Stockfish/src/value.h

/*
  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

  Stockfish is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  Stockfish is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/


#if !defined(VALUE_H_INCLUDED)
#define VALUE_H_INCLUDED

////
//// Includes
////

#include "piece.h"


////
//// Types
////

enum ValueType {
  VALUE_TYPE_NONE = 0,
  VALUE_TYPE_UPPER = 1,  // Upper bound
  VALUE_TYPE_LOWER = 2,  // Lower bound
  VALUE_TYPE_EXACT = 3,  // Exact score
  VALUE_TYPE_EVAL  = 4,  // Evaluation cache
  VALUE_TYPE_EV_UP = 5,  // Evaluation cache for upper bound
  VALUE_TYPE_EV_LO = 6   // Evaluation cache for lower bound
};


enum Value {
  VALUE_DRAW = 0,
  VALUE_KNOWN_WIN = 15000,
  VALUE_MATE = 30000,
  VALUE_INFINITE = 30001,
  VALUE_NONE = 30002
};


/// Score struct keeps a midgame and an endgame value in a single
/// ScoreValue 64 bit union.

enum Score;

inline Value eg_value(Score s) { return Value(int16_t(s & 0xffff)); }
inline Value mg_value(Score s) { return Value((int(s) + 32768) >> 16); }

inline Score make_score(int mg, int eg) { return Score((mg << 16) + eg); }

inline Score operator-(Score s) { return Score(-int(s)); }
inline Score operator+(Score s1, Score s2) { return Score(int(s1) + int(s2)); }
inline Score operator-(Score s1, Score s2) { return Score(int(s1) - int(s2)); }
inline void operator+=(Score& s1, Score s2) { s1 = Score(int(s1) + int(s2)); }
inline void operator-=(Score& s1, Score s2) { s1 = Score(int(s1) - int(s2)); }
inline Score operator*(int i, Score s) { return Score(i * int(s)); }
inline Score operator/(Score s, int i) { return Score(int(s) / i); }

// Only declared but not defined. We don't want to multiply two scores due to
// a very high risk of overflow. So user should explicitly convert to integer.
inline Score operator*(Score s1, Score s2);

// Following are only declared to prevent erroneus instantations
inline Score operator*(Score s, int i);
inline Score operator/(Score s1, Score s2);
inline Score operator+(Score s, int i);
inline Score operator+(int i, Score s);
inline Score operator-(Score s, int i);
inline Score operator-(int i, Score s);


////
//// Constants and variables
////

/// Piece values, middle game and endgame

/// Important: If the material values are changed, one must also
/// adjust the piece square tables, and the method game_phase() in the
/// Position class!
///
/// Values modified by Joona Kiiski

const Value PawnValueMidgame   = Value(0x0C6);
const Value PawnValueEndgame   = Value(0x102);
const Value KnightValueMidgame = Value(0x331);
const Value KnightValueEndgame = Value(0x34E);
const Value BishopValueMidgame = Value(0x344);
const Value BishopValueEndgame = Value(0x359);
const Value RookValueMidgame   = Value(0x4F6);
const Value RookValueEndgame   = Value(0x4FE);
const Value QueenValueMidgame  = Value(0x9D9);
const Value QueenValueEndgame  = Value(0x9FE);

const Value PieceValueMidgame[17] = {
  Value(0),
  PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
  RookValueMidgame, QueenValueMidgame,
  Value(0), Value(0), Value(0),
  PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
  RookValueMidgame, QueenValueMidgame,
  Value(0), Value(0), Value(0)
};

const Value PieceValueEndgame[17] = {
  Value(0),
  PawnValueEndgame, KnightValueEndgame, BishopValueEndgame,
  RookValueEndgame, QueenValueEndgame,
  Value(0), Value(0), Value(0),
  PawnValueEndgame, KnightValueEndgame, BishopValueEndgame,
  RookValueEndgame, QueenValueEndgame,
  Value(0), Value(0), Value(0)
};

/// Bonus for having the side to move (modified by Joona Kiiski)

const Score TempoValue = make_score(48, 22);


////
//// Inline functions
////

inline Value operator+ (Value v, int i) { return Value(int(v) + i); }
inline Value operator+ (Value v1, Value v2) { return Value(int(v1) + int(v2)); }
inline void operator+= (Value &v1, Value v2) {
  v1 = Value(int(v1) + int(v2));
}
inline Value operator- (Value v, int i) { return Value(int(v) - i); }
inline Value operator- (Value v) { return Value(-int(v)); }
inline Value operator- (Value v1, Value v2) { return Value(int(v1) - int(v2)); }
inline void operator-= (Value &v1, Value v2) {
  v1 = Value(int(v1) - int(v2));
}
inline Value operator* (Value v, int i) { return Value(int(v) * i); }
inline void operator*= (Value &v, int i) { v = Value(int(v) * i); }
inline Value operator* (int i, Value v) { return Value(int(v) * i); }
inline Value operator/ (Value v, int i) { return Value(int(v) / i); }
inline void operator/= (Value &v, int i) { v = Value(int(v) / i); }


inline Value value_mate_in(int ply) {
  return Value(VALUE_MATE - Value(ply));
}

inline Value value_mated_in(int ply) {
  return Value(-VALUE_MATE + Value(ply));
}

inline bool is_upper_bound(ValueType vt) {
  return (int(vt) & int(VALUE_TYPE_UPPER)) != 0;
}

inline bool is_lower_bound(ValueType vt) {
  return (int(vt) & int(VALUE_TYPE_LOWER)) != 0;
}

inline Value piece_value_midgame(PieceType pt) {
  return PieceValueMidgame[pt];
}

inline Value piece_value_endgame(PieceType pt) {
  return PieceValueEndgame[pt];
}

inline Value piece_value_midgame(Piece p) {
  return PieceValueMidgame[p];
}

inline Value piece_value_endgame(Piece p) {
  return PieceValueEndgame[p];
}


////
//// Prototypes
////

extern Value value_to_tt(Value v, int ply);
extern Value value_from_tt(Value v, int ply);
extern int value_to_centipawns(Value v);
extern Value value_from_centipawns(int cp);
extern const std::string value_to_string(Value v);


#endif // !defined(VALUE_H_INCLUDED)