[HP41] mcode question polling point entries

[Ángel Martin]

(03-24-2023 11:58 AM)MeindertKuipers Wrote:  Confirmed, same behavior with the original CCD ROM (in the HP41CL)

Sorry I can't find any clear reason for what you're experiencing.

Indeed the RTN address is relevant to the OS/X I/O_flag code, as it is the way to determine which native function has been executed prior to the partial_data_entry halt. So if your ROM alters the RTN stack then the OS/X will miss the chance to act upon the triggering event...

but this has nothing to do with the N register, or with any other register except the RTN address stack (i.e. if used PUSHADR, POPADR); however you're reporting that the issue appears only if you use N, right?

The obvious question is: can you use other register instead of N to avoid the problem?