Adapted Super Mario 64 movement code for GBA with Claude

This project adapts Super Mario 64’s movement and collision code to the Game Boy Advance’s 16.78 MHz ARM7, which has no floating-point unit. A software-rendered demo wraps the adapted gameplay in four levels. The default demo uses collision geometry and a wooden figure; an optional import step uses assets from a ROM supplied by the user.

How it was done

The README explicitly credits Claude Opus 5.5 with writing the code, test harness and engineering notes. The project uses the human-made SM64 decompilation as its behavioral reference and compares Mario’s state bit for bit against that reference. Optimization work is checked through frame replays, collision queries, emulator cycle timing and a second cycle-oriented emulator.

Results

The project reports an average 4.9× speedup for the movement code while preserving exact results, plus a four-level demo that reaches 30 fps on 99% of frames in a scripted emulator tour. A separate scripted check compares Mario’s position after every frame. The author says physical GBA hardware has not yet been tested. The ROM is built locally; none is included in the repository.

Reproduce

With Docker, build the provided image, then run make fetch, make test, make gba-opt-test and make demo; open build/demo/sm64demo.gba in mGBA. The default demo does not require a game ROM. To display the original model and levels, use your own compatible ROM with make import ROM=path/to/your/sm64.z64 and rebuild the demo.