     $D01B/53275/VIC+27:  Sprite to Background Display Priority

       +----------+---------------------------------------------------+
       | Bit  x   |   Sprite x: 0 = Sprite has higher Priority        |
       +----------+---------------------------------------------------+

       Higher Priority means sprite is in front of everything.

       Lower Priority means sprite is behind bit-combinations starting with
       1 (e.g. %1 in hires mode and %1x in multi-color mode) and in front of
       bit combinations starting with 0 (e.g. %0 in hires mode and %0x in
       multi-color mode). So we get the following priority-tables:

       Hires: Bit=0 < Sprite < Bit=1 ; Multi-Color: Bit=00 < Sprite < Bit = 10
                                                    Bit=01 <        < Bit = 11