/// <summary>
/// Perform an instruction (a command and an optional parameter) on the stack
/// </summary>
/// <param name="instruction">The instruction to execute</param>
public void ExecuteInstruction(CliffordInstruction instruction)
{
switch (instruction.Command)
{
case Command.Push:
{
if (!instruction.Parameter.HasValue)
{
throw new InvalidOperationException();
}
Push((int)instruction.Parameter);
break;
}
case Command.Pop:
{
Pop();
break;
}
case Command.Add:
{
int[] operands = GetOperands(2);
Push(operands[0] + operands[1]);
break;
}
case Command.Subtract:
{
int[] operands = GetOperands(2);
Push(operands[0] - operands[1]);
break;
}
case Command.Multiply:
{
int[] operands = GetOperands(2);
Push(operands[0] * operands[1]);
break;
}
case Command.Divide:
{
int[] operands = GetOperands(2);
Push(operands[0] / operands[1]);
break;
}
default: throw new InvalidOperationException();
}
}
/// <summary>
/// Clifford Engine entry point
/// </summary>
/// <param name="args">Unused</param>
static void Main(string[] args)
{
CliffordProgramCodeCollection codes = new CliffordProgramCodeCollection();
CliffordInstructionQueue instructions = new CliffordInstructionQueue();
CliffordStack stack = new CliffordStack();
// Get codes as a whitespace-separated string
string input = Console.ReadLine();
// Tokenise on whitespace
string[] commandsString = input.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
foreach (string command in commandsString)
{
if (!codes.Add(command))
{
Console.WriteLine("Warning. Failed to parse command: " + command);
}
}
// Generate Instructions
instructions = codes.GenerateInstructions();
if (instructions == null)
{
Console.WriteLine("Error generating instructions. Check input.");
return;
}
// Execute Instructions
while (!instructions.IsEmpty())
{
#if DEBUG
DisplayEngineState(stack, instructions);
#endif
CliffordInstruction instruction = instructions.FetchInstruction();
if (instruction != null)
{
stack.ExecuteInstruction(instruction);
}
}
// Display resultant stack
DisplayEngineState(stack);
// Stay alive!
Console.ReadLine();
}
/// <summary>
/// Adds a new instruction to the instruction queue
/// </summary>
/// <param name="instruction">The instruction to add</param>
public void AddInstruction(CliffordInstruction instruction)
{
instructions.Enqueue(instruction);
}