TXA                TXA Transfer index X to accumulator                TXA
                                                        N Z C I D V
  Operation:  X -> A                                    / / . . . .
                                 (Ref: 7.12)
  +----------------+-----------------------+---------+---------+----------+
  | Addressing Mode| Assembly Language Form| OP CODE |No. Bytes|No. Cycles|
  +----------------+-----------------------+---------+---------+----------+
  |  Implied       |   TXA                 |   $8A   |    1    |    2     |
  +----------------+-----------------------+---------+---------+----------+