In mulDoubleG (verify), the P-side wNAF-5 affine table (8 odd multiples
of P plus 8 GLV λ counterparts) is rebuilt from scratch on every call.
This costs ~437 field ops: 1 doublePoint + 7 addPoints + 8 β-multiplies
+ 1 batch inversion with full field inversion (~270 ops alone).
Add a 256-entry direct-mapped cache that stores these affine tables
keyed by the point's x-coordinate. On cache hit, the table build is
skipped entirely — the cached arrays are used directly (zero-copy).
This saves ~27% of mulDoubleG cost (~20% of total verify) for repeated
pubkeys. Combined with the liftX cache from the previous commit,
repeated-pubkey verifications now skip ~33% of the work.
JVM benchmark: verify ratio improved from 2.0x to 1.6-1.8x vs native C
(with the benchmark's 100% cache hit rate). Original baseline was 3.0x.
https://claude.ai/code/session_017UbWduFi1sLUsgVUMUH2nx
Claude
c7b164b845