Better check evasion move sorting

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index 00e673b2bd662b1e1c03523de1be4250bebf5e90..84c7ae8f1c65539101650b68492fe4a902de8f7d 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -36,10 +36,6 @@
 
 using std::string;
 
-namespace PSQT {
-  extern Score psq[PIECE_NB][SQUARE_NB];
-}
-
 namespace Zobrist {
 
   Key psq[PIECE_NB][SQUARE_NB];
@@ -172,6 +168,8 @@ void Position::init() {
   Zobrist::noPawns = rng.rand<Key>();
 
   // Prepare the cuckoo tables
+  std::memset(cuckoo, 0, sizeof(cuckoo));
+  std::memset(cuckooMove, 0, sizeof(cuckooMove));
   int count = 0;
   for (Piece pc : Pieces)
       for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1)
@@ -381,7 +379,6 @@ void Position::set_state(StateInfo* si) const {
   si->key = si->materialKey = 0;
   si->pawnKey = Zobrist::noPawns;
   si->nonPawnMaterial[WHITE] = si->nonPawnMaterial[BLACK] = VALUE_ZERO;
-  si->psq = SCORE_ZERO;
   si->checkersBB = attackers_to(square<KING>(sideToMove)) & pieces(~sideToMove);
 
   set_check_info(si);
@@ -391,7 +388,6 @@ void Position::set_state(StateInfo* si) const {
       Square s = pop_lsb(&b);
       Piece pc = piece_on(s);
       si->key ^= Zobrist::psq[pc][s];
-      si->psq += PSQT::psq[pc][s];
   }
 
   if (si->epSquare != SQ_NONE)
@@ -752,7 +748,6 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
       Square rfrom, rto;
       do_castling<true>(us, from, to, rfrom, rto);
 
-      st->psq += PSQT::psq[captured][rto] - PSQT::psq[captured][rfrom];
       k ^= Zobrist::psq[captured][rfrom] ^ Zobrist::psq[captured][rto];
       captured = NO_PIECE;
   }
@@ -791,9 +786,6 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
       st->materialKey ^= Zobrist::psq[captured][pieceCount[captured]];
       prefetch(thisThread->materialTable[st->materialKey]);
 
-      // Update incremental scores
-      st->psq -= PSQT::psq[captured][capsq];
-
       // Reset rule 50 counter
       st->rule50 = 0;
   }
@@ -847,9 +839,6 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
           st->materialKey ^=  Zobrist::psq[promotion][pieceCount[promotion]-1]
                             ^ Zobrist::psq[pc][pieceCount[pc]];
 
-          // Update incremental score
-          st->psq += PSQT::psq[promotion][to] - PSQT::psq[pc][to];
-
           // Update material
           st->nonPawnMaterial[us] += PieceValue[MG][promotion];
       }
@@ -862,9 +851,6 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
       st->rule50 = 0;
   }
 
-  // Update incremental scores
-  st->psq += PSQT::psq[pc][to] - PSQT::psq[pc][from];
-
   // Set capture piece
   st->capturedPiece = captured;
 
@@ -1153,7 +1139,7 @@ bool Position::has_repeated() const {
         if (end < i)
             return false;
 
-        StateInfo* stp = st->previous->previous;
+        StateInfo* stp = stc->previous->previous;
 
         do {
             stp = stp->previous->previous;
@@ -1193,14 +1179,15 @@ bool Position::has_game_cycle(int ply) const {
           || (j = H2(moveKey), cuckoo[j] == moveKey))
       {
           Move move = cuckooMove[j];
-          Square from = from_sq(move);
-          Square to = to_sq(move);
+          Square s1 = from_sq(move);
+          Square s2 = to_sq(move);
 
-          if (!(between_bb(from, to) & pieces()))
+          if (!(between_bb(s1, s2) & pieces()))
           {
-              // Take care to reverse the move in the no-progress case (opponent to move)
-              if (empty(from))
-                  move = make_move(to, from);
+              // In the cuckoo table, both moves Rc1c5 and Rc5c1 are stored in the same
+              // location. We select the legal one by reversing the move variable if necessary.
+              if (empty(s1))
+                  move = make_move(s2, s1);
 
               if (ply > i)
                   return true;