Tweak Late Move Reduction at root

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index edb40499392ed7b5b850a7eeb09f9f47eccc299f..db66f416559c7add343f9e035bff4b1842566868 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -55,13 +55,13 @@ constexpr Piece Pieces[] = { W_PAWN, W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING
 // valuable attacker for the side to move, remove the attacker we just found
 // from the bitboards and scan for new X-ray attacks behind it.
 
-template<int Pt>
+template<PieceType Pt>
 PieceType min_attacker(const Bitboard* byTypeBB, Square to, Bitboard stmAttackers,
                        Bitboard& occupied, Bitboard& attackers) {
 
   Bitboard b = stmAttackers & byTypeBB[Pt];
   if (!b)
-      return min_attacker<Pt + 1>(byTypeBB, to, stmAttackers, occupied, attackers);
+      return min_attacker<PieceType(Pt + 1)>(byTypeBB, to, stmAttackers, occupied, attackers);
 
   occupied ^= lsb(b); // Remove the attacker from occupied
 
@@ -77,7 +77,7 @@ PieceType min_attacker(const Bitboard* byTypeBB, Square to, Bitboard stmAttacker
   // X-ray may add already processed pieces because byTypeBB[] is constant: in
   // the rook example, now attackers contains _again_ rook in a7, so remove it.
   attackers &= occupied;
-  return (PieceType)Pt;
+  return Pt;
 }
 
 template<>
@@ -330,16 +330,15 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th
 void Position::set_castling_right(Color c, Square rfrom) {
 
   Square kfrom = square<KING>(c);
-  CastlingSide cs = kfrom < rfrom ? KING_SIDE : QUEEN_SIDE;
-  CastlingRight cr = (c | cs);
+  CastlingRights cr = c & (kfrom < rfrom ? KING_SIDE: QUEEN_SIDE);
 
   st->castlingRights |= cr;
   castlingRightsMask[kfrom] |= cr;
   castlingRightsMask[rfrom] |= cr;
   castlingRookSquare[cr] = rfrom;
 
-  Square kto = relative_square(c, cs == KING_SIDE ? SQ_G1 : SQ_C1);
-  Square rto = relative_square(c, cs == KING_SIDE ? SQ_F1 : SQ_D1);
+  Square kto = relative_square(c, cr & KING_SIDE ? SQ_G1 : SQ_C1);
+  Square rto = relative_square(c, cr & KING_SIDE ? SQ_F1 : SQ_D1);
 
   castlingPath[cr] =   (between_bb(rfrom, rto) | between_bb(kfrom, kto) | rto | kto)
                     & ~(square_bb(kfrom) | rfrom);
@@ -387,7 +386,7 @@ void Position::set_state(StateInfo* si) const {
       if (type_of(pc) == PAWN)
           si->pawnKey ^= Zobrist::psq[pc][s];
 
-      else if (type_of(pc) != PAWN && type_of(pc) != KING)
+      else if (type_of(pc) != KING)
           si->nonPawnMaterial[color_of(pc)] += PieceValue[MG][pc];
   }
 
@@ -491,7 +490,7 @@ Bitboard Position::slider_blockers(Bitboard sliders, Square s, Bitboard& pinners
   // Snipers are sliders that attack 's' when a piece and other snipers are removed
   Bitboard snipers = (  (PseudoAttacks[  ROOK][s] & pieces(QUEEN, ROOK))
                       | (PseudoAttacks[BISHOP][s] & pieces(QUEEN, BISHOP))) & sliders;
-  Bitboard occupancy = pieces() & ~snipers;
+  Bitboard occupancy = pieces() ^ snipers;
 
   while (snipers)
   {
@@ -882,7 +881,7 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
   if (end >= 4)
   {
       StateInfo* stp = st->previous->previous;
-      for (int i=4; i <= end; i += 2)
+      for (int i = 4; i <= end; i += 2)
       {
           stp = stp->previous->previous;
           if (stp->key == st->key)
@@ -1192,10 +1191,10 @@ bool Position::has_game_cycle(int ply) const {
               if (ply > i)
                   return true;
 
-              // For nodes before or at the root, check that the move is a repetition one
-              // rather than a move to the current position.
-              // In the cuckoo table, both moves Rc1c5 and Rc5c1 are stored in the same
-              // location, so we have to select which square to check.
+              // For nodes before or at the root, check that the move is a
+              // repetition rather than a move to the current position.
+              // In the cuckoo table, both moves Rc1c5 and Rc5c1 are stored in
+              // the same location, so we have to select which square to check.
               if (color_of(piece_on(empty(s1) ? s2 : s1)) != side_to_move())
                   continue;
 
@@ -1299,15 +1298,15 @@ bool Position::pos_is_ok() const {
               assert(0 && "pos_is_ok: Index");
   }
 
-  for (Color c = WHITE; c <= BLACK; ++c)
-      for (CastlingSide s = KING_SIDE; s <= QUEEN_SIDE; s = CastlingSide(s + 1))
+  for (Color c : { WHITE, BLACK })
+      for (CastlingRights cr : {c & KING_SIDE, c & QUEEN_SIDE})
       {
-          if (!can_castle(c | s))
+          if (!can_castle(cr))
               continue;
 
-          if (   piece_on(castlingRookSquare[c | s]) != make_piece(c, ROOK)
-              || castlingRightsMask[castlingRookSquare[c | s]] != (c | s)
-              || (castlingRightsMask[square<KING>(c)] & (c | s)) != (c | s))
+          if (   piece_on(castlingRookSquare[cr]) != make_piece(c, ROOK)
+              || castlingRightsMask[castlingRookSquare[cr]] != (cr)
+              || (castlingRightsMask[square<KING>(c)] & (cr)) != (cr))
               assert(0 && "pos_is_ok: Castling");
       }