mkMOD — prepare MOD files for V41
- MOD files are almost the same for V41
what are plug-in modules for real HP-41C/CV/CX.
mkMOD makes creating MOD files a cakewalk.
- Update 12/11/21:
- – Now context menu enables to extract ROMs (one by one),
– size of fields adjusted to V41 using NUL-terminated strings.
- Update 1/12/22:
- – fixed few rare cases like ROM with FAT but no CAT2 header.
Note: afore running this program read the QPL in
- A Brief Description
- Prerequisites, Install and Run it
- Controls of This Program
- Features, Constraints, Known Bugs
- The Fine Print
A Brief Description
MOD files expand the functions of an
HP-41C/CV/CX running under
which emulates the pocket calculator by simulating its Nut-CPU and few selected peripherals.
At first glance MOD files correspond virtually to
of the role model, which provide a remarkable expandability to users' requirements.
Taking a closer look, the difference is within those extensions which come with additional equipment
like IR printer module or card reader.
All complemental hardware must be simulated by the 'emulator' (for an outstanding example see
NutEm/PC and its
MOD files contain "only" the firmware and besides some metadata also the hint
which hardware it wants to run.
mkMOD (speak 'mka-mod or make-a-mod if you like) helps to prepare MOD files.
Only few users will make their own MODs, because the installation of V41 includes plenty of them,
just a few more than anybody will ever use.
Therefore mkMOD is only necessary when you do need to run a new ROM under V41
(as it lacks the ability to use ROM files directly),
or – MOD files may also determine the emulated calculator's OS –
in case you tinker around in this sector deep down below the engine bonnet.
Starting either from
mkMOD allows to modify almost all before filing the changes either as
- a file with metadata or
- a yet existing MOD file
The format of ROM files to include in the new MOD may be
- a new MOD file or
- a file with metadata to serve as future template.
For more details see readme.txt for MODMakeWin V1.1 (Sep 28, 2015)
– a tool to prepare single-page MODs only –
Warren Furlow's archive DVD or elsewhere.
- ZENROM listings or alike (a user-readable format),
- BIN files as used for
J-F Garnier's Emu41,
- ROM files like V41 used them decades ago, or
- other MOD files.
A Note About MOD Formats
V41 may currently use the two MOD file formats MOD1 and MOD2.
The later is said to be prefered by those specialist who like patching ROMs directly in the MOD file
using a hex-editor, so I was told.
mkMOD reads and writes MOD1 formatted MOD files only.
Modifying a ROM would just take the steps of extracting the ROM in question as ZENROM-alike listing,
"patch" or edit it in a text editor (as it is human-readable no hex-editor necessary),
take the changed ROM in (still opened) mkMOD and save the "mod MOD".
If few experts still prefer MOD2 format, it ain't a fault of my mkMOD.
Prerequisites, Install and Run it
To run mkMOD you need (in brackets what I used for the development):
To prepare MOD files you do need the ROM or ROMs for it in one of the
a. m. formats.
There is no automated installation procedure.
Unzip mkMOD.ZIP to a directory named at will, one of its own or not, it's up to you.
But! keep the organization of subdirectories (there are only 'HTML' and 'ROM'),
otherwise you will get no access from mkMOD to help or have to modify the program.
mkMOD expects ROMs in subdirectory 'ROM'.
Note: The ZIP bundles also few ROMs for first tests,
included a 'nut-cxp.MOD' from J-F Garnier
which is a 41CX patched to display lower case characters
(what works best with emulators which transliterate display output to letters, like NutEm/PC).
Another patch gives altering access to all flags.
Start mkMOD the same way like other ooREXX routines which require neither arguments nor options
(for example with a double click in Windows explorer to the mkMOD program file,
if its suffix corresponds to one of your choices at ooREXX installation).
Important errors are reported as messages, hints of minor importance
(like 'No file selected.' when cancelling file selection)
are displayed on the console window.
There is no functional disadvantage to run it without console.
Controls of mkMOD
If not yet obvious at first sight:
If you still have pending issues to resolve you do not belong to the target audience, sorry.
- The column of buttons to the left apply to the whole,
Load... loads a template (file type MOD or ROM2MOD),
Save as... saves metadata only (file type ROM2MOD),
Convert... saves a MOD file,
Quit — could this be a hidden Easter egg?
- the two buttons to the upper right apply to the current page,
Pick... let you include a ROM file, see a. m. formats,
Remove discards current page and reduces the number of pages,
- Up, Down
- change the sequence of pages by switching the current one (which remains the current),
- Previous, Next
- browse through the list of pages,
- other buttons
- are check boxes in 'pushlike' style,
- 'NumPages' (in the lower right of the 'Header' group)
- define how many pages are enclosed in the ROM to build,
- the spot to the lower in 'Page' group
- is to display findings of the selected ROM,
- the context menu (right mouse click)
- enables to extract the ROM of the actual page transformed to one of the
a. m. formats (except for MOD).
Features, Constraints, Known Bugs
- Are there features worth to mention?
- There is a "dirty flag" to indicate changes.
It is the asterisk in the mkMOD dialogue window's caption.
But there is no user torturing supervision if you quit w/o saving etc.
It is meant as a silent hint only.
- Are there significant limitations?
- Yes, one at least.
The ROM formats lack the direct access to ROM copies contained in LIF disk dumps.
You have to extract those relevant before running mkMOD.
And another one — the values of 'Header Custom' and 'Page Custom' are not editable.
- Known bugs?
- All known bugs are fixed.
Holler if you find a new one.
— As Christoph told me, the shown field size information would be too big by one,
for some C-distinctiveness (or anomaly?)
the last digit must be '00'x to work correctly.
From a C programmer's irrevocable point of view it is a documentation error.
To avoid futile sophistry and not to jeopardize V41 by correct but incompatible MODs
I adjust all text fields internally (until the day V41 gets fixed) but show the nominal size as before.
The fine print
(i) Do not use this program.
(ii) Any damage you cause with this program, intentional or by chance, is a violation of clause (i). Thus all consequences are completely at your own risk.
(iii) If you manage to improve this program you have to inform me as stipulated in following THE Q PUBLIC LICENSE (QPL).
(iv) In addition applies the QPL below:
THE Q PUBLIC LICENSE version 1.0
Copyright (C) 1999 Trolltech AS, Norway.
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