Hello all,

New material regarding the JPC ROM for the HP-71B:

First, I finally finished to collect the JPC ROM assembly source files. The original files are lost (AFAIK), and I had to rebuild them from various sources (Swap disks, paper issues of the JPC journal, personal archives, private communications). This release is based on the regular version D and includes the changes and fixes made by Rodger Rosenbaum in version X.

Secondly, I recently got a ROM image (merci Claude!) of the little-known official version E, which was released on end of 1989 by PPC-Paris shortly before the club experienced serious problems and collapsed.

More details on my JPC ROM page.

JPC ROM version F project:

This now allow us to think about a new version that would merge all JPC ROM improvements into a single and definitive edition.

So I would like to make a call for contributions: if you ever made some improvements, or are aware of bug fixes still to be done in the JPC ROM, and you want to participate to this project, please contact me. At least two people already expressed interest in working on a new JPC ROM version. Any suggestions are welcome, although I would prefer real (and debugged) code contribution!

I don't plan to write new HP-71B assembly code, so I will act more as an editor to collect the contributions and share them to the HP-71B user community.

Best regards.


Edited: 4 July 2006, 7:26 a.m.


Exciting news, JF!

Looking at your new pages, I see that the "E" version was 64KB, whereas the "D" and "X" versions were both 32KB. What was in "E" that doubled it in size? (I currently have the 32K "X" version on an EPROM, courtesy of Mike.)



The E included complementary editor and graphic functions which make for the added 32Ko.

You'll find the details in the Qrg addendum on Jean-Fran├žois site here.




Hi Howard,

Yes, version E is about 44kb long and thus a 64kb EPROM (or RAM) module is needed: 26ko for an improved version of the regular JPC LEX, plus 9kb for the XEDIT text editor (a fast, assembly language written, enhanced version of the slow HP EDTEXT editor), plus 9kb for the "Graphic Module" (a set of graphic keywords, close to the HP9000 RMB, to use a DeskJet/LaserJet as a plotter).


Edited: 6 July 2006, 2:33 p.m.


Thanks, JF.

After looking over the QRG, I'll stick with the X-version I have on an EPROM.

Glad these things are available to the community at last.

Anyone else still play with Symbolix?



After having used the Ex version for some time (trying almost every feature and playing with it a lot) I removed the module yesterday after a crash with a memory lost condtion which I believe was caused by the JPC ROM. Seems the software is too buggy still not beeing HP software quality standards. Two bugs I want to report: if all user flags are set you cannot toggle between CALC and BASIC modes. After the flags (or maybe some of it) are cleared you can do it again. Next I'm using the 41 Translator ROM. If you use the VIEW function/key several times to view the contents of a memory register then the 71B crashes. See above.


Hello Siegmar,

I'm *very* interested in collecting all known (or new) bugs of either the JPC ROM, or the HP mainframe or options.

However, the first bug you mentionned is not really a bug. This behaviour is trigged by flag 59 (no need to set all flags). This comes from the JPC ROM Assembler tabs functionality: when in the EDTEXT text editor, the CALC key is used to toggle the assembler tabs function (when it is activated, the space key jumps to the next field tab). The point is that the JPC ROM detects that EDTEXT is running by testing flag 59.

Regarding the 2nd bug, can you explain it further? I understand that the crash happens inside the HP41 simulator when using the HP41 VIEW function. Is that correct? Does it depend on the JPC Rom and HP71 flags as above? And please give me your actual VER$ string, I would like to reproduce it. It may be related to the JPC Rom cursor position viewing function (driven by the VIEW key in USER mode...)

We could think to remove these functions in a future JPC F version, if there is a general agreement on it. Using the EDTEXT editor to edit large assembly source files is no more the main usage of the HP71, I guess.



Hi J-F!

The first "bug" behaves exactly as you say.

Regarding the 2nd bug you are absolutely right it has to do with the cursor position viewing function. It displays a different value each time you use it and after several times: Memory lost and then: Missing ~SUB.

This happens with activated USER mode and inside the HP41 mode, Flags are not relevant.



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