public static bool ProgramHalts(InstructionProcessor processor)
{
var instructionExecutedTrackingArray = new bool[processor.Instructions.Length];
instructionExecutedTrackingArray[processor.CurrentInstructionPointer] = true;
while (!processor.Halted)
{
processor.Step();
if (processor.Halted)
{
continue;
}
if (instructionExecutedTrackingArray[processor.CurrentInstructionPointer])
{
return(false);
}
instructionExecutedTrackingArray[processor.CurrentInstructionPointer] = true;
}
return(true);
}
public int GetAccumulatorAfterFixingCode()
{
for (var i = 0; i < _instructions.Length; i++)
{
var instruction = _instructions[i];
if (instruction.Operator == Operator.Jmp || instruction.Operator == Operator.Nop)
{
var fixedInstructions = _instructions
.Select(i => new Instruction {
Operator = i.Operator, Operand = i.Operand
})
.ToArray();
fixedInstructions[i].Operator = instruction.Operator == Operator.Jmp ? Operator.Nop : Operator.Jmp;
var processor = new InstructionProcessor(fixedInstructions);
if (ProgramHalts(processor))
{
return(processor.Accumulator);
}
}
}
throw new Exception("Unable to fix code");
}
public int GetAccumulatorAtFirstLoop()
{
var instructionExecutedTrackingArray = new bool[_instructions.Length];
var instructionProcessor = new InstructionProcessor(_instructions);
instructionExecutedTrackingArray[instructionProcessor.CurrentInstructionPointer] = true;
while (!instructionProcessor.Halted)
{
instructionProcessor.Step();
if (instructionExecutedTrackingArray[instructionProcessor.CurrentInstructionPointer])
{
return(instructionProcessor.Accumulator);
}
instructionExecutedTrackingArray[instructionProcessor.CurrentInstructionPointer] = true;
}
return(instructionProcessor.Accumulator);
}
