; Input addresses
  .const KeyRead 0
  .const MouseGetPosX 1
  .const MouseGetPosY 2
  .const ScreenGetWidth 3
  .const ScreenGetHeight 4
  .const KeyReady 5

  ; Output addresses
  .const ScreenSetAddr 0
  .const ScreenWriteData 1
  .const CounterSetInterval 2
  .const CounterSetState 3
  
  ; Interrupt vectors
  .const InterruptVectorCounter 2
  .const InterruptVectorMouse 3
  .const InterruptVectorKeyboard 4