DCP                    DCP DEC memory, CMP memory                     DCP
                                                     N V - B D I Z C
  Operation:  M <- (M)-1, (A-M) -> NZC               ? ? - - - - ? ?

  +----------------+-----------------------+---------+---------+----------+
  | Addressing Mode| Assembly Language Form| OP CODE |No. Bytes|No. Cycles|
  +----------------+-----------------------+---------+---------+----------+
  |  Zeropage      |   DCP $FF             |   $C7   |    2    |    5     |
  |  Zeropage,X    |   DCP $FF,X           |   $D7   |    2    |    6     |
  |  Absolute      |   DCP $FFFF           |   $CF   |    3    |    6     |
  |  Absolute,X    |   DCP $FFFF,X         |   $DF   |    3    |    7*    |
  |  Absolute,Y    |   DCP $FFFF,Y         |   $DB   |    3    |    7*    |
  |  (Indirect,X)  |   DCP ($FF,X)         |   $C3   |    2    |    8     |
  |  (Indirect),Y  |   DCP ($FF),Y         |   $D3   |    2    |    8*    |
  +----------------+-----------------------+---------+---------+----------+
  * Add 1 if page boundary is crossed.