From e2af0e775b8943f0437c25b566ecf4165b15f518 Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Sun, 19 Oct 2008 17:54:18 +0200 Subject: [PATCH] Pawn move generator: dispatch at compile time Instead of function pointers use templates to dispatch shift operations. It is more clear and possibly also faster because branches are removed at compile time. Signed-off-by: Marco Costalba --- src/movegen.cpp | 180 +++++++++++++++++++++++------------------------- 1 file changed, 85 insertions(+), 95 deletions(-) diff --git a/src/movegen.cpp b/src/movegen.cpp index 3dfd8f6a..da8d08c3 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -32,29 +32,15 @@ namespace { - inline Bitboard forward_white(Bitboard b) { return b << 8; } - inline Bitboard forward_right_white(Bitboard b) { return b << 9; } - inline Bitboard forward_left_white(Bitboard b) { return b << 7; } - - inline Bitboard forward_black(Bitboard b) { return b >> 8; } - inline Bitboard forward_right_black(Bitboard b) { return b >> 7; } - inline Bitboard forward_left_black(Bitboard b) { return b >> 9; } - struct PawnOffsets { Bitboard Rank3BB, Rank8BB; Rank RANK_8; SquareDelta DELTA_N, DELTA_NE, DELTA_NW; Color us, them; - typedef Bitboard (*Shift_fn)(Bitboard b); - Shift_fn forward, forward_left, forward_right; }; - - const PawnOffsets WhitePawnOffsets = { Rank3BB, Rank8BB, RANK_8, DELTA_N, DELTA_NE, DELTA_NW, WHITE, BLACK, - &forward_white, forward_left_white, forward_right_white }; - - const PawnOffsets BlackPawnOffsets = { Rank6BB, Rank1BB, RANK_1, DELTA_S, DELTA_SE, DELTA_SW, BLACK, WHITE, - &forward_black, &forward_left_black, &forward_right_black }; + const PawnOffsets WhitePawnOffsets = { Rank3BB, Rank8BB, RANK_8, DELTA_N, DELTA_NE, DELTA_NW, WHITE, BLACK }; + const PawnOffsets BlackPawnOffsets = { Rank6BB, Rank1BB, RANK_1, DELTA_S, DELTA_SE, DELTA_SW, BLACK, WHITE }; int generate_castle_moves(const Position&, MoveStack*, Color); @@ -648,7 +634,7 @@ namespace { int n = 0; // Captures in the a1-h8 (a8-h1 for black) direction - Bitboard b1 = (ofs.forward_right)(pawns) & ~FileABB & enemyPieces; + Bitboard b1 = (C == WHITE ? pawns << 9 : pawns >> 7) & ~FileABB & enemyPieces; // Capturing promotions Bitboard b2 = b1 & ofs.Rank8BB; @@ -667,7 +653,7 @@ namespace { } // Captures in the h1-a8 (h8-a1 for black) direction - b1 = (ofs.forward_left)(pawns) & ~FileHBB & enemyPieces; + b1 = (C == WHITE ? pawns << 7 : pawns >> 9) & ~FileHBB & enemyPieces; // Capturing promotions b2 = b1 & ofs.Rank8BB; @@ -686,7 +672,7 @@ namespace { } // Non-capturing promotions - b1 = (ofs.forward)(pawns) & pos.empty_squares() & Rank8BB; + b1 = (C == WHITE ? pawns << 8 : pawns >> 8) & pos.empty_squares() & Rank8BB; while (b1) { sq = pop_1st_bit(&b1); @@ -725,7 +711,7 @@ namespace { int n = 0; // Underpromotion captures in the a1-h8 (a8-h1 for black) direction - b1 = ofs.forward_right(pawns) & ~FileABB & enemyPieces & ofs.Rank8BB; + b1 = (C == WHITE ? pawns << 9 : pawns >> 7) & ~FileABB & enemyPieces & ofs.Rank8BB; while (b1) { sq = pop_1st_bit(&b1); @@ -735,7 +721,7 @@ namespace { } // Underpromotion captures in the h1-a8 (h8-a1 for black) direction - b1 = ofs.forward_left(pawns) & ~FileHBB & enemyPieces & ofs.Rank8BB; + b1 = (C == WHITE ? pawns << 7 : pawns >> 9) & ~FileHBB & enemyPieces & ofs.Rank8BB; while (b1) { sq = pop_1st_bit(&b1); @@ -745,7 +731,7 @@ namespace { } // Single pawn pushes - b1 = ofs.forward(pawns) & emptySquares; + b1 = (C == WHITE ? pawns << 8 : pawns >> 8) & emptySquares; b2 = b1 & ofs.Rank8BB; while (b2) { @@ -762,7 +748,7 @@ namespace { } // Double pawn pushes - b2 = (ofs.forward(b1 & ofs.Rank3BB)) & emptySquares; + b2 = (C == WHITE ? (b1 & ofs.Rank3BB) << 8 : (b1 & ofs.Rank3BB) >> 8) & emptySquares; while (b2) { sq = pop_1st_bit(&b2); @@ -772,72 +758,6 @@ namespace { } - int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) { - - int n = 0; - - if (pos.can_castle(us)) - { - Color them = opposite_color(us); - Square ksq = pos.king_square(us); - - assert(pos.piece_on(ksq) == king_of_color(us)); - - if (pos.can_castle_kingside(us)) - { - Square rsq = pos.initial_kr_square(us); - Square g1 = relative_square(us, SQ_G1); - Square f1 = relative_square(us, SQ_F1); - Square s; - bool illegal = false; - - assert(pos.piece_on(rsq) == rook_of_color(us)); - - for (s = Min(ksq, g1); s <= Max(ksq, g1); s++) - if ( (s != ksq && s != rsq && pos.square_is_occupied(s)) - || pos.square_is_attacked(s, them)) - illegal = true; - - for (s = Min(rsq, f1); s <= Max(rsq, f1); s++) - if (s != ksq && s != rsq && pos.square_is_occupied(s)) - illegal = true; - - if (!illegal) - mlist[n++].move = make_castle_move(ksq, rsq); - } - - if (pos.can_castle_queenside(us)) - { - Square rsq = pos.initial_qr_square(us); - Square c1 = relative_square(us, SQ_C1); - Square d1 = relative_square(us, SQ_D1); - Square s; - bool illegal = false; - - assert(pos.piece_on(rsq) == rook_of_color(us)); - - for (s = Min(ksq, c1); s <= Max(ksq, c1); s++) - if ( (s != ksq && s != rsq && pos.square_is_occupied(s)) - || pos.square_is_attacked(s, them)) - illegal = true; - - for (s = Min(rsq, d1); s <= Max(rsq, d1); s++) - if (s != ksq && s != rsq && pos.square_is_occupied(s)) - illegal = true; - - if ( square_file(rsq) == FILE_B - && ( pos.piece_on(relative_square(us, SQ_A1)) == rook_of_color(them) - || pos.piece_on(relative_square(us, SQ_A1)) == queen_of_color(them))) - illegal = true; - - if (!illegal) - mlist[n++].move = make_castle_move(ksq, rsq); - } - } - return n; - } - - template int generate_pawn_checks(const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist, int n) { @@ -852,7 +772,7 @@ namespace { Bitboard b1 = pos.pawns(pos.side_to_move()) & ~file_bb(ksq), b2, b3; // Discovered checks, single pawn pushes - b2 = b3 = (ofs.forward)(b1 & dc) & ~ofs.Rank8BB & empty; + b2 = b3 = (C == WHITE ? (b1 & dc) << 8 : (b1 & dc) >> 8) & ~ofs.Rank8BB & empty; while (b3) { Square to = pop_1st_bit(&b3); @@ -860,7 +780,7 @@ namespace { } // Discovered checks, double pawn pushes - b3 = (ofs.forward)(b2 & ofs.Rank3BB) & empty; + b3 = (C == WHITE ? (b2 & ofs.Rank3BB) << 8 : (b2 & ofs.Rank3BB) >> 8) & empty; while (b3) { Square to = pop_1st_bit(&b3); @@ -873,7 +793,7 @@ namespace { b1 &= (~dc & neighboring_files_bb(ksq)); // FIXME why ~dc ?? // Direct checks, single pawn pushes - b2 = (ofs.forward)(b1) & empty; + b2 = (C == WHITE ? b1 << 8 : b1 >> 8) & empty; b3 = b2 & pos.pawn_attacks(ofs.them, ksq); while (b3) { @@ -882,7 +802,10 @@ namespace { } // Direct checks, double pawn pushes - b3 = (ofs.forward)(b2 & ofs.Rank3BB) & empty & pos.pawn_attacks(ofs.them, ksq); + b3 = (C == WHITE ? (b2 & ofs.Rank3BB) << 8 : (b2 & ofs.Rank3BB) >> 8) + & empty + & pos.pawn_attacks(ofs.them, ksq); + while (b3) { Square to = pop_1st_bit(&b3); @@ -902,7 +825,7 @@ namespace { // Single pawn pushes. We don't have to AND with empty squares here, // because the blocking squares will always be empty. - Bitboard b2 = (ofs.forward)(b1) & blockSquares; + Bitboard b2 = (C == WHITE ? b1 << 8 : b1 >> 8) & blockSquares; while (b2) { Square to = pop_1st_bit(&b2); @@ -920,7 +843,8 @@ namespace { } // Double pawn pushes - b2 = (ofs.forward)((ofs.forward)(b1) & pos.empty_squares() & ofs.Rank3BB) & blockSquares; + b2 = (C == WHITE ? b1 << 8 : b1 >> 8) & pos.empty_squares() & ofs.Rank3BB; + b2 = (C == WHITE ? b2 << 8 : b2 >> 8) & blockSquares;; while (b2) { Square to = pop_1st_bit(&b2); @@ -933,4 +857,70 @@ namespace { } return n; } + + + int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) { + + int n = 0; + + if (pos.can_castle(us)) + { + Color them = opposite_color(us); + Square ksq = pos.king_square(us); + + assert(pos.piece_on(ksq) == king_of_color(us)); + + if (pos.can_castle_kingside(us)) + { + Square rsq = pos.initial_kr_square(us); + Square g1 = relative_square(us, SQ_G1); + Square f1 = relative_square(us, SQ_F1); + Square s; + bool illegal = false; + + assert(pos.piece_on(rsq) == rook_of_color(us)); + + for (s = Min(ksq, g1); s <= Max(ksq, g1); s++) + if ( (s != ksq && s != rsq && pos.square_is_occupied(s)) + || pos.square_is_attacked(s, them)) + illegal = true; + + for (s = Min(rsq, f1); s <= Max(rsq, f1); s++) + if (s != ksq && s != rsq && pos.square_is_occupied(s)) + illegal = true; + + if (!illegal) + mlist[n++].move = make_castle_move(ksq, rsq); + } + + if (pos.can_castle_queenside(us)) + { + Square rsq = pos.initial_qr_square(us); + Square c1 = relative_square(us, SQ_C1); + Square d1 = relative_square(us, SQ_D1); + Square s; + bool illegal = false; + + assert(pos.piece_on(rsq) == rook_of_color(us)); + + for (s = Min(ksq, c1); s <= Max(ksq, c1); s++) + if ( (s != ksq && s != rsq && pos.square_is_occupied(s)) + || pos.square_is_attacked(s, them)) + illegal = true; + + for (s = Min(rsq, d1); s <= Max(rsq, d1); s++) + if (s != ksq && s != rsq && pos.square_is_occupied(s)) + illegal = true; + + if ( square_file(rsq) == FILE_B + && ( pos.piece_on(relative_square(us, SQ_A1)) == rook_of_color(them) + || pos.piece_on(relative_square(us, SQ_A1)) == queen_of_color(them))) + illegal = true; + + if (!illegal) + mlist[n++].move = make_castle_move(ksq, rsq); + } + } + return n; + } } -- 2.39.2