Someone compiled an NES's 6502 CPU into the weights of a stock Qwen3.5 model, and it runs real games.
How it works: The model predicts the CPU's execution log one token at a time. A small host program draws the picture, reads the controller and fires the vblank interrupt. A compiler computed the weights, so nobody trained them.
What runs: The 6502 core, 2 KB of work RAM and a cartridge's program ROM. For the bundled test games, every frame matches a conventional 6502 emulator exactly.
Speed: About 150 to 290 times slower than a real NES, at roughly 1,650 tokens per second on one CPU core.
Limits: NROM cartridges only, so bank-switched games don't run yet. No IRQs, no unofficial opcodes, and the PPU and APU aren't in the weights, so there's no sound.
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TL;DR of the article, generated automatically.
Someone compiled an NES's 6502 CPU into the weights of a stock Qwen3.5 model, and it runs real games.