X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=0686bf8d93aad1922859d93b19ea3ac0873be695;hp=4784e95d93aa25b142d9244aa419bfdb196519e3;hb=6dddcecb09df268d93810a1a38deb116f97672af;hpb=94dcac1feeb142a56ed2ebddb96ef672460f1d49
diff --git a/src/movegen.cpp b/src/movegen.cpp
index 4784e95d..88c31cfa 100644
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -1,7 +1,6 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@@ -17,677 +16,349 @@
along with this program. If not, see .
*/
-
-////
-//// Includes
-////
-
#include
-#include "bitcount.h"
#include "movegen.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
-////
+#include "position.h"
namespace {
- enum CastlingSide {
- KING_SIDE,
- QUEEN_SIDE
- };
-
- enum MoveType {
- CAPTURE,
- NON_CAPTURE,
- CHECK,
- EVASION
- };
-
- // Helper templates
- template
- MoveStack* generate_castle_moves(const Position&, MoveStack*);
-
- template
- MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square);
-
- // Template generate_piece_moves (captures and non-captures) with specializations and overloads
- template
- MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard);
-
- template<>
- MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard);
+ template
+ ExtMove* make_promotions(ExtMove* moveList, Square to, Square ksq) {
- template
- inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) {
+ if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
+ {
+ *moveList++ = make(to - D, to, QUEEN);
+ if (attacks_bb(to) & ksq)
+ *moveList++ = make(to - D, to, KNIGHT);
+ }
- assert(Piece == PAWN);
- assert(Type == CAPTURE || Type == NON_CAPTURE || Type == EVASION);
+ if (Type == QUIETS || Type == EVASIONS || Type == NON_EVASIONS)
+ {
+ *moveList++ = make(to - D, to, ROOK);
+ *moveList++ = make(to - D, to, BISHOP);
+ if (!(attacks_bb(to) & ksq))
+ *moveList++ = make(to - D, to, KNIGHT);
+ }
- return (us == WHITE ? generate_pawn_moves(p, m, t, SQ_NONE)
- : generate_pawn_moves(p, m, t, SQ_NONE));
+ return moveList;
}
- // Templates for non-capture checks generation
-
- template
- MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from);
-
- template
- MoveStack* generate_direct_checks(const Position&, MoveStack*, Color, Bitboard, Square);
-
- template<>
- inline MoveStack* generate_direct_checks(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) {
-
- return (us == WHITE ? generate_pawn_moves(p, m, dc, ksq)
- : generate_pawn_moves(p, m, dc, ksq));
- }
-}
+ template
+ ExtMove* generate_pawn_moves(const Position& pos, ExtMove* moveList, Bitboard target) {
-////
-//// Functions
-////
+ constexpr Color Them = ~Us;
+ constexpr Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
+ constexpr Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
+ constexpr Direction Up = pawn_push(Us);
+ constexpr Direction UpRight = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
+ constexpr Direction UpLeft = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
+ const Square ksq = pos.square(Them);
+ Bitboard emptySquares;
-/// generate_captures() generates all pseudo-legal captures and queen
-/// promotions. Returns a pointer to the end of the move list.
+ Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB;
+ Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB;
-MoveStack* generate_captures(const Position& pos, MoveStack* mlist) {
+ Bitboard enemies = (Type == EVASIONS ? pos.pieces(Them) & target:
+ Type == CAPTURES ? target : pos.pieces(Them));
- 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(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, target);
- return generate_piece_moves(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());
+ // Single and double pawn pushes, no promotions
+ if (Type != CAPTURES)
+ {
+ emptySquares = (Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces());
- Color us = pos.side_to_move();
- Bitboard target = pos.empty_squares();
-
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_castle_moves(pos, mlist);
- return generate_castle_moves(pos, mlist);
-}
+ Bitboard b1 = shift(pawnsNotOn7) & emptySquares;
+ Bitboard b2 = shift(b1 & TRank3BB) & emptySquares;
+ if (Type == EVASIONS) // Consider only blocking squares
+ {
+ b1 &= target;
+ b2 &= target;
+ }
-/// 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.
+ if (Type == QUIET_CHECKS)
+ {
+ b1 &= pawn_attacks_bb(Them, ksq);
+ b2 &= pawn_attacks_bb(Them, ksq);
+
+ // 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 discovered check
+ // promotion has been already generated amongst the captures.
+ Bitboard dcCandidateQuiets = pos.blockers_for_king(Them) & pawnsNotOn7;
+ if (dcCandidateQuiets)
+ {
+ Bitboard dc1 = shift(dcCandidateQuiets) & emptySquares & ~file_bb(ksq);
+ Bitboard dc2 = shift(dc1 & TRank3BB) & emptySquares;
-MoveStack* generate_non_capture_checks(const Position& pos, MoveStack* mlist) {
+ b1 |= dc1;
+ b2 |= dc2;
+ }
+ }
- assert(pos.is_ok());
- assert(!pos.is_check());
+ while (b1)
+ {
+ Square to = pop_lsb(&b1);
+ *moveList++ = make_move(to - Up, to);
+ }
- Color us = pos.side_to_move();
- Square ksq = pos.king_square(opposite_color(us));
- Bitboard dc = pos.discovered_check_candidates(us);
+ while (b2)
+ {
+ Square to = pop_lsb(&b2);
+ *moveList++ = make_move(to - Up - Up, to);
+ }
+ }
- assert(pos.piece_on(ksq) == piece_of_color_and_type(opposite_color(us), KING));
+ // Promotions and underpromotions
+ if (pawnsOn7)
+ {
+ if (Type == CAPTURES)
+ emptySquares = ~pos.pieces();
- // Discovered non-capture checks
- Bitboard b = dc;
- while (b)
- {
- Square 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(pos, mlist, from); break;
- case BISHOP: mlist = generate_discovered_checks(pos, mlist, from); break;
- case ROOK: mlist = generate_discovered_checks(pos, mlist, from); break;
- case KING: mlist = generate_discovered_checks(pos, mlist, from); break;
- default: assert(false); break;
- }
- }
+ if (Type == EVASIONS)
+ emptySquares &= target;
- // Direct non-capture checks
- mlist = generate_direct_checks(pos, mlist, us, dc, ksq);
- mlist = generate_direct_checks(pos, mlist, us, dc, ksq);
- mlist = generate_direct_checks(pos, mlist, us, dc, ksq);
- mlist = generate_direct_checks(pos, mlist, us, dc, ksq);
- return generate_direct_checks(pos, mlist, us, dc, ksq);
-}
+ Bitboard b1 = shift(pawnsOn7) & enemies;
+ Bitboard b2 = shift(pawnsOn7) & enemies;
+ Bitboard b3 = shift(pawnsOn7) & emptySquares;
+ while (b1)
+ moveList = make_promotions(moveList, pop_lsb(&b1), ksq);
-/// 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.
+ while (b2)
+ moveList = make_promotions(moveList, pop_lsb(&b2), ksq);
-MoveStack* generate_evasions(const Position& pos, MoveStack* mlist) {
+ while (b3)
+ moveList = make_promotions(moveList, pop_lsb(&b3), ksq);
+ }
- assert(pos.is_ok());
- assert(pos.is_check());
+ // Standard and en passant captures
+ if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
+ {
+ Bitboard b1 = shift(pawnsNotOn7) & enemies;
+ Bitboard b2 = shift(pawnsNotOn7) & enemies;
- Bitboard b;
- 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);
-
- // 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);
-
- assert(pos.color_of_piece_on(checksq) == opposite_color(us));
-
- 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(checksq);
- else
- sliderAttacks |= BishopPseudoAttacks[checksq] | pos.attacks_from(checksq);
- default:
- break;
- }
- } while (b);
+ while (b1)
+ {
+ Square to = pop_lsb(&b1);
+ *moveList++ = make_move(to - UpRight, to);
+ }
- // Generate evasions for king, capture and non capture moves
- b = pos.attacks_from(ksq) & ~pos.pieces_of_color(us) & ~sliderAttacks;
- from = ksq;
- SERIALIZE_MOVES(b);
-
- // Generate evasions for other pieces only if not double check
- if (checkersCnt > 1)
- return mlist;
-
- // Find squares where a blocking evasion or a capture of the
- // checker piece is possible.
- Bitboard target = squares_between(checksq, ksq) | checkers;
-
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, target);
- return generate_piece_moves(pos, mlist, us, target);
-}
+ while (b2)
+ {
+ Square to = pop_lsb(&b2);
+ *moveList++ = make_move(to - UpLeft, to);
+ }
+ if (pos.ep_square() != SQ_NONE)
+ {
+ assert(rank_of(pos.ep_square()) == relative_rank(Us, RANK_6));
-/// 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.
+ // An en passant capture cannot resolve a discovered check.
+ if (Type == EVASIONS && (target & (pos.ep_square() + Up)))
+ return moveList;
-MoveStack* generate_moves(const Position& pos, MoveStack* mlist, bool pseudoLegal) {
+ b1 = pawnsNotOn7 & pawn_attacks_bb(Them, pos.ep_square());
- assert(pos.is_ok());
+ assert(b1);
- MoveStack* last;
- Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
+ while (b1)
+ *moveList++ = make(pop_lsb(&b1), pos.ep_square());
+ }
+ }
- // Generate pseudo-legal moves
- if (pos.is_check())
- last = generate_evasions(pos, mlist);
- else {
- last = generate_captures(pos, mlist);
- last = generate_noncaptures(pos, last);
+ return moveList;
}
- if (pseudoLegal)
- return last;
-
- // Remove illegal moves from the list
- for (MoveStack* cur = mlist; cur != last; cur++)
- if (!pos.pl_move_is_legal(cur->move, pinned))
- {
- cur->move = (--last)->move;
- cur--;
- }
- return last;
-}
-/// 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.
+ template
+ ExtMove* generate_moves(const Position& pos, ExtMove* moveList, Bitboard piecesToMove, Bitboard target) {
-bool move_is_legal(const Position& pos, const Move m) {
+ static_assert(Pt != KING && Pt != PAWN, "Unsupported piece type in generate_moves()");
- MoveStack mlist[256];
- MoveStack* last = generate_moves(pos, mlist, true);
- for (MoveStack* cur = mlist; cur != last; cur++)
- if (cur->move == m)
- return pos.pl_move_is_legal(m, pos.pinned_pieces(pos.side_to_move()));
-
- return false;
-}
+ Bitboard bb = piecesToMove & pos.pieces(Pt);
+ if (!bb)
+ return moveList;
-/// 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.
-/// This version must only be used when the side to move is not in check.
+ [[maybe_unused]] const Bitboard checkSquares = pos.check_squares(Pt);
-bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
+ while (bb) {
+ Square from = pop_lsb(&bb);
- assert(pos.is_ok());
- assert(!pos.is_check());
- assert(move_is_ok(m));
- assert(pinned == pos.pinned_pieces(pos.side_to_move()));
+ Bitboard b = attacks_bb(from, pos.pieces()) & target;
+ if constexpr (Checks)
+ b &= checkSquares;
- // Use a slower but simpler function for uncommon cases
- if (move_is_ep(m) || move_is_castle(m))
- return move_is_legal(pos, m);
-
- 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);
-
- // 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;
-
- // A pawn move is a promotion iff the destination square is
- // on the 8/1th rank.
- if (( (square_rank(to) == RANK_8 && us == WHITE)
- ||(square_rank(to) == RANK_1 && us != WHITE)) != bool(move_is_promotion(m)))
- 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;
-
- case DELTA_N:
- case DELTA_S:
- // Pawn push. The destination square must be empty.
- if (!pos.square_is_empty(to))
- return false;
- break;
-
- 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;
-
- 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;
-
- default:
- return false;
- }
- // The move is pseudo-legal, check if it is also legal
- return pos.pl_move_is_legal(m, pinned);
- }
-
- // Luckly we can handle all the other pieces in one go
- return ( bit_is_set(pos.attacks_from(pc, from), to)
- && pos.pl_move_is_legal(m, pinned)
- && !move_is_promotion(m));
-}
-
-
-namespace {
-
- template
- MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
-
- Square from;
- Bitboard b;
- const Square* ptr = pos.piece_list_begin(us, Piece);
-
- while ((from = *ptr++) != SQ_NONE)
- {
- b = pos.attacks_from(from) & target;
- SERIALIZE_MOVES(b);
+ while (b)
+ *moveList++ = make_move(from, pop_lsb(&b));
}
- return mlist;
- }
- template<>
- MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
-
- Bitboard b;
- Square from = pos.king_square(us);
-
- b = pos.attacks_from(from) & target;
- SERIALIZE_MOVES(b);
- return mlist;
+ return moveList;
}
- template
- inline Bitboard move_pawns(Bitboard p) {
-
- 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
- inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard enemyPieces, bool possiblePromotion) {
+ template
+ ExtMove* generate_all(const Position& pos, ExtMove* moveList) {
- // 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);
+ static_assert(Type != LEGAL, "Unsupported type in generate_all()");
- Square to;
+ constexpr bool Checks = Type == QUIET_CHECKS; // Reduce template instantations
+ Bitboard target, piecesToMove = pos.pieces(Us);
- // Captures in the a1-h8 (a8-h1 for black) diagonal or in the h1-a8 (h8-a1 for black)
- Bitboard b1 = move_pawns(pawns) & ~TFileABB & enemyPieces;
+ if(Type == QUIET_CHECKS)
+ piecesToMove &= ~pos.blockers_for_king(~Us);
- // Capturing promotions and under-promotions
- if (possiblePromotion)
+ switch (Type)
{
- Bitboard b2 = b1 & TRank8BB;
- b1 &= ~TRank8BB;
- while (b2)
+ case CAPTURES:
+ target = pos.pieces(~Us);
+ break;
+ case QUIETS:
+ case QUIET_CHECKS:
+ target = ~pos.pieces();
+ break;
+ case EVASIONS:
{
- to = pop_1st_bit(&b2);
-
- if (Type == CAPTURE || Type == EVASION)
- (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, QUEEN);
-
- 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);
- }
-
- // 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);
+ Square checksq = lsb(pos.checkers());
+ target = between_bb(pos.square(Us), checksq) | checksq;
+ break;
}
+ case NON_EVASIONS:
+ target = ~pos.pieces(Us);
+ break;
}
- // Serialize standard captures
- if (Type == CAPTURE || Type == EVASION)
- SERIALIZE_MOVES_D(b1, -TTDELTA_NE);
+ moveList = generate_pawn_moves(pos, moveList, target);
+ moveList = generate_moves(pos, moveList, piecesToMove, target);
+ moveList = generate_moves(pos, moveList, piecesToMove, target);
+ moveList = generate_moves< ROOK, Checks>(pos, moveList, piecesToMove, target);
+ moveList = generate_moves< QUEEN, Checks>(pos, moveList, piecesToMove, target);
- return mlist;
- }
-
- template
- 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);
- bool possiblePromotion = pawns & TRank7BB;
-
- // Standard captures and capturing promotions and underpromotions
- if (Type == CAPTURE || Type == EVASION || possiblePromotion)
+ if (Type != QUIET_CHECKS && Type != EVASIONS)
{
- 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(mlist, pawns, enemyPieces, possiblePromotion);
- mlist = generate_pawn_captures(mlist, pawns, enemyPieces, possiblePromotion);
+ Square ksq = pos.square(Us);
+ Bitboard b = attacks_bb(ksq) & target;
+ while (b)
+ *moveList++ = make_move(ksq, pop_lsb(&b));
+
+ if ((Type != CAPTURES) && pos.can_castle(Us & ANY_CASTLING))
+ for (CastlingRights cr : { Us & KING_SIDE, Us & QUEEN_SIDE } )
+ if (!pos.castling_impeded(cr) && pos.can_castle(cr))
+ *moveList++ = make(ksq, pos.castling_rook_square(cr));
}
- // Non-capturing promotions and underpromotions
- if (possiblePromotion)
- {
- b1 = move_pawns(pawns) & TRank8BB & pos.empty_squares();
+ return moveList;
+ }
- if (Type == EVASION)
- b1 &= target; // Only blocking promotion pushes
+} // namespace
- while (b1)
- {
- to = pop_1st_bit(&b1);
- if (Type == CAPTURE || Type == EVASION)
- (*mlist++).move = make_promotion_move(to - TDELTA_N, to, QUEEN);
+/// Generates all pseudo-legal captures plus queen and checking knight promotions
+/// Generates all pseudo-legal non-captures and underpromotions(except checking knight)
+/// Generates all pseudo-legal captures and non-captures
+///
+/// Returns a pointer to the end of the move list.
- 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);
- }
+template
+ExtMove* generate(const Position& pos, ExtMove* moveList) {
- // 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(to), pos.king_square(Them)))
- (*mlist++).move = make_promotion_move(to - TDELTA_N, to, KNIGHT);
- }
- }
+ static_assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS, "Unsupported type in generate()");
+ assert(!pos.checkers());
- // Standard pawn pushes and double pushes
- if (Type != CAPTURE)
- {
- emptySquares = (Type == NON_CAPTURE ? target : pos.empty_squares());
-
- // Single and double pawn pushes
- b1 = move_pawns(pawns) & emptySquares & ~TRank8BB;
- b2 = move_pawns(b1 & TRank3BB) & emptySquares;
+ Color us = pos.side_to_move();
- // 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(ksq, Them);
- b2 &= pos.attacks_from(ksq, Them);
-
- // 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(pawns & target & ~file_bb(ksq)) & emptySquares & ~TRank8BB;
- Bitboard dc2 = move_pawns(dc1 & TRank3BB) & emptySquares;
+ return us == WHITE ? generate_all(pos, moveList)
+ : generate_all(pos, moveList);
+}
- b1 |= dc1;
- b2 |= dc2;
- }
- }
- SERIALIZE_MOVES_D(b1, -TDELTA_N);
- SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N);
- }
+// Explicit template instantiations
+template ExtMove* generate(const Position&, ExtMove*);
+template ExtMove* generate(const Position&, ExtMove*);
+template ExtMove* generate(const Position&, ExtMove*);
- // 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;
+/// generate generates all pseudo-legal non-captures.
+/// Returns a pointer to the end of the move list.
+template<>
+ExtMove* generate(const Position& pos, ExtMove* moveList) {
- b1 = pawns & pos.attacks_from(pos.ep_square(), Them);
+ assert(!pos.checkers());
- assert(b1 != EmptyBoardBB);
+ Color us = pos.side_to_move();
+ Bitboard dc = pos.blockers_for_king(~us) & pos.pieces(us) & ~pos.pieces(PAWN);
- while (b1)
- {
- to = pop_1st_bit(&b1);
- (*mlist++).move = make_ep_move(to, pos.ep_square());
- }
- }
- return mlist;
- }
+ while (dc)
+ {
+ Square from = pop_lsb(&dc);
+ PieceType pt = type_of(pos.piece_on(from));
- template
- MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) {
+ Bitboard b = attacks_bb(pt, from, pos.pieces()) & ~pos.pieces();
- assert(Piece != QUEEN);
+ if (pt == KING)
+ b &= ~attacks_bb(pos.square(~us));
- Bitboard b = pos.attacks_from(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;
+ while (b)
+ *moveList++ = make_move(from, pop_lsb(&b));
}
- template
- MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us,
- Bitboard dc, Square ksq) {
- assert(Piece != KING);
-
- Square from;
- Bitboard checkSqs;
- const Square* ptr = pos.piece_list_begin(us, Piece);
-
- if ((from = *ptr++) == SQ_NONE)
- return mlist;
-
- checkSqs = pos.attacks_from(ksq) & pos.empty_squares();
-
- do
- {
- if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs))
- || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs))
- || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
- continue;
-
- if (dc && bit_is_set(dc, from))
- continue;
+ return us == WHITE ? generate_all(pos, moveList)
+ : generate_all(pos, moveList);
+}
- Bitboard bb = pos.attacks_from(from) & checkSqs;
- SERIALIZE_MOVES(bb);
- } while ((from = *ptr++) != SQ_NONE);
+/// generate 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<>
+ExtMove* generate(const Position& pos, ExtMove* moveList) {
- return mlist;
- }
+ assert(pos.checkers());
- template
- MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist) {
-
- Color us = pos.side_to_move();
+ Color us = pos.side_to_move();
+ Square ksq = pos.square(us);
+ Bitboard sliderAttacks = 0;
+ Bitboard sliders = pos.checkers() & ~pos.pieces(KNIGHT, PAWN);
- 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);
+ // Find all the squares attacked by slider checkers. We will remove them from
+ // the king evasions in order to skip known illegal moves, which avoids any
+ // useless legality checks later on.
+ while (sliders)
+ sliderAttacks |= line_bb(ksq, pop_lsb(&sliders)) & ~pos.checkers();
- assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
+ // Generate evasions for king, capture and non capture moves
+ Bitboard b = attacks_bb(ksq) & ~pos.pieces(us) & ~sliderAttacks;
+ while (b)
+ *moveList++ = make_move(ksq, pop_lsb(&b));
- 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;
+ if (more_than_one(pos.checkers()))
+ return moveList; // Double check, only a king move can save the day
- assert(pos.piece_on(rsq) == piece_of_color_and_type(us, ROOK));
+ // Generate blocking evasions or captures of the checking piece
+ return us == WHITE ? generate_all(pos, moveList)
+ : generate_all(pos, moveList);
+}
- // 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;
- for (s = Min(rsq, s2); s <= Max(rsq, s2); s++)
- if (s != ksq && s != rsq && pos.square_is_occupied(s))
- illegal = true;
+/// generate generates all the legal moves in the given position
- 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;
+template<>
+ExtMove* generate(const Position& pos, ExtMove* moveList) {
- if (!illegal)
- (*mlist++).move = make_castle_move(ksq, rsq);
- }
- return mlist;
- }
+ Color us = pos.side_to_move();
+ Bitboard pinned = pos.blockers_for_king(us) & pos.pieces(us);
+ Square ksq = pos.square(us);
+ ExtMove* cur = moveList;
+
+ moveList = pos.checkers() ? generate(pos, moveList)
+ : generate(pos, moveList);
+ while (cur != moveList)
+ if ( (pinned || from_sq(*cur) == ksq || type_of(*cur) == EN_PASSANT)
+ && !pos.legal(*cur))
+ *cur = (--moveList)->move;
+ else
+ ++cur;
+
+ return moveList;
}