From: Marco Costalba Date: Sun, 9 Sep 2012 12:30:22 +0000 (+0200) Subject: Remove redundancy in move generation X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=1598a3edf851460a62a06493416554e1f7cf719c Remove redundancy in move generation Introduce generate_all_moves() and remove a good bunch of redundant code. No functional change. --- diff --git a/src/movegen.cpp b/src/movegen.cpp index 0686bf8d..0b46298b 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -31,7 +31,7 @@ (*mlist++).move = make_move(to - (d), to); } namespace { - template + template MoveStack* generate_castle(const Position& pos, MoveStack* mlist, Color us) { if (pos.castle_impeded(us, Side) || !pos.can_castle(make_castle_right(us, Side))) @@ -59,7 +59,7 @@ namespace { (*mlist++).move = make(kfrom, rfrom); - if (OnlyChecks && !pos.move_gives_check((mlist - 1)->move, CheckInfo(pos))) + if (Checks && !pos.move_gives_check((mlist - 1)->move, CheckInfo(pos))) mlist--; return mlist; @@ -79,7 +79,8 @@ namespace { template - inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7, Bitboard target, Square ksq) { + inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7, + Bitboard target, const CheckInfo* ci) { Bitboard b = move_pawns(pawnsOn7) & target; @@ -99,10 +100,10 @@ namespace { // Knight-promotion is the only one that can give a direct check not // already included in the queen-promotion. - if (Type == QUIET_CHECKS && (StepAttacksBB[W_KNIGHT][to] & ksq)) + if (Type == QUIET_CHECKS && (StepAttacksBB[W_KNIGHT][to] & ci->ksq)) (*mlist++).move = make(to - Delta, to, KNIGHT); else - (void)ksq; // Silence a warning under MSVC + (void)ci; // Silence a warning under MSVC } return mlist; @@ -110,7 +111,8 @@ namespace { template - MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, Square ksq = SQ_NONE) { + MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, + Bitboard target, const CheckInfo* ci) { // Compute our parametrized parameters at compile time, named according to // the point of view of white side. @@ -133,7 +135,7 @@ namespace { // Single and double pawn pushes, no promotions if (Type != CAPTURES) { - emptySquares = (Type == QUIETS ? target : ~pos.pieces()); + emptySquares = (Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces()); b1 = move_pawns(pawnsNotOn7) & emptySquares; b2 = move_pawns(b1 & TRank3BB) & emptySquares; @@ -146,16 +148,16 @@ namespace { if (Type == QUIET_CHECKS) { - b1 &= pos.attacks_from(ksq, Them); - b2 &= pos.attacks_from(ksq, Them); + b1 &= pos.attacks_from(ci->ksq, Them); + b2 &= pos.attacks_from(ci->ksq, Them); // Add pawn pushes which give discovered check. This is possible only // if the pawn is not on the same file as the enemy king, because we // don't generate captures. Note that a possible discovery check // promotion has been already generated among captures. - if (pawnsNotOn7 & target) // Target is dc bitboard + if (pawnsNotOn7 & ci->dcCandidates) { - dc1 = move_pawns(pawnsNotOn7 & target) & emptySquares & ~file_bb(ksq); + dc1 = move_pawns(pawnsNotOn7 & ci->dcCandidates) & emptySquares & ~file_bb(ci->ksq); dc2 = move_pawns(dc1 & TRank3BB) & emptySquares; b1 |= dc1; @@ -176,9 +178,9 @@ namespace { if (Type == EVASIONS) emptySquares &= target; - mlist = generate_promotions(mlist, pawnsOn7, enemies, ksq); - mlist = generate_promotions(mlist, pawnsOn7, enemies, ksq); - mlist = generate_promotions(mlist, pawnsOn7, emptySquares, ksq); + mlist = generate_promotions(mlist, pawnsOn7, enemies, ci); + mlist = generate_promotions(mlist, pawnsOn7, enemies, ci); + mlist = generate_promotions(mlist, pawnsOn7, emptySquares, ci); } // Standard and en-passant captures @@ -213,9 +215,9 @@ namespace { } - template FORCE_INLINE + template FORCE_INLINE MoveStack* generate_moves(const Position& pos, MoveStack* mlist, Color us, - Bitboard target, const CheckInfo* ci = NULL) { + Bitboard target, const CheckInfo* ci) { assert(Pt != KING && Pt != PAWN); @@ -223,7 +225,7 @@ namespace { for (Square from = *pl; from != SQ_NONE; from = *++pl) { - if (OnlyChecks) + if (Checks) { if ( (Pt == BISHOP || Pt == ROOK || Pt == QUEEN) && !(PseudoAttacks[Pt][from] & target & ci->checkSq[Pt])) @@ -235,7 +237,7 @@ namespace { Bitboard b = pos.attacks_from(from) & target; - if (OnlyChecks) + if (Checks) b &= ci->checkSq[Pt]; SERIALIZE(b); @@ -244,15 +246,41 @@ namespace { return mlist; } - template<> FORCE_INLINE - MoveStack* generate_moves(const Position& pos, MoveStack* mlist, Color us, - Bitboard target, const CheckInfo*) { + + FORCE_INLINE MoveStack* generate_king_moves(const Position& pos, MoveStack* mlist, + Color us, Bitboard target) { Square from = pos.king_square(us); Bitboard b = pos.attacks_from(from) & target; SERIALIZE(b); return mlist; } + + template FORCE_INLINE + MoveStack* generate_all_moves(const Position& pos, MoveStack* mlist, Color us, + Bitboard target, const CheckInfo* ci = NULL) { + + mlist = (us == WHITE ? generate_pawn_moves(pos, mlist, target, ci) + : generate_pawn_moves(pos, mlist, target, ci)); + + mlist = generate_moves(pos, mlist, us, target, ci); + mlist = generate_moves(pos, mlist, us, target, ci); + mlist = generate_moves(pos, mlist, us, target, ci); + mlist = generate_moves(pos, mlist, us, target, ci); + + if (Type != QUIET_CHECKS && Type != EVASIONS) + mlist = generate_king_moves(pos, mlist, us, target); + + if (Type != CAPTURES && Type != EVASIONS && pos.can_castle(us)) + { + mlist = generate_castle(pos, mlist, us); + mlist = generate_castle(pos, mlist, us); + } + + return mlist; + } + + } // namespace @@ -283,28 +311,13 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { else if (Type == NON_EVASIONS) target = ~pos.pieces(us); - mlist = (us == WHITE ? generate_pawn_moves(pos, mlist, target) - : generate_pawn_moves(pos, mlist, target)); - - mlist = generate_moves(pos, mlist, us, target); - mlist = generate_moves(pos, mlist, us, target); - mlist = generate_moves(pos, mlist, us, target); - mlist = generate_moves(pos, mlist, us, target); - mlist = generate_moves(pos, mlist, us, target); - - if (Type != CAPTURES && pos.can_castle(us)) - { - mlist = generate_castle(pos, mlist, us); - mlist = generate_castle(pos, mlist, us); - } - - return mlist; + return generate_all_moves(pos, mlist, us, target); } // Explicit template instantiations -template MoveStack* generate(const Position& pos, MoveStack* mlist); -template MoveStack* generate(const Position& pos, MoveStack* mlist); -template MoveStack* generate(const Position& pos, MoveStack* mlist); +template MoveStack* generate(const Position&, MoveStack*); +template MoveStack* generate(const Position&, MoveStack*); +template MoveStack* generate(const Position&, MoveStack*); /// generate generates all pseudo-legal non-captures and knight @@ -316,7 +329,6 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { Color us = pos.side_to_move(); CheckInfo ci(pos); - Bitboard empty = ~pos.pieces(); Bitboard dc = ci.dcCandidates; while (dc) @@ -335,21 +347,7 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { SERIALIZE(b); } - mlist = (us == WHITE ? generate_pawn_moves(pos, mlist, ci.dcCandidates, ci.ksq) - : generate_pawn_moves(pos, mlist, ci.dcCandidates, ci.ksq)); - - mlist = generate_moves(pos, mlist, us, empty, &ci); - mlist = generate_moves(pos, mlist, us, empty, &ci); - mlist = generate_moves(pos, mlist, us, empty, &ci); - mlist = generate_moves(pos, mlist, us, empty, &ci); - - if (pos.can_castle(us)) - { - mlist = generate_castle(pos, mlist, us); - mlist = generate_castle(pos, mlist, us); - } - - return mlist; + return generate_all_moves(pos, mlist, us, ~pos.pieces(), &ci); } @@ -360,19 +358,17 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { assert(pos.in_check()); - Bitboard b, target; Square from, checksq; int checkersCnt = 0; Color us = pos.side_to_move(); Square ksq = pos.king_square(us); Bitboard sliderAttacks = 0; - Bitboard checkers = pos.checkers(); + Bitboard b = pos.checkers(); - assert(checkers); + assert(pos.checkers()); // Find squares attacked by slider checkers, we will remove them from the king // evasions so to skip known illegal moves avoiding useless legality check later. - b = checkers; do { checkersCnt++; @@ -407,20 +403,13 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { from = ksq; SERIALIZE(b); - // Generate evasions for other pieces only if not under a double check if (checkersCnt > 1) - return mlist; - - // Blocking evasions or captures of the checking piece - target = between_bb(checksq, ksq) | checkers; + return mlist; // Double check, only a king move can save the day - mlist = (us == WHITE ? generate_pawn_moves(pos, mlist, target) - : generate_pawn_moves(pos, mlist, target)); + // Generate blocking evasions or captures of the checking piece + Bitboard target = between_bb(checksq, ksq) | pos.checkers(); - mlist = generate_moves(pos, mlist, us, target); - mlist = generate_moves(pos, mlist, us, target); - mlist = generate_moves(pos, mlist, us, target); - return generate_moves(pos, mlist, us, target); + return generate_all_moves(pos, mlist, us, target); }