Remove backmost_sq (#2190)

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 8d6f812a6d56cf5607e06f51c903f96cad0fc01f..bbcadceb3bed6a5d4c4944cc2e50b3bb0aa41a8e 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -35,9 +35,10 @@ namespace {
   constexpr Score Backward = S( 9, 24);
   constexpr Score Doubled  = S(11, 56);
   constexpr Score Isolated = S( 5, 15);
+  constexpr Score WeakUnopposed = S( 13, 27);
 
   // Connected pawn bonus
-  constexpr int Connected[RANK_NB] = { 0, 13, 17, 24, 59, 96, 171 };
+  constexpr int Connected[RANK_NB] = { 0, 7, 8, 12, 29, 48, 86 };
 
   // Strength of pawn shelter for our king by [distance from edge][rank].
   // RANK_1 = 0 is used for files where we have no pawn, or pawn is behind our king.
@@ -77,7 +78,7 @@ namespace {
     Bitboard ourPawns   = pos.pieces(  Us, PAWN);
     Bitboard theirPawns = pos.pieces(Them, PAWN);
 
-    e->passedPawns[Us] = e->pawnAttacksSpan[Us] = e->weakUnopposed[Us] = 0;
+    e->passedPawns[Us] = e->pawnAttacksSpan[Us] = 0;
     e->kingSquares[Us]   = SQ_NONE;
     e->pawnAttacks[Us]   = pawn_attacks_bb<Us>(ourPawns);
 
@@ -86,7 +87,6 @@ namespace {
     {
         assert(pos.piece_on(s) == make_piece(Us, PAWN));
 
-        File f = file_of(s);
         Rank r = relative_rank(Us, s);
 
         e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s);
@@ -97,7 +97,7 @@ namespace {
         lever      = theirPawns & PawnAttacks[Us][s];
         leverPush  = theirPawns & PawnAttacks[Us][s + Up];
         doubled    = ourPawns   & (s - Up);
-        neighbours = ourPawns   & adjacent_files_bb(f);
+        neighbours = ourPawns   & adjacent_files_bb(s);
         phalanx    = neighbours & rank_bb(s);
         support    = neighbours & rank_bb(s - Up);
 
@@ -110,9 +110,8 @@ namespace {
         // full attack info to evaluate them. Include also not passed pawns
         // which could become passed after one or two pawn pushes when are
         // not attacked more times than defended.
-        if (   !(stoppers ^ lever ^ leverPush)
-            && (support || !more_than_one(lever))
-            && popcount(phalanx) >= popcount(leverPush))
+        if (   !(stoppers ^ lever) ||
+              (!(stoppers ^ leverPush) && popcount(phalanx) >= popcount(leverPush)))
             e->passedPawns[Us] |= s;
 
         else if (stoppers == square_bb(s + Up) && r >= RANK_5)
@@ -126,15 +125,16 @@ namespace {
         // Score this pawn
         if (support | phalanx)
         {
-            int v = (phalanx ? 3 : 2) * Connected[r];
-            v = 17 * popcount(support) + (v >> (opposed + 1));
+            int v =  Connected[r] * (phalanx ? 3 : 2) / (opposed ? 2 : 1)
+                   + 17 * popcount(support);
+
             score += make_score(v, v * (r - 2) / 4);
         }
         else if (!neighbours)
-            score -= Isolated, e->weakUnopposed[Us] += !opposed;
+            score -= Isolated + WeakUnopposed * int(!opposed);
 
         else if (backward)
-            score -= Backward, e->weakUnopposed[Us] += !opposed;
+            score -= Backward + WeakUnopposed * int(!opposed);
 
         if (doubled && !support)
             score -= Doubled;
@@ -190,7 +190,7 @@ void Entry::evaluate_shelter(const Position& pos, Square ksq, Score& shelter) {
   for (File f = File(center - 1); f <= File(center + 1); ++f)
   {
       b = ourPawns & file_bb(f);
-      Rank ourRank = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;
+      Rank ourRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
 
       b = theirPawns & file_bb(f);
       Rank theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;