Structure of files in X-Mem

[grsbanks]

Just wondering if anyone can point me to any hidden resources for this.

I've been doing some work reverse-engineering the data held in the RAM of an HP-41, working off this diagram:

http://www.hpmuseum.org/prog/synth41.htm#mm

I've nailed the structure of user key assignments and alarm data, I'm just struggling with the organisation of X-Mem right now. If anyone has pointers to information describing the structure, not of the files themselves stored in there because that's obviously application-dependent, but of the data chaining the files together and "telling" the HP-41 what files are there, where they are and what size they are.

Thanks in advance.

[rprosperi]

(01-29-2018 10:31 AM)grsbanks Wrote:  Just wondering if anyone can point me to any hidden resources for this.

I've been doing some work reverse-engineering the data held in the RAM of an HP-41, working off this diagram:

http://www.hpmuseum.org/prog/synth41.htm#mm

I've nailed the structure of user key assignments and alarm data, I'm just struggling with the organisation of X-Mem right now. If anyone has pointers to information describing the structure, not of the files themselves stored in there because that's obviously application-dependent, but of the data chaining the files together and "telling" the HP-41 what files are there, where they are and what size they are.

Thanks in advance.

The structure and layout of XM is described and illustrated precisely on p.8 of Jeremy Smith's "HP-41 Synthetic Quick Reference Guide", which is available on TOS. It's likely this info is also in Wlodek's '41 book, but I don't have that handy at the moment.

This resource is packed full of all kinds of similar '41 internals and should be a primary source for all such explorations. It also details main RAM, registers, KA's, Alarms, etc. You'll like it.

A similar, but more ambitious and updated, resource is Poul Kaarup's HP-41CX Programmers Handbook, also available on TOS (otherwise, I'd add a link).

Both are needed for complete info.

[hth]

The VASM listings contains the source code for the Extended Memory module and the layout is described there.

Håkan

[grsbanks]

Thanks for the pointers.

Sadly I was unable to locate the "HP-41 Synthetic Quick Reference Guide" on TOS but I was able to find the other document, which sadly doesn't contain the info I'm looking for, although it did clear up one point I was unsure of regarding KAs.

An internet search on "VASM extended memory" or "VASM HP-41C" doesn't yield anything relevant so I'm none the wiser on that particular score.

[rprosperi]

(01-29-2018 04:51 PM)grsbanks Wrote:  Thanks for the pointers.

Sadly I was unable to locate the "HP-41 Synthetic Quick Reference Guide" on TOS but I was able to find the other document, which sadly doesn't contain the info I'm looking for, although it did clear up one point I was unsure of regarding KAs.

An internet search on "VASM extended memory" or "VASM HP-41C" doesn't yield anything relevant so I'm none the wiser on that particular score.

On TOS, search for "Jeremy Smith" - I verified it's there before posting.

[grsbanks]

It was that easy -- d'oh!

Thanks. Now reading

[hth]

On the same place (TOS) you can search for "Extended Functions VASM", page 83 is probably where you want to start.

Håkan