _state.BitmapRegister2[6], _state.BitmapRegister2[7],
_state.CharConvDmaActive, _state.CharConvBpp, _state.CharConvFormat, _state.CharConvWidth, _state.CharConvCounter
_state.CharConvDmaActive, _state.CharConvBpp, _state.CharConvFormat, _state.CharConvWidth, _state.CharConvCounter,
_state.VarLenCurrentBit
);
s.Stream(_lastAccessMemType, _openBus);

5
Core/Sa1.h
View File

@ -10,6 +10,10 @@ class Sa1Cpu;
class MemoryManager;
class BaseCartridge;
//TODO: Implement write protection flags
//TODO: Bitmap projection at $6000
//TODO: Timers
class Sa1 : public BaseCoprocessor
{
private:
@ -40,6 +44,7 @@ private:
void UpdateVectorMappings();
void UpdateSaveRamMappings();
void IncVarLenPosition();
void CalculateMathOpResult();
void RunCharConvertType2();

7
Core/Sa1Types.h
View File

@ -99,9 +99,10 @@ struct Sa1State
uint64_t MathOpResult;
uint8_t MathOverflow;
bool VariableLengthAutoIncrement;
uint8_t VariableLength;
uint32_t VariableLengthAddress;
bool VarLenAutoInc;
uint8_t VarLenBitCount;
uint32_t VarLenAddress;
uint8_t VarLenCurrentBit;
uint8_t Banks[4];
};