public void Start()
{
SetBank(0);
SetInstructionPointer(0);
var context = new ExecutionContext(_program);
try
{
while (true)
{
int address = GetCurrentInstructionAddress();
context.SetInstructionAddress(address);
context.Opcode = (Opcode)context.GetNextByte();
context.ResultStatus = InstructionStatus.NotImplemented;
ExecutionCycle(context);
}
}
catch (McuException /*mex*/)
{
// TODO
}
}
private void Process_UNARY(ExecutionContext context)
{
const byte v = (byte)UnaryArg.V;
bool useVar = ((byte)context.Opcode & v) == v;
byte opArg = context.GetNextByte();
int value = useVar ? GetVariable(opArg) : GetMemoryByPointer(opArg);
switch (context.Opcode)
{
case Opcode.RU_INC_V:
case Opcode.RU_INC_M:
value++;
if (value > 255)
{
value %= 256;
SetCarryBit(true);
}
else
{
SetCarryBit(false);
}
SetZeroBit(value == 0);
context.ResultStatus = InstructionStatus.Normal;
break;
case Opcode.RU_DEC_V:
case Opcode.RU_DEC_M:
break;
case Opcode.RU_NOT_V:
case Opcode.RU_NOT_M:
break;
case Opcode.RU_ROL_V:
case Opcode.RU_ROL_M:
break;
case Opcode.RU_ROR_V:
case Opcode.RU_ROR_M:
break;
default:
throw new McuException();
}
if (useVar)
{
SetVariable(opArg, (byte)value);
}
else
{
SetMemoryByPointer(opArg, (byte)value);
}
}
private void Process_FLOW(ExecutionContext context)
{
switch (context.Opcode)
{
case Opcode.VO_NOP:
context.ResultStatus = InstructionStatus.Normal;
break;
case Opcode.VO_STOP:
break;
case Opcode.VO_RET:
break;
case Opcode.UO_JMP_C:
case Opcode.UO_JMP_V:
case Opcode.BO_JMP_FAR:
byte ip;
switch ((FlowJumpAddress)((byte)context.Opcode - FlowCommand.JMP))
{
case FlowJumpAddress.C:
ip = context.GetNextByte();
break;
case FlowJumpAddress.V:
ip = GetVariable(context.GetNextByte());
break;
case FlowJumpAddress.FAR:
ip = context.GetNextByte();
SetBank(context.GetNextByte());
break;
default:
throw new McuException();
}
SetInstructionPointer(ip);
context.ResultStatus = InstructionStatus.Jumped;
break;
case Opcode.UO_JZ_C:
case Opcode.UO_JZ_V:
case Opcode.BO_JZ_FAR:
break;
case Opcode.UO_JNZ_C:
case Opcode.UO_JNZ_V:
case Opcode.BO_JNZ_FAR:
break;
case Opcode.UO_CALL_C:
case Opcode.UO_CALL_V:
case Opcode.BO_CALL_FAR:
break;
default:
throw new McuException();
}
}
