X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fmovegen.cpp;h=6f932cd05de6befd53b89737c5e0aadae1cdb516;hb=ee0afea1e57e4c39140c838b9f9f2d5c7c061e6b;hp=d942d9c290c47abc77f90b770f49f4cc56fc7162;hpb=8e85aa3a65f75de20167c2194c95e44bdc0c910e;p=stockfish
diff --git a/src/movegen.cpp b/src/movegen.cpp
index d942d9c2..6f932cd0 100644
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -1,17 +1,18 @@
/*
- Glaurung, a UCI chess playing engine.
- Copyright (C) 2004-2008 Tord Romstad
+ 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
- Glaurung is free software: you can redistribute it and/or modify
+ Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
-
- Glaurung is distributed in the hope that it will be useful,
+
+ Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
-
+
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
@@ -23,8 +24,16 @@
#include
+#include "bitcount.h"
#include "movegen.h"
+#include "types.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
@@ -32,461 +41,375 @@
namespace {
- inline Bitboard forward_white(Bitboard b) { return b << 8; }
- inline Bitboard forward_right_white(Bitboard b) { return b << 9; }
- inline Bitboard forward_left_white(Bitboard b) { return b << 7; }
+ enum CastlingSide {
+ KING_SIDE,
+ QUEEN_SIDE
+ };
- inline Bitboard forward_black(Bitboard b) { return b >> 8; }
- inline Bitboard forward_right_black(Bitboard b) { return b >> 7; }
- inline Bitboard forward_left_black(Bitboard b) { return b >> 9; }
+ template
+ MoveStack* generate_castle_moves(const Position&, MoveStack*, Color us);
- struct PawnOffsets {
+ template
+ MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square);
- Bitboard Rank3BB, Rank8BB;
- Rank RANK_8;
- SquareDelta DELTA_N, DELTA_NE, DELTA_NW;
- Color us, them;
- typedef Bitboard (*Shift_fn)(Bitboard b);
- Shift_fn forward, forward_left, forward_right;
- };
+ template
+ inline MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) {
- const PawnOffsets WhitePawnOffsets = { Rank3BB, Rank8BB, RANK_8, DELTA_N, DELTA_NE, DELTA_NW, WHITE, BLACK,
- &forward_white, forward_left_white, forward_right_white };
-
- const PawnOffsets BlackPawnOffsets = { Rank6BB, Rank1BB, RANK_1, DELTA_S, DELTA_SE, DELTA_SW, BLACK, WHITE,
- &forward_black, &forward_left_black, &forward_right_black };
-
- int generate_pawn_captures(const PawnOffsets&, const Position&, MoveStack*);
- int generate_pawn_noncaptures(const PawnOffsets&, const Position&, MoveStack*);
- int generate_pawn_checks(const PawnOffsets&, const Position&, Bitboard, Square, MoveStack*, int);
- int generate_piece_checks(PieceType, const Position&, Bitboard, Bitboard, Square, MoveStack*, int);
- int generate_piece_moves(PieceType, const Position&, MoveStack*, Color, Bitboard);
- int generate_castle_moves(const Position&, MoveStack*, Color);
- int generate_piece_blocking_evasions(PieceType, const Position&, Bitboard, Bitboard, MoveStack*, int);
- int generate_pawn_blocking_evasions(const PawnOffsets&, const Position&, Bitboard, Bitboard, MoveStack*, int);
-}
+ assert(Piece != QUEEN);
+ 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;
+ }
-////
-//// Functions
-////
+ template
+ inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us,
+ Bitboard dc, Square ksq) {
+ assert(Piece != KING);
+ Bitboard checkSqs, b;
+ Square from;
+ const Square* ptr = pos.piece_list_begin(us, Piece);
-/// generate_captures generates() all pseudo-legal captures and queen
-/// promotions. The return value is the number of moves generated.
+ if ((from = *ptr++) == SQ_NONE)
+ return mlist;
-int generate_captures(const Position& pos, MoveStack* mlist) {
+ checkSqs = pos.attacks_from(ksq) & pos.empty_squares();
- assert(pos.is_ok());
- assert(!pos.is_check());
+ do
+ {
+ if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs))
+ || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs))
+ || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
+ continue;
- Color us = pos.side_to_move();
- Bitboard target = pos.pieces_of_color(opposite_color(us));
- int n;
+ if (dc && bit_is_set(dc, from))
+ continue;
- if (us == WHITE)
- n = generate_pawn_captures(WhitePawnOffsets, pos, mlist);
- else
- n = generate_pawn_captures(BlackPawnOffsets, pos, mlist);
+ b = pos.attacks_from(from) & checkSqs;
+ SERIALIZE_MOVES(b);
- for (PieceType pce = KNIGHT; pce <= KING; pce++)
- n += generate_piece_moves(pce, pos, mlist+n, us, target);
+ } while ((from = *ptr++) != SQ_NONE);
- return n;
-}
+ return mlist;
+ }
+ template<>
+ FORCE_INLINE MoveStack* generate_direct_checks(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) {
-/// generate_noncaptures() generates all pseudo-legal non-captures and
-/// underpromotions. The return value is the number of moves generated.
+ return (us == WHITE ? generate_pawn_moves(p, m, dc, ksq)
+ : generate_pawn_moves(p, m, dc, ksq));
+ }
-int generate_noncaptures(const Position& pos, MoveStack *mlist) {
+ template
+ FORCE_INLINE MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) {
- assert(pos.is_ok());
- assert(!pos.is_check());
+ assert(Piece == PAWN);
+ assert(Type == MV_CAPTURE || Type == MV_NON_CAPTURE || Type == MV_EVASION);
- Color us = pos.side_to_move();
- Bitboard target = pos.empty_squares();
- int n;
+ return (us == WHITE ? generate_pawn_moves(p, m, t, SQ_NONE)
+ : generate_pawn_moves(p, m, t, SQ_NONE));
+ }
- if (us == WHITE)
- n = generate_pawn_noncaptures(WhitePawnOffsets, pos, mlist);
- else
- n = generate_pawn_noncaptures(BlackPawnOffsets, pos, mlist);
+ template
+ FORCE_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);
- for (PieceType pce = KNIGHT; pce <= KING; pce++)
- n += generate_piece_moves(pce, pos, mlist+n, us, target);
+ if (*ptr != SQ_NONE)
+ {
+ do {
+ from = *ptr;
+ b = pos.attacks_from(from) & target;
+ SERIALIZE_MOVES(b);
+ } while (*++ptr != SQ_NONE);
+ }
+ return mlist;
+ }
+
+ template<>
+ FORCE_INLINE 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;
+ }
- n += generate_castle_moves(pos, mlist+n, us);
- return n;
}
+////
+//// Functions
+////
+
-/// generate_checks() generates all pseudo-legal non-capturing, non-promoting
-/// checks, except castling moves (will add this later). It returns the
-/// number of generated moves.
+/// 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.
-int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
+template
+MoveStack* generate(const Position& pos, MoveStack* mlist) {
assert(pos.is_ok());
assert(!pos.is_check());
- int n;
Color us = pos.side_to_move();
- Square ksq = pos.king_square(opposite_color(us));
-
- assert(pos.piece_on(ksq) == king_of_color(opposite_color(us)));
+ Bitboard target;
- dc = pos.discovered_check_candidates(us);
-
- // Pawn moves
- if (us == WHITE)
- n = generate_pawn_checks(WhitePawnOffsets, pos, dc, ksq, mlist, 0);
+ if (Type == MV_CAPTURE || Type == MV_NON_EVASION)
+ target = pos.pieces_of_color(opposite_color(us));
+ else if (Type == MV_NON_CAPTURE)
+ target = pos.empty_squares();
else
- n = generate_pawn_checks(BlackPawnOffsets, pos, dc, ksq, mlist, 0);
-
- // Pieces moves
- Bitboard b = pos.knights(us);
- if (b)
- n = generate_piece_checks(KNIGHT, pos, b, dc, ksq, mlist, n);
+ assert(false);
- b = pos.bishops(us);
- if (b)
- n = generate_piece_checks(BISHOP, pos, b, dc, ksq, mlist, n);
-
- b = pos.rooks(us);
- if (b)
- n = generate_piece_checks(ROOK, pos, b, dc, ksq, mlist, n);
+ if (Type == 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);
- b = pos.queens(us);
- if (b)
- n = generate_piece_checks(QUEEN, pos, b, dc, ksq, mlist, n);
+ 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);
- // King moves
- Square from = pos.king_square(us);
- if (bit_is_set(dc, from))
+ if (Type != MV_CAPTURE)
{
- b = pos.king_attacks(from) & pos.empty_squares() & ~QueenPseudoAttacks[ksq];
- while (b)
- {
- Square to = pop_1st_bit(&b);
- mlist[n++].move = make_move(from, to);
- }
+ if (pos.can_castle_kingside(us))
+ mlist = generate_castle_moves(pos, mlist, us);
+
+ if (pos.can_castle_queenside(us))
+ mlist = generate_castle_moves(pos, mlist, us);
}
- // TODO: Castling moves!
-
- return n;
+ 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);
-/// generate_evasions() generates all check evasions when the side to move is
-/// in check. Unlike the other move generation functions, this one generates
-/// only legal moves. It returns the number of generated moves. This
-/// function is very ugly, and needs cleaning up some time later. FIXME
-int generate_evasions(const Position& pos, MoveStack* mlist) {
+/// 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) {
assert(pos.is_ok());
- assert(pos.is_check());
+ assert(!pos.is_check());
+ Bitboard b, dc;
+ Square from;
Color us = pos.side_to_move();
- Color them = opposite_color(us);
- Square ksq = pos.king_square(us);
- Square from, to;
- int n = 0;
+ Square ksq = pos.king_square(opposite_color(us));
- assert(pos.piece_on(ksq) == king_of_color(us));
-
- // Generate evasions for king
- Bitboard b1 = pos.king_attacks(ksq) & ~pos.pieces_of_color(us);
- Bitboard b2 = pos.occupied_squares();
- clear_bit(&b2, ksq);
+ assert(pos.piece_on(ksq) == piece_of_color_and_type(opposite_color(us), KING));
- while (b1)
+ // Discovered non-capture checks
+ b = dc = pos.discovered_check_candidates(us);
+
+ while (b)
{
- Square to = pop_1st_bit(&b1);
-
- // Make sure to is not attacked by the other side. This is a bit ugly,
- // because we can't use Position::square_is_attacked. Instead we use
- // the low-level bishop_attacks_bb and rook_attacks_bb with the bitboard
- // b2 (the occupied squares with the king removed) in order to test whether
- // the king will remain in check on the destination square.
- if (!( (bishop_attacks_bb(to, b2) & pos.bishops_and_queens(them))
- || (rook_attacks_bb(to, b2) & pos.rooks_and_queens(them))
- || (pos.knight_attacks(to) & pos.knights(them))
- || (pos.pawn_attacks(us, to) & pos.pawns(them))
- || (pos.king_attacks(to) & pos.kings(them))))
-
- mlist[n++].move = make_move(ksq, to);
+ 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;
+ }
}
- // Generate evasions for other pieces only if not double check. We use a
- // simple bit twiddling hack here rather than calling count_1s in order to
- // save some time (we know that pos.checkers() has at most two nonzero bits).
- Bitboard checkers = pos.checkers();
+ // 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);
+}
- if (!(checkers & (checkers - 1))) // Only one bit set?
- {
- Square checksq = first_1(checkers);
- assert(pos.color_of_piece_on(checksq) == them);
+/// 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) {
- // Find pinned pieces
- Bitboard not_pinned = ~pos.pinned_pieces(us);
+ assert(pos.is_ok());
+ assert(pos.is_check());
- // Generate captures of the checking piece
+ 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;
- // Pawn captures
- b1 = pos.pawn_attacks(them, checksq) & pos.pawns(us) & not_pinned;
- while (b1)
- {
- from = pop_1st_bit(&b1);
- if (relative_rank(us, checksq) == RANK_8)
- {
- mlist[n++].move = make_promotion_move(from, checksq, QUEEN);
- mlist[n++].move = make_promotion_move(from, checksq, ROOK);
- mlist[n++].move = make_promotion_move(from, checksq, BISHOP);
- mlist[n++].move = make_promotion_move(from, checksq, KNIGHT);
- } else
- mlist[n++].move = make_move(from, checksq);
- }
+ assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
+ assert(checkers);
- // Pieces captures
- b1 = (pos.knight_attacks(checksq) & pos.knights(us))
- | (pos.bishop_attacks(checksq) & pos.bishops_and_queens(us))
- | (pos.rook_attacks(checksq) & pos.rooks_and_queens(us))
- & not_pinned;
+ // 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)
- {
- from = pop_1st_bit(&b1);
- mlist[n++].move = make_move(from, checksq);
- }
+ assert(pos.color_of_piece_on(checksq) == opposite_color(us));
- // Blocking check evasions are possible only if the checking piece is
- // a slider
- if (checkers & pos.sliders())
+ switch (pos.type_of_piece_on(checksq))
{
- Bitboard blockSquares = squares_between(checksq, ksq);
-
- assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB);
-
- // Pawn moves. Because a blocking evasion can never be a capture, we
- // only generate pawn pushes.
- if (us == WHITE)
- n = generate_pawn_blocking_evasions(WhitePawnOffsets, pos, not_pinned, blockSquares, mlist, n);
+ 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
- n = generate_pawn_blocking_evasions(BlackPawnOffsets, pos, not_pinned, blockSquares, mlist, n);
+ 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);
+
+ // 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.
+ 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);
+}
- // Pieces moves
- b1 = pos.knights(us) & not_pinned;
- if (b1)
- n = generate_piece_blocking_evasions(KNIGHT, pos, b1, blockSquares, mlist, n);
- b1 = pos.bishops(us) & not_pinned;
- if (b1)
- n = generate_piece_blocking_evasions(BISHOP, pos, b1, blockSquares, mlist, n);
+/// generate computes a complete list of legal
+/// or pseudo-legal moves in the current position.
+template<>
+inline MoveStack* generate(const Position& pos, MoveStack* mlist) {
- b1 = pos.rooks(us) & not_pinned;
- if (b1)
- n = generate_piece_blocking_evasions(ROOK, pos, b1, blockSquares, mlist, n);
+ assert(pos.is_ok());
- b1 = pos.queens(us) & not_pinned;
- if (b1)
- n = generate_piece_blocking_evasions(QUEEN, pos, b1, blockSquares, mlist, n);
- }
+ return pos.is_check() ? generate(pos, mlist)
+ : generate(pos, mlist);
+}
- // Finally, the ugly special case of en passant captures. An en passant
- // capture can only be a check evasion if the check is not a discovered
- // check. If pos.ep_square() is set, the last move made must have been
- // a double pawn push. If, furthermore, the checking piece is a pawn,
- // an en passant check evasion may be possible.
- if (pos.ep_square() != SQ_NONE && (checkers & pos.pawns(them)))
- {
- to = pos.ep_square();
- b1 = pos.pawn_attacks(them, to) & pos.pawns(us);
+template<>
+MoveStack* generate(const Position& pos, MoveStack* mlist) {
- assert(b1 != EmptyBoardBB);
-
- b1 &= not_pinned;
- while (b1)
- {
- from = pop_1st_bit(&b1);
-
- // Before generating the move, we have to make sure it is legal.
- // This is somewhat tricky, because the two disappearing pawns may
- // cause new "discovered checks". We test this by removing the
- // two relevant bits from the occupied squares bitboard, and using
- // the low-level bitboard functions for bishop and rook attacks.
- b2 = pos.occupied_squares();
- clear_bit(&b2, from);
- clear_bit(&b2, checksq);
- if (!( (bishop_attacks_bb(ksq, b2) & pos.bishops_and_queens(them))
- ||(rook_attacks_bb(ksq, b2) & pos.rooks_and_queens(them))))
-
- mlist[n++].move = make_ep_move(from, to);
- }
- }
- }
- return n;
-}
+ assert(pos.is_ok());
+ MoveStack *last, *cur = mlist;
+ Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
-/// generate_legal_moves() computes a complete list of legal moves in the
-/// current position. This function is not very fast, and should be used
-/// only in situations where performance is unimportant. It wouldn't be
-/// very hard to write an efficient legal move generator, but for the moment
-/// we don't need it.
+ last = generate(pos, mlist);
-int generate_legal_moves(const Position& pos, MoveStack* 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;
- assert(pos.is_ok());
+ return last;
+}
- if (pos.is_check())
- return generate_evasions(pos, mlist);
- // Generate pseudo-legal moves:
- int n = generate_captures(pos, mlist);
- n += generate_noncaptures(pos, mlist + n);
+/// 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.
- Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
+bool move_is_legal(const Position& pos, const Move m) {
+
+ MoveStack mlist[MOVES_MAX];
+ MoveStack *cur, *last = generate(pos, mlist);
- // Remove illegal moves from the list:
- for (int i = 0; i < n; i++)
- if (!pos.move_is_legal(mlist[i].move, pinned))
- mlist[i--].move = mlist[--n].move;
+ 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 n;
+ return false;
}
-/// generate_move_if_legal() takes a position and a (not necessarily
-/// pseudo-legal) move and a pinned pieces bitboard as input, and tests
-/// whether the move is legal. If the move is legal, the move itself is
-/// returned. If not, the function returns MOVE_NONE. This function must
-/// only be used when the side to move is not in check.
+/// 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.
-Move generate_move_if_legal(const Position &pos, Move m, Bitboard pinned) {
+bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
assert(pos.is_ok());
- assert(!pos.is_check());
- assert(move_is_ok(m));
+ assert(pinned == pos.pinned_pieces(pos.side_to_move()));
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 MOVE_NONE;
-
- Square to = move_to(m);
-
- // En passant moves
- if (move_is_ep(m))
- {
- // The piece must be a pawn and destination square must be the
- // en passant square.
- if ( type_of_piece(pc) != PAWN
- || to != pos.ep_square())
- return MOVE_NONE;
-
- assert(pos.square_is_empty(to));
- assert(pos.piece_on(to - pawn_push(us)) == pawn_of_color(them));
-
- // The move is pseudo-legal. If it is legal, return it.
- return (pos.move_is_legal(m) ? m : MOVE_NONE);
- }
-
- // Castling moves
- if (move_is_short_castle(m))
- {
- // The piece must be a king and side to move must still have
- // the right to castle kingside.
- if ( type_of_piece(pc) != KING
- ||!pos.can_castle_kingside(us))
- return MOVE_NONE;
-
- assert(from == pos.king_square(us));
- assert(to == pos.initial_kr_square(us));
- assert(pos.piece_on(to) == rook_of_color(us));
-
- Square g1 = relative_square(us, SQ_G1);
- Square f1 = relative_square(us, SQ_F1);
- Square s;
- bool illegal = false;
-
- // Check if any of the squares between king and rook
- // is occupied or under attack.
- for (s = Min(from, g1); s <= Max(from, g1); s++)
- if ( (s != from && s != to && !pos.square_is_empty(s))
- || pos.square_is_attacked(s, them))
- illegal = true;
-
- // Check if any of the squares between king and rook
- // is occupied.
- for (s = Min(to, f1); s <= Max(to, f1); s++)
- if (s != from && s != to && !pos.square_is_empty(s))
- illegal = true;
-
- return (!illegal ? m : MOVE_NONE);
- }
-
- if (move_is_long_castle(m))
- {
- // The piece must be a king and side to move must still have
- // the right to castle kingside.
- if ( type_of_piece(pc) != KING
- ||!pos.can_castle_queenside(us))
- return MOVE_NONE;
-
- assert(from == pos.king_square(us));
- assert(to == pos.initial_qr_square(us));
- assert(pos.piece_on(to) == rook_of_color(us));
-
- Square c1 = relative_square(us, SQ_C1);
- Square d1 = relative_square(us, SQ_D1);
- Square s;
- bool illegal = false;
-
- for (s = Min(from, c1); s <= Max(from, c1); s++)
- if( (s != from && s != to && !pos.square_is_empty(s))
- || pos.square_is_attacked(s, them))
- illegal = true;
-
- for (s = Min(to, d1); s <= Max(to, d1); s++)
- if(s != from && s != to && !pos.square_is_empty(s))
- illegal = true;
-
- if ( square_file(to) == FILE_B
- && ( pos.piece_on(to + DELTA_W) == rook_of_color(them)
- || pos.piece_on(to + DELTA_W) == queen_of_color(them)))
- illegal = true;
-
- return (!illegal ? m : MOVE_NONE);
- }
-
- // Normal moves
+ return false;
// The destination square cannot be occupied by a friendly piece
if (pos.color_of_piece_on(to) == us)
- return MOVE_NONE;
+ return false;
- // Proceed according to the type of the moving piece.
+ // Handle the special case of a pawn move
if (type_of_piece(pc) == PAWN)
- {
- // If the destination square is on the 8/1th rank, the move must
- // be a promotion.
- if ( ( (square_rank(to) == RANK_8 && us == WHITE)
- ||(square_rank(to) == RANK_1 && us != WHITE))
- && !move_promotion(m))
- return MOVE_NONE;
-
- // Proceed according to the square delta between the source and
- // destionation squares.
- switch (to - from)
+ {
+ // 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:
@@ -495,14 +418,14 @@ Move generate_move_if_legal(const Position &pos, Move m, Bitboard pinned) {
// 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 MOVE_NONE;
+ return false;
break;
case DELTA_N:
case DELTA_S:
// Pawn push. The destination square must be empty.
if (!pos.square_is_empty(to))
- return MOVE_NONE;
+ return false;
break;
case DELTA_NN:
@@ -512,7 +435,7 @@ Move generate_move_if_legal(const Position &pos, Move m, Bitboard pinned) {
if ( square_rank(to) != RANK_4
|| !pos.square_is_empty(to)
|| !pos.square_is_empty(from + DELTA_N))
- return MOVE_NONE;
+ return false;
break;
case DELTA_SS:
@@ -522,381 +445,222 @@ Move generate_move_if_legal(const Position &pos, Move m, Bitboard pinned) {
if ( square_rank(to) != RANK_5
|| !pos.square_is_empty(to)
|| !pos.square_is_empty(from + DELTA_S))
- return MOVE_NONE;
+ return false;
break;
default:
- return MOVE_NONE;
+ return false;
}
- // The move is pseudo-legal. Return it if it is legal.
- return (pos.move_is_legal(m) ? m : MOVE_NONE);
}
+ else if (!bit_is_set(pos.attacks_from(pc, from), to))
+ return false;
- // Luckly we can handle all the other pieces in one go
- return ( pos.piece_attacks_square(from, to)
- && pos.move_is_legal(m)
- && !move_promotion(m) ? m : MOVE_NONE);
+ // 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 {
- int generate_pawn_captures(const PawnOffsets& ofs, const Position& pos, MoveStack* mlist) {
-
- Bitboard pawns = pos.pawns(ofs.us);
- Bitboard enemyPieces = pos.pieces_of_color(ofs.them);
- Square sq;
- int n = 0;
-
- // Captures in the a1-h8 (a8-h1 for black) direction
- Bitboard b1 = (ofs.forward_right)(pawns) & ~FileABB & enemyPieces;
-
- // Capturing promotions
- Bitboard b2 = b1 & ofs.Rank8BB;
- while (b2)
- {
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NE, sq, QUEEN);
- }
-
- // Capturing non-promotions
- b2 = b1 & ~ofs.Rank8BB;
- while (b2)
- {
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_move(sq - ofs.DELTA_NE, sq);
- }
-
- // Captures in the h1-a8 (h8-a1 for black) direction
- b1 = (ofs.forward_left)(pawns) & ~FileHBB & enemyPieces;
-
- // Capturing promotions
- b2 = b1 & ofs.Rank8BB;
- while (b2)
- {
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NW, sq, QUEEN);
- }
-
- // Capturing non-promotions
- b2 = b1 & ~ofs.Rank8BB;
- while (b2)
- {
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_move(sq - ofs.DELTA_NW, sq);
- }
-
- // Non-capturing promotions
- b1 = (ofs.forward)(pawns) & pos.empty_squares() & Rank8BB;
- while (b1)
- {
- sq = pop_1st_bit(&b1);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_N, sq, QUEEN);
- }
-
- // En passant captures
- if (pos.ep_square() != SQ_NONE)
- {
- assert(ofs.us != WHITE || square_rank(pos.ep_square()) == RANK_6);
- assert(ofs.us != BLACK || square_rank(pos.ep_square()) == RANK_3);
+ template
+ inline Bitboard move_pawns(Bitboard p) {
- b1 = pawns & pos.pawn_attacks(ofs.them, pos.ep_square());
- assert(b1 != EmptyBoardBB);
-
- while (b1)
- {
- sq = pop_1st_bit(&b1);
- mlist[n++].move = make_ep_move(sq, pos.ep_square());
- }
- }
- return n;
+ 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) {
- int generate_pawn_noncaptures(const PawnOffsets& ofs, const Position& pos, MoveStack* mlist) {
-
- Bitboard pawns = pos.pawns(ofs.us);
- Bitboard enemyPieces = pos.pieces_of_color(ofs.them);
- Bitboard emptySquares = pos.empty_squares();
- Bitboard b1, b2;
- Square sq;
- int n = 0;
-
- // Underpromotion captures in the a1-h8 (a8-h1 for black) direction
- b1 = ofs.forward_right(pawns) & ~FileABB & enemyPieces & ofs.Rank8BB;
- while (b1)
- {
- sq = pop_1st_bit(&b1);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NE, sq, ROOK);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NE, sq, BISHOP);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NE, sq, KNIGHT);
- }
-
- // Underpromotion captures in the h1-a8 (h8-a1 for black) direction
- b1 = ofs.forward_left(pawns) & ~FileHBB & enemyPieces & ofs.Rank8BB;
- while (b1)
- {
- sq = pop_1st_bit(&b1);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NW, sq, ROOK);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NW, sq, BISHOP);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NW, sq, KNIGHT);
- }
+ const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB);
- // Single pawn pushes
- b1 = ofs.forward(pawns) & emptySquares;
- b2 = b1 & ofs.Rank8BB;
- while (b2)
- {
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_N, sq, ROOK);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_N, sq, BISHOP);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_N, sq, KNIGHT);
- }
- b2 = b1 & ~ofs.Rank8BB;
- while (b2)
- {
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_move(sq - ofs.DELTA_N, sq);
- }
+ Bitboard b;
+ Square to;
- // Double pawn pushes
- b2 = (ofs.forward(b1 & ofs.Rank3BB)) & emptySquares;
- while (b2)
- {
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_move(sq - ofs.DELTA_N - ofs.DELTA_N, sq);
- }
- return n;
+ // 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) {
- int generate_piece_moves(PieceType piece, const Position &pos, MoveStack *mlist,
- Color side, Bitboard target) {
+ const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB);
- const Piece_attacks_fn mem_fn = piece_attacks_fn[piece];
- Square from, to;
Bitboard b;
- int n = 0;
+ Square to;
- for (int i = 0; i < pos.piece_count(side, piece); i++)
- {
- from = pos.piece_list(side, piece, i);
- b = (pos.*mem_fn)(from) & target;
- while (b)
- {
- to = pop_1st_bit(&b);
- mlist[n++].move = make_move(from, to);
- }
- }
- return n;
- }
-
-
- int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) {
+ // Promotions and under-promotions, both captures and non-captures
+ b = move_pawns(pawnsOn7) & target;
- int n = 0;
+ if (Delta != DELTA_N && Delta != DELTA_S)
+ b &= ~TFileABB;
- if (pos.can_castle(us))
+ while (b)
{
- Color them = opposite_color(us);
- Square ksq = pos.king_square(us);
+ to = pop_1st_bit(&b);
- assert(pos.piece_on(ksq) == king_of_color(us));
+ if (Type == MV_CAPTURE || Type == MV_EVASION)
+ (*mlist++).move = make_promotion_move(to - Delta, to, QUEEN);
- if (pos.can_castle_kingside(us))
+ if (Type == MV_NON_CAPTURE || Type == MV_EVASION)
{
- Square rsq = pos.initial_kr_square(us);
- Square g1 = relative_square(us, SQ_G1);
- Square f1 = relative_square(us, SQ_F1);
- Square s;
- bool illegal = false;
-
- assert(pos.piece_on(rsq) == rook_of_color(us));
-
- for (s = Min(ksq, g1); s <= Max(ksq, g1); s++)
- if ( (s != ksq && s != rsq && pos.square_is_occupied(s))
- || pos.square_is_attacked(s, them))
- illegal = true;
-
- for (s = Min(rsq, f1); s <= Max(rsq, f1); s++)
- if (s != ksq && s != rsq && pos.square_is_occupied(s))
- illegal = true;
-
- if (!illegal)
- mlist[n++].move = make_castle_move(ksq, rsq);
- }
+ (*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 (pos.can_castle_queenside(us))
- {
- Square rsq = pos.initial_qr_square(us);
- Square c1 = relative_square(us, SQ_C1);
- Square d1 = relative_square(us, SQ_D1);
- Square s;
- bool illegal = false;
-
- assert(pos.piece_on(rsq) == rook_of_color(us));
-
- for (s = Min(ksq, c1); s <= Max(ksq, c1); s++)
- if ( (s != ksq && s != rsq && pos.square_is_occupied(s))
- || pos.square_is_attacked(s, them))
- illegal = true;
-
- for (s = Min(rsq, d1); s <= Max(rsq, d1); s++)
- if (s != ksq && s != rsq && pos.square_is_occupied(s))
- illegal = true;
-
- if ( square_file(rsq) == FILE_B
- && ( pos.piece_on(relative_square(us, SQ_A1)) == rook_of_color(them)
- || pos.piece_on(relative_square(us, SQ_A1)) == queen_of_color(them)))
- illegal = true;
-
- if (!illegal)
- mlist[n++].move = make_castle_move(ksq, rsq);
- }
+ // 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 n;
+ return mlist;
}
- int generate_piece_checks(PieceType pce, const Position& pos, Bitboard target,
- Bitboard dc, Square ksq, MoveStack* mlist, int n) {
-
- const Piece_attacks_fn mem_fn = piece_attacks_fn[pce];
-
- // Discovered checks
- Bitboard b = target & dc;
- while (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)
{
- Square from = pop_1st_bit(&b);
- Bitboard bb = (pos.*mem_fn)(from) & pos.empty_squares();
- while (bb)
- {
- Square to = pop_1st_bit(&bb);
- mlist[n++].move = make_move(from, to);
- }
+ emptySquares = (Type == MV_NON_CAPTURE ? target : pos.empty_squares());
+ pawnPushes = move_pawns(pawns & ~TRank7BB) & emptySquares;
}
- // Direct checks
- b = target & ~dc;
- Bitboard checkSqs = (pos.*mem_fn)(ksq) & pos.empty_squares();
- while (b)
+ if (Type == MV_EVASION)
{
- Square from = pop_1st_bit(&b);
- Bitboard bb = (pos.*mem_fn)(from) & checkSqs;
- while (bb)
- {
- Square to = pop_1st_bit(&bb);
- mlist[n++].move = make_move(from, to);
- }
+ emptySquares &= target; // Only blocking squares
+ enemyPieces &= target; // Capture only the checker piece
}
- return n;
- }
-
- int generate_pawn_checks(const PawnOffsets& ofs, const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist, int n)
- {
- // Pawn moves 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.
- Bitboard empty = pos.empty_squares();
- // Find all friendly pawns not on the enemy king's file
- Bitboard b1 = pos.pawns(pos.side_to_move()) & ~file_bb(ksq), b2, b3;
-
- // Discovered checks, single pawn pushes
- b2 = b3 = (ofs.forward)(b1 & dc) & ~ofs.Rank8BB & empty;
- while (b3)
+ // Promotions and underpromotions
+ if (pawnsOn7)
{
- Square to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - ofs.DELTA_N, to);
+ 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);
}
- // Discovered checks, double pawn pushes
- b3 = (ofs.forward)(b2 & ofs.Rank3BB) & empty;
- while (b3)
+ // Standard captures
+ if (Type == MV_CAPTURE || Type == MV_EVASION)
{
- Square to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - ofs.DELTA_N - ofs.DELTA_N, to);
+ mlist = generate_pawn_captures(mlist, pawns, enemyPieces);
+ mlist = generate_pawn_captures(mlist, pawns, enemyPieces);
}
- // Direct checks. These are possible only for pawns on neighboring files
- // of the enemy king
-
- b1 &= (~dc & neighboring_files_bb(ksq)); // FIXME why ~dc ??
-
- // Direct checks, single pawn pushes
- b2 = (ofs.forward)(b1) & empty;
- b3 = b2 & pos.pawn_attacks(ofs.them, ksq);
- while (b3)
+ // Single and double pawn pushes
+ if (Type != MV_CAPTURE)
{
- Square to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - ofs.DELTA_N, to);
+ 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;
+
+ b1 |= dc1;
+ b2 |= dc2;
+ }
+ }
+ SERIALIZE_MOVES_D(b1, -TDELTA_N);
+ SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N);
}
- // Direct checks, double pawn pushes
- b3 = (ofs.forward)(b2 & ofs.Rank3BB) & empty & pos.pawn_attacks(ofs.them, ksq);
- while (b3)
+ // En passant captures
+ if ((Type == MV_CAPTURE || Type == MV_EVASION) && pos.ep_square() != SQ_NONE)
{
- Square to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - ofs.DELTA_N - ofs.DELTA_N, to);
- }
- return n;
- }
+ 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;
- int generate_piece_blocking_evasions(PieceType pce, const Position& pos, Bitboard b,
- Bitboard blockSquares, MoveStack* mlist, int n) {
+ b1 = pawns & pos.attacks_from(pos.ep_square(), Them);
- const Piece_attacks_fn mem_fn = piece_attacks_fn[pce];
+ assert(b1 != EmptyBoardBB);
- while (b)
- {
- Square from = pop_1st_bit(&b);
- Bitboard bb = (pos.*mem_fn)(from) & blockSquares;
- while (bb)
+ while (b1)
{
- Square to = pop_1st_bit(&bb);
- mlist[n++].move = make_move(from, to);
+ to = pop_1st_bit(&b1);
+ (*mlist++).move = make_ep_move(to, pos.ep_square());
}
}
- return n;
+ return mlist;
}
+ template
+ MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist, Color us) {
- int generate_pawn_blocking_evasions(const PawnOffsets& ofs, const Position& pos, Bitboard not_pinned,
- Bitboard blockSquares, MoveStack* mlist, int n) {
- // Find non-pinned pawns
- Bitboard b1 = pos.pawns(ofs.us) & not_pinned;
+ Color them = opposite_color(us);
+ Square ksq = pos.king_square(us);
- // Single pawn pushes. We don't have to AND with empty squares here,
- // because the blocking squares will always be empty.
- Bitboard b2 = (ofs.forward)(b1) & blockSquares;
- while (b2)
- {
- Square to = pop_1st_bit(&b2);
+ assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
- assert(pos.piece_on(to) == EMPTY);
+ 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 (square_rank(to) == ofs.RANK_8)
- {
- mlist[n++].move = make_promotion_move(to - ofs.DELTA_N, to, QUEEN);
- mlist[n++].move = make_promotion_move(to - ofs.DELTA_N, to, ROOK);
- mlist[n++].move = make_promotion_move(to - ofs.DELTA_N, to, BISHOP);
- mlist[n++].move = make_promotion_move(to - ofs.DELTA_N, to, KNIGHT);
- } else
- mlist[n++].move = make_move(to - ofs.DELTA_N, to);
- }
+ assert(pos.piece_on(rsq) == piece_of_color_and_type(us, ROOK));
- // Double pawn pushes
- b2 = (ofs.forward)((ofs.forward)(b1) & pos.empty_squares() & ofs.Rank3BB) & blockSquares;
- while (b2)
- {
- Square to = pop_1st_bit(&b2);
+ // 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;
- assert(pos.piece_on(to) == EMPTY);
- assert(ofs.us != WHITE || square_rank(to) == RANK_4);
- assert(ofs.us != BLACK || square_rank(to) == RANK_5);
+ for (s = Min(rsq, s2); s <= Max(rsq, s2); s++)
+ if (s != ksq && s != rsq && pos.square_is_occupied(s))
+ illegal = true;
- mlist[n++].move = make_move(to - ofs.DELTA_N - ofs.DELTA_N, to);
- }
- return n;
+ 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;
+
+ if (!illegal)
+ (*mlist++).move = make_castle_move(ksq, rsq);
+
+ return mlist;
}
-}
+
+} // namespace