Soul Player C64 makes Commodore 64 speak
Soul Player C64 is an open-source demo of a real 2-layer, decoder-only transformer running on an unmodified Commodore 64 at 1 MHz. The project packages the full pipeline: training a small int8 model, exporting weights, assembling 6502/6510 code, and loading a ready-to-run disk image from floppy. It is technically extreme rather than practical, with about 25K parameters, real multi-head attention, and response times on the order of minutes per reply, but it is a serious engineering proof that modern transformer concepts can be squeezed into very old hardware.
This is less a product in the conventional sense than a flex that proves how far you can push constrained systems when you are willing to trade speed for architectural purity.
- –The core novelty is genuine transformer inference on a stock C64, not a mocked-up simulation.
- –The repo includes training, build, test, and runtime tooling, which makes it reproducible rather than just a one-off stunt.
- –The model is tiny by modern standards, so the achievement is the systems work, quantization, and integer arithmetic discipline.
- –The value is strongest for retrocomputing, ML systems curiosity, and educational demos, not for utility.
- –The project’s performance profile makes it impractical as a chatbot, but that is also what makes it memorable.
DISCOVERED
45d ago
2026-04-21
PUBLISHED
45d ago
2026-04-20
RELEVANCE
AUTHOR
adunk