Recording Investigation Notes

Recording Investigation Notes

When an experiment, capture, or debugging session on the NPU produces a non-obvious conclusion, record it here so the next person (or agent) doesn't re-derive it.

Where it goes

• A new register meaning, tile layout, limit, or encoding detail → add it to regcmd ISA Reference (the durable reference).
• A milestone, result, or a path that did/didn't work → append a dated entry to the Reverse-Engineering Roadmap.
• A ruled-out interpretation → add it to the "Ruled out" section of the ISA Reference with why it failed, so it isn't re-walked.
• An operational how-to (build, add an SoC) → that belongs in the repo (README.md, docs/), not the wiki.

How to write it

• State the conclusion first, then the evidence. Quote concrete numbers (shapes, register values, mismatch counts, tok/s) — the value is in the specifics.
• Note the SoC and conditions (the validated board is RK3588; numbers can be SoC-specific).
• If a finding fixed a bug, name the regression case that now guards it.
• Prefer capture→diff→decode evidence over speculation; mark unverified hypotheses as such.