HP-41 ROM Polling Point at FF5

[Dan Grelinger]

Do any HP-41C microcode experts know this? Is the ROM Polling Points at HxFF5 called after every function is executed, or only after a function is executed in a running program?

I ask as this may be a way for Monte to solve his hidden flag storage problem.

[Ángel Martin]

From Ken Emery´s book:

"This address is polled after any RPN function is executed, if user flag 53 or peripheral flag 13 is set. This includes execution of functions during a User code program, and is called the main running loop interrupt".

So it'd appear that yes, it's also polled in RUN mode for a RPN function - which I don't believe includes the auto-off feature.... but testing is the ultimate proof.

However the pFF7 polling point is used also in the auto-off event, so that may be way to address this issue?

Edited: 12 Jan 2013, 3:48 a.m. after one or more responses were posted

[Monte Dalrymple]

The only time that I have seen the xFF5 address polled is after the SHIFT-ON sequence to display the time.

I currently plan to try to use the xFF8 polling address to store the hidden flag and turbo state. This address appears to be polled before every entry into Light Sleep, which would guarantee that these status bits and turbo state would be correct after waking up from an auto-off.