1239 lines
36 KiB
C++
1239 lines
36 KiB
C++
/*
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Glaurung, a UCI chess playing engine.
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Copyright (C) 2004-2008 Tord Romstad
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Glaurung is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Glaurung is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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////
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//// Includes
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////
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#include <cassert>
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#include "movegen.h"
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////
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//// Local definitions
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////
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namespace {
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int generate_white_pawn_captures(const Position &pos, MoveStack *mlist);
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int generate_black_pawn_captures(const Position &pos, MoveStack *mlist);
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int generate_white_pawn_noncaptures(const Position &pos, MoveStack *mlist);
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int generate_black_pawn_noncaptures(const Position &pos, MoveStack *mlist);
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int generate_knight_moves(const Position &pos, MoveStack *mlist,
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Color side, Bitboard target);
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int generate_bishop_moves(const Position &pos, MoveStack *mlist,
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Color side, Bitboard target);
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int generate_rook_moves(const Position &pos, MoveStack *mlist,
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Color side, Bitboard target);
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int generate_queen_moves(const Position &pos, MoveStack *mlist,
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Color side, Bitboard target);
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int generate_king_moves(const Position &pos, MoveStack *mlist,
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Square from, Bitboard target);
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int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us);
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}
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////
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//// Functions
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////
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/// generate_captures generates() all pseudo-legal captures and queen
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/// promotions. The return value is the number of moves generated.
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int generate_captures(const Position &pos, MoveStack *mlist) {
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Color us = pos.side_to_move();
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Bitboard target = pos.pieces_of_color(opposite_color(us));
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int n = 0;
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assert(pos.is_ok());
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assert(!pos.is_check());
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if(us == WHITE)
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n += generate_white_pawn_captures(pos, mlist);
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else
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n += generate_black_pawn_captures(pos, mlist);
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n += generate_knight_moves(pos, mlist+n, us, target);
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n += generate_bishop_moves(pos, mlist+n, us, target);
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n += generate_rook_moves(pos, mlist+n, us, target);
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n += generate_queen_moves(pos, mlist+n, us, target);
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n += generate_king_moves(pos, mlist+n, pos.king_square(us), target);
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return n;
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}
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/// generate_noncaptures() generates all pseudo-legal non-captures and
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/// underpromotions. The return value is the number of moves generated.
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int generate_noncaptures(const Position &pos, MoveStack *mlist) {
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Color us = pos.side_to_move();
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Bitboard target = pos.empty_squares();
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int n = 0;
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assert(pos.is_ok());
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assert(!pos.is_check());
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if(us == WHITE)
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n += generate_white_pawn_noncaptures(pos, mlist);
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else
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n += generate_black_pawn_noncaptures(pos, mlist);
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n += generate_knight_moves(pos, mlist+n, us, target);
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n += generate_bishop_moves(pos, mlist+n, us, target);
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n += generate_rook_moves(pos, mlist+n, us, target);
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n += generate_queen_moves(pos, mlist+n, us, target);
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n += generate_king_moves(pos, mlist+n, pos.king_square(us), target);
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n += generate_castle_moves(pos, mlist+n, us);
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return n;
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}
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/// generate_checks() generates all pseudo-legal non-capturing, non-promoting
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/// checks, except castling moves (will add this later). It returns the
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/// number of generated moves.
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int generate_checks(const Position &pos, MoveStack *mlist, Bitboard dc) {
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Color us, them;
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Square ksq, from, to;
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Bitboard empty, checkSqs, b1, b2, b3;
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int n = 0;
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assert(pos.is_ok());
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assert(!pos.is_check());
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us = pos.side_to_move();
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them = opposite_color(us);
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ksq = pos.king_square(them);
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assert(pos.piece_on(ksq) == king_of_color(them));
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dc = pos.discovered_check_candidates(us);
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empty = pos.empty_squares();
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// Pawn moves. This is somewhat messy, and we use separate code for white
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// and black, because we can't shift by negative numbers in C/C++. :-(
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if(us == WHITE) {
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// Pawn moves which give discovered check. This is possible only if the
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// pawn is not on the same file as the enemy king, because we don't
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// generate captures.
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// Find all friendly pawns not on the enemy king's file:
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b1 = pos.pawns(us) & ~file_bb(ksq);
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// Discovered checks, single pawn pushes:
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b2 = b3 = ((b1 & dc) << 8) & ~Rank8BB & empty;
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(to - DELTA_N, to);
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}
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// Discovered checks, double pawn pushes:
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b3 = ((b2 & Rank3BB) << 8) & empty;
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to);
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}
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// Direct checks. These are possible only for pawns on neighboring files
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// of the enemy king:
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b1 &= (~dc & neighboring_files_bb(ksq));
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// Direct checks, single pawn pushes:
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b2 = (b1 << 8) & empty;
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b3 = b2 & pos.black_pawn_attacks(ksq);
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(to - DELTA_N, to);
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}
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// Direct checks, double pawn pushes:
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b3 = ((b2 & Rank3BB) << 8) & empty & pos.black_pawn_attacks(ksq);
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to);
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}
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}
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else { // (us == BLACK)
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// Pawn moves which give discovered check. This is possible only if the
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// pawn is not on the same file as the enemy king, because we don't
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// generate captures.
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// Find all friendly pawns not on the enemy king's file:
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b1 = pos.pawns(us) & ~file_bb(ksq);
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// Discovered checks, single pawn pushes:
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b2 = b3 = ((b1 & dc) >> 8) & ~Rank1BB & empty;
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(to - DELTA_S, to);
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}
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// Discovered checks, double pawn pushes:
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b3 = ((b2 & Rank6BB) >> 8) & empty;
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to);
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}
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// Direct checks. These are possible only for pawns on neighboring files
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// of the enemy king:
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b1 &= (~dc & neighboring_files_bb(ksq));
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// Direct checks, single pawn pushes:
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b2 = (b1 >> 8) & empty;
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b3 = b2 & pos.white_pawn_attacks(ksq);
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(to - DELTA_S, to);
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}
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// Direct checks, double pawn pushes:
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b3 = ((b2 & Rank6BB) >> 8) & empty & pos.black_pawn_attacks(ksq);
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to);
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}
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}
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// Knight moves
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b1 = pos.knights(us);
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if(b1) {
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// Discovered knight checks:
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b2 = b1 & dc;
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while(b2) {
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from = pop_1st_bit(&b2);
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b3 = pos.knight_attacks(from) & empty;
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(from, to);
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}
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}
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// Direct knight checks:
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b2 = b1 & ~dc;
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checkSqs = pos.knight_attacks(ksq) & empty;
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while(b2) {
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from = pop_1st_bit(&b2);
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b3 = pos.knight_attacks(from) & checkSqs;
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(from, to);
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}
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}
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}
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// Bishop moves
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b1 = pos.bishops(us);
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if(b1) {
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// Discovered bishop checks:
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b2 = b1 & dc;
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while(b2) {
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from = pop_1st_bit(&b2);
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b3 = pos.bishop_attacks(from) & empty;
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(from, to);
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}
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}
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// Direct bishop checks:
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b2 = b1 & ~dc;
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checkSqs = pos.bishop_attacks(ksq) & empty;
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while(b2) {
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from = pop_1st_bit(&b2);
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b3 = pos.bishop_attacks(from) & checkSqs;
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(from, to);
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}
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}
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}
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// Rook moves
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b1 = pos.rooks(us);
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if(b1) {
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// Discovered rook checks:
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b2 = b1 & dc;
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while(b2) {
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from = pop_1st_bit(&b2);
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b3 = pos.rook_attacks(from) & empty;
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(from, to);
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}
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}
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// Direct rook checks:
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b2 = b1 & ~dc;
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checkSqs = pos.rook_attacks(ksq) & empty;
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while(b2) {
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from = pop_1st_bit(&b2);
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b3 = pos.rook_attacks(from) & checkSqs;
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while(b3) {
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to = pop_1st_bit(&b3);
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mlist[n++].move = make_move(from, to);
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}
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}
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}
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// Queen moves
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b1 = pos.queens(us);
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if(b1) {
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// Discovered queen checks are impossible!
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// Direct queen checks:
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checkSqs = pos.queen_attacks(ksq) & empty;
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while(b1) {
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from = pop_1st_bit(&b1);
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b2 = pos.queen_attacks(from) & checkSqs;
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while(b2) {
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to = pop_1st_bit(&b2);
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mlist[n++].move = make_move(from, to);
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}
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}
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}
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// King moves
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from = pos.king_square(us);
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if(bit_is_set(dc, from)) {
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b1 = pos.king_attacks(from) & empty & ~QueenPseudoAttacks[ksq];
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while(b1) {
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to = pop_1st_bit(&b1);
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mlist[n++].move = make_move(from, to);
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}
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}
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// TODO: Castling moves!
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return n;
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}
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/// generate_evasions() generates all check evasions when the side to move is
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/// in check. Unlike the other move generation functions, this one generates
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/// only legal moves. It returns the number of generated moves. This
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/// function is very ugly, and needs cleaning up some time later. FIXME
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int generate_evasions(const Position &pos, MoveStack *mlist) {
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Color us, them;
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Bitboard checkers = pos.checkers();
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Bitboard pinned, b1, b2;
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Square ksq, from, to;
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int n = 0;
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assert(pos.is_ok());
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assert(pos.is_check());
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us = pos.side_to_move();
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them = opposite_color(us);
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ksq = pos.king_square(us);
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assert(pos.piece_on(ksq) == king_of_color(us));
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// Generate evasions for king:
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b1 = pos.king_attacks(ksq) & ~pos.pieces_of_color(us);
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b2 = pos.occupied_squares();
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clear_bit(&b2, ksq);
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while(b1) {
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to = pop_1st_bit(&b1);
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// Make sure to is not attacked by the other side. This is a bit ugly,
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// because we can't use Position::square_is_attacked. Instead we use
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// the low-level bishop_attacks_bb and rook_attacks_bb with the bitboard
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// b2 (the occupied squares with the king removed) in order to test whether
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// the king will remain in check on the destination square.
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if(((pos.pawn_attacks(us, to) & pos.pawns(them)) == EmptyBoardBB) &&
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((pos.knight_attacks(to) & pos.knights(them)) == EmptyBoardBB) &&
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((pos.king_attacks(to) & pos.kings(them)) == EmptyBoardBB) &&
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((bishop_attacks_bb(to, b2) & pos.bishops_and_queens(them))
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== EmptyBoardBB) &&
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((rook_attacks_bb(to, b2) & pos.rooks_and_queens(them)) == EmptyBoardBB))
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mlist[n++].move = make_move(ksq, to);
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}
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// Generate evasions for other pieces only if not double check. We use a
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// simple bit twiddling hack here rather than calling count_1s in order to
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// save some time (we know that pos.checkers() has at most two nonzero bits).
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if(!(checkers & (checkers - 1))) {
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Square checksq = first_1(checkers);
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assert(pos.color_of_piece_on(checksq) == them);
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// Find pinned pieces:
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pinned = pos.pinned_pieces(us);
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// Generate captures of the checking piece:
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// Pawn captures:
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b1 = pos.pawn_attacks(them, checksq) & pos.pawns(us) & ~pinned;
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while(b1) {
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from = pop_1st_bit(&b1);
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if(pawn_rank(us, checksq) == RANK_8) {
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mlist[n++].move = make_promotion_move(from, checksq, QUEEN);
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mlist[n++].move = make_promotion_move(from, checksq, ROOK);
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mlist[n++].move = make_promotion_move(from, checksq, BISHOP);
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mlist[n++].move = make_promotion_move(from, checksq, KNIGHT);
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}
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else
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mlist[n++].move = make_move(from, checksq);
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}
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// Knight captures:
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b1 = pos.knight_attacks(checksq) & pos.knights(us) & ~pinned;
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while(b1) {
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from = pop_1st_bit(&b1);
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mlist[n++].move = make_move(from, checksq);
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}
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// Bishop and queen captures:
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b1 = pos.bishop_attacks(checksq) & pos.bishops_and_queens(us)
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& ~pinned;
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while(b1) {
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from = pop_1st_bit(&b1);
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mlist[n++].move = make_move(from, checksq);
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}
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// Rook and queen captures:
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b1 = pos.rook_attacks(checksq) & pos.rooks_and_queens(us)
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& ~pinned;
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while(b1) {
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from = pop_1st_bit(&b1);
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mlist[n++].move = make_move(from, checksq);
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}
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// Blocking check evasions are possible only if the checking piece is
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// a slider:
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if(checkers & pos.sliders()) {
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Bitboard blockSquares = squares_between(checksq, ksq);
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assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB);
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// Pawn moves. Because a blocking evasion can never be a capture, we
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// only generate pawn pushes. As so often, the code for pawns is a bit
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// ugly, and uses separate clauses for white and black pawns. :-(
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if(us == WHITE) {
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// Find non-pinned pawns:
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b1 = pos.pawns(WHITE) & ~pinned;
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// Single pawn pushes. We don't have to AND with empty squares here,
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// because the blocking squares will always be empty.
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b2 = (b1 << 8) & blockSquares;
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while(b2) {
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to = pop_1st_bit(&b2);
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assert(pos.piece_on(to) == EMPTY);
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if(square_rank(to) == RANK_8) {
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mlist[n++].move = make_promotion_move(to - DELTA_N, to, QUEEN);
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mlist[n++].move = make_promotion_move(to - DELTA_N, to, ROOK);
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mlist[n++].move = make_promotion_move(to - DELTA_N, to, BISHOP);
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mlist[n++].move = make_promotion_move(to - DELTA_N, to, KNIGHT);
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}
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else
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mlist[n++].move = make_move(to - DELTA_N, to);
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}
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// Double pawn pushes.
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b2 = (((b1 << 8) & pos.empty_squares() & Rank3BB) << 8) & blockSquares;
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while(b2) {
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to = pop_1st_bit(&b2);
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assert(pos.piece_on(to) == EMPTY);
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assert(square_rank(to) == RANK_4);
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mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to);
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}
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}
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else { // (us == BLACK)
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// Find non-pinned pawns:
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b1 = pos.pawns(BLACK) & ~pinned;
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// Single pawn pushes. We don't have to AND with empty squares here,
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// because the blocking squares will always be empty.
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b2 = (b1 >> 8) & blockSquares;
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while(b2) {
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to = pop_1st_bit(&b2);
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assert(pos.piece_on(to) == EMPTY);
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if(square_rank(to) == RANK_1) {
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mlist[n++].move = make_promotion_move(to - DELTA_S, to, QUEEN);
|
|
mlist[n++].move = make_promotion_move(to - DELTA_S, to, ROOK);
|
|
mlist[n++].move = make_promotion_move(to - DELTA_S, to, BISHOP);
|
|
mlist[n++].move = make_promotion_move(to - DELTA_S, to, KNIGHT);
|
|
}
|
|
else
|
|
mlist[n++].move = make_move(to - DELTA_S, to);
|
|
}
|
|
// Double pawn pushes.
|
|
b2 = (((b1 >> 8) & pos.empty_squares() & Rank6BB) >> 8) & blockSquares;
|
|
while(b2) {
|
|
to = pop_1st_bit(&b2);
|
|
assert(pos.piece_on(to) == EMPTY);
|
|
assert(square_rank(to) == RANK_5);
|
|
mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to);
|
|
}
|
|
}
|
|
|
|
// Knight moves
|
|
b1 = pos.knights(us) & ~pinned;
|
|
while(b1) {
|
|
from = pop_1st_bit(&b1);
|
|
b2 = pos.knight_attacks(from) & blockSquares;
|
|
while(b2) {
|
|
to = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(from, to);
|
|
}
|
|
}
|
|
|
|
// Bishop moves
|
|
b1 = pos.bishops(us) & ~pinned;
|
|
while(b1) {
|
|
from = pop_1st_bit(&b1);
|
|
b2 = pos.bishop_attacks(from) & blockSquares;
|
|
while(b2) {
|
|
to = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(from, to);
|
|
}
|
|
}
|
|
|
|
// Rook moves
|
|
b1 = pos.rooks(us) & ~pinned;
|
|
while(b1) {
|
|
from = pop_1st_bit(&b1);
|
|
b2 = pos.rook_attacks(from) & blockSquares;
|
|
while(b2) {
|
|
to = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(from, to);
|
|
}
|
|
}
|
|
|
|
// Queen moves
|
|
b1 = pos.queens(us) & ~pinned;
|
|
while(b1) {
|
|
from = pop_1st_bit(&b1);
|
|
b2 = pos.queen_attacks(from) & blockSquares;
|
|
while(b2) {
|
|
to = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(from, to);
|
|
}
|
|
}
|
|
}
|
|
|
|
// 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);
|
|
assert(b1 != EmptyBoardBB);
|
|
b1 &= ~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))
|
|
== EmptyBoardBB) &&
|
|
((rook_attacks_bb(ksq, b2) & pos.rooks_and_queens(them))
|
|
== EmptyBoardBB))
|
|
mlist[n++].move = make_ep_move(from, to);
|
|
}
|
|
}
|
|
}
|
|
|
|
return n;
|
|
}
|
|
|
|
|
|
/// 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.
|
|
|
|
int generate_legal_moves(const Position &pos, MoveStack *mlist) {
|
|
assert(pos.is_ok());
|
|
|
|
if(pos.is_check())
|
|
return generate_evasions(pos, mlist);
|
|
else {
|
|
int i, n;
|
|
Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
|
|
|
|
// Generate pseudo-legal moves:
|
|
n = generate_captures(pos, mlist);
|
|
n += generate_noncaptures(pos, mlist + n);
|
|
|
|
// Remove illegal moves from the list:
|
|
for(i = 0; i < n; i++) {
|
|
if(!pos.move_is_legal(mlist[i].move, pinned))
|
|
mlist[i--].move = mlist[--n].move;
|
|
}
|
|
|
|
return n;
|
|
}
|
|
}
|
|
|
|
|
|
/// 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.
|
|
|
|
Move generate_move_if_legal(const Position &pos, Move m, Bitboard pinned) {
|
|
Color us, them;
|
|
Square from, to;
|
|
Piece pc;
|
|
|
|
assert(pos.is_ok());
|
|
assert(!pos.is_check());
|
|
assert(move_is_ok(m));
|
|
|
|
us = pos.side_to_move();
|
|
them = opposite_color(us);
|
|
from = move_from(m);
|
|
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 MOVE_NONE;
|
|
|
|
to = move_to(m);
|
|
|
|
// En passant moves:
|
|
if(move_is_ep(m)) {
|
|
|
|
// The piece must be a pawn:
|
|
if(type_of_piece(pc) != PAWN)
|
|
return MOVE_NONE;
|
|
|
|
// The destination square must be the en passant square:
|
|
if(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.
|
|
if(pos.move_is_legal(m))
|
|
return m;
|
|
else
|
|
return MOVE_NONE;
|
|
}
|
|
|
|
// Castling moves:
|
|
else if(move_is_short_castle(m)) {
|
|
|
|
// The piece must be a king:
|
|
if(type_of_piece(pc) != KING)
|
|
return MOVE_NONE;
|
|
|
|
// The side to move must still have the right to castle kingside:
|
|
if(!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;
|
|
|
|
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;
|
|
for(s = Min(to, f1); s <= Max(to, f1); s++)
|
|
if(s != from && s != to && !pos.square_is_empty(s))
|
|
illegal = true;
|
|
|
|
if(!illegal)
|
|
return m;
|
|
else
|
|
return MOVE_NONE;
|
|
}
|
|
else if(move_is_long_castle(m)) {
|
|
|
|
// The piece must be a king:
|
|
if(type_of_piece(pc) != KING)
|
|
return MOVE_NONE;
|
|
|
|
// The side to move must still have the right to castle kingside:
|
|
if(!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;
|
|
|
|
if(!illegal)
|
|
return m;
|
|
else
|
|
return MOVE_NONE;
|
|
}
|
|
|
|
// Normal moves
|
|
else {
|
|
|
|
// The destination square cannot be occupied by a friendly piece:
|
|
if(pos.color_of_piece_on(to) == us)
|
|
return MOVE_NONE;
|
|
|
|
// Proceed according to the type of the moving piece.
|
|
switch(type_of_piece(pc)) {
|
|
|
|
case PAWN:
|
|
// Pawn moves, as usual, are somewhat messy.
|
|
if(us == WHITE) {
|
|
// If the destination square is on the 8th rank, the move must be a
|
|
// promotion.
|
|
if(square_rank(to) == RANK_8 && !move_promotion(m))
|
|
return MOVE_NONE;
|
|
|
|
// Proceed according to the square delta between the source and
|
|
// destionation squares.
|
|
switch(to - from) {
|
|
|
|
case DELTA_NW: case DELTA_NE:
|
|
// 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;
|
|
break;
|
|
|
|
case DELTA_N:
|
|
// Pawn push. The destination square must be empty.
|
|
if(!pos.square_is_empty(to))
|
|
return MOVE_NONE;
|
|
break;
|
|
|
|
case DELTA_NN:
|
|
// Double 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 MOVE_NONE;
|
|
break;
|
|
|
|
default:
|
|
return MOVE_NONE;
|
|
}
|
|
}
|
|
else { // (us == BLACK)
|
|
// If the destination square is on the 1st rank, the move must be a
|
|
// promotion.
|
|
if(square_rank(to) == RANK_1 && !move_promotion(m))
|
|
return MOVE_NONE;
|
|
|
|
// Proceed according to the square delta between the source and
|
|
// destionation squares.
|
|
switch(to - from) {
|
|
|
|
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 MOVE_NONE;
|
|
break;
|
|
|
|
case DELTA_S:
|
|
// Pawn push. The destination square must be empty.
|
|
if(!pos.square_is_empty(to))
|
|
return MOVE_NONE;
|
|
break;
|
|
|
|
case DELTA_SS:
|
|
// Double 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 MOVE_NONE;
|
|
break;
|
|
|
|
default:
|
|
return MOVE_NONE;
|
|
}
|
|
}
|
|
// The move is pseudo-legal. Return it if it is legal.
|
|
if(pos.move_is_legal(m))
|
|
return m;
|
|
else
|
|
return MOVE_NONE;
|
|
break;
|
|
|
|
case KNIGHT:
|
|
if(pos.knight_attacks_square(from, to) && pos.move_is_legal(m) &&
|
|
!move_promotion(m))
|
|
return m;
|
|
else
|
|
return MOVE_NONE;
|
|
break;
|
|
|
|
case BISHOP:
|
|
if(pos.bishop_attacks_square(from, to) && pos.move_is_legal(m) &&
|
|
!move_promotion(m))
|
|
return m;
|
|
else
|
|
return MOVE_NONE;
|
|
break;
|
|
|
|
case ROOK:
|
|
if(pos.rook_attacks_square(from, to) && pos.move_is_legal(m) &&
|
|
!move_promotion(m))
|
|
return m;
|
|
else
|
|
return MOVE_NONE;
|
|
break;
|
|
|
|
case QUEEN:
|
|
if(pos.queen_attacks_square(from, to) && pos.move_is_legal(m) &&
|
|
!move_promotion(m))
|
|
return m;
|
|
else
|
|
return MOVE_NONE;
|
|
break;
|
|
|
|
case KING:
|
|
if(pos.king_attacks_square(from, to) && pos.move_is_legal(m) &&
|
|
!move_promotion(m))
|
|
return m;
|
|
else
|
|
return MOVE_NONE;
|
|
break;
|
|
|
|
default:
|
|
assert(false);
|
|
}
|
|
}
|
|
|
|
assert(false);
|
|
return MOVE_NONE;
|
|
}
|
|
|
|
|
|
namespace {
|
|
|
|
int generate_white_pawn_captures(const Position &pos, MoveStack *mlist) {
|
|
Bitboard pawns = pos.pawns(WHITE);
|
|
Bitboard enemyPieces = pos.pieces_of_color(BLACK);
|
|
Bitboard b1, b2;
|
|
Square sq;
|
|
int n = 0;
|
|
|
|
// Captures in the a1-h8 direction:
|
|
b1 = (pawns << 9) & ~FileABB & enemyPieces;
|
|
|
|
// Promotions:
|
|
b2 = b1 & Rank8BB;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, QUEEN);
|
|
}
|
|
|
|
// Non-promotions:
|
|
b2 = b1 & ~Rank8BB;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(sq - DELTA_NE, sq);
|
|
}
|
|
|
|
// Captures in the h1-a8 direction:
|
|
b1 = (pawns << 7) & ~FileHBB & enemyPieces;
|
|
|
|
// Promotions:
|
|
b2 = b1 & Rank8BB;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, QUEEN);
|
|
}
|
|
|
|
// Non-promotions:
|
|
b2 = b1 & ~Rank8BB;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(sq - DELTA_NW, sq);
|
|
}
|
|
|
|
// Non-capturing promotions:
|
|
b1 = (pawns << 8) & pos.empty_squares() & Rank8BB;
|
|
while(b1) {
|
|
sq = pop_1st_bit(&b1);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, QUEEN);
|
|
}
|
|
|
|
// En passant captures:
|
|
if(pos.ep_square() != SQ_NONE) {
|
|
assert(square_rank(pos.ep_square()) == RANK_6);
|
|
b1 = pawns & pos.black_pawn_attacks(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;
|
|
}
|
|
|
|
|
|
int generate_black_pawn_captures(const Position &pos, MoveStack *mlist) {
|
|
Bitboard pawns = pos.pawns(BLACK);
|
|
Bitboard enemyPieces = pos.pieces_of_color(WHITE);
|
|
Bitboard b1, b2;
|
|
Square sq;
|
|
int n = 0;
|
|
|
|
// Captures in the a8-h1 direction:
|
|
b1 = (pawns >> 7) & ~FileABB & enemyPieces;
|
|
|
|
// Promotions:
|
|
b2 = b1 & Rank1BB;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, QUEEN);
|
|
}
|
|
|
|
// Non-promotions:
|
|
b2 = b1 & ~Rank1BB;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(sq - DELTA_SE, sq);
|
|
}
|
|
|
|
// Captures in the h8-a1 direction:
|
|
b1 = (pawns >> 9) & ~FileHBB & enemyPieces;
|
|
|
|
// Promotions:
|
|
b2 = b1 & Rank1BB;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, QUEEN);
|
|
}
|
|
|
|
// Non-promotions:
|
|
b2 = b1 & ~Rank1BB;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(sq - DELTA_SW, sq);
|
|
}
|
|
|
|
// Non-capturing promotions:
|
|
b1 = (pawns >> 8) & pos.empty_squares() & Rank1BB;
|
|
while(b1) {
|
|
sq = pop_1st_bit(&b1);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, QUEEN);
|
|
}
|
|
|
|
// En passant captures:
|
|
if(pos.ep_square() != SQ_NONE) {
|
|
assert(square_rank(pos.ep_square()) == RANK_3);
|
|
b1 = pawns & pos.white_pawn_attacks(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;
|
|
}
|
|
|
|
|
|
int generate_white_pawn_noncaptures(const Position &pos, MoveStack *mlist) {
|
|
Bitboard pawns = pos.pawns(WHITE);
|
|
Bitboard enemyPieces = pos.pieces_of_color(BLACK);
|
|
Bitboard emptySquares = pos.empty_squares();
|
|
Bitboard b1, b2;
|
|
Square sq;
|
|
int n = 0;
|
|
|
|
// Underpromotion captures in the a1-h8 direction:
|
|
b1 = (pawns << 9) & ~FileABB & enemyPieces & Rank8BB;
|
|
while(b1) {
|
|
sq = pop_1st_bit(&b1);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, ROOK);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, BISHOP);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, KNIGHT);
|
|
}
|
|
|
|
// Underpromotion captures in the h1-a8 direction:
|
|
b1 = (pawns << 7) & ~FileHBB & enemyPieces & Rank8BB;
|
|
while(b1) {
|
|
sq = pop_1st_bit(&b1);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, ROOK);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, BISHOP);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, KNIGHT);
|
|
}
|
|
|
|
// Single pawn pushes:
|
|
b1 = (pawns << 8) & emptySquares;
|
|
b2 = b1 & Rank8BB;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, ROOK);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, BISHOP);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, KNIGHT);
|
|
}
|
|
b2 = b1 & ~Rank8BB;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(sq - DELTA_N, sq);
|
|
}
|
|
|
|
// Double pawn pushes:
|
|
b2 = ((b1 & Rank3BB) << 8) & emptySquares;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(sq - DELTA_N - DELTA_N, sq);
|
|
}
|
|
|
|
return n;
|
|
}
|
|
|
|
|
|
int generate_black_pawn_noncaptures(const Position &pos, MoveStack *mlist) {
|
|
Bitboard pawns = pos.pawns(BLACK);
|
|
Bitboard enemyPieces = pos.pieces_of_color(WHITE);
|
|
Bitboard emptySquares = pos.empty_squares();
|
|
Bitboard b1, b2;
|
|
Square sq;
|
|
int n = 0;
|
|
|
|
// Underpromotion captures in the a8-h1 direction:
|
|
b1 = (pawns >> 7) & ~FileABB & enemyPieces & Rank1BB;
|
|
while(b1) {
|
|
sq = pop_1st_bit(&b1);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, ROOK);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, BISHOP);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, KNIGHT);
|
|
}
|
|
|
|
// Underpromotion captures in the h8-a1 direction:
|
|
b1 = (pawns >> 9) & ~FileHBB & enemyPieces & Rank1BB;
|
|
while(b1) {
|
|
sq = pop_1st_bit(&b1);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, ROOK);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, BISHOP);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, KNIGHT);
|
|
}
|
|
|
|
// Single pawn pushes:
|
|
b1 = (pawns >> 8) & emptySquares;
|
|
b2 = b1 & Rank1BB;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, ROOK);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, BISHOP);
|
|
mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, KNIGHT);
|
|
}
|
|
b2 = b1 & ~Rank1BB;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(sq - DELTA_S, sq);
|
|
}
|
|
|
|
// Double pawn pushes:
|
|
b2 = ((b1 & Rank6BB) >> 8) & emptySquares;
|
|
while(b2) {
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(sq - DELTA_S - DELTA_S, sq);
|
|
}
|
|
|
|
return n;
|
|
}
|
|
|
|
|
|
int generate_knight_moves(const Position &pos, MoveStack *mlist,
|
|
Color side, Bitboard target) {
|
|
Square from, to;
|
|
Bitboard b;
|
|
int i, n = 0;
|
|
|
|
for(i = 0; i < pos.knight_count(side); i++) {
|
|
from = pos.knight_list(side, i);
|
|
b = pos.knight_attacks(from) & target;
|
|
while(b) {
|
|
to = pop_1st_bit(&b);
|
|
mlist[n++].move = make_move(from, to);
|
|
}
|
|
}
|
|
return n;
|
|
}
|
|
|
|
|
|
int generate_bishop_moves(const Position &pos, MoveStack *mlist,
|
|
Color side, Bitboard target) {
|
|
Square from, to;
|
|
Bitboard b;
|
|
int i, n = 0;
|
|
|
|
for(i = 0; i < pos.bishop_count(side); i++) {
|
|
from = pos.bishop_list(side, i);
|
|
b = pos.bishop_attacks(from) & target;
|
|
while(b) {
|
|
to = pop_1st_bit(&b);
|
|
mlist[n++].move = make_move(from, to);
|
|
}
|
|
}
|
|
return n;
|
|
}
|
|
|
|
|
|
int generate_rook_moves(const Position &pos, MoveStack *mlist,
|
|
Color side, Bitboard target) {
|
|
Square from, to;
|
|
Bitboard b;
|
|
int i, n = 0;
|
|
|
|
for(i = 0; i < pos.rook_count(side); i++) {
|
|
from = pos.rook_list(side, i);
|
|
b = pos.rook_attacks(from) & target;
|
|
while(b) {
|
|
to = pop_1st_bit(&b);
|
|
mlist[n++].move = make_move(from, to);
|
|
}
|
|
}
|
|
return n;
|
|
}
|
|
|
|
|
|
int generate_queen_moves(const Position &pos, MoveStack *mlist,
|
|
Color side, Bitboard target) {
|
|
Square from, to;
|
|
Bitboard b;
|
|
int i, n = 0;
|
|
|
|
for(i = 0; i < pos.queen_count(side); i++) {
|
|
from = pos.queen_list(side, i);
|
|
b = pos.queen_attacks(from) & target;
|
|
while(b) {
|
|
to = pop_1st_bit(&b);
|
|
mlist[n++].move = make_move(from, to);
|
|
}
|
|
}
|
|
return n;
|
|
}
|
|
|
|
|
|
int generate_king_moves(const Position &pos, MoveStack *mlist,
|
|
Square from, Bitboard target) {
|
|
Square to;
|
|
Bitboard b;
|
|
int n = 0;
|
|
|
|
b = pos.king_attacks(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) {
|
|
int n = 0;
|
|
|
|
if(pos.can_castle(us)) {
|
|
Color them = opposite_color(us);
|
|
Square ksq = pos.king_square(us);
|
|
assert(pos.piece_on(ksq) == king_of_color(us));
|
|
|
|
if(pos.can_castle_kingside(us)) {
|
|
Square rsq = pos.initial_kr_square(us);
|
|
Square g1 = relative_square(us, SQ_G1);
|
|
Square f1 = relative_square(us, SQ_F1);
|
|
Square s;
|
|
bool illegal = false;
|
|
|
|
assert(pos.piece_on(rsq) == rook_of_color(us));
|
|
|
|
for(s = Min(ksq, g1); s <= Max(ksq, g1); s++)
|
|
if((s != ksq && s != rsq && pos.square_is_occupied(s))
|
|
|| pos.square_is_attacked(s, them))
|
|
illegal = true;
|
|
for(s = Min(rsq, f1); s <= Max(rsq, f1); s++)
|
|
if(s != ksq && s != rsq && pos.square_is_occupied(s))
|
|
illegal = true;
|
|
|
|
if(!illegal)
|
|
mlist[n++].move = make_castle_move(ksq, rsq);
|
|
}
|
|
|
|
if(pos.can_castle_queenside(us)) {
|
|
Square rsq = pos.initial_qr_square(us);
|
|
Square c1 = relative_square(us, SQ_C1);
|
|
Square d1 = relative_square(us, SQ_D1);
|
|
Square s;
|
|
bool illegal = false;
|
|
|
|
assert(pos.piece_on(rsq) == rook_of_color(us));
|
|
|
|
for(s = Min(ksq, c1); s <= Max(ksq, c1); s++)
|
|
if((s != ksq && s != rsq && pos.square_is_occupied(s))
|
|
|| pos.square_is_attacked(s, them))
|
|
illegal = true;
|
|
for(s = Min(rsq, d1); s <= Max(rsq, d1); s++)
|
|
if(s != ksq && s != rsq && pos.square_is_occupied(s))
|
|
illegal = true;
|
|
if(square_file(rsq) == FILE_B &&
|
|
(pos.piece_on(relative_square(us, SQ_A1)) == rook_of_color(them) ||
|
|
pos.piece_on(relative_square(us, SQ_A1)) == queen_of_color(them)))
|
|
illegal = true;
|
|
|
|
if(!illegal)
|
|
mlist[n++].move = make_castle_move(ksq, rsq);
|
|
}
|
|
}
|
|
|
|
return n;
|
|
}
|
|
|
|
}
|