twig.

bench 3375486

src/evaluate.cpp

@@ -156,6 +156,7 @@ namespace {
 
   // Assorted bonuses and penalties
   constexpr Score BishopPawns        = S(  3,  7);
+  constexpr Score BishopPawns1       = S(  2,  4);
   constexpr Score CloseEnemies       = S(  6,  0);
   constexpr Score CorneredBishop     = S( 50, 50);
   constexpr Score Hanging            = S( 57, 32);
@@ -345,9 +346,11 @@ namespace {
                 // Penalty according to number of pawns on the same color square as the
                 // bishop, bigger when the center files are blocked with pawns.
                 Bitboard blocked = pos.pieces(Us, PAWN) & shift<Down>(pos.pieces());
-
+                Bitboard protectedPawns = pos.pieces(Them, PAWN) & attackedBy[Them][PAWN] & ~attackedBy[Us][PAWN];
                 score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s)
                                      * (1 + popcount(blocked & CenterFiles));
+                score -= BishopPawns1 * pe->pawns_on_same_color_squares(Them, s) 
+                                      * popcount(protectedPawns & CenterFiles);
 
                 // Bonus for bishop on a long diagonal which can "see" both center squares
                 if (more_than_one(attacks_bb<BISHOP>(s, pos.pieces(PAWN)) & Center))