From 7c84b39a42bfcada7e9eafd745a9616aaa8f9c1c Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Wed, 4 Mar 2009 14:50:39 +0100 Subject: [PATCH] Avoid to call useless sliders attacks in update_checkers() Quickly filter out some calls to sliders attacks when we already know that will fail for sure. No functional change. Signed-off-by: Marco Costalba --- src/position.cpp | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/src/position.cpp b/src/position.cpp index 21839d6a..65964b82 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -648,7 +648,18 @@ template inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square from, Square to, Bitboard dcCandidates) { - if (Piece != KING && bit_is_set(piece_attacks(ksq), to)) + const bool Bishop = (Piece == QUEEN || Piece == BISHOP); + const bool Rook = (Piece == QUEEN || Piece == ROOK); + const bool Slider = Bishop || Rook; + + if ( ( (Bishop && bit_is_set(BishopPseudoAttacks[ksq], to)) + || (Rook && bit_is_set(RookPseudoAttacks[ksq], to))) + && bit_is_set(piece_attacks(ksq), to)) // slow, try to early skip + set_bit(pCheckersBB, to); + + else if ( Piece != KING + && !Slider + && bit_is_set(piece_attacks(ksq), to)) set_bit(pCheckersBB, to); if (Piece != QUEEN && bit_is_set(dcCandidates, from)) -- 2.39.2