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Rogier · (This post was last modified: 05-28-2018 05:06 PM by Rogier.)

Back in the 80's is wrote a RPN-simulator for my ZX-Spectrum. That program is now lost forever since neither the ZX-Spectrum, nor the tapes I used to save my programs, nor the hand-written hardcopies have survived.

However, when my parents bought their first PC, I started converting the program to GWBasic, expanding it in the process. Recently I stumbled upon an archive backup with a working executable + application programs dating from 1990. It is not a "final" version and lacking in some parts, but it will calculate and run quite complex programs (like my Code-guessing/Mastermind program).

It is basically a HP-33C/E, but with 9 Registers, 99 Program steps, 1 Flag and 3 User definable keys. No continuous memory, but capability for loading and storing programs. I left out quite a number of functions. Sometimes out of necessity (when you decide to use one-letter function names, you'll notice that you run out of logical choices really fast), sometimes it's just weird (where's y^x?).
Oh, one important extra: it features a HELP-routine that tells you where I have hidden all the functions.

Screenprint:

The screenprint shows the situation after running the program I loaded (not Mastermind), starting at line 1. The thumbnail-picture shows HELP page 2 (texts in Dutch).