MVN                      MVN Block Move Negative                      MVN

 65816 only!
                                                        N V M X D I Z C
  Operation:                                            . . . . . . . .

  +----------------+-----------------------+---------+---------+----------+
  | Addressing Mode| Assembly Language Form| OP CODE |No. Bytes|No. Cycles|
  +----------------+-----------------------+---------+---------+----------+
  | Block Negative |   MVN $FF,$FF         |   $54   |    3    |  7/byte  |
  +----------------+-----------------------+---------+---------+----------+
   X-Register = Source Address
   Y-Register = Destination Address
   Accumulator = Number of Bytes to move -1
   $FF,$FF = Source Bank, Destination Bank

   Attention: In memory the order of the Bank-bytes is the other way
   around (i.e. Dest, Src)! Some assemblers use this order as syntax,
   although it is not correct.

   Keep also in mind that the Data-Bank-Register will be set to Dest-Bank.

   MVN is used when the destination start address is lower (more negative)
   than the source start address.