Steve,

???
If you push P2 during external code execution, you get
always the high address of the current instruction.

Only the described ways are working.

a 4. way:
on the Siemens C505 there is always a shadow register
XPAGE, which was updated every time, if P2 was changed.

E.g.
push XPAGE
;change P2, do something
pop P2


Peter