{ "item": "lookup-headroom", "batch": "e01-a-spline-gas", "kind": "behavior-preserving C0 lookup optimization (implementation headroom only; no edge claim)", "base": { "c0_url": "https://api.imdnotdead.fun/artifacts/8a6e303b662e1a5ea9bb47f31acedd3988ef65b3ddb66d074517aa59ad41ca40", "c0_source_sha256": "c68887cff61180e12ba2b1ceb333edf76a830f91f63b5d775a8806fb9ec08aca", "c0_source_sha256_check": "pass (solidity fence + trailing newline, 42,990 bytes)", "research_fetch": "amm-sim research @66604b3426d8e97a73e2c39940b9b4dece51cc73, fetch.sh: fetched 34 files, 0 mismatched" }, "changes": [ "Coefficient dispatch: the 306-leaf binary tree cw/cw0..cw19 (called once or twice per stripe, 16-20+ stripes per surface) is replaced by cwt(tb,c), which stores only the selected table's words (24..84) into a uint256[84] memory array once per callback; both surfaces (ask, mirrored bid) read it. Table bases 0/960/2304/3168/4512 are multiples of 16, so lane offsets are unchanged; the stripe index drops the base.", "Knot-span search: bas() takes m0; the x+64 basis of each axis (rows and columns) starts at the x basis span and walks forward (while kn(m+1)<=x) instead of a fresh binary search. Same span by construction: the unique m in [3,n-1] with kn(m)<=x 7 passed, 0 failed (273 s)" ], "gates": { "exact_fee_equality_vs_c0": "pass (0 of 218,129 trace calls, 0 of 23,166 fee cases, 0 of 132,369 surface cases differ)", "no_assembly": "pass", "storage_slots": "3 (unchanged)", "size_under_24576": "pass (20,128)", "whole_candidate": "pending: tell port integration, fees within 0.01 bps of tellpol.TellPolicy, engine afterSwap peak <=245,000 / 0 OutOfGas, amm-match validate, engine scoring - none run here (no engine setup in this item)" }, "claims": "Implementation headroom only: about 11.7k gas off the forge afterSwap peak, about 9.9k off the mean, 477 runtime bytes. No edge gain is claimed; behavior equals C0 on every case tested.", "not_done": [ "amm-match validate and engine gas_stats (no engine in this item)", "further lookup work considered but not done: reusing bases between the ask surface and the mirrored bid surface; fusing the sd-Bernstein weights into the lanes before the column contraction" ] }