Simplified discovered check connected_moves()

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 3512f20e376b8f354947b93399a0be740e3c11e3..8b5f3b2b6d8c6171575a31f1cb3e3afcfe8327f3 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -79,16 +79,9 @@ namespace {
     Move pv[PLY_MAX_PLUS_2];
   };
 
-  // RootMoveList struct is just a vector of RootMove objects,
-  // with an handful of methods above the standard ones.
+  // RootMoveList struct is mainly a std::vector of RootMove objects
   struct RootMoveList : public std::vector<RootMove> {
-
-    typedef std::vector<RootMove> Base;
-
     void init(Position& pos, Move searchMoves[]);
-    void sort() { insertion_sort<RootMove, Base::iterator>(begin(), end()); }
-    void sort_first(int n) { insertion_sort<RootMove, Base::iterator>(begin(), begin() + n); }
-
     int bestMoveChanges;
   };
 
@@ -400,7 +393,7 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) {
   NodesSincePoll = 0;
   current_search_time(get_system_time());
   Limits = limits;
-  TimeMgr.init(Limits, pos.full_moves());
+  TimeMgr.init(Limits, pos.startpos_ply_counter());
 
   // Set output steram in normal or chess960 mode
   cout << set960(pos.is_chess960());
@@ -733,7 +726,14 @@ namespace {
     if (PvNode && thread.maxPly < ss->ply)
         thread.maxPly = ss->ply;
 
-    if (SpNode)
+    // Step 1. Initialize node and poll. Polling can abort search
+    if (!SpNode)
+    {
+        ss->currentMove = ss->bestMove = threatMove = (ss+1)->excludedMove = MOVE_NONE;
+        (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
+        (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
+    }
+    else
     {
         sp = ss->sp;
         tte = NULL;
@@ -742,11 +742,6 @@ namespace {
         goto split_point_start;
     }
 
-    // Step 1. Initialize node and poll. Polling can abort search
-    ss->currentMove = ss->bestMove = threatMove = (ss+1)->excludedMove = MOVE_NONE;
-    (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
-    (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
-
     if (pos.thread() == 0 && ++NodesSincePoll > NodesBetweenPolls)
     {
         NodesSincePoll = 0;
@@ -1217,7 +1212,7 @@ split_point_start: // At split points actual search starts from here
               // because all the values but the first are usually set to
               // -VALUE_INFINITE and we want to keep the same order for all
               // the moves but the new PV that goes to head.
-              Rml.sort_first(moveCount);
+              sort<RootMove>(Rml.begin(), Rml.begin() + moveCount);
 
               // Update alpha. In multi-pv we don't use aspiration window, so set
               // alpha equal to minimum score among the PV lines searched so far.
@@ -1553,7 +1548,8 @@ split_point_start: // At split points actual search starts from here
   bool connected_moves(const Position& pos, Move m1, Move m2) {
 
     Square f1, t1, f2, t2;
-    Piece p;
+    Piece p1, p2;
+    Square ksq;
 
     assert(m1 && move_is_ok(m1));
     assert(m2 && move_is_ok(m2));
@@ -1571,26 +1567,24 @@ split_point_start: // At split points actual search starts from here
         return true;
 
     // Case 3: Moving through the vacated square
-    if (   piece_is_slider(pos.piece_on(f2))
+    p2 = pos.piece_on(f2);
+    if (   piece_is_slider(p2)
         && bit_is_set(squares_between(f2, t2), f1))
       return true;
 
     // Case 4: The destination square for m2 is defended by the moving piece in m1
-    p = pos.piece_on(t1);
-    if (bit_is_set(pos.attacks_from(p, t1), t2))
+    p1 = pos.piece_on(t1);
+    if (bit_is_set(pos.attacks_from(p1, t1), t2))
         return true;
 
     // Case 5: Discovered check, checking piece is the piece moved in m1
-    if (    piece_is_slider(p)
-        &&  bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), f2)
-        && !bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), t2))
+    ksq = pos.king_square(pos.side_to_move());
+    if (    piece_is_slider(p1)
+        &&  bit_is_set(squares_between(t1, ksq), f2))
     {
-        // discovered_check_candidates() works also if the Position's side to
-        // move is the opposite of the checking piece.
-        Color them = opposite_color(pos.side_to_move());
-        Bitboard dcCandidates = pos.discovered_check_candidates(them);
-
-        if (bit_is_set(dcCandidates, f2))
+        Bitboard occ = pos.occupied_squares();
+        clear_bit(&occ, f2);
+        if (bit_is_set(pos.attacks_from(p1, t1, occ), ksq))
             return true;
     }
     return false;
@@ -2091,7 +2085,7 @@ split_point_start: // At split points actual search starts from here
                 break;
             }
 
-    Rml.sort();
+    sort<RootMove>(Rml.begin(), Rml.end());
   }
 
 } // namespace