Switch to Crafty-style killer ordering; fix mvNullmoveRefutations type-mixing bug and add a quiet-refutation killer backfill.

Killer tiers now try both of this ply's own killers before either
ply-2-back one, matching Crafty's ordering. Two earlier attempts at
this same swap were reverted for regressing; this pass lands on top of
NumLeftoverMovesToSelect (more SelectBestWithHistory budget to reach
these lower-tier slots) and a real bug fix below, and beats interleaved
order head-to-head on solves, node count, and first-move beta cutoff
across the three curated suites.

The bug: mvNullmoveRefutations's empty-killer-slot backfill could only
ever contain a capturing move (TryNullmovePruning only wrote it inside
the capture-refutation branch), but IS_SAME_MOVE's mask includes the
pCaptured bits, so that backfilled value could never match a real
quiet candidate -- the backfill was silently dead code. Fixed by
recording genuinely quiet null-move refutations into a new, separate
mvNullmoveQuietRefutations array (kept separate so it can't clobber the
capture history mvNullmoveRefutations still needs for the
Botvinnik-Markoff same-piece-two-squares extension check) and
backfilling the regular killer table from that instead. The
check-evasion killer table intentionally does *not* get this backfill:
a null-move refutation can never legitimately be an escaping-check
move (null moves can't deliver check), so backfilling there risks
IS_SAME_MOVE cross-context false positives instead of the old
guaranteed-inert no-op.

Measured at sd10 across ecm_ringers/ecm_confident_quick/ecm_hard_quick
against head_reference (commit d11e973): 115/191 solves (vs. 116
baseline), 924.36M total nodes (vs. 933.23M), first-move beta cutoff
within 0.1-0.9 points of baseline on all three suites -- and clearly
better than the same fix under interleaved order (113/191 solves,
963.10M nodes), which loses to head_reference on every metric.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EortUUkDVpsfrbqshBJYJg

1 files changed, 360 insertions, 0 deletions

diff --git a/tests/ecm_confident_quick.ep_ b/tests/ecm_confident_quick.ep_
new file mode 100644
index 0000000..876de2a
--- /dev/null
+++ b/tests/ecm_confident_quick.ep_
@@ -0,0 +1,360 @@
+setboard 2r2bk1/4qp2/3n2p1/2R1p1Np/2p1N3/r6P/1Q3PP1/3R2K1 w - -
+solution Rxc8
+id "ECM.035"
+go
+setboard r2b1rk1/5qp1/2p2P2/2p3Pp/p6P/2Q5/PPP5/2KR2R1 w - -
+solution g6
+id "ECM.147"
+go
+setboard r1b2rk1/1pqp1ppp/p1n1pn2/5N2/8/2PBB3/P1P2PPP/R2QR1K1 w - -
+solution Nxg7
+id "ECM.280"
+go
+setboard r1b1r1k1/pp3p1p/1q2p1pQ/2b1P1B1/8/P2B3P/1P3PP1/2R1R1K1 w - -
+solution Rxc5
+id "ECM.339"
+go
+setboard 3r1rk1/1pq1bppp/p7/n2RN3/P7/1P6/1B2QPPP/R5K1 w - -
+solution Nd7
+id "ECM.382"
+go
+setboard r1b2rk1/1p3pbp/2p3p1/p1q5/1P6/1Q4P1/1P2PPBP/R1B1R1K1 b - -
+solution Be6
+id "ECM.591"
+go
+setboard 2kr3r/ppp1qpp1/2p5/2b2b2/2P1pPP1/1P2P1p1/PBQPB3/RN2K1R1 b Q -
+solution Rh1
+id "ECM.610"
+go
+setboard 5rk1/pbrn1ppp/1ppN1q2/2P1p3/3P4/1PRB4/P3QPPP/5RK1 w - -
+solution Bxh7+
+id "ECM.672"
+go
+setboard rq1r1bk1/1b3pp1/3pn2p/1n2BN1P/1P2P3/3R1NP1/3Q1PB1/2R3K1 w - -
+solution Bxg7
+id "ECM.728"
+go
+setboard 2r3k1/pbq1np1p/1p1b1Bp1/8/6QP/2P2N2/B4PP1/4R1K1 w - -
+solution Bxf7+
+id "ECM.733"
+go
+setboard 6k1/p1qb1p1p/1p3np1/2b2p2/2B5/2P3N1/PP2QPPP/4N1K1 b - -
+solution Bxf2+
+id "ECM.005"
+go
+setboard r1b1r1k1/p1p3pp/2p2n2/2bp4/5P2/3BBQPq/PPPK3P/R4N1R b - -
+solution Bg4
+id "ECM.008"
+go
+setboard 3r4/1b2k3/1pq1pp2/p3n1pr/2P5/5PPN/PP1N1QP1/R2R2K1 b - -
+solution Rxh3
+id "ECM.009"
+go
+setboard r1b2r1k/3nN2p/p2Q1p2/8/4PP2/1R6/q1PK2PP/4R3 w - -
+solution Qd5
+id "ECM.033"
+go
+setboard 2k4r/ppp1n1p1/2n2qb1/2N5/Q1P3p1/P2r3P/1P3PB1/R1B2RK1 w - -
+solution Qb5
+id "ECM.037"
+go
+setboard r1b1rnk1/1p3pb1/1qpp2p1/2n5/2PNP2p/1PN3PP/3R1PBK/BR1Q4 b - -
+solution Rxa1
+id "ECM.039"
+go
+setboard 5r1k/pb2r1bp/1p2B1p1/n7/4qNQ1/4B3/P4PPP/2RR2K1 w - -
+solution Rd4
+id "ECM.080"
+go
+setboard 1r3rk1/5pp1/1n2qn1p/1p1pPNb1/2pP2QP/2P5/1PB3P1/R1B1R1K1 w - -
+solution exf6
+id "ECM.082"
+go
+setboard r1k4r/ppp1b3/5Npp/4pb1Q/8/1B2B3/PqP2PPP/2RR2K1 w - -
+solution Qxf5+
+id "ECM.107"
+go
+setboard r1b1rk2/pp3ppQ/1np5/4q3/2B4N/4P3/PP3PP1/2R2K1R w - -
+solution Qg8+
+id "ECM.114"
+go
+setboard rnb1r1k1/pp5p/2pp2p1/4b3/2P1P2q/1NN1BPp1/PP1QB1P1/3RR1K1 b - -
+solution Bf4
+id "ECM.140"
+go
+setboard 1r2k2r/p5bp/4p1p1/q2pn3/1p2N1P1/6QP/PPP5/1KBR3R w k -
+solution Bh6
+id "ECM.149"
+go
+setboard 3qn2k/1p3Bp1/rbn4p/2p5/p1P2p2/P2b2PP/1BQNRP2/1R4K1 w - -
+solution Qxd3
+id "ECM.173"
+go
+setboard 1q6/2rk1p2/p1n1b1rN/3p2p1/8/3Q4/PP1B1PPP/2R1R1K1 w - -
+solution Nxf7
+id "ECM.176"
+go
+setboard 3r2k1/p2r1p1p/1pR1p1qP/3P1pP1/3R4/1P2Q3/P4K2/8 w - -
+solution dxe6
+id "ECM.183"
+go
+setboard 1r3rk1/p4pbp/q1p2pp1/3p1b2/1n1P1P1B/PB3N2/1PPQR1PP/2KR4 b - -
+solution Bxc2
+id "ECM.194"
+go
+setboard 2q1r1k1/1b3pbp/3p2p1/1Ppn3n/5P2/5B2/1P1B2PP/R2NNQ1K b - -
+solution Ndxf4
+id "ECM.208"
+go
+setboard 8/2p2Q1p/1rp5/p3q1kp/P7/2P2RP1/5PK1/8 w - -
+solution Rf5+
+id "ECM.233"
+go
+setboard 6k1/3b1p1p/6p1/2BPR3/8/4Q2P/1q3rPK/8 w - -
+solution Re8+
+id "ECM.235"
+go
+setboard 6rr/1b3k1p/pbqppPn1/1p5Q/4PN2/P6R/1PP3BP/2B2R1K w - -
+solution Qxh7+
+id "ECM.243"
+go
+setboard 2r1rbk1/5pp1/bq5p/1pnBPN2/6Q1/N7/5PPP/R2R2K1 w - -
+solution Bxf7+
+id "ECM.250"
+go
+setboard r5k1/pp2ppb1/4qn2/r3B1p1/3P4/3QNP1R/PP2K1P1/7R w - -
+solution Bxf6
+id "ECM.252"
+go
+setboard 1R2br1k/5r1p/p2p1P2/6RQ/3p1P2/4p2B/q6P/5N1K w - -
+solution Rxe8
+id "ECM.253"
+go
+setboard 4Rnk1/2p2pp1/3r3p/p2P4/P5Q1/1B5P/5PK1/q7 w - -
+solution Rxf8+
+id "ECM.257"
+go
+setboard r2qk2r/1pp2ppp/p3pnn1/6N1/1B1P2P1/1Q2P2P/PP3PK1/R6R b kq -
+solution Nh4+
+id "ECM.272"
+go
+setboard 5r1k/1pqb3p/2n5/p1pB4/2Pp1r1P/1P5P/R2N2K1/3Q1R2 b - -
+solution Bxh3+
+id "ECM.282"
+go
+setboard r1rbb3/1R3pkp/2pBp1p1/p3P3/q6P/6P1/P2Q1P2/1R3BK1 w - -
+solution R1b4
+id "ECM.316"
+go
+setboard r3r1k1/pbqn1ppp/1p3n2/1Pb5/2p5/5N1P/PBQ1BPP1/1N1R1RK1 b - -
+solution Rxe2
+id "ECM.337"
+go
+setboard 1k2r2r/1bpQN2p/1p6/P3p2q/4np2/2P2N2/2P2PPP/R3R1K1 b - -
+solution Rxe7
+id "ECM.340"
+go
+setboard 2b1r2k/2Q4p/4q3/1pp5/3b4/4NP2/1P3BP1/3R2K1 w - -
+solution Rxd4
+id "ECM.348"
+go
+setboard 2rq3r/5p2/p3pkbQ/3p4/3N4/2P4R/P4PP1/4R1K1 w - -
+solution Rf3+
+id "ECM.352"
+go
+setboard r3r1k1/4pp1p/b5pB/q1pP4/3b4/2N4P/PP4P1/R2RQ2K w - -
+solution Rxd4
+id "ECM.357"
+go
+setboard r3k3/1pqb1p2/p3p3/4n2r/3N1Q2/2P5/PP4B1/4RRK1 w q -
+solution Rxe5
+id "ECM.364"
+go
+setboard 7k/p1p1r2p/1p1pnr1q/5pp1/2PPPp2/2PB1P1P/P2Q1PRK/7R b - -
+solution g4
+id "ECM.372"
+go
+setboard 7k/5rp1/p1bQB2p/1p4nN/4P3/1Pq5/P5PP/3R3K b - -
+solution Bxe4
+id "ECM.386"
+go
+setboard r3r1k1/1pp2p1b/7p/2Q5/2PP2p1/2P1NpPq/P2R1P1P/6RK b - -
+solution Rxe3
+id "ECM.391"
+go
+setboard 3r2k1/pb3p1p/1q4p1/2b1P3/1Pp5/2P1p1P1/P3Q1BP/R1B4K b - -
+solution Qc6
+id "ECM.400"
+go
+setboard 1r1q1k2/R4pp1/5p1r/1p1p1n1p/3Pb2N/1BP5/2P1Q1PP/4R1K1 w - -
+solution Qxe4
+id "ECM.405"
+go
+setboard 8/2R4p/2R3bk/8/5N1P/1p3PP1/2pqP1K1/8 w - -
+solution g4
+id "ECM.426"
+go
+setboard 2r3k1/n3qppp/1B1r1n2/N7/N4P2/1Q4PP/P5B1/R1b4K b - -
+solution Qe1+
+id "ECM.444"
+go
+setboard 7r/2p1q1k1/1p3r1p/p1pPpPp1/2P1P1P1/PP6/3Q2KR/7R w - -
+solution Qxg5+
+id "ECM.445"
+go
+setboard 6r1/6rk/3p3p/p2Rp3/R1PqPp1b/2N2Q2/6PP/7K b - -
+solution Rxg2
+id "ECM.450"
+go
+setboard r2r3k/ppq3pp/2p1n3/4NQ2/3P4/1B6/PP3PPP/6K1 w - -
+solution Ng6+
+id "ECM.454"
+go
+setboard r2q1rk1/pp1n2pp/2pb4/1P1p3n/P1PPpP2/4P2b/1BNNBP1P/R2QR1K1 b - -
+solution Nxf4
+id "ECM.496"
+go
+setboard r2qkr2/1p3pQp/2p1b3/1B1pN3/1p6/8/1P1K1PPP/2B1R3 w q -
+solution Nxc6
+id "ECM.502"
+go
+setboard 1k1r2r1/p1p3q1/2p2p2/3pn3/1P1b2bB/1QN5/P4PPP/1R2RBK1 b - -
+solution Nf3+
+id "ECM.519"
+go
+setboard r2q4/5p1P/2p1bR2/ppk1p1P1/3pB2Q/8/PPP5/6K1 w - -
+solution g6
+id "ECM.521"
+go
+setboard 5r1k/1q2R3/8/6Q1/8/8/6P1/7K b - -
+solution Rf1+
+id "ECM.548"
+go
+setboard r5r1/4q2k/p2p3p/5p2/4p3/P2QR3/1PP2PPP/4R1K1 w - -
+solution Rxe4
+id "ECM.558"
+go
+setboard 1r4nk/3b2bp/3p4/3P3p/2pNPq2/P1N2p1P/1P3Q2/1R4KR b - -
+solution Rxb2
+id "ECM.570"
+go
+setboard 4r1k1/1ppQr1p1/1p1p1pP1/3P3p/7P/1P3q2/P1P5/1KRR4 w - -
+solution Re1
+id "ECM.574"
+go
+setboard 4k3/4Bp2/1p2nP1P/2p5/2K1b1B1/8/P7/8 w - -
+solution Bf3
+id "ECM.584"
+go
+setboard 1r3qk1/pb3p1p/1pn2PpQ/2pN4/3r4/5B2/PPP4P/4RRK1 w - -
+solution Ne7+
+id "ECM.611"
+go
+setboard 8/p3q1k1/6p1/1p3nP1/2pp1QBr/P2P4/1PP2K2/R7 b - -
+solution Qe3+
+id "ECM.618"
+go
+setboard 3q1k2/5p2/p5pN/1b2Q2P/8/8/5PPK/8 w - -
+solution Qh8+
+id "ECM.622"
+go
+setboard 8/6kP/6p1/1p1pP3/pP6/P1n2K2/2N5/8 w - -
+solution e6
+id "ECM.638"
+go
+setboard 5r2/R4p2/5P1k/4PK2/1p6/8/8/8 w - -
+solution Rxf7
+id "ECM.643"
+go
+setboard 1r1qr1k1/5p1p/1n2p1p1/pp1pP1P1/2pP1BB1/PnP3P1/1P3PK1/1R1Q3R w - -
+solution Rxh7
+id "ECM.663"
+go
+setboard 1r2rnk1/2R2bpp/p2q4/1p1N2R1/5P2/1Q1B3P/PP4P1/7K w - -
+solution Rxg7+
+id "ECM.702"
+go
+setboard 4rrk1/2qb2pp/p5P1/1p2p3/1b2P3/2N5/PPPQ4/1K1R2R1 w - -
+solution gxh7+
+id "ECM.704"
+go
+setboard 3r1rk1/5pp1/pq1n1n1p/2pPR3/2B2P2/1PBQ2RP/P5P1/6K1 w - -
+solution Rxg7+
+id "ECM.715"
+go
+setboard rn3rk1/ppq2ppp/2pb1nb1/5N2/2BP4/8/PPP1N1P1/R1B1QR1K w - -
+solution Nxg7
+id "ECM.716"
+go
+setboard r4rk1/1p1q1ppp/p1b4B/8/2R3R1/P2P4/1b1N1QPP/6K1 w - -
+solution Bxg7
+id "ECM.723"
+go
+setboard r1bqkbnr/pp2ppp1/2p4p/3n2N1/2BP4/5N2/PPP2PPP/R1BQK2R w KQkq -
+solution Nxf7
+id "ECM.731"
+go
+setboard r2qr1k1/1ppb1p1p/p1np2p1/7Q/3PP2b/1B2N2P/PP3PP1/R1B2RK1 w - -
+solution Bxf7+
+id "ECM.732"
+go
+setboard r2r2k1/1b2qpp1/1p2n3/p1b1p2p/4P1n1/PP1B2PP/1B1NQP2/R3NRK1 b - -
+solution Nxf2
+id "ECM.736"
+go
+setboard 2r1r1k1/1pq1bp1p/p3pnp1/P2n2N1/7R/2P4P/1PB1QPP1/2B1R1K1 w - -
+solution Nxf7
+id "ECM.748"
+go
+setboard 2rqrbk1/pb1n1p1p/1p2pnp1/4N3/2BP1N2/1P2Q3/PB3PPP/3R1RK1 w - -
+solution Nxf7
+id "ECM.757"
+go
+setboard r1bqrbk1/5p1p/2pp2nB/pp5Q/4P3/PBNPR2P/1P4P1/R5K1 w - -
+solution Bxf7+
+id "ECM.759"
+go
+setboard r2r4/p4pk1/2p3p1/1p1nPR2/5p1Q/2N5/PPPq4/1K4R1 w - -
+solution e6
+id "ECM.807"
+go
+setboard r2q1rk1/pp2ppb1/3pn1pQ/3R4/2P3B1/4BR2/PP4PP/6K1 w - -
+solution Qxg6
+id "ECM.813"
+go
+setboard r2q1rk1/pb1nbp1p/1p2p1p1/4N1BQ/2PP4/P7/5PPP/RB2R1K1 w - -
+solution Nxg6
+id "ECM.817"
+go
+setboard k7/pp1N4/4P3/5P2/8/5p2/1R6/B4Knq w - -
+solution Nb6+
+id "ECM.823"
+go
+setboard 1rbq2k1/b1p3pp/p1Pp4/3Ppr2/8/5N2/PPQ2PPP/R1B2RK1 b - -
+solution Rxf3
+id "ECM.826"
+go
+setboard 1n2r3/p1pq1kp1/1b1pNpp1/3P4/5RP1/3Q3P/1B3P2/6K1 w - -
+solution Bxf6
+id "ECM.830"
+go
+setboard r1b1k1nr/3n1p1p/1qpBp1p1/pp2b3/4PN2/PBN2Q2/1PP2PPP/2KR3R w kq -
+solution Nxe6
+id "ECM.842"
+go
+setboard r3k2r/1q3ppp/p3p3/2b1P3/p2N1Q2/P7/1PP3PP/3R1R1K w kq -
+solution Nxe6
+id "ECM.845"
+go
+setboard 1r6/5pk1/p1b2qpp/P1P1n3/1N6/Q5NP/5PP1/3R2K1 b - -
+solution Bxg2
+id "ECM.859"
+go
+setboard 2R5/p3q1kp/6p1/3p4/b2P2p1/Pr4N1/5Q2/3K3R w - -
+solution Nf5+
+id "ECM.861"
+go
+setboard 1r3r2/6kp/3p1pp1/qnp1pP2/1p2P2N/3P4/PPPQ1P1P/1K1R2R1 w - -
+solution fxg6
+id "ECM.870"
+go