SHX                                                                   SHX

                                                        N V - B D I Z C
  Operation:  M <- (X) /\ (PCH+1)                       . . . . . . . .

  +----------------+-----------------------+---------+---------+----------+
  | Addressing Mode| Assembly Language Form| OP CODE |No. Bytes|No. Cycles|
  +----------------+-----------------------+---------+---------+----------+
  |  Absolute,Y    |   SHX $FFFF,Y         |   $9E   |    3    |    5     |
  +----------------+-----------------------+---------+---------+----------+

  Note: Sometimes the "/\ (PCH+1)" drops off. Also page boundary crossing
  won't work as expected (the bank where the value is stored may be equal
  to the value stored).

  Warning: This opcode is said to be unstable!