Alisha:

It is possible to backup the DPTR similar to the way you describe. It is also possible to use the push and pop instructions as:

PUSH DPH
PUSH DPL
...execute code to do other things with DPTR
POP DPL
POP DPH

Your scheme can be used to save DPTR as a "buffer pointer" foe use next time you come into a subroutine for example.

What I showed above is useful when you come into some code and you want to save what is in DPTR during the time that you use DPTR with a new intermediate value.

Michael Karas