Mastodawn

A new Exploring Uncut post where I write about my progress with implementing a Mandelbrot set on an STM32 board: some surprises and learnings to get the FPU working with #EmbeddedSwift, learning about call-clobbered vs callee-saved registers and using ChatGPT not for vibe coding but as a debugging and learning tool.

https://www.ericbariaux.com/posts/exploring-uncut-20260303

Exploring Uncut - March 3rd, 2026

Introduction This time, the focus is solely on providing an update on my exploration of getting a Mandelbrot set renderer running on an STM32F746G-DISCO board. I had hoped to also cover “The Egg Project” and some Home Assistant improvements I’ve been working on. However, there is already plenty to discuss here, and the other projects have been moving forward more slowly due to a collection of minor but frustrating issues, from ordering the wrong components, to chasing down unexpected sensor behavior, to tracking a Wi-Fi authentication failure caused by a simple case mismatch.

Bokeh

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Axel Mar 4

@ebariaux
One of the first things I did with my Acorn Archimedes (25 MHz ARM),
was write a mandelbrot set in fixed-point assembly. We discovered some interesting visual artifacts due to bugs in the implementation 🙂

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Eric Bariaux Mar 4

@axel Nice, when it comes to art, bugs are sometimes welcomed and can lead to interesting discoveries.

The Archimedes was a really nice machine.

Back in those days, I was playing quite a bit with Mandelbrot sets on different machines.
Must have been around 1990, I had a 286 PC with a dual screen setup. One Hercules monitor would display a CLI like interface where I entered the coordinates to be drawn and see progress and one VGA display would render the set.

Coded that in C IIRC.