X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=e17a3e340b939206662d259d8f58a42259585708;hp=49dc07fe671ef0885ca9b5fbfd29a8fd2cc885ad;hb=dc8c6ea2d149cfe9ce17fc9652b9ff90585c7fd8;hpb=0901e12102cf61559e6bfbbda0a040c72048dc8c

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 49dc07fe..e17a3e34 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -150,6 +150,8 @@ namespace {
 
   #undef S
 
+  const Score BishopPinBonus = make_score(66, 11);
+
   // Bonus for having the side to move (modified by Joona Kiiski)
   const Score Tempo = make_score(24, 11);
 
@@ -577,22 +579,15 @@ Value do_evaluate(const Position& pos, Value& margin) {
 
         mobility += MobilityBonus[Piece][mob];
 
-        // Add a bonus if a slider is pinning an enemy piece
-        if (   (Piece == BISHOP || Piece == ROOK || Piece == QUEEN)
-            && (PseudoAttacks[Piece][pos.king_square(Them)] & s))
-        {
-            b = BetweenBB[s][pos.king_square(Them)] & pos.pieces();
-
-            assert(b);
-
-            if (!more_than_one(b) && (b & pos.pieces(Them)))
-                score += ThreatBonus[Piece][type_of(pos.piece_on(lsb(b)))];
-        }
-
         // Decrease score if we are attacked by an enemy pawn. Remaining part
         // of threat evaluation must be done later when we have full attack info.
         if (ei.attackedBy[Them][PAWN] & s)
             score -= ThreatenedByPawnPenalty[Piece];
+        else if (Piece == BISHOP && (PseudoAttacks[Piece][pos.king_square(Them)] & s)) {
+             const Bitboard between = BetweenBB[s][pos.king_square(Them)] & pos.pieces();
+             if (!more_than_one(between))
+                 score += BishopPinBonus;
+        }
 
         // Bishop and knight outposts squares
         if (    (Piece == BISHOP || Piece == KNIGHT)
@@ -699,8 +694,7 @@ Value do_evaluate(const Position& pos, Value& margin) {
                       & ~ei.attackedBy[Them][0];
 
     if (undefendedMinors)
-        score += more_than_one(undefendedMinors) ? UndefendedMinorPenalty * 2
-                                                 : UndefendedMinorPenalty;
+        score += UndefendedMinorPenalty;
 
     // Enemy pieces not defended by a pawn and under our attack
     weakEnemies =  pos.pieces(Them)