RTI                    RTI Return from interrupt                      RTI
                                                        N Z C I D V
  Operation:  P from Stack, PC from Stack                From Stack
                                 (Ref: 9.6)
  +----------------+-----------------------+---------+---------+----------+
  | Addressing Mode| Assembly Language Form| OP CODE |No. Bytes|No. Cycles|
  +----------------+-----------------------+---------+---------+----------+
  |  Implied       |   RTI                 |   $40   |    1    |    6     |
  +----------------+-----------------------+---------+---------+----------+