anchor.diff:              DecrementRefreshCounter()
               readMemory(0x3F00 ||| refreshCounter) |> ignore
           match GetMemoryAccessCycle() with
  +            | -1 -> ()
               |  0 -> if (config.CyclesPerRasterLine < 64) then readG() else readI()
               |  2 |  4 -> readI()
               |  6 -> readP(0)
  
positive.code:         mobMobCollision.[5] <- false
          mobMobCollision.[6] <- false
          mobMobCollision.[7] <- false
          oldValue
  
      // Sprite-background Collision (1F)
      let mobDataCollision = Array.create 8 false
      let GetMobDataCollision () =
          (if mobDataCollision.[0] then 0x01 else 0x00) |||
  
negative.code:                     0
          aec <- baCounter > 0 && IsPhi0()
  
      // Border Unit
      let mutable borderVerticalEnabled = false
      let mutable borderMainEnabled = false
      let mutable borderEnableDelay = 0
  
  
      // ========================================================================
      // Internal Units
  