Generalize shift_bb() to handle double pushes

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 1d52d30cd9ccdb8f746d11eb10d89ebc26ed3dc4..b1422ac67eccb50fefdebde17d7396d01b0542db 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -583,7 +583,7 @@ namespace {
 
     const Color Them = (Us == WHITE ? BLACK : WHITE);
 
-    Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
+    Bitboard b, squaresToQueen, defendedSquares, unsafeSquares;
     Score score = SCORE_ZERO;
 
     b = ei.pi->passed_pawns(Us);
@@ -633,33 +633,22 @@ namespace {
                 else
                     defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
 
-                // If there aren't any enemy attacks, then assign a huge bonus.
-                // The bonus will be a bit smaller if at least the block square
-                // isn't attacked, otherwise assign the smallest possible bonus.
-                int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 3;
+                // If there aren't any enemy attacks, assign a big bonus. Otherwise
+                // assign a smaller bonus if the block square isn't attacked.
+                int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 0;
 
-                // Assign a big bonus if the path to the queen is fully defended,
-                // otherwise assign a bit less of a bonus if at least the block
-                // square is defended.
+                // If the path to queen is fully defended, assign a big bonus.
+                // Otherwise assign a smaller bonus if the block square is defended.
                 if (defendedSquares == squaresToQueen)
                     k += 6;
 
                 else if (defendedSquares & blockSq)
-                    k += (unsafeSquares & defendedSquares) == unsafeSquares ? 4 : 2;
+                    k += 4;
 
                 mbonus += Value(k * rr), ebonus += Value(k * rr);
             }
         } // rr != 0
 
-        // Increase the bonus if the passed pawn is supported by a friendly pawn
-        // on the same rank and a bit smaller if it's on the previous rank.
-        supportingPawns = pos.pieces(Us, PAWN) & adjacent_files_bb(file_of(s));
-        if (supportingPawns & rank_bb(s))
-            ebonus += Value(r * 20);
-
-        else if (supportingPawns & rank_bb(s - pawn_push(Us)))
-            ebonus += Value(r * 12);
-
         // Rook pawns are a special case: They are sometimes worse, and
         // sometimes better than other passed pawns. It is difficult to find
         // good rules for determining whether they are good or bad. For now,
@@ -713,7 +702,9 @@ namespace {
   template<Color Us>
   int evaluate_space(const Position& pos, const EvalInfo& ei) {
 
-    const Color Them = (Us == WHITE ? BLACK : WHITE);
+    const Color  Them     = (Us == WHITE ? BLACK    : WHITE);
+    const Square Down     = (Us == WHITE ? DELTA_S  : DELTA_N);
+    const Square DownDown = (Us == WHITE ? DELTA_SS : DELTA_NN);
 
     // Find the safe squares for our pieces inside the area defined by
     // SpaceMask[]. A square is unsafe if it is attacked by an enemy
@@ -725,8 +716,8 @@ namespace {
 
     // Find all squares which are at most three squares behind some friendly pawn
     Bitboard behind = pos.pieces(Us, PAWN);
-    behind |= (Us == WHITE ? behind >>  8 : behind <<  8);
-    behind |= (Us == WHITE ? behind >> 16 : behind << 16);
+    behind |= shift_bb<    Down>(behind);
+    behind |= shift_bb<DownDown>(behind);
 
     // Since SpaceMask[Us] is fully on our half of the board
     assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);