Avoid misuse of StepAttacksBB for pawns

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 10f67236f61500bcddd8e237005a9e323eeae1ed..0e57f01fffc089c2b00dc60b776800467f7c93f0 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -32,10 +32,10 @@ namespace {
   #define S(mg, eg) make_score(mg, eg)
 
   // Isolated pawn penalty by opposed flag
-  const Score Isolated[2] = { S(45, 40), S(30, 27) };
+  const Score Isolated[] = { S(45, 40), S(30, 27) };
 
   // Backward pawn penalty by opposed flag
-  const Score Backward[2] = { S(56, 33), S(41, 19) };
+  const Score Backward[] = { S(56, 33), S(41, 19) };
 
   // Unsupported pawn penalty for pawns which are neither isolated or backward
   const Score Unsupported = S(17, 8);
@@ -131,7 +131,7 @@ namespace {
         stoppers   = theirPawns & passed_pawn_mask(Us, s);
         lever      = theirPawns & pawnAttacksBB[s];
         leverPush  = theirPawns & pawnAttacksBB[s + Up];
-        doubled    = ourPawns   & (s + Up);
+        doubled    = ourPawns   & (s - Up);
         neighbours = ourPawns   & adjacent_files_bb(f);
         phalanx    = neighbours & rank_bb(s);
         supported  = neighbours & rank_bb(s - Up);
@@ -177,8 +177,8 @@ namespace {
         if (connected)
             score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)];
 
-        if (doubled)
-            score -= Doubled;
+        if (doubled && !supported)
+           score -= Doubled;
 
         if (lever)
             score += Lever[relative_rank(Us, s)];