Printing Disassembler

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Hans Otten

Jan 19, 2023, 3:27:11 AMJan 19
to PAL 6502 computer

In 1982 I wrote/composed a program to have disassembled code on paper, with page numbers. To hack for example the KB9 I needed hardcopy to analyze it.

The core routine of the disassembler is the well-known Steve Wozniak/Allen Baum 1876 article A 6502 Disassembler from Apple
The program is a console program. I build it with the then current hardware and software of my KIM-1, MICRO ADE, casssette files, video uppercase 24x16 as output, ASCII keyboard as input 40K RAM, H14 Heathkit matrix printer. Input 
I restored the source and the binary from cassette tape and published it on my website. Not a program you can run on a KIM-1 or PAL-1, it does not use the TTY routines.

A week ago Glen Deas, a KIM-1 user, mailed me his version V2 of the program. He changed the syntax to modern 6502, and replaced the I/O with standard KIM TTY.  SOme little problems remained.

I was pleasantly surprised and could not resist picking up his source and cleaning it up/fixing/convert to lowercase/improve it.
Unbelievable what a modern PC adds to the productivity! Notepad++ as IDE with TASM32 as assembler, KIM-1 Simulator as test/debugger toolchain.  Matter of minutes to find a bug. I will write a page on my KIM-1 toolchain one of these days. 

So now V3 of PRDIS is available. Ready to run on a  KIM-1/PAL-1.  

 Printing Disassembler – Retro Computing (

Attched a screenshot of PRDIS, and a photo of my workplace in 1982

screenshotprdis.jpgwerkkamer 1982.jpg

Hans Otten

Jan 19, 2023, 3:31:17 AMJan 19
to PAL 6502 computer
 Steve Wozniak/Allen Baum 1876 article A 6502 Disassembler from Apple: 1976 ;)

Neil Andretti

Jan 19, 2023, 3:56:29 AMJan 19
to PAL 6502 computer
You guys are amazing. It's wonderful to see the old software come to life again.  Thanks Glen and thanks Hans.
Some minutes ago I recalled Bob Leedom and his games. He told me he used Pen and Paper and assembled everything by Hand.
Life is a lot easier right now. But it did not lose it's magic.


Jim McClanahan

Jan 19, 2023, 8:05:51 AMJan 19
to Neil Andretti, PAL 6502 computer
I did my share of hand assembly back in the early 1980s, but that was a lot easier than hand disassembly. I'll have to tinker with this. Thanks for sharing!


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Hans Otten

Jan 19, 2023, 12:55:06 PMJan 19
to PAL 6502 computer
I wrote down my choice of toolchain for retro development.
My retro toolchain – Retro Computing (   

Will Senn

Jan 19, 2023, 2:36:42 PMJan 19
Yay. More folks should do the same (document their dev stacks) for those who come behind. It's pretty hard coming in from the outside to figure out not only how to get something working, but also how to build things from scratch. So, kudos Hans and thank you.


GN Liu

Jan 20, 2023, 7:20:47 AMJan 20
to PAL 6502 computer
Thank you all for sharing this amazing history! I didn't have the opportunity to experience this back in the day, and thanks to all the veteran users from the 70's, we can try it out today!!!

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