Standard:

   $DE00 and $DE01 registers are active. $DF00-$DFFF contain the last page
   of the selected 8K-bank of either ROM or RAM, whatever is selected. RAM
   can only be accessed in $8000-$9FFF. ROM can be mapped to $8000, $A000 or
   $E000 with the corresponding status on GAME and EXROM.

   Note: If the AllowBank bit ($DE01, Bit 1) is not set, the $DF00-$DFFF area
   will always access bank 0 of the RAM, so the older cartridge images will
   work. The AllowBank bit does not have any effect on the ROM mirror in that
   area.

 Freeze:

   ROM is mapped to $E000-$FFFF, bank 0 is active directly after Freeze.
   Writing to bits 0 and 1 of the $DE00 register will have no effect on GAME
   and EXROM. RAM can be selected and used in $DE02 or $DF00, respectively,
   but not in $8000. Banking bits work, so you have full read access to the
   ROM, and access to up to four RAM pages with the AllowBank bit set (minus
   2 bytes if REU compatible bit is set). You should leave this memory map
   as soon as possible by setting bit 6 of $DE00 because C64 RAM in the
   $E000 area is not available, and you don't have control of the GAME and
   EXROM lines.

 REU compatible:

   $DE00 and $DE01 registers are active. $DE02-$DEFF contain a mirror of
   $9E02-$9EFF of the selected 8K-bank of either ROM or RAM, whatever is
   selected. RAM can only be accessed in $8000-$9FFF. ROM can be mapped to
   $8000, $A000 or $E000 with the corresponding status on GAME and EXROM.
   $DF00 stays free for use with the 17xx Ram Expansion Unit (REU).

   Note: If the AllowBank bit ($DE01, Bit 1) is not set, the $DF00-$DFFF area
   will always access bank 0 of the RAM, so the older cartridge images will
   work. The AllowBank bit does not have any effect on the ROM mirror in that
   area.