void DoReturn(IGifValue returnValue)
{
if (stack.Count == 0)
{
halted = true;
return;
}
else
{
GifStackFrame returnFrame = stack.Pop();
runningRegister = returnFrame.runningRegister;
switch (returnFrame.RHSInstruction)
{
case 0xCCC: // Assign
bool failure;
returnValue.Write(returnFrame.LHSValue.Read(), out failure);
if (failure)
{
DoReturn(returnValue);
}
break;
case 0xC8C: // Call
stack.Push(new GifStackFrame(returnFrame.runningRegister));
current = returnFrame.LHSValue;
runningRegister = returnValue.Read();
break;
case 0xCC4: // Retarget
ColorRGB lhsColor = returnFrame.LHSValue.Read();
ColorRGB rhsColor = returnValue.Read();
registerTargets[rhsColor.R16, rhsColor.G16, rhsColor.B16] = registerTargets[lhsColor.R16, lhsColor.G16, lhsColor.B16];
current = new GifCursor(rhsColor, GetRegisterPosition(rhsColor), GetRegisterTarget(rhsColor));
break;
default:
break;
}
}
}
public void Tick()
{
if (halted)
{
return;
}
ColorRGB programPosition = registerPositions[runningRegister];
GifCube program = GetRegisterTarget(runningRegister);
ColorRGB instruction = program[programPosition];
ColorRGB currentColor = current.Read();
// point to the next instruction
bool overflow;
registerPositions[runningRegister] = registerPositions[runningRegister].Increment(out overflow);
if (overflow)
{
halted = true;
return;
}
switch (instruction.hexSignature)
{
case 0x000: // Return
DoReturn(current);
break;
case 0xCCC: // Assign
stack.Push(new GifStackFrame(current, 0xCCC, runningRegister));
break;
case 0xC8C: // Call
stack.Push(new GifStackFrame(current, 0xC8C, runningRegister));
break;
case 0xC04: // Load GIF
break;
case 0xC84: // Save GIF
//registerTargets[currentColor.R16, currentColor.G16, currentColor.B16].Save(GetRegisterName(currentColor) + ".gif");
break;
case 0xCC4: // Retarget
stack.Push(new GifStackFrame(current, 0xCC4, runningRegister));
break;
case 0x00C: // RegisterPos
current = new GifCursor(currentColor, currentColor, registerPositions);
break;
case 0x08C: // RegisterVal
current = new GifCursor(currentColor, registerPositions[currentColor], registerTargets[currentColor.R16, currentColor.G16, currentColor.B16]);
break;
case 0x0CC: // Data
current = new GifCursor(ColorRGB.White, currentColor, registerTargets[15, 15, 15]);
break;
case 0xC0C: // Modify
bool failed;
registerPositions[runningRegister] = registerPositions[runningRegister] + new ColorRGB(48, 0, 0);
current = Modify(currentColor,
new ColorRGB[] {
program[programPosition + new ColorRGB(16, 0, 0)],
program[programPosition + new ColorRGB(32, 0, 0)],
program[programPosition + new ColorRGB(48, 0, 0)]
},
out failed
);
if (failed)
{
DoReturn(current);
}
break;
default:
current = new GifCursor(runningRegister, programPosition, program);
break;
}
}