X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fevaluate.cpp;h=6377faf20d0881b0c13b8b63de39b41da65a6169;hb=759d129e4760938ded462a05061b421e18990937;hp=e39bcb4a8e99721820fa637151ace370d009f5d9;hpb=06a8fd2154db41c4e438a1b065c1471d0dfd5815;p=stockfish

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index e39bcb4a..6377faf2 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -171,6 +171,7 @@ namespace {
   constexpr Score KnightOnQueen      = S( 21, 11);
   constexpr Score LongDiagonalBishop = S( 22,  0);
   constexpr Score MinorBehindPawn    = S( 16,  0);
+  constexpr Score Overload           = S( 10,  5);
   constexpr Score PawnlessFlank      = S( 20, 80);
   constexpr Score RookOnPawn         = S(  8, 24);
   constexpr Score SliderOnQueen      = S( 42, 21);
@@ -300,6 +301,7 @@ namespace {
     Bitboard b, bb;
     Square s;
     Score score = SCORE_ZERO;
+    int mob;
 
     attackedBy[Us][Pt] = 0;
 
@@ -324,7 +326,8 @@ namespace {
             kingAttacksCount[Us] += popcount(b & attackedBy[Them][KING]);
         }
 
-        int mob = popcount(b & mobilityArea[Us]);
+        mob = (Pt == KNIGHT || Pt == BISHOP) ? popcount(b & mobilityArea[Us] & ~pos.pieces(Us, QUEEN))
+                                             : popcount(b & mobilityArea[Us]);
 
         mobility[Us] += MobilityBonus[Pt - 2][mob];
 
@@ -518,7 +521,7 @@ namespace {
     Bitboard b, weak, defended, nonPawnEnemies, stronglyProtected, safeThreats;
     Score score = SCORE_ZERO;
 
-    // Non-pawn enemies attacked by a pawn
+    // Non-pawn enemies
     nonPawnEnemies = pos.pieces(Them) ^ pos.pieces(Them, PAWN);
 
     // Our safe or protected pawns
@@ -606,6 +609,12 @@ namespace {
     b = (pos.pieces(Us) ^ pos.pieces(Us, PAWN, KING)) & attackedBy[Us][ALL_PIECES];
     score += Connectivity * popcount(b);
 
+    // Bonus for overload (non-pawn enemies attacked and defended exactly once)
+    b =  nonPawnEnemies
+       & attackedBy[Us][ALL_PIECES]   & ~attackedBy2[Us]
+       & attackedBy[Them][ALL_PIECES] & ~attackedBy2[Them];
+    score += Overload * popcount(b);
+
     if (T)
         Trace::add(THREAT, Us, score);