$D018/53272/VIC+24:   VIC Memory Control Register

   +----------+---------------------------------------------------+
   | Bits 7-4 |   Video Matrix Base Address (inside VIC)          |
   | Bit  3   |   Bitmap-Mode: Select Base Address (inside VIC)   |
   | Bits 3-1 |   Character Dot-Data Base Address (inside VIC)    |
   | Bit  0   |   Unused                                          |
   +----------+---------------------------------------------------+