Skip to content

docs: confirm U64E comb 48 MHz point at n=6 — 18.39 s median#64

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
JC-000 merged 1 commit into from
Jul 26, 2026
Merged

docs: confirm U64E comb 48 MHz point at n=6 — 18.39 s median #64

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 7 additions & 3 deletions CLAUDE.md
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -644,9 +644,13 @@ three v0.6.0 profiles at HEAD, n=2 medians of the RFC 6979 vector,
so the whole device delta is localized to REU DMA, not the CPU
core.
- **comb profile: parity at 16/32 MHz, +12% at 48 MHz** (18.4 vs
16.5 s). Plausibly the Lim-Lee table fetches from REU bank 2 —
a DMA-anchored cost whose share grows with clock — but a single
n=2 point; re-measure before leaning on it.
16.5 s). The U64E side is confirmed: a 2026-07-26 rerun at n=6
per positive vector gave median 18.39 s, spread 18.31-18.45 s
(±0.4%) across all three vectors. Plausibly the Lim-Lee table
fetches from REU bank 2 — a DMA-anchored cost whose share grows
with clock. The residual uncertainty is the C64U's 16.5 s
(itself n=2); re-measure that side before treating the gap as
exactly 12%.
- Crossovers vs REU shift down on the U64E because its REU floor
is higher: onchip wins above ~18 MHz (C64U: ~22), comb above
~5 MHz (C64U: ~7). Comb still dominates no-comb onchip at
Expand Down