4.9x Faster, Still Bit-Exact: Claude Ported Super Mario 64's Physics to a Game Boy Advance
- Level Advanced
- Setup1–3 hrs (estimated)
- Evidence Some evidence
- CostNot stated in source
- No-codeNo
What they did
A developer steered but wrote no code while Claude ported Super Mario 64's movement and collision code to the Game Boy Advance, a 16.8 MHz chip with no floating-point unit. Mario's state matches the original game bit for bit on every test frame, two rounds of optimization made it 4.9x faster on average, and the free demo runs 4 levels at 30 fps on about 98% of frames.
How it went
Open-source MIT repo (github.com/Kodoque1/sm64-gba) with CI tests; README reports bit-exact parity vs the decomp, 4.9x average and 8.4x worst-frame speedup, 30 fps on 98% of frames. Tested in mGBA emulator only, not real hardware. No Nintendo assets included
Worth knowing
- Open-source MIT repo (github.com/Kodoque1/sm64-gba) with CI tests; README reports bit-exact parity vs the decomp, 4.9x average and 8.4x worst-frame speedup, 30 fps on 98% of frames. Tested in mGBA emulator only, not real hardware. No Nintendo assets included.
Prompt
Cleaned version rewritten from the source — not a direct quote.
I want to port [the core logic of an existing open-source project] to [a much weaker device]. Work in this order: 1) Build a test that compares your version's output against the original on every step, and make sure a deliberately broken build fails it. 2) Get a bit-exact port first, even if it's slow. 3) Then optimize, re-running the comparison test after every change, and report speed before and after. Keep engineering notes in the README explaining each trade-off. Don't include any copyrighted assets.
Recommended
Try it in Grok Bot
- Copy the prompt (button below).
- Open Grok Bot chat and paste it. Replace any [bracketed] placeholders.
- Connect the listed tools (as needed) as connectors when Grok Bot asks.
- If the task repeats, ask: "Make this a daily routine."
Alternatives: the same prompt works in Claude, ChatGPT Agent, OpenClaw.
Set it up
Stack: Claude (Opus 5.5) + GBA toolchain + mGBA emulator
- Read the original source for full context.
- Connect the tools your agent needs.
- Paste the prompt and replace [bracketed] placeholders.
- Run once manually and check the output before scheduling it.
Generic suggested steps, not from the source.
Evidence
Open-source MIT repo (github.com/Kodoque1/sm64-gba) with CI tests; README reports bit-exact parity vs the decomp, 4.9x average and 8.4x worst-frame speedup, 30 fps on 98% of frames. Tested in mGBA emulator only, not real hardware. No Nintendo assets included
Source: Reddit · 2026-10-18 · Verified by us: not yet · Report broken or outdated