c3d/db48x

RPL runtime for the DM42 calculator, in the spirit of HP48/49/50

DB48X: A modern implementation of RPL

The DB48X project intends to rebuild and improve the user experience of the HP48 family of calculators, notably their "Reverse Polish Lisp" (RPL) language with its rich set of data types and built-in functions, and Lisp-level programming power.

The project in this repository is presently targeting the SwissMicro DM42 and DM32 calculators. It leverages their built-in software platform, known as DMCP. There is also a simulator that is tested on macOS or Linux, and you can even try it in your browser

In the long-term, the vision is to be able to port DB48X on a number of different physical calculator platforms, like the ARM-based HP50 and related machines (HP49, HP48Gii, etc), and the HP Prime (at least the G1, since the G2 seems a bit more locked down), maybe others. The basis for that work can be found in the DB48X project.

This project was presented at FOSDEM 2023 and FOSDEM 2024

Why name the project DB48X?

DB stands for "Dave and Bill", who are more commonly known as Hewlett and Packard. The order is reversed compared to HP, since they reportedly chose the order at random, and it's about time Dave Packard was given preeminence.

Part of Dave and Bill's great legacy (beyond giving birth to the Silicon Valley) is a legendary series of calculators. The HP48 remains one of my favorites, notably for its rich built-in programming language, known as Reverse Polish Lisp (RPL). This project aims at recreating a decent successor to the HP48, at least in spirit.

State of the project

This is currently UNSTABLE and INCOMPLETE software. Please only consider installing this if you are a developer and interested in contributing. Or else, have a paperclip at hand just in case you need to reset your calculator.

The detailed current status is described in the STATUS file.

How to build this project

There is a separate document explaining how to build this project. The simulator includes a test suite, which you should run before submitting patches. To run these tests, pass the -T option to the simulator, or hit the F12 key in the simulator.

Built-in documentation

The calculator features an extensive built-in documentation that uses a restricted version of Markdown. You access that built-in help by holding a key down, or using the Help command

• Design overview
• Keyboard interaction
• Soft menus

Other documentation

There is DMCP interface doc in progress see DMCP IFC doc (or you can download html zip from doc directory).

The source code of the DM42PGM program is also quite informative about the capabilities of the DMCP.