X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=be848cf1a6acb370e1ddf262b4f79762ba187f56;hp=b130247bea5f151cd810ec3e73ddd8b1a1204a83;hb=22a5f91aa79e065387e780bbffc1bbadfd84e8d6;hpb=57b3ca916fdf12ad4ad3dfdcd215379e908b12be
diff --git a/src/movegen.cpp b/src/movegen.cpp
index b130247b..be848cf1 100644
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -1,7 +1,7 @@
/*
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
@@ -17,650 +17,429 @@
along with this program. If not, see .
*/
-
-////
-//// Includes
-////
-
#include
-#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_lsb(&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_lsb(&b); \
+ (*mlist++).move = make_move(to - (d), to); }
namespace {
- enum CastlingSide {
- KING_SIDE,
- QUEEN_SIDE
- };
+ template
+ MoveStack* generate_castle(const Position& pos, MoveStack* mlist, Color us) {
- template
- MoveStack* generate_castle_moves(const Position&, MoveStack*);
-
- template
- MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square);
-
- template
- inline MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) {
+ if (pos.castle_impeded(us, Side) || !pos.can_castle(make_castle_right(us, Side)))
+ return mlist;
- assert(Piece != QUEEN);
+ // 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 rfrom = pos.castle_rook_square(us, Side);
+ Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1);
+ Bitboard enemies = pos.pieces(~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;
- }
+ assert(!pos.in_check());
- template
- inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us,
- Bitboard dc, Square ksq) {
- assert(Piece != KING);
+ const int K = Chess960 ? kto > kfrom ? -1 : 1
+ : Side == KING_SIDE ? -1 : 1;
- Bitboard checkSqs, b;
- Square from;
- const Square* ptr = pos.piece_list_begin(us, Piece);
+ for (Square s = kto; s != kfrom; s += (Square)K)
+ if (pos.attackers_to(s) & enemies)
+ return mlist;
- if ((from = *ptr++) == SQ_NONE)
+ // 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 (Chess960 && (pos.attackers_to(kto, pos.pieces() ^ rfrom) & enemies))
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;
+ (*mlist++).move = make(kfrom, rfrom);
- if (dc && bit_is_set(dc, from))
- continue;
-
- b = pos.attacks_from(from) & checkSqs;
- SERIALIZE_MOVES(b);
-
- } while ((from = *ptr++) != SQ_NONE);
+ if (Checks && !pos.move_gives_check((mlist - 1)->move, CheckInfo(pos)))
+ mlist--;
return mlist;
}
- 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
- inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) {
-
- assert(Piece == PAWN);
- assert(Type == MV_CAPTURE || Type == MV_NON_CAPTURE || Type == MV_EVASION);
+ template
+ inline Bitboard move_pawns(Bitboard p) {
- return (us == WHITE ? generate_pawn_moves(p, m, t, SQ_NONE)
- : generate_pawn_moves(p, m, t, SQ_NONE));
+ 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;
}
- template
- inline MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
- Bitboard b;
- Square from;
- const Square* ptr = pos.piece_list_begin(us, Piece);
+ template
+ inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7,
+ Bitboard target, const CheckInfo* ci) {
+
+ Bitboard b = move_pawns(pawnsOn7) & target;
- if (*ptr != SQ_NONE)
+ while (b)
{
- do {
- from = *ptr;
- b = pos.attacks_from(from) & target;
- SERIALIZE_MOVES(b);
- } while (*++ptr != SQ_NONE);
- }
- return mlist;
- }
+ Square to = pop_lsb(&b);
- template<>
- inline MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
+ if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
+ (*mlist++).move = make(to - Delta, to, QUEEN);
- Bitboard b;
- Square from = pos.king_square(us);
+ if (Type == QUIETS || Type == EVASIONS || Type == NON_EVASIONS)
+ {
+ (*mlist++).move = make(to - Delta, to, ROOK);
+ (*mlist++).move = make(to - Delta, to, BISHOP);
+ (*mlist++).move = make(to - Delta, to, KNIGHT);
+ }
+
+ // 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] & ci->ksq))
+ (*mlist++).move = make(to - Delta, to, KNIGHT);
+ else
+ (void)ci; // Silence a warning under MSVC
+ }
- b = pos.attacks_from(from) & target;
- SERIALIZE_MOVES(b);
return mlist;
}
-}
-////
-//// Functions
-////
-
-
-/// generate generates all pseudo-legal captures and queen
-/// promotions. Returns a pointer to the end of the move list.
-///
-/// generate generates all pseudo-legal non-captures and
-/// underpromotions. Returns a pointer to the end of the move list.
-///
-/// generate generates all pseudo-legal captures and
-/// non-captures. Returns a pointer to the end of the move list.
+ template
+ MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist,
+ Bitboard target, const CheckInfo* ci) {
-template
-MoveStack* generate(const Position& pos, MoveStack* mlist) {
+ // 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);
- assert(pos.is_ok());
- assert(!pos.is_check());
+ Bitboard b1, b2, dc1, dc2, emptySquares;
- Color us = pos.side_to_move();
- Bitboard target;
+ Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB;
+ Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB;
- if (T == MV_CAPTURE || T == MV_NON_EVASION)
- target = pos.pieces_of_color(opposite_color(us));
- else if (T == MV_NON_CAPTURE)
- target = pos.empty_squares();
- else
- assert(false);
+ Bitboard enemies = (Type == EVASIONS ? pos.pieces(Them) & target:
+ Type == CAPTURES ? target : pos.pieces(Them));
- if (T == MV_NON_EVASION)
- {
- mlist = generate_piece_moves(pos, mlist, us, target);
- mlist = generate_piece_moves(pos, mlist, us, pos.empty_squares());
- target |= pos.empty_squares();
- }
- else
- mlist = generate_piece_moves(pos, mlist, us, target);
+ // Single and double pawn pushes, no promotions
+ if (Type != CAPTURES)
+ {
+ emptySquares = (Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces());
- 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);
+ b1 = move_pawns(pawnsNotOn7) & emptySquares;
+ b2 = move_pawns(b1 & TRank3BB) & emptySquares;
- if (T != MV_CAPTURE)
- {
- mlist = generate_castle_moves(pos, mlist);
- mlist = generate_castle_moves(pos, mlist);
- }
-
- return mlist;
-}
-
-// Explicit template instantiation
-template MoveStack* generate(const Position& pos, MoveStack* mlist);
-template MoveStack* generate(const Position& pos, MoveStack* mlist);
-template MoveStack* generate(const Position& pos, MoveStack* mlist);
+ if (Type == EVASIONS) // Consider only blocking squares
+ {
+ b1 &= target;
+ b2 &= target;
+ }
+ if (Type == QUIET_CHECKS)
+ {
+ b1 &= pos.attacks_from(ci->ksq, Them);
+ b2 &= pos.attacks_from(ci->ksq, Them);
-/// 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<>
-MoveStack* generate(const Position& pos, MoveStack* mlist) {
+ // 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 & ci->dcCandidates)
+ {
+ dc1 = move_pawns(pawnsNotOn7 & ci->dcCandidates) & emptySquares & ~file_bb(ci->ksq);
+ dc2 = move_pawns(dc1 & TRank3BB) & emptySquares;
- assert(pos.is_ok());
- assert(!pos.is_check());
+ b1 |= dc1;
+ b2 |= dc2;
+ }
+ }
- Bitboard b, dc;
- Square from;
- Color us = pos.side_to_move();
- Square ksq = pos.king_square(opposite_color(us));
+ SERIALIZE_PAWNS(b1, UP);
+ SERIALIZE_PAWNS(b2, UP + UP);
+ }
- assert(pos.piece_on(ksq) == piece_of_color_and_type(opposite_color(us), KING));
+ // Promotions and underpromotions
+ if (pawnsOn7 && (Type != EVASIONS || (target & TRank8BB)))
+ {
+ if (Type == CAPTURES)
+ emptySquares = ~pos.pieces();
- // Discovered non-capture checks
- b = dc = pos.discovered_check_candidates(us);
+ if (Type == EVASIONS)
+ emptySquares &= target;
- 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(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;
- }
- }
+ mlist = generate_promotions(mlist, pawnsOn7, enemies, ci);
+ mlist = generate_promotions(mlist, pawnsOn7, enemies, ci);
+ mlist = generate_promotions(mlist, pawnsOn7, emptySquares, ci);
+ }
- // 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);
-}
+ // Standard and en-passant captures
+ if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
+ {
+ b1 = move_pawns(pawnsNotOn7) & enemies;
+ b2 = move_pawns(pawnsNotOn7) & enemies;
+ SERIALIZE_PAWNS(b1, RIGHT);
+ SERIALIZE_PAWNS(b2, LEFT);
-/// 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.
-template<>
-MoveStack* generate(const Position& pos, MoveStack* mlist) {
+ if (pos.ep_square() != SQ_NONE)
+ {
+ assert(rank_of(pos.ep_square()) == relative_rank(Us, RANK_6));
- assert(pos.is_ok());
- assert(pos.is_check());
+ // 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 == EVASIONS && !(target & (pos.ep_square() - UP)))
+ return mlist;
- 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;
+ b1 = pawnsNotOn7 & pos.attacks_from(pos.ep_square(), Them);
- assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
- assert(checkers);
+ assert(b1);
- // 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);
+ while (b1)
+ (*mlist++).move = make(pop_lsb(&b1), pos.ep_square());
+ }
+ }
- assert(pos.color_of_piece_on(checksq) == opposite_color(us));
+ return mlist;
+ }
- 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 (RookPseudoAttacks[checksq] & (1ULL << ksq))
- sliderAttacks |= RookPseudoAttacks[checksq] | pos.attacks_from(checksq);
- else
- sliderAttacks |= BishopPseudoAttacks[checksq] | pos.attacks_from(checksq);
- default:
- break;
- }
- } while (b);
- // 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);
+ template FORCE_INLINE
+ MoveStack* generate_moves(const Position& pos, MoveStack* mlist, Color us,
+ Bitboard target, const CheckInfo* ci) {
- // Generate evasions for other pieces only if not double check
- if (checkersCnt > 1)
- return mlist;
+ assert(Pt != KING && Pt != PAWN);
- // Find squares where a blocking evasion or a capture of the
- // checker piece is possible.
- target = squares_between(checksq, ksq) | checkers;
+ const Square* pl = pos.piece_list(us, Pt);
- 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);
-}
+ for (Square from = *pl; from != SQ_NONE; from = *++pl)
+ {
+ if (Checks)
+ {
+ if ( (Pt == BISHOP || Pt == ROOK || Pt == QUEEN)
+ && !(PseudoAttacks[Pt][from] & target & ci->checkSq[Pt]))
+ continue;
+ if (ci->dcCandidates && (ci->dcCandidates & from))
+ continue;
+ }
-/// generate computes a complete list of legal
-/// or pseudo-legal moves in the current position.
-template<>
-inline MoveStack* generate(const Position& pos, MoveStack* mlist) {
+ Bitboard b = pos.attacks_from(from) & target;
- assert(pos.is_ok());
+ if (Checks)
+ b &= ci->checkSq[Pt];
- return pos.is_check() ? generate(pos, mlist)
- : generate(pos, mlist);
-}
+ SERIALIZE(b);
+ }
-template<>
-MoveStack* generate(const Position& pos, MoveStack* mlist) {
+ return mlist;
+ }
- assert(pos.is_ok());
- MoveStack *last, *cur = mlist;
- Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
+ 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;
+ }
- last = generate(pos, mlist);
- // Remove illegal moves from the list
- while (cur != last)
- if (pos.pl_move_is_legal(cur->move, pinned))
- cur++;
- else
- cur->move = (--last)->move;
+ template FORCE_INLINE
+ MoveStack* generate_all_moves(const Position& pos, MoveStack* mlist, Color us,
+ Bitboard target, const CheckInfo* ci = NULL) {
- return last;
-}
+ 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);
-/// 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.
+ if (Type != QUIET_CHECKS && Type != EVASIONS)
+ mlist = generate_king_moves(pos, mlist, us, target);
-bool move_is_legal(const Position& pos, const Move m) {
+ if (Type != CAPTURES && Type != EVASIONS && pos.can_castle(us))
+ {
+ if (pos.is_chess960())
+ {
+ mlist = generate_castle(pos, mlist, us);
+ mlist = generate_castle(pos, mlist, us);
+ }
+ else
+ {
+ mlist = generate_castle(pos, mlist, us);
+ mlist = generate_castle(pos, mlist, us);
+ }
+ }
- MoveStack mlist[MOVES_MAX];
- MoveStack *cur, *last = generate(pos, mlist);
+ return mlist;
+ }
- for (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;
-}
+} // namespace
-/// 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.
+/// generate generates all pseudo-legal captures and queen
+/// promotions. Returns a pointer to the end of the move list.
+///
+/// generate generates all pseudo-legal non-captures and
+/// underpromotions. Returns a pointer to the end of the move list.
+///
+/// generate generates all pseudo-legal captures and
+/// non-captures. Returns a pointer to the end of the move list.
-bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
+template
+MoveStack* generate(const Position& pos, MoveStack* mlist) {
- assert(pos.is_ok());
- assert(pinned == pos.pinned_pieces(pos.side_to_move()));
+ assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS);
+ assert(!pos.in_check());
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;
-
- case DELTA_N:
- case DELTA_S:
- // Pawn push. The destination square must be empty.
- if (!pos.square_is_empty(to))
- return false;
- break;
+ Bitboard target;
- 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 (Type == CAPTURES)
+ target = pos.pieces(~us);
- 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;
+ else if (Type == QUIETS)
+ target = ~pos.pieces();
- default:
- return false;
- }
- }
- else if (!bit_is_set(pos.attacks_from(pc, from), to))
- return false;
+ else if (Type == NON_EVASIONS)
+ target = ~pos.pieces(us);
- // 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);
+ return generate_all_moves(pos, mlist, us, target);
}
+// Explicit template instantiations
+template MoveStack* generate(const Position&, MoveStack*);
+template MoveStack* generate(const Position&, MoveStack*);
+template MoveStack* generate(const Position&, MoveStack*);
-namespace {
-
- template
- inline Bitboard move_pawns(Bitboard p) {
-
- return Delta == DELTA_N ? p << 8 : Delta == DELTA_S ? p >> 8 :
- Delta == DELTA_NE ? p << 9 : Delta == DELTA_SE ? p >> 7 :
- Delta == DELTA_NW ? p << 7 : Delta == DELTA_SW ? p >> 9 : p;
- }
-
- template
- inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard target) {
-
- const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB);
- Bitboard b;
- Square to;
-
- // Captures in the a1-h8 (a8-h1 for black) diagonal or in the h1-a8 (h8-a1 for black)
- b = move_pawns(pawns) & target & ~TFileABB;
- SERIALIZE_MOVES_D(b, -Delta);
- return mlist;
- }
-
- template
- inline MoveStack* generate_promotions(const Position& pos, MoveStack* mlist, Bitboard pawnsOn7, Bitboard target) {
-
- const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB);
+/// generate 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(const Position& pos, MoveStack* mlist) {
- Bitboard b;
- Square to;
+ assert(!pos.in_check());
- // Promotions and under-promotions, both captures and non-captures
- b = move_pawns(pawnsOn7) & target;
+ Color us = pos.side_to_move();
+ CheckInfo ci(pos);
+ Bitboard dc = ci.dcCandidates;
- if (Delta != DELTA_N && Delta != DELTA_S)
- b &= ~TFileABB;
+ while (dc)
+ {
+ Square from = pop_lsb(&dc);
+ PieceType pt = type_of(pos.piece_on(from));
- while (b)
- {
- to = pop_1st_bit(&b);
+ if (pt == PAWN)
+ continue; // Will be generated togheter with direct checks
- if (Type == MV_CAPTURE || Type == MV_EVASION)
- (*mlist++).move = make_promotion_move(to - Delta, to, QUEEN);
+ Bitboard b = pos.attacks_from(Piece(pt), from) & ~pos.pieces();
- if (Type == MV_NON_CAPTURE || Type == MV_EVASION)
- {
- (*mlist++).move = make_promotion_move(to - Delta, to, ROOK);
- (*mlist++).move = make_promotion_move(to - Delta, to, BISHOP);
- (*mlist++).move = make_promotion_move(to - Delta, to, KNIGHT);
- }
+ if (pt == KING)
+ b &= ~PseudoAttacks[QUEEN][ci.ksq];
- // This is the only possible under promotion that can give a check
- // not already included in the queen-promotion.
- if ( Type == MV_CHECK
- && bit_is_set(pos.attacks_from(to), pos.king_square(opposite_color(Us))))
- (*mlist++).move = make_promotion_move(to - Delta, to, KNIGHT);
- else (void)pos; // Silence a warning under MSVC
- }
- return mlist;
+ SERIALIZE(b);
}
- template
- MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, Square ksq) {
-
- // Calculate 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 TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
- const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
- const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
- const SquareDelta TDELTA_NE = (Us == WHITE ? DELTA_NE : DELTA_SE);
- const SquareDelta TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW);
-
- Square to;
- Bitboard b1, b2, dc1, dc2, pawnPushes, emptySquares;
- Bitboard pawns = pos.pieces(PAWN, Us);
- Bitboard pawnsOn7 = pawns & TRank7BB;
- Bitboard enemyPieces = (Type == MV_CAPTURE ? target : pos.pieces_of_color(Them));
-
- // Pre-calculate pawn pushes before changing emptySquares definition
- if (Type != MV_CAPTURE)
- {
- emptySquares = (Type == MV_NON_CAPTURE ? target : pos.empty_squares());
- pawnPushes = move_pawns(pawns & ~TRank7BB) & emptySquares;
- }
-
- if (Type == MV_EVASION)
- {
- emptySquares &= target; // Only blocking squares
- enemyPieces &= target; // Capture only the checker piece
- }
-
- // Promotions and underpromotions
- if (pawnsOn7)
- {
- if (Type == MV_CAPTURE)
- emptySquares = pos.empty_squares();
-
- pawns &= ~TRank7BB;
- mlist = generate_promotions(pos, mlist, pawnsOn7, enemyPieces);
- mlist = generate_promotions(pos, mlist, pawnsOn7, enemyPieces);
- mlist = generate_promotions(pos, mlist, pawnsOn7, emptySquares);
- }
-
- // Standard captures
- if (Type == MV_CAPTURE || Type == MV_EVASION)
- {
- mlist = generate_pawn_captures(mlist, pawns, enemyPieces);
- mlist = generate_pawn_captures(mlist, pawns, enemyPieces);
- }
+ return generate_all_moves(pos, mlist, us, ~pos.pieces(), &ci);
+}
- // Single and double pawn pushes
- if (Type != MV_CAPTURE)
- {
- b1 = pawnPushes & emptySquares;
- b2 = move_pawns(pawnPushes & TRank3BB) & emptySquares;
- if (Type == MV_CHECK)
- {
- // Consider only pawn moves which give direct checks
- b1 &= pos.attacks_from(ksq, Them);
- b2 &= pos.attacks_from(ksq, Them);
-
- // Add 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
- {
- dc1 = move_pawns(pawns & target & ~file_bb(ksq)) & emptySquares;
- dc2 = move_pawns(dc1 & TRank3BB) & emptySquares;
+/// 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<>
+MoveStack* generate(const Position& pos, MoveStack* mlist) {
- b1 |= dc1;
- b2 |= dc2;
- }
- }
- SERIALIZE_MOVES_D(b1, -TDELTA_N);
- SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N);
- }
+ assert(pos.in_check());
- // En passant captures
- if ((Type == MV_CAPTURE || Type == MV_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 == MV_EVASION && !bit_is_set(target, pos.ep_square() - TDELTA_N))
- return mlist;
+ Square from, checksq;
+ int checkersCnt = 0;
+ Color us = pos.side_to_move();
+ Square ksq = pos.king_square(us);
+ Bitboard sliderAttacks = 0;
+ Bitboard b = pos.checkers();
- b1 = pawns & pos.attacks_from(pos.ep_square(), Them);
+ assert(pos.checkers());
- assert(b1 != EmptyBoardBB);
+ // 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.
+ do
+ {
+ checkersCnt++;
+ checksq = pop_lsb(&b);
- while (b1)
- {
- to = pop_1st_bit(&b1);
- (*mlist++).move = make_ep_move(to, pos.ep_square());
- }
- }
- return mlist;
- }
+ assert(color_of(pos.piece_on(checksq)) == ~us);
- template
- MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist) {
+ 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 (between_bb(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(checksq);
- Color us = pos.side_to_move();
+ default:
+ break;
+ }
+ } while (b);
- 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);
+ // Generate evasions for king, capture and non capture moves
+ b = pos.attacks_from(ksq) & ~pos.pieces(us) & ~sliderAttacks;
+ from = ksq;
+ SERIALIZE(b);
- assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
+ if (checkersCnt > 1)
+ return mlist; // Double check, only a king move can save the day
- 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;
+ // Generate blocking evasions or captures of the checking piece
+ Bitboard target = between_bb(checksq, ksq) | pos.checkers();
- assert(pos.piece_on(rsq) == piece_of_color_and_type(us, ROOK));
+ return generate_all_moves(pos, mlist, us, target);
+}
- // 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<>
+MoveStack* generate(const Position& pos, MoveStack* mlist) {
+
+ MoveStack *end, *cur = mlist;
+ Bitboard pinned = pos.pinned_pieces();
+ Square ksq = pos.king_square(pos.side_to_move());
+
+ end = pos.in_check() ? generate(pos, mlist)
+ : generate(pos, mlist);
+ while (cur != end)
+ if ( (pinned || from_sq(cur->move) == ksq || type_of(cur->move) == ENPASSANT)
+ && !pos.pl_move_is_legal(cur->move, pinned))
+ cur->move = (--end)->move;
+ else
+ cur++;
- if (!illegal)
- (*mlist++).move = make_castle_move(ksq, rsq);
- }
- return mlist;
- }
+ return end;
}