X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=b8f7807b68aa5eb225a5b3aabcee248e6c5f06fb;hp=21839d6abaf32e52e48d027e4a9b626864496fc3;hb=b870f5a091793ea423de78e74f5652b9307cfcbd;hpb=68e711aac603388d38490521cf336b535aa10c91

diff --git a/src/position.cpp b/src/position.cpp
index 21839d6a..b8f7807b 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -358,6 +358,24 @@ Bitboard Position::hidden_checkers(Color c) const {
 }
 
 
+/// Position:pinned_pieces() returns a bitboard of all pinned (against the
+/// king) pieces for the given color.
+
+Bitboard Position::pinned_pieces(Color c) const {
+
+  return hidden_checkers<true>(c);
+}
+
+
+/// Position:discovered_check_candidates() returns a bitboard containing all
+/// pieces for the given side which are candidates for giving a discovered
+/// check.
+
+Bitboard Position::discovered_check_candidates(Color c) const {
+
+  return hidden_checkers<false>(c);
+}
+
 /// Position::attacks_to() computes a bitboard containing all pieces which
 /// attacks a given square. There are two versions of this function: One
 /// which finds attackers of both colors, and one which only finds the
@@ -461,7 +479,6 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
       return true;
 
   Color us = side_to_move();
-  Color them = opposite_color(us);
   Square from = move_from(m);
   Square ksq = king_square(us);
 
@@ -473,6 +490,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
   // after the move is made
   if (move_is_ep(m))
   {
+      Color them = opposite_color(us);
       Square to = move_to(m);
       Square capsq = make_square(square_file(to), square_rank(from));
       Bitboard b = occupied_squares();
@@ -493,11 +511,12 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
   // If the moving piece is a king, check whether the destination
   // square is attacked by the opponent.
   if (from == ksq)
-      return !(square_is_attacked(move_to(m), them));
+      return !(square_is_attacked(move_to(m), opposite_color(us)));
 
   // A non-king move is legal if and only if it is not pinned or it
   // is moving along the ray towards or away from the king.
-  return (   !bit_is_set(pinned, from)
+  return (   !pinned
+          || !bit_is_set(pinned, from)
           || (direction_between_squares(from, ksq) == direction_between_squares(move_to(m), ksq)));
 }
 
@@ -533,7 +552,8 @@ bool Position::move_is_check(Move m, Bitboard dcCandidates) const {
       if (bit_is_set(pawn_attacks(them, ksq), to)) // Normal check?
           return true;
 
-      if (    bit_is_set(dcCandidates, from)      // Discovered check?
+      if (   dcCandidates // Discovered check?
+          && bit_is_set(dcCandidates, from)
           && (direction_between_squares(from, ksq) != direction_between_squares(to, ksq)))
           return true;
 
@@ -572,22 +592,26 @@ bool Position::move_is_check(Move m, Bitboard dcCandidates) const {
       }
       return false;
 
+  // Test discovered check and normal check according to piece type
   case KNIGHT:
-    return   bit_is_set(dcCandidates, from)              // Discovered check?
-          || bit_is_set(piece_attacks<KNIGHT>(ksq), to); // Normal check?
+    return   (dcCandidates && bit_is_set(dcCandidates, from))
+          || bit_is_set(piece_attacks<KNIGHT>(ksq), to);
 
   case BISHOP:
-    return   bit_is_set(dcCandidates, from)              // Discovered check?
-          || bit_is_set(piece_attacks<BISHOP>(ksq), to); // Normal check?
+    return   (dcCandidates && bit_is_set(dcCandidates, from))
+          || (   direction_between_squares(ksq, to) != DIR_NONE
+              && bit_is_set(piece_attacks<BISHOP>(ksq), to));
 
   case ROOK:
-    return   bit_is_set(dcCandidates, from)              // Discovered check?
-          || bit_is_set(piece_attacks<ROOK>(ksq), to);   // Normal check?
+    return   (dcCandidates && bit_is_set(dcCandidates, from))
+          || (   direction_between_squares(ksq, to) != DIR_NONE
+              && bit_is_set(piece_attacks<ROOK>(ksq), to));
 
   case QUEEN:
       // Discovered checks are impossible!
       assert(!bit_is_set(dcCandidates, from));
-      return bit_is_set(piece_attacks<QUEEN>(ksq), to);  // Normal check?
+      return (   direction_between_squares(ksq, to) != DIR_NONE
+              && bit_is_set(piece_attacks<QUEEN>(ksq), to));
 
   case KING:
       // Discovered check?
@@ -648,7 +672,18 @@ template<PieceType Piece>
 inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square from,
                                       Square to, Bitboard dcCandidates) {
 
-  if (Piece != KING && bit_is_set(piece_attacks<Piece>(ksq), to))
+  const bool Bishop = (Piece == QUEEN || Piece == BISHOP);
+  const bool Rook   = (Piece == QUEEN || Piece == ROOK);
+  const bool Slider = Bishop || Rook;
+
+  if (  (   (Bishop && bit_is_set(BishopPseudoAttacks[ksq], to))
+         || (Rook   && bit_is_set(RookPseudoAttacks[ksq], to)))
+      && bit_is_set(piece_attacks<Piece>(ksq), to)) // slow, try to early skip
+      set_bit(pCheckersBB, to);
+
+  else if (   Piece != KING
+           && !Slider
+           && bit_is_set(piece_attacks<Piece>(ksq), to))
       set_bit(pCheckersBB, to);
 
   if (Piece != QUEEN && bit_is_set(dcCandidates, from))
@@ -1197,7 +1232,7 @@ void Position::undo_move(Move m) {
           board[to] = EMPTY;
   }
 
-  // Finally point out state pointer back to the previous state
+  // Finally point our state pointer back to the previous state
   st = st->previous;
 
   assert(is_ok());
@@ -1403,7 +1438,7 @@ void Position::undo_ep_move(Move m) {
 /// Position::do_null_move makes() a "null move": It switches the side to move
 /// and updates the hash key without executing any move on the board.
 
-void Position::do_null_move(StateInfo& newSt) {
+void Position::do_null_move(StateInfo& backupSt) {
 
   assert(is_ok());
   assert(!is_check());
@@ -1411,10 +1446,12 @@ void Position::do_null_move(StateInfo& newSt) {
   // Back up the information necessary to undo the null move to the supplied
   // StateInfo object. In the case of a null move, the only thing we need to
   // remember is the last move made and the en passant square.
-  newSt.lastMove = st->lastMove;
-  newSt.epSquare = st->epSquare;
-  newSt.previous = st->previous;
-  st->previous = &newSt;
+  // Note that differently from normal case here backupSt is actually used as
+  // a backup storage not as a new state to be used.
+  backupSt.lastMove = st->lastMove;
+  backupSt.epSquare = st->epSquare;
+  backupSt.previous = st->previous;
+  st->previous = &backupSt;
 
   // Save the current key to the history[] array, in order to be able to
   // detect repetition draws.
@@ -1444,7 +1481,7 @@ void Position::undo_null_move() {
   assert(is_ok());
   assert(!is_check());
 
-  // Restore information from the our StateInfo object
+  // Restore information from the our backup StateInfo object
   st->lastMove = st->previous->lastMove;
   st->epSquare = st->previous->epSquare;
   st->previous = st->previous->previous;
@@ -1817,15 +1854,14 @@ Value Position::compute_value() const {
 Value Position::compute_non_pawn_material(Color c) const {
 
   Value result = Value(0);
-  Square s;
 
   for (PieceType pt = KNIGHT; pt <= QUEEN; pt++)
   {
       Bitboard b = pieces_of_color_and_type(c, pt);
-      while(b)
+      while (b)
       {
-          s = pop_1st_bit(&b);
-          assert(piece_on(s) == piece_of_color_and_type(c, pt));
+          assert(piece_on(first_1(b)) == piece_of_color_and_type(c, pt));
+          pop_1st_bit(&b);
           result += piece_value_midgame(pt);
       }
   }