Micro optimize open files calculation

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 07decab1fd4c52e9c490f5468c5f4c94d9d73b31..658a570079509e1aee2efad52bef96c887705e8f 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -40,23 +40,26 @@ namespace {
 
   #define S(mg, eg) make_score(mg, eg)
 
-  // Doubled pawn penalty by file
-  const Score DoubledPawnPenalty[8] = {
-    S(13, 43), S(20, 48), S(23, 48), S(23, 48),
-    S(23, 48), S(23, 48), S(20, 48), S(13, 43)
-  };
-
-  // Isolated pawn penalty by file
-  const Score IsolatedPawnPenalty[8] = {
-    S(25, 30), S(36, 35), S(40, 35), S(40, 35),
-    S(40, 35), S(40, 35), S(36, 35), S(25, 30)
-  };
-
-  // Backward pawn penalty by file
-  const Score BackwardPawnPenalty[8] = {
-    S(20, 28), S(29, 31), S(33, 31), S(33, 31),
-    S(33, 31), S(33, 31), S(29, 31), S(20, 28)
-  };
+  // Doubled pawn penalty by opposed flag and file
+  const Score DoubledPawnPenalty[2][8] = {
+  { S(13, 43), S(20, 48), S(23, 48), S(23, 48),
+    S(23, 48), S(23, 48), S(20, 48), S(13, 43) },
+  { S(13, 43), S(20, 48), S(23, 48), S(23, 48),
+    S(23, 48), S(23, 48), S(20, 48), S(13, 43) }};
+
+  // Isolated pawn penalty by opposed flag and file
+  const Score IsolatedPawnPenalty[2][8] = {
+  { S(37, 45), S(54, 52), S(60, 52), S(60, 52),
+    S(60, 52), S(60, 52), S(54, 52), S(37, 45) },
+  { S(25, 30), S(36, 35), S(40, 35), S(40, 35),
+    S(40, 35), S(40, 35), S(36, 35), S(25, 30) }};
+
+  // Backward pawn penalty by opposed flag and file
+  const Score BackwardPawnPenalty[2][8] = {
+  { S(30, 42), S(43, 46), S(49, 46), S(49, 46),
+    S(49, 46), S(49, 46), S(43, 46), S(30, 42) },
+  { S(20, 28), S(29, 31), S(33, 31), S(33, 31),
+    S(33, 31), S(33, 31), S(29, 31), S(20, 28) }};
 
   // Pawn chain membership bonus by file
   const Score ChainBonus[8] = {
@@ -90,6 +93,7 @@ PawnInfoTable::PawnInfoTable() {
                 << " bytes for pawn hash table." << std::endl;
       Application::exit_with_failure();
   }
+  memset(entries, 0, PawnTableSize * sizeof(PawnInfo));
 }
 
 
@@ -120,18 +124,19 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) const {
 
   // Clear the PawnInfo object, and set the key
   memset(pi, 0, sizeof(PawnInfo));
+  pi->halfOpenFiles[WHITE] = pi->halfOpenFiles[BLACK] = 0xFF;
   pi->kingSquares[WHITE] = pi->kingSquares[BLACK] = SQ_NONE;
   pi->key = key;
 
   // Calculate pawn attacks
-  Bitboard whitePawns = pos.pieces(PAWN, WHITE);
-  Bitboard blackPawns = pos.pieces(PAWN, BLACK);
-  pi->pawnAttacks[WHITE] = ((whitePawns << 9) & ~FileABB) | ((whitePawns << 7) & ~FileHBB);
-  pi->pawnAttacks[BLACK] = ((blackPawns >> 7) & ~FileABB) | ((blackPawns >> 9) & ~FileHBB);
+  Bitboard wPawns = pos.pieces(PAWN, WHITE);
+  Bitboard bPawns = pos.pieces(PAWN, BLACK);
+  pi->pawnAttacks[WHITE] = ((wPawns << 9) & ~FileABB) | ((wPawns << 7) & ~FileHBB);
+  pi->pawnAttacks[BLACK] = ((bPawns >> 7) & ~FileABB) | ((bPawns >> 9) & ~FileHBB);
 
   // Evaluate pawns for both colors
-  pi->value =  evaluate_pawns<WHITE>(pos, whitePawns, blackPawns, pi)
-             - evaluate_pawns<BLACK>(pos, blackPawns, whitePawns, pi);
+  pi->value =  evaluate_pawns<WHITE>(pos, wPawns, bPawns, pi)
+             - evaluate_pawns<BLACK>(pos, bPawns, wPawns, pi);
   return pi;
 }
 
@@ -150,11 +155,6 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
   const BitCountType Max15 = CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
   const Square* ptr = pos.piece_list_begin(Us, PAWN);
 
-  // Initialize halfOpenFiles[]
-  for (f = FILE_A; f <= FILE_H; f++)
-      if (!(ourPawns & file_bb(f)))
-          pi->halfOpenFiles[Us] |= (1 << f);
-
   // Loop through all pawns of the current color and score each pawn
   while ((s = *ptr++) != SQ_NONE)
   {
@@ -163,6 +163,9 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
       f = square_file(s);
       r = square_rank(s);
 
+      // This file cannot be half open
+      pi->halfOpenFiles[Us] &= ~(1 << f);
+
       // Our rank plus previous one. Used for chain detection.
       b = rank_bb(r) | rank_bb(Us == WHITE ? r - Rank(1) : r + Rank(1));
 
@@ -222,20 +225,14 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
 
       // Score this pawn
       if (isolated)
-      {
-          value -= IsolatedPawnPenalty[f];
-          if (!opposed)
-              value -= IsolatedPawnPenalty[f] / 2;
-      }
+          value -= IsolatedPawnPenalty[opposed][f];
+
       if (doubled)
-          value -= DoubledPawnPenalty[f];
+          value -= DoubledPawnPenalty[opposed][f];
 
       if (backward)
-      {
-          value -= BackwardPawnPenalty[f];
-          if (!opposed)
-              value -= BackwardPawnPenalty[f] / 2;
-      }
+          value -= BackwardPawnPenalty[opposed][f];
+
       if (chain)
           value += ChainBonus[f];
 
@@ -245,4 +242,3 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
 
   return value;
 }
-