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Confirmed self-play regression traced to a stale test_vs_head.sh reference
binary (typhoon_allbitboards/550ea81, deleted): every "vs head" comparison
since 92fc412 (Sep 4) was checking new work against that fixed Sep-4
snapshot, never against real HEAD or the working tree. Rebuilt clean
reference binaries directly from git and re-verified everything from
scratch.
This commit lands only the pieces confirmed safe against clean 434fa04
(fast st1 match, ~30-40 games, score ~0.44-0.55, consistent with parity;
plus a DEBUG-build smoke test pass):
- recogn.c, fen.c: real bugfixes
- data.c, draw.c, ics.c: whitespace only
- x64.asm: retires the asm GetAttacks implementation now that chess.h's
GetAttacks macro unconditionally selects the already-verified-faster
_GetAttacksBB bitboard version instead of a three-way build-flag
toggle (GETATTACKS_BITBOARD/CROUTINES/asm default)
- see.c, testsee.c: SEE/test-harness updates supporting that default
- root.c: per-tier eval-exit reporting (super-lazy counters currently
always read 0 -- accurate, since no super-lazy exit exists yet)
- main.c: startup banner update, InitEval() call, TestRecogn() added to
the #ifdef TEST self-test sequence
- command.c: InitEval() DNA-reload hook, new qsearchfutility diagnostic
- dynamic.c: minor changes
- chess.h: the GetAttacks default change above, three
FUTILITY_BASE_MARGIN_* compatibility aliases (all still equal to the
original flat FUTILITY_BASE_MARGIN -- search.c has not been split into
per-tier margins here), placeholder super-lazy counters, and an
EvalPasserRaces -> _EvalPasserRacesAgainstLoneKings rename (confirmed
byte-identical body) to match recogn.c's call site
- eval.c: the same rename, plus a no-op InitEval() stub (nothing to
initialize until the ROOK_FULL_HALF_OPEN_BONUS cache below exists)
Deliberately NOT included: the full eval.c overhaul (~1770 lines) and
search.c's qsearch-futility rework (~650 lines), including yesterday's
loosened SUPER_LAZY_MARGIN_BY_ARMY/FUTILITY_BASE_MARGIN_BY_SOURCE tables.
Reverting just those two tables while keeping the rest of the eval.c
overhaul still lost badly to 434fa04 (0.20 over 10 games), so the
regression isn't fully explained by the margins alone -- the eval.c
overhaul needs careful, incremental re-verification against this commit
as the new baseline, not a bulk re-apply. Full original work preserved in
git stash (stash@{0} as of this commit) for that follow-up.
Note: two pre-existing, position/state-dependent assertion crashes were
found during this verification (util.c:1093 WalkPV, recogn.c:1359
_SanityCheckRecognizers), both reproducing on unmodified 434fa04 -- not
introduced by anything here, not yet root-caused.
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Ka9o3S2eKqh4jNfmxVZ6fH
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chess.h: add POSITION::bbOccupied (full-board occupancy, both colors,
every piece including kings), maintained incrementally alongside
bbPieces/bbPawns rather than rebuilt on demand -- resolves the open
question in EVAL.md section 0 about whether this is worth doing given
both generate.c and the planned eval.c mobility rewrite need it.
move.c: SlidePiece/SlidePawn/LiftPiece/PlacePiece and their
WithoutSigs variants now maintain bbOccupied at the same choke points
that already maintain bbPieces/bbPawns -- unconditionally, since
occupancy doesn't care about piece type or color. Kings only ever
move through SlidePiece/SlidePieceWithoutSigs (never Lift/Place), so
no separate king-specific update site was needed.
fen.c: populate bbOccupied when parsing a FEN.
board.c: VerifyPositionConsistency cross-checks pos->bbOccupied
against a from-scratch rebuild, same pattern already used for
bbPieces/bbPawns.
generate.c/movesup.c/see.c: replace call sites that rebuilt full
occupancy via _BuildFullOccupiedBB/_BuildOccupiedBB with direct reads
of pos->bbOccupied; delete see.c's _BuildOccupiedBB, which was a
byte-for-byte duplicate of generate.c's _BuildFullOccupiedBB (kept
only as the from-scratch ground truth for the new consistency check
and testgenerate.c's benchmark harness).
testsup.c: GenerateRandomLegalPosition builds POSITIONs by poking
rgSquare/bbPieces/bbPawns directly, bypassing both move.c and fen.c --
a third construction path the above missed. It never set bbOccupied,
so the new VerifyPositionConsistency check failed on every generated
position, and since generation retries until a position verifies, the
self-test suite spun forever (100% CPU, no progress) instead of
crashing outright. Fixed by setting bbOccupied at all four placement
sites (both kings, pawn, non-pawn piece). Full self-test suite and
precommit_check.sh verified clean afterward.
board_representation/EVAL.md: record the bbOccupied decision and
rationale, resolving section 0's open question.
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01P6g6iF6mD1Hau6nCZCzwYj
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default on
Implements the full board_representation/MOVEGEN_MIGRATION.md scope:
bitboard-backed generators for all six not-in-check piece types plus
the JumpTable-avoiding whole-node dispatch fork (_GenerateAllMovesBB),
the in-check escape path (king flight + block/capture), and
movesup.c's ExposesCheck/FasterExposesCheck/ExposesCheckEp/IsAttacked/
InCheck bitboard equivalents. Nine toggles total
(GENERATE_{KNIGHT,KING,ROOK,BISHOP,QUEEN,PAWN}_BITBOARD,
GENERATE_ESCAPES_{KING,BLOCK}_BITBOARD, EXPOSESCHECK_BITBOARD,
ISATTACKED_BITBOARD), all now on by default in GNUmakefile --
DISABLE_BITBOARD_MOVEGEN=1 opts back into the mailbox path, which
remains fully present and compiled either way.
Correctness verified via perft (Kiwipete, Position 4), the move-set
comparison harness across 20,000 random positions, all nine toggles
combined cleanly (15/15 runs, after fixing a GenerateRandomLegalPosition
en-passant-sentinel bug in the test harness), and sd10 on all three
curated suites showing zero solve-count regression vs head_reference
(the ecm_hard_quick delta traced to unrelated intervening commits).
Speed: most individual generators land near parity by design (mailbox's
per-square walk was already close to O(destination count)); the real,
consistent wins are the dispatch-layer fork (up to 23% in dense
positions) and IsAttackedBB (0.73x-0.93x of mailbox).
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01AbHkVrm5KUyzLwWd3GHmo6
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Board-representation migration, sections 2-3 (GetAttacks half):
- board.c: VerifyPositionConsistency's bbPieces consistency check
(migration section 2), verified clean via gmake TEST=1 with the
assert live.
- POSITION.bbPawns[2]: new incrementally-maintained per-color pawn
location bitboard (chess.h), maintained at the same 6 move.c sites
as bbPieces, populated from scratch in fen.c. Distinct from the
pawn-hash-keyed bbPawnLocations; this one needs no
SEARCHER_THREAD_CONTEXT, so it's reachable from GetAttacks's actual
call sites (which only ever have a POSITION*).
- data.c/chess.h/main.c: g_RookRayAll/g_BishopRayAll (all 4 per-square
ray directions pre-ORed) and g_PawnAttackOriginBB[2][128] startup
tables, plus FastFirstBit/FastLastBit (static inline bsf/bsr
wrappers, chess.h) -- supporting tables/helpers for the primitive
below.
- see.c: _WhoAttacksSquareBB (bitboard "who attacks square X" query)
and _GetAttacksBB (SEE_LIST-populating PoC wrapping it), side by
side with the existing SlowGetAttacks/asm GetAttacks -- not wired
into the GetAttacks macro yet (section 6), pure addition.
- testsee.c: SeeListsAreEqual made order-independent (SEE() sorts the
list right after GetAttacks returns, so order was never semantically
significant); TestGetAttacks extended to run _GetAttacksBB as a
third comparison across the existing 20,000-random-position sweep;
added an interleaved asm/Slow/BB cycles-per-call benchmark across
opening/middlegame/endgame positions.
- testsup.c: fixed GenerateRandomLegalPosition (used by the sweep
above) to maintain bbPieces/bbPawns at its two hand-placement sites
-- a latent gap since section 1 that made its own
VerifyPositionConsistency legality gate almost always reject
generated positions, causing large, variable retry-loop slowdowns.
Verified: 20,000-position x every-square x both-colors correctness
sweep passes (gmake TEST=1), precommit_check.sh clean (self-test +
DEBUG smoke test). Benchmark: _GetAttacksBB is ~0.53-0.55x asm
GetAttacks's cycles/call (opening/middlegame) and ~0.89x (endgame) --
faster, not just equivalent, primarily from replacing bbOccupied's
up-to-16-iteration pawn loop with two bbPawns ORs, plus a
g_PawnAttackOriginBB table lookup replacing per-call pawn-delta
arithmetic and per-direction/per-side-group early-outs in the slider
walk. See board_representation/MIGRATION.md section 3 for the full
writeup, including a reverted approach that measured slower and why,
and the CountKingSafetyDefects half's re-scoped (not yet implemented)
design.
Also confirmed (not caused by this work, not fixed here): a
pre-existing non-deterministic MP-race assertion in util.c:1093's PV
printing, reproduced independently on a clean HEAD checkout.
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Jntky4yGUTyQVaGCXms4F2
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