public void PushContext(WamInstructionStream instructionStream)
{
if (instructionStream == null)
{
throw new ArgumentNullException("instructionStream");
}
var context = new WamContext();
_contextStack.Push(context);
CurrentContext = context;
State = WamMachineStates.Run;
InstructionPointer = new WamInstructionPointer(instructionStream);
ReturnInstructionPointer = WamInstructionPointer.Undefined;
StackIndex = 0;
Environment = null;
ChoicePoint = null;
ArgumentRegisters.Clear();
TemporaryRegisters.Clear();
CurrentStructure = null;
CurrentStructureIndex = -1;
}
ExecutionResults OnProceed(WamInstruction instruction)
{
StackIndex -= 1;
InstructionPointer = ReturnInstructionPointer;
ReturnInstructionPointer = WamInstructionPointer.Undefined;
TemporaryRegisters.Clear();
return(ExecutionResults.None);
}
public void SetInstructionStream(WamInstructionStream instructionStream)
{
if (instructionStream == null)
{
throw new ArgumentNullException("instructionStream");
}
ReturnInstructionPointer = InstructionPointer.GetNext();
CutChoicePoint = ChoicePoint;
TemporaryRegisters.Clear();
StackIndex += 1;
InstructionPointer = new WamInstructionPointer(instructionStream);
}
ExecutionResults OnExecute(WamInstruction instruction)
{
var instructionPointer = GetInstructionPointer(instruction.Functor, 0);
if (instructionPointer == WamInstructionPointer.Undefined)
{
return(ExecutionResults.Failure);
}
if (StackIndex >= StackSizeLimit)
{
return(ExecutionResults.Failure);
}
CutChoicePoint = ChoicePoint;
TemporaryRegisters.Clear();
InstructionPointer = instructionPointer;
return(ExecutionResults.None);
}
