Introduce SimpleHash class

[stockfish] / src / pawns.h

diff --git a/src/pawns.h b/src/pawns.h
index 557580e11ca3f41ee674ab8a58ee1362249fe39f..e41044091566050567d413cb2d5888dba6585538 100644 (file)
--- a/src/pawns.h
+++ b/src/pawns.h
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2009 Marco Costalba
+  Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -26,71 +26,66 @@
 ////
 
 #include "bitboard.h"
+#include "position.h"
+#include "tt.h"
 #include "value.h"
 
+
 ////
 //// Types
 ////
 
+const int PawnTableSize = 16384;
+
 /// PawnInfo is a class which contains various information about a pawn
 /// structure. Currently, it only includes a middle game and an end game
 /// pawn structure evaluation, and a bitboard of passed pawns. We may want
 /// to add further information in the future. A lookup to the pawn hash table
 /// (performed by calling the get_pawn_info method in a PawnInfoTable object)
 /// returns a pointer to a PawnInfo object.
-class Position;
-
 class PawnInfo {
 
   friend class PawnInfoTable;
 
 public:
-  PawnInfo() { clear(); }
-
-  Score value() const;
-  Value kingside_storm_value(Color c) const;
-  Value queenside_storm_value(Color c) const;
+  Score pawns_value() const;
   Bitboard pawn_attacks(Color c) const;
-  Bitboard passed_pawns() const;
+  Bitboard passed_pawns(Color c) const;
   int file_is_half_open(Color c, File f) const;
   int has_open_file_to_left(Color c, File f) const;
   int has_open_file_to_right(Color c, File f) const;
-  int get_king_shelter(const Position& pos, Color c, Square ksq);
+
+  template<Color Us>
+  Score king_shelter(const Position& pos, Square ksq);
 
 private:
-  void clear();
-  int updateShelter(const Position& pos, Color c, Square ksq);
+  template<Color Us>
+  Score updateShelter(const Position& pos, Square ksq);
 
   Key key;
-  Bitboard passedPawns;
+  Bitboard passedPawns[2];
   Bitboard pawnAttacks[2];
-  int16_t mgValue, egValue;
-  int16_t ksStormValue[2], qsStormValue[2];
-  uint8_t halfOpenFiles[2];
   Square kingSquares[2];
-  uint8_t kingShelters[2];
+  Score value;
+  int halfOpenFiles[2];
+  Score kingShelters[2];
 };
 
-/// The PawnInfoTable class represents a pawn hash table.  It is basically
-/// just an array of PawnInfo objects and a few methods for accessing these
-/// objects.  The most important method is get_pawn_info, which looks up a
-/// position in the table and returns a pointer to a PawnInfo object.
 
-class PawnInfoTable {
+/// The PawnInfoTable class represents a pawn hash table. The most important
+/// method is get_pawn_info, which returns a pointer to a PawnInfo object.
+
+class PawnInfoTable : public SimpleHash<PawnInfo, PawnTableSize> {
+
+  enum SideType { KingSide, QueenSide };
 
 public:
-  PawnInfoTable(unsigned numOfEntries);
-  ~PawnInfoTable();
-  PawnInfo* get_pawn_info(const Position& pos);
+  PawnInfo* get_pawn_info(const Position& pos) const;
+  void prefetch(Key key) const;
 
 private:
-  typedef std::pair<Value, Value> Values;
-
   template<Color Us>
-  Values evaluate_pawns(const Position& pos, Bitboard ourPawns, Bitboard theirPawns, PawnInfo* pi);
-
-  unsigned size;
-  PawnInfo* entries;
+  Score evaluate_pawns(const Position& pos, Bitboard ourPawns, Bitboard theirPawns, PawnInfo* pi) const;
 };
 
 
@@ -98,24 +93,23 @@ private:
 //// Inline functions
 ////
 
-inline Score PawnInfo::value() const {
-  return Score(mgValue, egValue);
+inline void PawnInfoTable::prefetch(Key key) const {
+
+    unsigned index = unsigned(key & (PawnTableSize - 1));
+    PawnInfo* pi = entries + index;
+    ::prefetch((char*) pi);
 }
 
-inline Bitboard PawnInfo::passed_pawns() const {
-  return passedPawns;
+inline Score PawnInfo::pawns_value() const {
+  return value;
 }
 
 inline Bitboard PawnInfo::pawn_attacks(Color c) const {
   return pawnAttacks[c];
 }
 
-inline Value PawnInfo::kingside_storm_value(Color c) const {
-  return Value(ksStormValue[c]);
-}
-
-inline Value PawnInfo::queenside_storm_value(Color c) const {
-  return Value(qsStormValue[c]);
+inline Bitboard PawnInfo::passed_pawns(Color c) const {
+  return passedPawns[c];
 }
 
 inline int PawnInfo::file_is_half_open(Color c, File f) const {
@@ -130,8 +124,34 @@ inline int PawnInfo::has_open_file_to_right(Color c, File f) const {
   return halfOpenFiles[c] & ~((1 << int(f+1)) - 1);
 }
 
-inline int PawnInfo::get_king_shelter(const Position& pos, Color c, Square ksq) {
-  return (kingSquares[c] == ksq ? kingShelters[c] : updateShelter(pos, c, ksq));
+/// PawnInfo::updateShelter() calculates and caches king shelter. It is called
+/// only when king square changes, about 20% of total king_shelter() calls.
+template<Color Us>
+Score PawnInfo::updateShelter(const Position& pos, Square ksq) {
+
+  const int Shift = (Us == WHITE ? 8 : -8);
+
+  Bitboard pawns;
+  int r, shelter = 0;
+
+  if (relative_rank(Us, ksq) <= RANK_4)
+  {
+      pawns = pos.pieces(PAWN, Us) & this_and_neighboring_files_bb(ksq);
+      r = square_rank(ksq) * 8;
+      for (int i = 1; i < 4; i++)
+      {
+          r += Shift;
+          shelter += BitCount8Bit[(pawns >> r) & 0xFF] * (128 >> i);
+      }
+  }
+  kingSquares[Us] = ksq;
+  kingShelters[Us] = make_score(shelter, 0);
+  return kingShelters[Us];
+}
+
+template<Color Us>
+inline Score PawnInfo::king_shelter(const Position& pos, Square ksq) {
+  return kingSquares[Us] == ksq ? kingShelters[Us] : updateShelter<Us>(pos, ksq);
 }
 
 #endif // !defined(PAWNS_H_INCLUDED)