X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fevaluate.cpp;h=409024f1112685bcc97e0008d0bb23ee28c38dc9;hb=7eda7335fd147c394de6aa13debc75f4b6639eb0;hp=fe4eef57493c8ed3a601120dc7fee3233e7a1b5d;hpb=7f4c7cd785fed40b4c778c1b21f1cc99621bab32;p=stockfish

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index fe4eef57..409024f1 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -677,8 +677,7 @@ Value do_evaluate(const Position& pos, Value& margin) {
     Score score = SCORE_ZERO;
 
     // Undefended minors get penalized even if not under attack
-    undefendedMinors =  pos.pieces(Them)
-                      & (pos.pieces(BISHOP) | pos.pieces(KNIGHT))
+    undefendedMinors =  pos.pieces(Them, BISHOP, KNIGHT)
                       & ~ei.attackedBy[Them][ALL_PIECES];
 
     if (undefendedMinors)
@@ -900,16 +899,19 @@ Value do_evaluate(const Position& pos, Value& margin) {
                 else
                     unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
 
-                // If there aren't enemy attacks or pieces along the path to queen give
-                // huge bonus. Even bigger if we protect the pawn's path.
-                if (!unsafeSquares)
-                    ebonus += Value(rr * (squaresToQueen == defendedSquares ? 17 : 15));
-                else
-                    // OK, there are enemy attacks or pieces (but not pawns). Are those
-                    // squares which are attacked by the enemy also attacked by us ?
-                    // If yes, big bonus (but smaller than when there are no enemy attacks),
-                    // if no, somewhat smaller bonus.
-                    ebonus += Value(rr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
+                // If there aren't enemy attacks huge bonus, a bit smaller if at
+                // least block square is not attacked, otherwise smallest bonus.
+                int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 3;
+
+                // Big bonus if the path to queen is fully defended, a bit less
+                // if at least block square is defended.
+                if (defendedSquares == squaresToQueen)
+                    k += 6;
+
+                else if (defendedSquares & blockSq)
+                    k += (unsafeSquares & defendedSquares) == unsafeSquares ? 4 : 2;
+
+                mbonus += Value(k * rr), ebonus += Value(k * rr);
             }
         } // rr != 0