anchor.diff:                          else
                               characterBankPointer ||| (GetVideoMatrixLineMemory() &&& 0xFF) ||| rowCounter
                       else
  -                        SetVideoMatrixLineMemory(0)
                           0x3FFF
  -                )
  -            graphicsShiftRegister <- (graphicsShiftRegister <<< 8) ||| (data &&& 0xFF)
  +                ) &&& 0xFF
               IncrementVideoCounter()
           let readI () =
               readMemory(0x3FFF) |> ignore
  
positive.code:         ClockRasterCounter()
          ClockBaAec()
          ClockMemoryInterface()
          ClockIrq()
  
          // *** TODO ***
  
  
      // ========================================================================
  
negative.code:     // Sprite shift registers
      let mobShiftRegister = Array.create 8 0
      let mobShiftRegisterEnable = Array.create 8 false
      let mobShiftRegisterOutput = Array.create 8 0
  
      // Display/Idle state
      let mutable displayState = false
  