Some Observations on Geir Isene's ROM Offerings


As I get more adept with EMU41, PIL-Box, and NoV-64, I have been keen to explore what else is out there. As many know, Geir presents several MOD and ROM files on his site consisting of content from the HP41 User Library Solutions books. I was interested in the High Level Math (HL_MATH.ROM), Physics (PHYSICS.ROM) and Test Statistics (TESTS.ROM) modules.

When burned to NoV-64, the Physics and High-Level modules show up in a CAT 2 list just like any other commercially produced module of FOCAL programs, like the Math Pac, Stat Pac, PPC, etc.

TESTS.ROM, on the other hand, does not appear in a standard CAT 2 listing. The little program 'TESTS runs fine in EMU41 in the absence of HEPAX, displaying or printing Geir's website URL. But on my NoV-64, where the presence of HEPAX is obligatory, whether or not 'TESTS runs seems on what else, if anything, in in HEPAX RAM. Basically, if HEPAX RAM is empty, XEQ 'TESTS returns NONEXISTENT. If there are user programs in my HEPAX RAM, XEQ 'TESTS will execute my own user program with which it shares the same XROM number. If something other than a program is the first program in my HEPAX RAM, XEQ 'TESTS will carry on correctly.

I am curious as to the difference in behaviour. My guess is that the Physics and High Level Math ROMs are assembled in such a way that they behave as standard 4K modules irrespective of where they reside, where TESTS.ROM is a copy of a HEPAX page, the contents of which do not appear in CAT and which may conflict with other programs in HEPAX RAM if HEPAX is present.

Any enlightenment would be most appreciated.




Some of the ROMs have been created with the very simple solution that anyone with a NOV rom can do; Simply enter the programs from the library with a Wand, save them to HEPAX RAM and transfer the ROM to the PC via PIL BOX. I added a small program first in the listing that is the name of the rom. BUT, for CAT 2 t register, the first program needs to be longer than 7 characters so that it cannot be easily entered via the keyboard. But to do that, you would have to go in (via HEXEDIT for instance) and change the label of the first program.

My idea was to get many people to come along and turn the solution books into modules the easy way, not having to know anything about MCODE to get it done. That is why I left the modules as they are - no MCODE'ing, no loooong first label, no CAT 2 listing. Proof of concept.


You can't type in LBLs longer than seven characters from the keyboard.

But you CAN write them as a text file and hp41uc compiles things to a LIF file just fine.

I have one of my own sets of user routines in a HEPAX page at the moment. It is late here, but I will try to experiment with this idea tomorrow.



Nah, that's not enough.

Dumped the ROM image according to Angel's directions in the NoV-64 manual, created a ROM using RAM2ROM4.exe, added the result to EMU41.

I can navigated to all of my routines via GTO [label], but the long initial label does not show up in EMU41.

Have to learn some M-CODE...



It's real easy to change the labels to longer than 7 characters using HEXEDIT from HEPAX. The only reason I didn't was that I wanted to create new FOCAL modules out of the solutions book without using any MCODE. All the programs from the solution book is there - the drawback being the invisibility to CAT 2.


Have to learn some M-CODE...

A step by step example of how to compose a ROM is given in Part 2 of the HEPAX manual (Section 12, pp. 153). There, the prerequisites for an orderly FAT and the ROM naming convention is given.

Of course, every seriously interested person shouldn't miss Ken Emery's "HP-41 MCODE for Beginners".

Eventually, by some well placed manipulations you can get Isene's ROM to show up in CAT 2.

Good luck

All that's required is a small "section header" function with length longer than 7 chars to be placed in the first entry of the FAT.

The CCD-style CAT'2 will show any function as header regardless of its length if its name starts with the hyphen chrs "-", code 0x20D.

The function could look like this:

083 "C"

00E "N"

006 "F"

020 " "

013 "S"

005 "E"

00C "L"

20C "-"


you can place it anywhere in the ROM, just make sure it's the first FAT entry.


PS. BTW there's a new revision of the High-Level Math ROM, correcting a problem with the IGAB program.

Edited: 5 June 2012, 8:35 a.m.


you can place it anywhere in the ROM, just make sure it's the first FAT entry.

If we are going into details here, make also sure that the FAT entry linking to the ROM name should have the MCODE header then.

00x	First and second line of FAT entry
0yz with xyz denoting the address where return is (RTN, 3E0)

I noticed that the FAT entry of the Isene ROM shows
200	A FAT header starting with "2" denotes a FOCAL program, and for instance links to
0A0 the address n0A0 with "LBL ISENE-1" which doesn't show up with CAT 2.
(n denotes the page where the ROM is plugged in)


The CCD-style CAT'2 will show any function as header regardless of its length if its name starts with the hyphen chrs "-", code 0x20D.

The CCD OSX module's CAT[gull]2 will show function headers even in the absence of a hyphen.

Indeed, I don't complete grasp the scope and purpose of the CCD modules, but given that I am working with a CV I really do appreciate how the presence of a CCD renders a CAT 2 listing in a compressed fashion, as on a CX.



PS. BTW there's a new revision of the High-Level Math ROM, correcting a problem with the IGAB program.

Ángel, where is the most up-to-date version? The one at TAS isn't dated.

Many thanks,



I just checked - the version at TOS is the old/bad one. I should submit the new one today, will be glad to send it to you as well if you send me an email at my registered forum address.



leslie dot wright at rogers dot blackberry dot net

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