X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=867a7f0b947aa00c74f8bc2bf5734a79e63acecc;hp=ceface349ef375f3359b91531cfc041e87c8389e;hb=853e2a9495afbe5789727c4c666c73c8276d8585;hpb=21fc66c2466f86a7ee12221e197b6e6708f4512b diff --git a/src/position.cpp b/src/position.cpp index ceface34..867a7f0b 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -490,6 +490,16 @@ Bitboard Position::attackers_to(Square s) const { | (attacks_from(s) & pieces(KING)); } +Bitboard Position::attackers_to(Square s, Bitboard occ) const { + + return (attacks_from(s, BLACK) & pieces(PAWN, WHITE)) + | (attacks_from(s, WHITE) & pieces(PAWN, BLACK)) + | (attacks_from(s) & pieces(KNIGHT)) + | (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN)) + | (bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN)) + | (attacks_from(s) & pieces(KING)); +} + /// Position::attacks_from() computes a bitboard of all attacks /// of a given piece put in a given square. @@ -570,14 +580,18 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { assert(move_is_ok(m)); assert(pinned == pinned_pieces(side_to_move())); + Color us = side_to_move(); + Square from = move_from(m); + + assert(color_of_piece_on(from) == us); + assert(piece_on(king_square(us)) == make_piece(us, KING)); + // En passant captures are a tricky special case. Because they are // rather uncommon, we do it simply by testing whether the king is attacked // after the move is made if (move_is_ep(m)) { - Color us = side_to_move(); Color them = opposite_color(us); - Square from = move_from(m); Square to = move_to(m); Square capsq = make_square(square_file(to), square_rank(from)); Square ksq = king_square(us); @@ -596,12 +610,6 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { && !(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, them)); } - Color us = side_to_move(); - Square from = move_from(m); - - assert(color_of_piece_on(from) == us); - assert(piece_on(king_square(us)) == make_piece(us, KING)); - // If the moving piece is a king, check whether the destination // square is attacked by the opponent. Castling moves are checked // for legality during move generation. @@ -616,55 +624,32 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { } -/// Position::pl_move_is_evasion() tests whether a pseudo-legal move is a legal evasion - -bool Position::pl_move_is_evasion(Move m, Bitboard pinned) const -{ - assert(in_check()); - - Color us = side_to_move(); - Square from = move_from(m); - Square to = move_to(m); - - // King moves and en-passant captures are verified in pl_move_is_legal() - if (type_of_piece_on(from) == KING || move_is_ep(m)) - return pl_move_is_legal(m, pinned); - - Bitboard target = checkers(); - Square checksq = pop_1st_bit(&target); - - if (target) // double check ? - return false; - - // Our move must be a blocking evasion or a capture of the checking piece - target = squares_between(checksq, king_square(us)) | checkers(); - return bit_is_set(target, to) && pl_move_is_legal(m, pinned); -} - -/// Position::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. +/// Position::move_is_pl_slow() takes a position and a move and tests whether +/// the move is pseudo legal. This version is not very fast and should be used +/// only in non time-critical paths. -bool Position::move_is_legal(const Move m) const { +bool Position::move_is_pl_slow(const Move m) const { MoveStack mlist[MAX_MOVES]; - MoveStack *cur, *last = generate(*this, mlist); + MoveStack *cur, *last; + + last = in_check() ? generate(*this, mlist) + : generate(*this, mlist); - for (cur = mlist; cur != last; cur++) + for (cur = mlist; cur != last; cur++) if (cur->move == m) - return pl_move_is_legal(m, pinned_pieces(sideToMove)); + return true; return false; } -/// Fast version of Position::move_is_legal() that takes a position a move and -/// a bitboard of pinned pieces as input, and tests whether the move is legal. +/// Fast version of Position::move_is_pl() that takes a position a move and a +/// bitboard of pinned pieces as input, and tests whether the move is pseudo legal. -bool Position::move_is_legal(const Move m, Bitboard pinned) const { +bool Position::move_is_pl(const Move m) const { assert(is_ok()); - assert(pinned == pinned_pieces(sideToMove)); Color us = sideToMove; Color them = opposite_color(sideToMove); @@ -674,7 +659,7 @@ bool Position::move_is_legal(const Move m, Bitboard pinned) const { // Use a slower but simpler function for uncommon cases if (move_is_special(m)) - return move_is_legal(m); + return move_is_pl_slow(m); // Is not a promotion, so promotion piece must be empty if (move_promotion_piece(m) - 2 != PIECE_TYPE_NONE) @@ -754,8 +739,33 @@ bool Position::move_is_legal(const Move m, Bitboard pinned) const { else if (!bit_is_set(attacks_from(pc, from), to)) return false; - // The move is pseudo-legal, check if it is also legal - return in_check() ? pl_move_is_evasion(m, pinned) : pl_move_is_legal(m, pinned); + if (in_check()) + { + // In case of king moves under check we have to remove king so to catch + // as invalid moves like b1a1 when opposite queen is on c1. + if (type_of_piece_on(from) == KING) + { + Bitboard b = occupied_squares(); + clear_bit(&b, from); + if (attackers_to(move_to(m), b) & pieces_of_color(opposite_color(us))) + return false; + } + else + { + Bitboard target = checkers(); + Square checksq = pop_1st_bit(&target); + + if (target) // double check ? In this case a king move is required + return false; + + // Our move must be a blocking evasion or a capture of the checking piece + target = squares_between(checksq, king_square(us)) | checkers(); + if (!bit_is_set(target, move_to(m))) + return false; + } + } + + return true; } @@ -1548,12 +1558,7 @@ int Position::see(Move m) const { // Find all attackers to the destination square, with the moving piece // removed, but possibly an X-ray attacker added behind it. clear_bit(&occupied, from); - attackers = (rook_attacks_bb(to, occupied) & pieces(ROOK, QUEEN)) - | (bishop_attacks_bb(to, occupied)& pieces(BISHOP, QUEEN)) - | (attacks_from(to) & pieces(KNIGHT)) - | (attacks_from(to) & pieces(KING)) - | (attacks_from(to, WHITE) & pieces(PAWN, BLACK)) - | (attacks_from(to, BLACK) & pieces(PAWN, WHITE)); + attackers = attackers_to(to, occupied); // If the opponent has no attackers we are finished stm = opposite_color(color_of_piece_on(from));