Donald Catto wrote:
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"I looked at your previous posts on this topic. Can you explain how to read the P2 latch when executing from internal code space?"

From internal code space P2 act no longer as high address byte and so it can be read back like P1 and P3.




"I don't understand how using the DPTR is going to help reading the P2 latch. Please explain."

If P2 no longer used as high address byte on such instructions like "MOVX A,@R0", then its content was dont care and so it must never be saved.



"Surely the JBC instruction in the following method will change the P2 latch contents?"

Mostly the reason to read it out was to change it anyway. So only the point, that now ACC contain the original state, was important to restore P2 later.


All these suggestions only related to such applications, if external memory was connected and P2 was used as high byte address on some memory routines.


And using the XPAGE register on the Infineon C505 was the easiest way.



Peter