Pure Silicon Demo Coding: No CPU, No Memory, Just 4k Gates

https://www.a1k0n.net/2025/12/19/tiny-tapeout-demo.html

#HackerNews #PureSiliconDemo #Coding #NoCPU #NoMemory #4kGates

We’ve shared the source for the #nocpu demo on GitHub. The framework is of course included, so if you like what you see, go ahead and use it.

Surprise! It’s written in Dart. Okay it’s not really, but maybe kinda? You decide. Dart is just hosting the DSL and metaprogramming environment.

https://github.com/askeksa/NoCpuDemo

#demoscene

I was part of this project, and what a fun one it was! It's the first Amiga demo I've contributed to in probably 25 years. And I cannot believe we won Alternative Platform at #evoke2025

Half a year ago, Blueberry started talking about doing a NoCPU demo to introduce a new compo category and somehow managed to talk me into joining the project. Actually, it wasn't that difficult. The NoCPU idea is obviously to make demos without using the CPU, only the Amiga's custom chipset. Way back when, I wrote this Protracker player for WinAMP called Oldsk00l, so I knew my way around the MOD format, and we would be needing a MOD player. It was really quite serendipitous -over the years I've thought a lot about how the custom chipset is Turing complete, and also wondering why exactly didn't we just compile a MOD to code, instead of interpreting it at runtime. It's basically just a list of instructions, right? Just compile it. So I got to implement this idea, which was hugely satisfying. Simply compiling a MOD to a huge copper list. It has to be the world's fastest MOD player, at least in terms of CPU usage. I mean, it seems unlikely that another player in the future might hand back the CPU more cycles than it spends playing the MOD. But never say never, I guess.

Other things I did were the interference effect, which I always wanted to try in this many bitplanes, the blitter tornado/chaos zoomer, which I hadn't implemented before, and the kaleidoscope effects.

Truthfully, Blueberry did all of the heavy lifting with his extensive framework for building copper and blitter instructions, handling memory allocation and reuse, and so forth. It almost made selfmodifying copperblits three levels deep trivial. His checkerboard and (perhaps surprisingly) the many, many transitions are really clever stuff. He made everything come together, and it is very much his demo.

https://www.youtube.com/watch?v=OXT5MrDdyB8

#evoke #evoke2025 #nocpu #demoscene

I love how amiga #demoscene has embraced the #nocpu concept and ran away with it: https://github.com/askeksa/NoCpuChallenge

The invitation to this challenge "No-CPU Challenge by Demostue Allstars" released at #Evoke2025 party is quite damn cool. It's probably the most impressive nocpu demo I've seen so far:
- Demozoo: https://demozoo.org/productions/376675/
- Pouet: https://www.pouet.net/prod.php?which=104753

Video capture of the demo: https://youtu.be/OXT5MrDdyB8

My early input to this nocpu scene can be seen here: https://infosec.exchange/@harrysintonen/112627238742582618

#evoke #demoparty