Introduce SimpleHash class

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 4cd1a316db626d31aff71562e8fabce012cc7971..0846344223137f93a2372c737b6a553609e8c5a4 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -81,27 +81,6 @@ namespace {
 //// Functions
 ////
 
-/// PawnInfoTable c'tor and d'tor instantiated one each thread
-
-PawnInfoTable::PawnInfoTable() {
-
-  entries = new PawnInfo[PawnTableSize];
-
-  if (!entries)
-  {
-      std::cerr << "Failed to allocate " << (PawnTableSize * sizeof(PawnInfo))
-                << " bytes for pawn hash table." << std::endl;
-      Application::exit_with_failure();
-  }
-  memset(entries, 0, PawnTableSize * sizeof(PawnInfo));
-}
-
-
-PawnInfoTable::~PawnInfoTable() {
-
-  delete [] entries;
-}
-
 
 /// PawnInfoTable::get_pawn_info() takes a position object as input, computes
 /// a PawnInfo object, and returns a pointer to it. The result is also stored
@@ -113,8 +92,7 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) const {
   assert(pos.is_ok());
 
   Key key = pos.get_pawn_key();
-  unsigned index = unsigned(key & (PawnTableSize - 1));
-  PawnInfo* pi = entries + index;
+  PawnInfo* pi = find(key);
 
   // If pi->key matches the position's pawn hash key, it means that we
   // have analysed this pawn structure before, and we can simply return
@@ -124,18 +102,19 @@ 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;
 }
 
@@ -154,11 +133,6 @@ 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)
   {
@@ -167,13 +141,16 @@ 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));
 
       // Passed, isolated, doubled or member of a pawn
       // chain (but not the backward one) ?
       passed   = !(theirPawns & passed_pawn_mask(Us, s));
-      doubled  =   ourPawns   & squares_behind(Us, s);
+      doubled  =   ourPawns   & squares_in_front_of(Us, s);
       opposed  =   theirPawns & squares_in_front_of(Us, s);
       isolated = !(ourPawns   & neighboring_files_bb(f));
       chain    =   ourPawns   & neighboring_files_bb(f) & b;
@@ -213,15 +190,10 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
                  && (b = attack_span_mask(opposite_color(Us), s + pawn_push(Us)) & ourPawns) != EmptyBoardBB
                  &&  count_1s<Max15>(b) >= count_1s<Max15>(attack_span_mask(Us, s) & theirPawns);
 
-      // In order to prevent doubled passed pawns from receiving a too big
-      // bonus, only the frontmost passed pawn on each file is considered as
-      // a true passed pawn.
-      if (passed && (ourPawns & squares_in_front_of(Us, s)))
-          passed = false;
-
       // Mark the pawn as passed. Pawn will be properly scored in evaluation
-      // because we need full attack info to evaluate passed pawns.
-      if (passed)
+      // because we need full attack info to evaluate passed pawns. Only the
+      // frontmost passed pawn on each file is considered a true passed pawn.
+      if (passed && !doubled)
           set_bit(&(pi->passedPawns[Us]), s);
 
       // Score this pawn
@@ -240,6 +212,5 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
       if (candidate)
           value += CandidateBonus[relative_rank(Us, s)];
   }
-
   return value;
 }