/// <summary>
/// Instruction Decoder for Disassembly
/// </summary>
private static Operation InstructionDecode(uint MemoryLocation)
{
ushort memoryOpCode = Functions.BytesToWord(Memory.Data[MemoryLocation], Memory.Data[MemoryLocation + 1]);
// a new operation does not interfere with the executing
Operation instruction = null;
if (InstructionSet.OperationsList[(ushort)(memoryOpCode & 0x0fe03)] != null)
{
instruction = new Operation()
{
AddressingModeDestination = InstructionSet.OperationsList[(ushort)(memoryOpCode & 0x0fe03)].AddressingModeDestination,
AddressingModeSource = InstructionSet.OperationsList[(ushort)(memoryOpCode & 0x0fe03)].AddressingModeSource,
Context = InstructionSet.OperationsList[(ushort)(memoryOpCode & 0x0fe03)].Context,
Length = InstructionSet.OperationsList[(ushort)(memoryOpCode & 0x0fe03)].Length,
Mnemonic = InstructionSet.OperationsList[(ushort)(memoryOpCode & 0x0fe03)].Mnemonic,
OpCode = InstructionSet.OperationsList[(ushort)(memoryOpCode & 0x0fe03)].OpCode,
OpCodeValue = memoryOpCode,
Type = InstructionSet.OperationsList[(ushort)(memoryOpCode & 0x0fe03)].Type,
Width = InstructionSet.OperationsList[(ushort)(memoryOpCode & 0x0fe03)].Width,
};
}
if (MemoryLocation < 0x020 || instruction == null)
{
return(new Operation()
{
OpCode = memoryOpCode,
OpCodeValue = memoryOpCode,
Type = OperationType.Undefined,
Width = OperationWidth.Word,
Mnemonic = "DW",
Cycles = 0,
Length = 2,
Operands = new List <Operand>()
{
new Operand()
{
AddressingMode = AddressingMode.Immediate,
Notation = OperandNotation.Destination,
Symbol = string.Format("${0}", Convert.ToString(memoryOpCode, 16).ToUpper().PadLeft(4, '0')),
Value = memoryOpCode
}
}
});
}
//else if (instruction == null)
// throw new Exception("oh no no no no...");
ushort opcode = (ushort)(instruction.OpCodeValue & 0x0fe00);
if (instruction.Type == OperationType.Implicit)
{
// specific with bwb, correct mnemonic else passed as is
if ((instruction.OpCodeValue & 0x020) > 0)
{
switch (opcode)
{
case 0x08600:
instruction.Mnemonic = "CLI";
break;
}
}
return(instruction);
}
else
{
// specific with bwb, correct mnemonic
if ((instruction.OpCodeValue & 0x020) > 0)
{
switch (opcode)
{
case 0x04e00:
instruction.Mnemonic = "JZ";
break;
case 0x05200:
instruction.Mnemonic = "JO";
break;
case 0x05600:
instruction.Mnemonic = "JC";
break;
case 0x05a00:
instruction.Mnemonic = "JN";
break;
case 0x0f200:
instruction.Mnemonic = "JRZ";
break;
case 0x04c00:
instruction.Mnemonic = "SRSET";
break;
}
}
// operands with addressing modes
// destination addressing
switch (instruction.AddressingModeDestination)
{
case AddressingMode.MemoryReference:
case AddressingMode.Immediate:
instruction.Operands.Add(DispatchOperand(Functions.BytesToWord(Memory.Data[MemoryLocation + 2], Memory.Data[MemoryLocation + 3]), instruction.AddressingModeDestination, OperandNotation.Destination, (ushort)(instruction.Context == OperationContext.Relative ? MemoryLocation + instruction.Length : 0)));
break;
case AddressingMode.RegisterDirect:
case AddressingMode.RegisterReference:
instruction.Operands.Add(DispatchOperand(memoryOpCode, instruction.AddressingModeDestination, OperandNotation.Destination, (ushort)(instruction.Context == OperationContext.Relative ? MemoryLocation + instruction.Length : 0)));
break;
case AddressingMode.StackPointer:
instruction.Operands.Add(new Operand()
{
AddressingMode = AddressingMode.StackPointer,
Notation = OperandNotation.Destination,
Symbol = "SP",
Value = 0,
});
break;
case AddressingMode.ProgramCounter:
instruction.Operands.Add(new Operand()
{
AddressingMode = AddressingMode.ProgramCounter,
Notation = OperandNotation.Destination,
Symbol = "PC",
Value = 0,
});
break;
case AddressingMode.StatusRegister:
instruction.Operands.Add(new Operand()
{
AddressingMode = AddressingMode.StatusRegister,
Notation = OperandNotation.Destination,
Symbol = "SR",
Value = 0,
});
break;
}
// source addressing
switch (instruction.AddressingModeSource)
{
case AddressingMode.Immediate:
case AddressingMode.MemoryReference:
if (instruction.AddressingModeDestination == AddressingMode.MemoryReference || instruction.AddressingModeDestination == AddressingMode.Immediate)
{
instruction.Operands.Add(DispatchOperand(Functions.BytesToWord(Memory.Data[MemoryLocation + 4], Memory.Data[MemoryLocation + 5]), instruction.AddressingModeSource, OperandNotation.Source, (ushort)(instruction.Context == OperationContext.Relative ? MemoryLocation + instruction.Length : 0)));
}
else
{
// register reference
instruction.Operands.Add(DispatchOperand(Functions.BytesToWord(Memory.Data[MemoryLocation + 2], Memory.Data[MemoryLocation + 3]), instruction.AddressingModeSource, OperandNotation.Source, (ushort)(instruction.Context == OperationContext.Relative ? MemoryLocation + instruction.Length : 0)));
}
break;
case AddressingMode.ImmediateQuick:
case AddressingMode.RegisterDirect:
case AddressingMode.RegisterReference:
if (instruction.AddressingModeDestination == AddressingMode.Internal)
{
instruction.Operands.Add(DispatchOperand(memoryOpCode, instruction.AddressingModeSource, OperandNotation.Destination, 0));
}
else
{
instruction.Operands.Add(DispatchOperand(memoryOpCode, instruction.AddressingModeSource, OperandNotation.Source, 0));
}
break;
case AddressingMode.StackPointer:
instruction.Operands.Add(new Operand()
{
AddressingMode = AddressingMode.StackPointer,
Notation = OperandNotation.Source,
Symbol = "SP",
Value = 0,
});
break;
case AddressingMode.ProgramCounter:
instruction.Operands.Add(new Operand()
{
AddressingMode = AddressingMode.ProgramCounter,
Notation = OperandNotation.Source,
Symbol = "PC",
Value = 0,
});
break;
case AddressingMode.StatusRegister:
instruction.Operands.Add(new Operand()
{
AddressingMode = AddressingMode.StatusRegister,
Notation = OperandNotation.Source,
Symbol = "SR",
Value = 0,
});
break;
}
}
return(instruction);
}
// debug helper
public static Operation Disassembly(uint memIndex)
{
DasmSymbol symbol = BinFileDasmRecord.SymbolsList.Where(w => w.DecimalValue == memIndex).FirstOrDefault();
Operation instruction = InstructionDecode(memIndex);
if (symbol != null)
{
if (!symbol.isLabel)
{
// make variable
ushort dataWordValue = Functions.BytesToWord(Memory.Data[memIndex], Memory.Data[memIndex + 1]);
DasmSymbol valueSymbol = BinFileDasmRecord.SymbolsList.Where(w => w.isLabel == true && w.DecimalValue == dataWordValue).FirstOrDefault();
instruction = new Operation()
{
OpCode = dataWordValue,
OpCodeValue = dataWordValue,
Length = 2,
Mnemonic = "DW",
Type = OperationType.Undefined,
Operands = new List <Operand>()
{
new Operand()
{
Value = dataWordValue,
Symbol = valueSymbol == null?
string.Format("${0}", Convert.ToString(dataWordValue, 16).ToUpper().PadLeft(4, '0')) :
valueSymbol.Name
}
}
};
}
}
// undefined mnemonic passed as is
if (instruction.Type != OperationType.Undefined)
{
if (instruction.Width == OperationWidth.Mixed)
{
instruction.Mnemonic += (instruction.OpCodeValue & 0x020) != 0 ? ".B" : string.Empty;
}
foreach (Operand op in instruction.Operands)
{
DasmSymbol valueSymbol = BinFileDasmRecord.SymbolsList.Where(w => w.DecimalValue == op.Value).FirstOrDefault();
// jumps see labels
if (instruction.Type != OperationType.Branch && valueSymbol != null)
{
// not jumps see vars reference
if (valueSymbol.isLabel && instruction.Context != OperationContext.Relative)
{
valueSymbol = null;
}
}
// lovely operands values to dump if doMonitor
switch (op.AddressingMode)
{
case AddressingMode.RegisterDirect:
op.DebugText = string.Format("{0}={1}", op.Symbol, Convert.ToString(State.A[op.Value], 16).PadLeft(4, '0'));
break;
case AddressingMode.RegisterReference:
op.DebugText = string.Format("{0}={1}", op.Symbol, Convert.ToString(Functions.BytesToWord(Memory.Data[State.A[op.Value]], Memory.Data[State.A[op.Value] + 1]), 16).PadLeft(4, '0'));
break;
case AddressingMode.ImmediateQuick:
op.DebugText = string.Format("{0}={1}", op.Symbol, op.Value);
break;
case AddressingMode.Immediate:
if (valueSymbol != null) // && instruction.Type == OperationType.Branch)
{
op.Symbol = valueSymbol.Name;
}
op.DebugText = string.Format("{0}={1}", op.Symbol, Convert.ToString(op.Value, 16).PadLeft(4, '0'));
break;
case AddressingMode.MemoryReference:
if (valueSymbol != null)
{
op.Symbol = string.Format("({0})", valueSymbol.Name);
}
op.DebugText = string.Format("{0}={1}", op.Symbol, Convert.ToString(Functions.BytesToWord(Memory.Data[op.Value], Memory.Data[op.Value + 1]), 16).PadLeft(4, '0'));
break;
case AddressingMode.StackPointer:
op.DebugText = string.Format("{0}={1}", "SP", Convert.ToString(State.SP, 16).PadLeft(4, '0'));
break;
case AddressingMode.StatusRegister:
op.DebugText = string.Format("{0}={1}", "SR", StatusRegisterValue());
break;
case AddressingMode.ProgramCounter:
op.DebugText = string.Format("{0}={1}", "PC", Convert.ToString(State.PC, 16).PadLeft(4, '0'));;
break;
}
}
}
instruction.DebugText = instruction.Mnemonic;
if (instruction.Type == OperationType.Undefined || instruction.AddressingModeSource == AddressingMode.Internal || instruction.AddressingModeDestination == AddressingMode.Internal)
{
instruction.DebugText += " " + instruction.Operands[0].Symbol;
}
else if (instruction.Type == OperationType.Memory && instruction.AddressingModeDestination == AddressingMode.StackPointer)
{
instruction.DebugText += instruction.Operands[0].Symbol + " ";
}
else if (instruction.Type == OperationType.Memory && instruction.AddressingModeSource == AddressingMode.Internal)
{
instruction.DebugText += " " + instruction.Operands[0].Symbol + " ";
}
else
{
instruction.DebugText += instruction.Operands.Count() > 0 ? " " + instruction.Operands[0].Symbol + "," : string.Empty;
}
// GETSP
if (instruction.Type == OperationType.Memory && instruction.AddressingModeSource == AddressingMode.StackPointer)
{
instruction.DebugText = "GETSP" + " " + instruction.Operands[0].Symbol;
}
else
{
instruction.DebugText += instruction.Operands.Count() > 1 ? instruction.Operands[1].Symbol : string.Empty;
}
return(instruction);
}
