/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
-////
-//// Includes
-////
-
+#include <algorithm>
#include <cassert>
-#include "bitcount.h"
#include "movegen.h"
+#include "position.h"
-// Simple macro to wrap a very common while loop, no facny, no flexibility,
-// hardcoded list name 'mlist' and from square 'from'.
-#define SERIALIZE_MOVES(b) while (b) (*mlist++).move = make_move(from, pop_1st_bit(&b))
-
-// Version used for pawns, where the 'from' square is given as a delta from the 'to' square
-#define SERIALIZE_MOVES_D(b, d) while (b) { to = pop_1st_bit(&b); (*mlist++).move = make_move(to + (d), to); }
-
-////
-//// Local definitions
-////
+/// Simple macro to wrap a very common while loop, no facny, no flexibility,
+/// hardcoded names 'mlist' and 'from'.
+#define SERIALIZE(b) while (b) (*mlist++).move = make_move(from, pop_1st_bit(&b))
+/// Version used for pawns, where the 'from' square is given as a delta from the 'to' square
+#define SERIALIZE_PAWNS(b, d) while (b) { Square to = pop_1st_bit(&b); \
+ (*mlist++).move = make_move(to - (d), to); }
namespace {
- enum CastlingSide {
- KING_SIDE,
- QUEEN_SIDE
- };
-
- enum MoveType {
- CAPTURE,
- NON_CAPTURE,
- CHECK,
- EVASION
- };
-
- // Helper templates
- template<CastlingSide Side>
- MoveStack* generate_castle_moves(const Position&, MoveStack*);
-
- template<Color Us, MoveType Type>
- MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square);
-
- // Template generate_piece_moves (captures and non-captures) with specializations and overloads
- template<PieceType>
- MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard);
+ template<CastlingSide Side, bool OnlyChecks>
+ MoveStack* generate_castle(const Position& pos, MoveStack* mlist, Color us) {
- template<>
- MoveStack* generate_piece_moves<KING>(const Position&, MoveStack*, Color, Bitboard);
+ CastleRight cr = CastleRight((Side == KING_SIDE ? WHITE_OO : WHITE_OOO) << us);
- template<PieceType Piece, MoveType Type>
- inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) {
+ if (pos.castle_impeded(us, Side) || !pos.can_castle(cr))
+ return mlist;
- assert(Piece == PAWN);
- assert(Type == CAPTURE || Type == NON_CAPTURE || Type == EVASION);
+ // After castling, the rook and king final positions are the same in Chess960
+ // as they would be in standard chess.
+ Square kfrom = pos.king_square(us);
+ Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1);
+ Square rfrom = pos.castle_rook_square(us, Side);
+ Bitboard enemies = pos.pieces(~us);
- return (us == WHITE ? generate_pawn_moves<WHITE, Type>(p, m, t, SQ_NONE)
- : generate_pawn_moves<BLACK, Type>(p, m, t, SQ_NONE));
- }
+ assert(!pos.in_check());
- // Templates for non-capture checks generation
+ for (Square s = std::min(kfrom, kto), e = std::max(kfrom, kto); s <= e; s++)
+ if ( s != kfrom // We are not in check
+ && (pos.attackers_to(s) & enemies))
+ return mlist;
- template<PieceType Piece>
- MoveStack* generate_discovered_checks(const Position&, MoveStack*, Square);
+ // Because we generate only legal castling moves we need to verify that
+ // when moving the castling rook we do not discover some hidden checker.
+ // For instance an enemy queen in SQ_A1 when castling rook is in SQ_B1.
+ if ( pos.is_chess960()
+ && (pos.attackers_to(kto, pos.pieces() ^ rfrom) & enemies))
+ return mlist;
- template<PieceType>
- MoveStack* generate_direct_checks(const Position&, MoveStack*, Color, Bitboard, Square);
+ (*mlist++).move = make_castle(kfrom, rfrom);
- template<>
- inline MoveStack* generate_direct_checks<PAWN>(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) {
+ if (OnlyChecks && !pos.move_gives_check((mlist - 1)->move, CheckInfo(pos)))
+ mlist--;
- return (us == WHITE ? generate_pawn_moves<WHITE, CHECK>(p, m, dc, ksq)
- : generate_pawn_moves<BLACK, CHECK>(p, m, dc, ksq));
+ return mlist;
}
-}
-
-
-////
-//// Functions
-////
-
-
-/// generate_captures() generates all pseudo-legal captures and queen
-/// promotions. Returns a pointer to the end of the move list.
-
-MoveStack* generate_captures(const Position& pos, MoveStack* mlist) {
-
- assert(pos.is_ok());
- assert(!pos.is_check());
-
- Color us = pos.side_to_move();
- Bitboard target = pos.pieces_of_color(opposite_color(us));
-
- mlist = generate_piece_moves<QUEEN>(pos, mlist, us, target);
- mlist = generate_piece_moves<ROOK>(pos, mlist, us, target);
- mlist = generate_piece_moves<BISHOP>(pos, mlist, us, target);
- mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, target);
- mlist = generate_piece_moves<PAWN, CAPTURE>(pos, mlist, us, target);
- return generate_piece_moves<KING>(pos, mlist, us, target);
-}
-
-
-/// generate_noncaptures() generates all pseudo-legal non-captures and
-/// underpromotions. Returns a pointer to the end of the move list.
-
-MoveStack* generate_noncaptures(const Position& pos, MoveStack* mlist) {
- assert(pos.is_ok());
- assert(!pos.is_check());
- Color us = pos.side_to_move();
- Bitboard target = pos.empty_squares();
-
- mlist = generate_piece_moves<PAWN, NON_CAPTURE>(pos, mlist, us, target);
- mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, target);
- mlist = generate_piece_moves<BISHOP>(pos, mlist, us, target);
- mlist = generate_piece_moves<ROOK>(pos, mlist, us, target);
- mlist = generate_piece_moves<QUEEN>(pos, mlist, us, target);
- mlist = generate_piece_moves<KING>(pos, mlist, us, target);
- mlist = generate_castle_moves<KING_SIDE>(pos, mlist);
- return generate_castle_moves<QUEEN_SIDE>(pos, mlist);
-}
-
-
-/// generate_non_evasions() generates all pseudo-legal captures and
-/// non-captures. Returns a pointer to the end of the move list.
-
-MoveStack* generate_non_evasions(const Position& pos, MoveStack* mlist) {
-
- assert(pos.is_ok());
- assert(!pos.is_check());
-
- Color us = pos.side_to_move();
- Bitboard target = pos.pieces_of_color(opposite_color(us));
-
- mlist = generate_piece_moves<PAWN, CAPTURE>(pos, mlist, us, target);
- mlist = generate_piece_moves<PAWN, NON_CAPTURE>(pos, mlist, us, pos.empty_squares());
-
- target |= pos.empty_squares();
+ template<Square Delta>
+ inline Bitboard move_pawns(Bitboard p) {
- mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, target);
- mlist = generate_piece_moves<BISHOP>(pos, mlist, us, target);
- mlist = generate_piece_moves<ROOK>(pos, mlist, us, target);
- mlist = generate_piece_moves<QUEEN>(pos, mlist, us, target);
- mlist = generate_piece_moves<KING>(pos, mlist, us, target);
- mlist = generate_castle_moves<KING_SIDE>(pos, mlist);
- return generate_castle_moves<QUEEN_SIDE>(pos, mlist);
-}
+ return Delta == DELTA_N ? p << 8
+ : Delta == DELTA_S ? p >> 8
+ : Delta == DELTA_NE ? (p & ~FileHBB) << 9
+ : Delta == DELTA_SE ? (p & ~FileHBB) >> 7
+ : Delta == DELTA_NW ? (p & ~FileABB) << 7
+ : Delta == DELTA_SW ? (p & ~FileABB) >> 9 : 0;
+ }
-/// generate_non_capture_checks() generates all pseudo-legal non-captures and knight
-/// underpromotions that give check. Returns a pointer to the end of the move list.
+ template<MoveType Type, Square Delta>
+ inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7, Bitboard target, Square ksq) {
-MoveStack* generate_non_capture_checks(const Position& pos, MoveStack* mlist) {
+ Bitboard b = move_pawns<Delta>(pawnsOn7) & target;
- assert(pos.is_ok());
- assert(!pos.is_check());
+ while (b)
+ {
+ Square to = pop_1st_bit(&b);
- Bitboard b, dc;
- Square from;
- Color us = pos.side_to_move();
- Square ksq = pos.king_square(opposite_color(us));
+ if (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION)
+ (*mlist++).move = make_promotion(to - Delta, to, QUEEN);
- assert(pos.piece_on(ksq) == piece_of_color_and_type(opposite_color(us), KING));
+ if (Type == MV_QUIET || Type == MV_EVASION || Type == MV_NON_EVASION)
+ {
+ (*mlist++).move = make_promotion(to - Delta, to, ROOK);
+ (*mlist++).move = make_promotion(to - Delta, to, BISHOP);
+ (*mlist++).move = make_promotion(to - Delta, to, KNIGHT);
+ }
- // Discovered non-capture checks
- b = dc = pos.discovered_check_candidates(us);
+ // Knight-promotion is the only one that can give a direct check not
+ // already included in the queen-promotion.
+ if (Type == MV_QUIET_CHECK && (StepAttacksBB[W_KNIGHT][to] & ksq))
+ (*mlist++).move = make_promotion(to - Delta, to, KNIGHT);
+ else
+ (void)ksq; // Silence a warning under MSVC
+ }
- while (b)
- {
- from = pop_1st_bit(&b);
- switch (pos.type_of_piece_on(from))
- {
- case PAWN: /* Will be generated togheter with pawns direct checks */ break;
- case KNIGHT: mlist = generate_discovered_checks<KNIGHT>(pos, mlist, from); break;
- case BISHOP: mlist = generate_discovered_checks<BISHOP>(pos, mlist, from); break;
- case ROOK: mlist = generate_discovered_checks<ROOK>(pos, mlist, from); break;
- case KING: mlist = generate_discovered_checks<KING>(pos, mlist, from); break;
- default: assert(false); break;
- }
+ return mlist;
}
- // Direct non-capture checks
- mlist = generate_direct_checks<PAWN>(pos, mlist, us, dc, ksq);
- mlist = generate_direct_checks<KNIGHT>(pos, mlist, us, dc, ksq);
- mlist = generate_direct_checks<BISHOP>(pos, mlist, us, dc, ksq);
- mlist = generate_direct_checks<ROOK>(pos, mlist, us, dc, ksq);
- return generate_direct_checks<QUEEN>(pos, mlist, us, dc, ksq);
-}
+ template<Color Us, MoveType Type>
+ MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, Square ksq = SQ_NONE) {
-/// generate_evasions() generates all pseudo-legal check evasions when
-/// the side to move is in check. Returns a pointer to the end of the move list.
-
-MoveStack* generate_evasions(const Position& pos, MoveStack* mlist) {
-
- assert(pos.is_ok());
- assert(pos.is_check());
-
- Bitboard b, target;
- Square from, checksq;
- int checkersCnt = 0;
- Color us = pos.side_to_move();
- Square ksq = pos.king_square(us);
- Bitboard checkers = pos.checkers();
- Bitboard sliderAttacks = EmptyBoardBB;
-
- assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
- assert(checkers);
+ // Compute our parametrized parameters at compile time, named according to
+ // the point of view of white side.
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
+ const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
+ const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
+ const Square UP = (Us == WHITE ? DELTA_N : DELTA_S);
+ const Square RIGHT = (Us == WHITE ? DELTA_NE : DELTA_SW);
+ const Square LEFT = (Us == WHITE ? DELTA_NW : DELTA_SE);
- // Find squares attacked by slider checkers, we will remove
- // them from the king evasions set so to early skip known
- // illegal moves and avoid an useless legality check later.
- b = checkers;
- do
- {
- checkersCnt++;
- checksq = pop_1st_bit(&b);
+ Bitboard b1, b2, dc1, dc2, emptySquares;
- assert(pos.color_of_piece_on(checksq) == opposite_color(us));
+ Bitboard pawnsOn7 = pos.pieces(PAWN, Us) & TRank7BB;
+ Bitboard pawnsNotOn7 = pos.pieces(PAWN, Us) & ~TRank7BB;
- switch (pos.type_of_piece_on(checksq))
- {
- case BISHOP: sliderAttacks |= BishopPseudoAttacks[checksq]; break;
- case ROOK: sliderAttacks |= RookPseudoAttacks[checksq]; break;
- case QUEEN:
- // In case of a queen remove also squares attacked in the other direction to
- // avoid possible illegal moves when queen and king are on adjacent squares.
- if (direction_is_straight(checksq, ksq))
- sliderAttacks |= RookPseudoAttacks[checksq] | pos.attacks_from<BISHOP>(checksq);
- else
- sliderAttacks |= BishopPseudoAttacks[checksq] | pos.attacks_from<ROOK>(checksq);
- default:
- break;
- }
- } while (b);
+ Bitboard enemies = (Type == MV_EVASION ? pos.pieces(Them) & target:
+ Type == MV_CAPTURE ? target : pos.pieces(Them));
- // Generate evasions for king, capture and non capture moves
- b = pos.attacks_from<KING>(ksq) & ~pos.pieces_of_color(us) & ~sliderAttacks;
- from = ksq;
- SERIALIZE_MOVES(b);
+ // Single and double pawn pushes, no promotions
+ if (Type != MV_CAPTURE)
+ {
+ emptySquares = (Type == MV_QUIET ? target : ~pos.pieces());
- // Generate evasions for other pieces only if not double check
- if (checkersCnt > 1)
- return mlist;
+ b1 = move_pawns<UP>(pawnsNotOn7) & emptySquares;
+ b2 = move_pawns<UP>(b1 & TRank3BB) & emptySquares;
- // Find squares where a blocking evasion or a capture of the
- // checker piece is possible.
- target = squares_between(checksq, ksq) | checkers;
+ if (Type == MV_EVASION) // Consider only blocking squares
+ {
+ b1 &= target;
+ b2 &= target;
+ }
- mlist = generate_piece_moves<PAWN, EVASION>(pos, mlist, us, target);
- mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, target);
- mlist = generate_piece_moves<BISHOP>(pos, mlist, us, target);
- mlist = generate_piece_moves<ROOK>(pos, mlist, us, target);
- return generate_piece_moves<QUEEN>(pos, mlist, us, target);
-}
+ if (Type == MV_QUIET_CHECK)
+ {
+ b1 &= pos.attacks_from<PAWN>(ksq, Them);
+ b2 &= pos.attacks_from<PAWN>(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
+ {
+ dc1 = move_pawns<UP>(pawnsNotOn7 & target) & emptySquares & ~file_bb(ksq);
+ dc2 = move_pawns<UP>(dc1 & TRank3BB) & emptySquares;
-/// generate_moves() computes a complete list of legal or pseudo-legal moves in
-/// the current position. This function is not very fast, and should be used
-/// only in non time-critical paths.
+ b1 |= dc1;
+ b2 |= dc2;
+ }
+ }
-MoveStack* generate_moves(const Position& pos, MoveStack* mlist, bool pseudoLegal) {
+ SERIALIZE_PAWNS(b1, UP);
+ SERIALIZE_PAWNS(b2, UP + UP);
+ }
- assert(pos.is_ok());
+ // Promotions and underpromotions
+ if (pawnsOn7 && (Type != MV_EVASION || (target & TRank8BB)))
+ {
+ if (Type == MV_CAPTURE)
+ emptySquares = ~pos.pieces();
- MoveStack *last, *cur = mlist;
- Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
+ if (Type == MV_EVASION)
+ emptySquares &= target;
- // Generate pseudo-legal moves
- last = pos.is_check() ? generate_evasions(pos, mlist)
- : generate_non_evasions(pos, mlist);
- if (pseudoLegal)
- return last;
+ mlist = generate_promotions<Type, RIGHT>(mlist, pawnsOn7, enemies, ksq);
+ mlist = generate_promotions<Type, LEFT>(mlist, pawnsOn7, enemies, ksq);
+ mlist = generate_promotions<Type, UP>(mlist, pawnsOn7, emptySquares, ksq);
+ }
- // Remove illegal moves from the list
- while (cur != last)
- if (pos.pl_move_is_legal(cur->move, pinned))
- cur++;
- else
- cur->move = (--last)->move;
+ // Standard and en-passant captures
+ if (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION)
+ {
+ b1 = move_pawns<RIGHT>(pawnsNotOn7) & enemies;
+ b2 = move_pawns<LEFT >(pawnsNotOn7) & enemies;
- return last;
-}
+ SERIALIZE_PAWNS(b1, RIGHT);
+ SERIALIZE_PAWNS(b2, LEFT);
+ if (pos.ep_square() != SQ_NONE)
+ {
+ assert(rank_of(pos.ep_square()) == relative_rank(Us, RANK_6));
-/// move_is_legal() takes a position and a (not necessarily pseudo-legal)
-/// move and tests whether the move is legal. This version is not very fast
-/// and should be used only in non time-critical paths.
+ // An en passant capture can be an evasion only if the checking piece
+ // is the double pushed pawn and so is in the target. Otherwise this
+ // is a discovery check and we are forced to do otherwise.
+ if (Type == MV_EVASION && !(target & (pos.ep_square() - UP)))
+ return mlist;
-bool move_is_legal(const Position& pos, const Move m) {
+ b1 = pawnsNotOn7 & pos.attacks_from<PAWN>(pos.ep_square(), Them);
- MoveStack mlist[256];
- MoveStack *cur, *last = generate_moves(pos, mlist, true);
+ assert(b1);
- for (cur = mlist; cur != last; cur++)
- if (cur->move == m)
- return pos.pl_move_is_legal(m, pos.pinned_pieces(pos.side_to_move()));
+ while (b1)
+ (*mlist++).move = make_enpassant(pop_1st_bit(&b1), pos.ep_square());
+ }
+ }
- return false;
-}
+ return mlist;
+ }
-/// Fast version of move_is_legal() that takes a position a move and a
-/// bitboard of pinned pieces as input, and tests whether the move is legal.
+ template<PieceType Pt>
+ inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist,
+ Color us, const CheckInfo& ci) {
+ assert(Pt != KING && Pt != PAWN);
-bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
+ Bitboard b, target;
+ Square from;
+ const Square* pl = pos.piece_list(us, Pt);
- assert(pos.is_ok());
- assert(move_is_ok(m));
- assert(pinned == pos.pinned_pieces(pos.side_to_move()));
+ if (*pl != SQ_NONE)
+ {
+ target = ci.checkSq[Pt] & ~pos.pieces(); // Non capture checks only
- Color us = pos.side_to_move();
- Color them = opposite_color(us);
- Square from = move_from(m);
- Square to = move_to(m);
- Piece pc = pos.piece_on(from);
-
- // Use a slower but simpler function for uncommon cases
- if (move_is_special(m))
- return move_is_legal(pos, m);
-
- // If the from square is not occupied by a piece belonging to the side to
- // move, the move is obviously not legal.
- if (color_of_piece(pc) != us)
- return false;
-
- // The destination square cannot be occupied by a friendly piece
- if (pos.color_of_piece_on(to) == us)
- return false;
-
- // Handle the special case of a pawn move
- if (type_of_piece(pc) == PAWN)
- {
- // Move direction must be compatible with pawn color
- int direction = to - from;
- if ((us == WHITE) != (direction > 0))
- return false;
-
- // We have already handled promotion moves, so destination
- // cannot be on the 8/1th rank.
- if (square_rank(to) == RANK_8 || square_rank(to) == RANK_1)
- return false;
-
- // Proceed according to the square delta between the origin and
- // destination squares.
- switch (direction)
- {
- case DELTA_NW:
- case DELTA_NE:
- case DELTA_SW:
- case DELTA_SE:
- // Capture. The destination square must be occupied by an enemy
- // piece (en passant captures was handled earlier).
- if (pos.color_of_piece_on(to) != them)
- return false;
- break;
+ do {
+ from = *pl;
- case DELTA_N:
- case DELTA_S:
- // Pawn push. The destination square must be empty.
- if (!pos.square_is_empty(to))
- return false;
- break;
+ if ( (Pt == BISHOP || Pt == ROOK || Pt == QUEEN)
+ && !(PseudoAttacks[Pt][from] & target))
+ continue;
- case DELTA_NN:
- // Double white pawn push. The destination square must be on the fourth
- // rank, and both the destination square and the square between the
- // source and destination squares must be empty.
- if ( square_rank(to) != RANK_4
- || !pos.square_is_empty(to)
- || !pos.square_is_empty(from + DELTA_N))
- return false;
- break;
+ if (ci.dcCandidates && (ci.dcCandidates & from))
+ continue;
- case DELTA_SS:
- // Double black pawn push. The destination square must be on the fifth
- // rank, and both the destination square and the square between the
- // source and destination squares must be empty.
- if ( square_rank(to) != RANK_5
- || !pos.square_is_empty(to)
- || !pos.square_is_empty(from + DELTA_S))
- return false;
- break;
+ b = pos.attacks_from<Pt>(from) & target;
+ SERIALIZE(b);
+ } while (*++pl != SQ_NONE);
+ }
- default:
- return false;
- }
+ return mlist;
}
- else if (!bit_is_set(pos.attacks_from(pc, from), to))
- return false;
-
- // The move is pseudo-legal, check if it is also legal
- return pos.is_check() ? pos.pl_move_is_evasion(m, pinned) : pos.pl_move_is_legal(m, pinned);
-}
-
-namespace {
- template<PieceType Piece>
- MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
+ template<PieceType Pt>
+ FORCE_INLINE MoveStack* generate_moves(const Position& pos, MoveStack* mlist,
+ Color us, Bitboard target) {
+ assert(Pt != KING && Pt != PAWN);
Bitboard b;
Square from;
- const Square* ptr = pos.piece_list_begin(us, Piece);
+ const Square* pl = pos.piece_list(us, Pt);
- if (*ptr != SQ_NONE)
- {
+ if (*pl != SQ_NONE)
do {
- from = *ptr;
- b = pos.attacks_from<Piece>(from) & target;
- SERIALIZE_MOVES(b);
- } while (*++ptr != SQ_NONE);
- }
+ from = *pl;
+ b = pos.attacks_from<Pt>(from) & target;
+ SERIALIZE(b);
+ } while (*++pl != SQ_NONE);
+
return mlist;
}
- template<>
- MoveStack* generate_piece_moves<KING>(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
- Bitboard b;
+ template<>
+ FORCE_INLINE MoveStack* generate_moves<KING>(const Position& pos, MoveStack* mlist,
+ Color us, Bitboard target) {
Square from = pos.king_square(us);
-
- b = pos.attacks_from<KING>(from) & target;
- SERIALIZE_MOVES(b);
+ Bitboard b = pos.attacks_from<KING>(from) & target;
+ SERIALIZE(b);
return mlist;
}
- template<Color Us, SquareDelta Direction>
- inline Bitboard move_pawns(Bitboard p) {
+} // namespace
- if (Direction == DELTA_N)
- return Us == WHITE ? p << 8 : p >> 8;
- else if (Direction == DELTA_NE)
- return Us == WHITE ? p << 9 : p >> 7;
- else if (Direction == DELTA_NW)
- return Us == WHITE ? p << 7 : p >> 9;
- else
- return p;
- }
- template<Color Us, MoveType Type, SquareDelta Diagonal>
- inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard enemyPieces) {
+/// generate<MV_CAPTURE> generates all pseudo-legal captures and queen
+/// promotions. Returns a pointer to the end of the move list.
+///
+/// generate<MV_QUIET> generates all pseudo-legal non-captures and
+/// underpromotions. Returns a pointer to the end of the move list.
+///
+/// generate<MV_NON_EVASION> generates all pseudo-legal captures and
+/// non-captures. Returns a pointer to the end of the move list.
- // Calculate our parametrized parameters at compile time
- const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
- const Bitboard TFileABB = (Diagonal == DELTA_NE ? FileABB : FileHBB);
- const SquareDelta TDELTA_NE = (Us == WHITE ? DELTA_NE : DELTA_SE);
- const SquareDelta TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW);
- const SquareDelta TTDELTA_NE = (Diagonal == DELTA_NE ? TDELTA_NE : TDELTA_NW);
+template<MoveType Type>
+MoveStack* generate(const Position& pos, MoveStack* mlist) {
- Bitboard b1, b2;
- Square to;
+ assert(Type == MV_CAPTURE || Type == MV_QUIET || Type == MV_NON_EVASION);
+ assert(!pos.in_check());
- // Captures in the a1-h8 (a8-h1 for black) diagonal or in the h1-a8 (h8-a1 for black)
- b1 = move_pawns<Us, Diagonal>(pawns) & ~TFileABB & enemyPieces;
+ Color us = pos.side_to_move();
+ Bitboard target;
- // Capturing promotions and under-promotions
- if (b1 & TRank8BB)
- {
- b2 = b1 & TRank8BB;
- b1 &= ~TRank8BB;
- while (b2)
- {
- to = pop_1st_bit(&b2);
+ if (Type == MV_CAPTURE)
+ target = pos.pieces(~us);
- if (Type == CAPTURE || Type == EVASION)
- (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, QUEEN);
+ else if (Type == MV_QUIET)
+ target = ~pos.pieces();
- if (Type == NON_CAPTURE || Type == EVASION)
- {
- (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, ROOK);
- (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, BISHOP);
- (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, KNIGHT);
- }
+ else if (Type == MV_NON_EVASION)
+ target = ~pos.pieces(us);
- // This is the only possible under promotion that can give a check
- // not already included in the queen-promotion. It is not sure that
- // the promoted knight will give check, but it doesn't worth to verify.
- if (Type == CHECK)
- (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, KNIGHT);
- }
- }
+ mlist = (us == WHITE ? generate_pawn_moves<WHITE, Type>(pos, mlist, target)
+ : generate_pawn_moves<BLACK, Type>(pos, mlist, target));
- // Serialize standard captures
- if (Type == CAPTURE || Type == EVASION)
- SERIALIZE_MOVES_D(b1, -TTDELTA_NE);
+ mlist = generate_moves<KNIGHT>(pos, mlist, us, target);
+ mlist = generate_moves<BISHOP>(pos, mlist, us, target);
+ mlist = generate_moves<ROOK>(pos, mlist, us, target);
+ mlist = generate_moves<QUEEN>(pos, mlist, us, target);
+ mlist = generate_moves<KING>(pos, mlist, us, target);
- return mlist;
+ if (Type != MV_CAPTURE && pos.can_castle(us))
+ {
+ mlist = generate_castle<KING_SIDE, false>(pos, mlist, us);
+ mlist = generate_castle<QUEEN_SIDE, false>(pos, mlist, us);
}
- template<Color Us, MoveType Type>
- MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, Square ksq) {
-
- // Calculate our parametrized parameters at compile time
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
- const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
- const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
- const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
-
- Square to;
- Bitboard b1, b2, enemyPieces, emptySquares;
- Bitboard pawns = pos.pieces(PAWN, Us);
-
- // Standard captures and capturing promotions and underpromotions
- if (Type == CAPTURE || Type == EVASION || (pawns & TRank7BB))
- {
- enemyPieces = (Type == CAPTURE ? target : pos.pieces_of_color(opposite_color(Us)));
-
- if (Type == EVASION)
- enemyPieces &= target; // Capture only the checker piece
-
- mlist = generate_pawn_captures<Us, Type, DELTA_NE>(mlist, pawns, enemyPieces);
- mlist = generate_pawn_captures<Us, Type, DELTA_NW>(mlist, pawns, enemyPieces);
- }
+ return mlist;
+}
- // Non-capturing promotions and underpromotions
- if (pawns & TRank7BB)
- {
- b1 = move_pawns<Us, DELTA_N>(pawns) & TRank8BB & pos.empty_squares();
+// Explicit template instantiations
+template MoveStack* generate<MV_CAPTURE>(const Position& pos, MoveStack* mlist);
+template MoveStack* generate<MV_QUIET>(const Position& pos, MoveStack* mlist);
+template MoveStack* generate<MV_NON_EVASION>(const Position& pos, MoveStack* mlist);
- if (Type == EVASION)
- b1 &= target; // Only blocking promotion pushes
- while (b1)
- {
- to = pop_1st_bit(&b1);
-
- if (Type == CAPTURE || Type == EVASION)
- (*mlist++).move = make_promotion_move(to - TDELTA_N, to, QUEEN);
+/// generate<MV_QUIET_CHECK> generates all pseudo-legal non-captures and knight
+/// underpromotions that give check. Returns a pointer to the end of the move list.
+template<>
+MoveStack* generate<MV_QUIET_CHECK>(const Position& pos, MoveStack* mlist) {
- if (Type == NON_CAPTURE || Type == EVASION)
- {
- (*mlist++).move = make_promotion_move(to - TDELTA_N, to, ROOK);
- (*mlist++).move = make_promotion_move(to - TDELTA_N, to, BISHOP);
- (*mlist++).move = make_promotion_move(to - TDELTA_N, to, KNIGHT);
- }
+ assert(!pos.in_check());
- // This is the only possible under promotion that can give a check
- // not already included in the queen-promotion.
- if (Type == CHECK && bit_is_set(pos.attacks_from<KNIGHT>(to), pos.king_square(Them)))
- (*mlist++).move = make_promotion_move(to - TDELTA_N, to, KNIGHT);
- }
- }
+ Color us = pos.side_to_move();
+ CheckInfo ci(pos);
+ Bitboard dc = ci.dcCandidates;
- // Standard pawn pushes and double pushes
- if (Type != CAPTURE)
- {
- emptySquares = (Type == NON_CAPTURE ? target : pos.empty_squares());
+ while (dc)
+ {
+ Square from = pop_1st_bit(&dc);
+ PieceType pt = type_of(pos.piece_on(from));
- // Single and double pawn pushes
- b1 = move_pawns<Us, DELTA_N>(pawns) & emptySquares & ~TRank8BB;
- b2 = move_pawns<Us, DELTA_N>(b1 & TRank3BB) & emptySquares;
+ if (pt == PAWN)
+ continue; // Will be generated togheter with direct checks
- // Filter out unwanted pushes according to the move type
- if (Type == EVASION)
- {
- b1 &= target;
- b2 &= target;
- }
- else if (Type == CHECK)
- {
- // Pawn moves which give direct cheks
- b1 &= pos.attacks_from<PAWN>(ksq, Them);
- b2 &= pos.attacks_from<PAWN>(ksq, Them);
+ Bitboard b = pos.attacks_from(Piece(pt), from) & ~pos.pieces();
- // Pawn moves which gives 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.
- if (pawns & target) // For CHECK type target is dc bitboard
- {
- Bitboard dc1 = move_pawns<Us, DELTA_N>(pawns & target & ~file_bb(ksq)) & emptySquares & ~TRank8BB;
- Bitboard dc2 = move_pawns<Us, DELTA_N>(dc1 & TRank3BB) & emptySquares;
+ if (pt == KING)
+ b &= ~PseudoAttacks[QUEEN][ci.ksq];
- b1 |= dc1;
- b2 |= dc2;
- }
- }
- SERIALIZE_MOVES_D(b1, -TDELTA_N);
- SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N);
- }
-
- // En passant captures
- if ((Type == CAPTURE || Type == EVASION) && pos.ep_square() != SQ_NONE)
- {
- assert(Us != WHITE || square_rank(pos.ep_square()) == RANK_6);
- assert(Us != BLACK || square_rank(pos.ep_square()) == RANK_3);
-
- // An en passant capture can be an evasion only if the checking piece
- // is the double pushed pawn and so is in the target. Otherwise this
- // is a discovery check and we are forced to do otherwise.
- if (Type == EVASION && !bit_is_set(target, pos.ep_square() - TDELTA_N))
- return mlist;
+ SERIALIZE(b);
+ }
- b1 = pawns & pos.attacks_from<PAWN>(pos.ep_square(), Them);
+ mlist = (us == WHITE ? generate_pawn_moves<WHITE, MV_QUIET_CHECK>(pos, mlist, ci.dcCandidates, ci.ksq)
+ : generate_pawn_moves<BLACK, MV_QUIET_CHECK>(pos, mlist, ci.dcCandidates, ci.ksq));
- assert(b1 != EmptyBoardBB);
+ mlist = generate_direct_checks<KNIGHT>(pos, mlist, us, ci);
+ mlist = generate_direct_checks<BISHOP>(pos, mlist, us, ci);
+ mlist = generate_direct_checks<ROOK>(pos, mlist, us, ci);
+ mlist = generate_direct_checks<QUEEN>(pos, mlist, us, ci);
- while (b1)
- {
- to = pop_1st_bit(&b1);
- (*mlist++).move = make_ep_move(to, pos.ep_square());
- }
- }
- return mlist;
+ if (pos.can_castle(us))
+ {
+ mlist = generate_castle<KING_SIDE, true>(pos, mlist, us);
+ mlist = generate_castle<QUEEN_SIDE, true>(pos, mlist, us);
}
- template<PieceType Piece>
- MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) {
-
- assert(Piece != QUEEN);
+ return mlist;
+}
- Bitboard b = pos.attacks_from<Piece>(from) & pos.empty_squares();
- if (Piece == KING)
- {
- Square ksq = pos.king_square(opposite_color(pos.side_to_move()));
- b &= ~QueenPseudoAttacks[ksq];
- }
- SERIALIZE_MOVES(b);
- return mlist;
- }
- template<PieceType Piece>
- MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us,
- Bitboard dc, Square ksq) {
- assert(Piece != KING);
+/// generate<MV_EVASION> generates all pseudo-legal check evasions when the side
+/// to move is in check. Returns a pointer to the end of the move list.
+template<>
+MoveStack* generate<MV_EVASION>(const Position& pos, MoveStack* mlist) {
- Bitboard checkSqs, b;
- Square from;
- const Square* ptr = pos.piece_list_begin(us, Piece);
+ assert(pos.in_check());
- if ((from = *ptr++) == SQ_NONE)
- return mlist;
+ 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();
- checkSqs = pos.attacks_from<Piece>(ksq) & pos.empty_squares();
+ assert(checkers);
- do
- {
- if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs))
- || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs))
- || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
- continue;
+ // 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++;
+ checksq = pop_1st_bit(&b);
- if (dc && bit_is_set(dc, from))
- continue;
+ assert(color_of(pos.piece_on(checksq)) == ~us);
- b = pos.attacks_from<Piece>(from) & checkSqs;
- SERIALIZE_MOVES(b);
+ switch (type_of(pos.piece_on(checksq)))
+ {
+ case BISHOP: sliderAttacks |= PseudoAttacks[BISHOP][checksq]; break;
+ case ROOK: sliderAttacks |= PseudoAttacks[ROOK][checksq]; break;
+ case QUEEN:
+ // If queen and king are far or not on a diagonal line we can safely
+ // remove all the squares attacked in the other direction becuase are
+ // not reachable by the king anyway.
+ if (squares_between(ksq, checksq) || !(PseudoAttacks[BISHOP][checksq] & ksq))
+ sliderAttacks |= PseudoAttacks[QUEEN][checksq];
+
+ // Otherwise we need to use real rook attacks to check if king is safe
+ // to move in the other direction. For example: king in B2, queen in A1
+ // a knight in B1, and we can safely move to C1.
+ else
+ sliderAttacks |= PseudoAttacks[BISHOP][checksq] | pos.attacks_from<ROOK>(checksq);
- } while ((from = *ptr++) != SQ_NONE);
+ default:
+ break;
+ }
+ } while (b);
- return mlist;
- }
+ // Generate evasions for king, capture and non capture moves
+ b = pos.attacks_from<KING>(ksq) & ~pos.pieces(us) & ~sliderAttacks;
+ from = ksq;
+ SERIALIZE(b);
- template<CastlingSide Side>
- MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist) {
+ // Generate evasions for other pieces only if not under a double check
+ if (checkersCnt > 1)
+ return mlist;
- Color us = pos.side_to_move();
+ // Blocking evasions or captures of the checking piece
+ target = squares_between(checksq, ksq) | checkers;
- if ( (Side == KING_SIDE && pos.can_castle_kingside(us))
- ||(Side == QUEEN_SIDE && pos.can_castle_queenside(us)))
- {
- Color them = opposite_color(us);
- Square ksq = pos.king_square(us);
+ mlist = (us == WHITE ? generate_pawn_moves<WHITE, MV_EVASION>(pos, mlist, target)
+ : generate_pawn_moves<BLACK, MV_EVASION>(pos, mlist, target));
- assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
+ mlist = generate_moves<KNIGHT>(pos, mlist, us, target);
+ mlist = generate_moves<BISHOP>(pos, mlist, us, target);
+ mlist = generate_moves<ROOK>(pos, mlist, us, target);
+ return generate_moves<QUEEN>(pos, mlist, us, target);
+}
- Square rsq = (Side == KING_SIDE ? pos.initial_kr_square(us) : pos.initial_qr_square(us));
- Square s1 = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1);
- Square s2 = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1);
- Square s;
- bool illegal = false;
- assert(pos.piece_on(rsq) == piece_of_color_and_type(us, ROOK));
+/// generate<MV_LEGAL> generates all the legal moves in the given position
- // It is a bit complicated to correctly handle Chess960
- for (s = Min(ksq, s1); s <= Max(ksq, s1); s++)
- if ( (s != ksq && s != rsq && pos.square_is_occupied(s))
- ||(pos.attackers_to(s) & pos.pieces_of_color(them)))
- illegal = true;
+template<>
+MoveStack* generate<MV_LEGAL>(const Position& pos, MoveStack* mlist) {
- for (s = Min(rsq, s2); s <= Max(rsq, s2); s++)
- if (s != ksq && s != rsq && pos.square_is_occupied(s))
- illegal = true;
+ MoveStack *last, *cur = mlist;
+ Bitboard pinned = pos.pinned_pieces();
- if ( Side == QUEEN_SIDE
- && square_file(rsq) == FILE_B
- && ( pos.piece_on(relative_square(us, SQ_A1)) == piece_of_color_and_type(them, ROOK)
- || pos.piece_on(relative_square(us, SQ_A1)) == piece_of_color_and_type(them, QUEEN)))
- illegal = true;
+ last = pos.in_check() ? generate<MV_EVASION>(pos, mlist)
+ : generate<MV_NON_EVASION>(pos, mlist);
+ while (cur != last)
+ if (!pos.pl_move_is_legal(cur->move, pinned))
+ cur->move = (--last)->move;
+ else
+ cur++;
- if (!illegal)
- (*mlist++).move = make_castle_move(ksq, rsq);
- }
- return mlist;
- }
+ return last;
}
projects / stockfish / blobdiff