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Anyone interested in a SDK41 compatible version of the 41C VASM source files?
05-16-2018, 07:42 PM
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Anyone interested in a SDK41 compatible version of the 41C VASM source files?
If so you're lucky: I have one (GFF version), but it needs some work before publication so I would like to gauge the interest to define what priority to put on it. By interest I mean : who would use it for real output (to recompile the 41C ROM) and not just in case, for archiving purposes?

Historical background:
10 years ago there was a question on this forum about searchable versions of the HP 41 VASM listings: MCODE - anyone interested in a searchable VASM pdf? .
This was the trigger for me to start working on a text version of the VASM listings, I started with OCR but the output was pretty low quality and required manual adjustments. I decided that the best way to ensure that the result text file would be error free was to create a rom file from it and check this rom file vs. the original 41C rom for consistency.
As the development tools used with the VASM listings are not available anymore, I had to use the SDK41 assembler and linker to create the rom files. This means that I had to find a way to create a SDK41 compatible source file from the VASM text files. So I wrote some perl scripts to process the VASM text file and convert it to a SDK41 compatible format. This was a very iterative process as I progressed slowly through the original VASM listing, enriching the conversion script as I found new instructions or new line structures.

I was close to the end of this work when Jackie F. Woldering published in February 2013 his own version of the VASM listings in txt and pdf format. I was a bit disappointed as I was not aware we were working in parallel on the VASM listings, but anyway I completed my work up to the point where I could generate rom files that were identical to the original ones. This was the proof that the assembly instructions in my VASM text files were correct, however to check the consistency of the comments the rom files were useless, so I checked my VASM text file vs. Jackie’s version. This helped me to fix numerous typos in the comments but I found also that Jackie had made several modifications to the original comments:
  • Fixing typos in original comments
  • Replacing some abbreviated words by full words
  • Rewriting some sentences
I must say that during this check process I found much more errors in my VASM txt file than in Jackie’s file. I’m amazed by the level of quality he achieved in converting the VASM listings to a text file.
At that point I stopped any work and as after the publication of Jackie’s file nobody seemed to need to generate a ROM file, it went very very low on my priority list.

The recent thread about open sourcing the HP calculator software reminded me about this work, and I think it’s a good time to bring it back.

So there is now to my knowledge two text versions of the original VASM listings:
  • Jackie’s version with improved comments (and a few mistakes)
  • My version with the correct assembly instructions and original comments – also available in a SDK41 compatible format that can be used to generate roms
My plan is to publish at some point:
  • My VASM text and pdf files (similar to the ones published by Jackie)
  • The perl scripts to generate the SDK41 source files from the VASM text file and the process to do so
  • The SDK41 source files, the batch files to generate the ROMs from these source files and how to check the generated roms vs. the original roms
  • The differences between my VASM text file and Jackie’s file

Now my questions to you:
  • What would you do if you had access to a SDK41 compatible version of the 41C VASM source files?
  • Do you prefer the original comments or the improved ones from Jackie?
  • Would you see a need for a similar SDK41 compatible version of the HFF VASM listings?
  • Any other suggestion on this topic?
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