The NES's 6502 CPU (the core of its 2A03 chip), its 2 KB of work RAM, and a cartridge's program ROM run inside a standard Qwen3_5ForCausalLM checkpoint. Nobody trained these weights; a compiler computed every one. When you play a game, the model predicts the CPU's execution log one token at a time. A small host program plays the rest of the console around it: it draws the picture, reads the controller, and fires the vblank interrupt.
nesformer builds on Qwenputer by Divyansh Agrawal, which compiled a CHIP-8 and then a RISC-V CPU into Qwen3.5-4B. It reuses Qwenputer's compiler and its central trick: the model's Gated DeltaNet state is the machine's memory.
Every CPU token in these runs came from the model. For the bundled test games, every frame also matches a conventional 6502 emulator's output exactly (see How it was checked).
