Claude f2623cb62b

sha256/computing: track byte offsets directly to skip per-iter shift ...

The phased compression driver was computing the schedule/round
*index* per iteration and then shifting it left by 2 to get the
byte offset (`schedule_one(i << 2)`, `round_one(r << 2)`). The
shift compiles to two ASLs per iteration — cheap, but pure dead
work since the byte offset is just the previous one + 4.

Track the byte offset as the loop counter and bump it by 4 each
iteration. The schedule and round APIs already wanted byte
offsets, so the call sites also get a touch shorter (no more
intermediate `var i: u8 = first_idx + step`).

Strict cycle savings are tiny — a handful per iteration — so
this is more about not leaving obviously redundant work in the
inner loop than a meaningful perf win. Hash output unchanged
(still AE9145DB…4E0D for "NES"); no other examples affected;
emulator harness 34/34.

https://claude.ai/code/session_01FRmSBruVWCufm3LsUVMs8v

2026-04-16 17:17:10 +00:00

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