X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=41c9e15d16247d6e27762add2b08f45658c24162;hp=ef456307cafbacb4479a53627a7a1d7b58aa362d;hb=2f465927363e3e753dfb65d67f9b126afc34f4fa;hpb=ddccb5355cabb7d1a9bf2c0fe3c51b3da0234260

diff --git a/src/pawns.cpp b/src/pawns.cpp
index ef456307..41c9e15d 100644
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -61,6 +61,14 @@ namespace {
   // Unsupported pawn penalty
   const Score UnsupportedPawnPenalty = S(20, 10);
 
+  // Center bind bonus: Two pawns controlling the same central square
+  const Bitboard CenterBindMask[COLOR_NB] = {
+    (FileDBB | FileEBB) & (Rank5BB | Rank6BB | Rank7BB),
+    (FileDBB | FileEBB) & (Rank4BB | Rank3BB | Rank2BB)
+  };
+
+  const Score CenterBind = S(16, 0);
+
   // Weakness of our pawn shelter in front of the king by [distance from edge][rank]
   const Value ShelterWeakness[][RANK_NB] = {
   { V( 99), V(20), V(26), V(54), V(85), V( 92), V(108) },
@@ -195,6 +203,10 @@ namespace {
     b = e->semiopenFiles[Us] ^ 0xFF;
     e->pawnSpan[Us] = b ? int(msb(b) - lsb(b)) : 0;
 
+    // Center binds: Two pawns controlling the same central square
+    b = shift_bb<Right>(ourPawns) & shift_bb<Left>(ourPawns) & CenterBindMask[Us];
+    score += popcount<Max15>(b) * CenterBind;
+
     return score;
   }
 
@@ -215,7 +227,8 @@ void init()
           for (Rank r = RANK_2; r < RANK_8; ++r)
           {
               int bonus = Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0);
-              Connected[opposed][phalanx][r] = make_score(bonus / 2, bonus >> opposed);
+              bonus >>= opposed;
+              Connected[opposed][phalanx][r] = make_score( 3 * bonus / 2, bonus);
           }
 }