checkInput:
   ld a, %00100000
   ld [$FF00], a

   ld a, [$FF00]
   cpl
   AND %00000001
   cp 0
   call z, moveLeft

   ld a, [$FF00]
   cpl
   AND %00000010
   cp 0
   call z, moveRight

   ld a, [$FF00]
   cpl
   AND %00000100
   cp 0
   call z, jump
   ret

; move ball to the right
moveRight:
   ld a, [Ball_PosX]
   inc a
   ld [Ball_PosX], a
   ret

; move ball to the left
moveLeft:
   ld a, [Ball_PosX]
   dec a
   ld [Ball_PosX], a
   ret

;jump with ball
jump:
   ld a, [Ball_PosY]
   dec a
   ld [Ball_PosY], a
   ret