Any volunteers to compile en entrypoint list for HP42S ?

[G-SAN]

Are there any volunteers to compile an entrypoint list for the HP-42S ROM(s) ?

It would be used with SASM

[dlidstrom]

I don’t think the HP42S ROM has ever been extracted ?

[Thomas Klemm]

(02-21-2024 07:44 PM)dlidstrom Wrote:  I don’t think the HP42S ROM has ever been extracted ?

I once used CPROMUPL to dump the ROM of my HP-42S to an HP-48GX.
Christoph is a wizard.

[Raymond Del Tondo]

Wlodek once published a book named "Customize your HP-28",
which included an (incomplete) entries list of the HP-28.
That might be a good base.
Also, there are several articles about entry points of the HP-42S.

[G-SAN]

I dumped my ROM (version C) via de ML code that Christoph G made, in combination with a HP Ir receiver and an Arduino (using the sketch made by Meindert Cuypers, which I adapted to dump the binary codes directly to my iMac). On iMac I piped this bytestream to a file, which was then converted by another tool of Christoph to the ROM format that I now use in the emulator EMU42.

So the ROM of an HP-42S has most certainly been dumped, and I have copies of rev A and rev B as well. Some searching on french forums gave me a link to all three ROM dumps in a ZIP file.

The problem - as Christoph G also made clear - is that HP never released the ROMs themselves, nor any VASM listings. And it seems illigal to just make the ROMs available for public download.

So I started to compile a memory map in Excel, based on the information available here on the Museum, HPCalc.org and other places. That is not exactly a ROM dump, but a description of how it is built. Seems slightly less illigal in my mind.

I found some messagestrings in the ROM dump, some entrypoins are mentioned here and in other places, but most of the area between 00000h and 1FFFFh is uncharted territory for me.

If there are other people with information about interesting addresses between these two (nibble) addresses, let me know.

Also tips on how to keep this information in a manageble form (instead of Excel) is appreciated.

The thing that triggered me is that it is indeed possible to use XFCN function after adding a FRAM on the second place on the board. This gives the possibility to add funtions, although it is a lot harder then making a new ROM for HP41.

Regarding the HP28S ROM entry points: so far I found no matches in the code, so it looks like the HP42S ROM is structured similar, but not quite the same.

And I still am in the process of getting to grips with EMU42 tracing and the debugger. Both are excellent tools, but using them is not trivial when trying to map what happens when for example the BEEP function is used).

So, anyone with an intereset in HP42S ROM: I would like to share information, just let me know.

Gert