#undef S
#undef V
+
+ template<Color Us>
+ Score evaluate_pawns(const Position& pos, Bitboard ourPawns,
+ Bitboard theirPawns, Pawns::Entry* e) {
+
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+
+ Bitboard b;
+ Square s;
+ File f;
+ Rank r;
+ bool passed, isolated, doubled, opposed, chain, backward, candidate;
+ Score value = SCORE_ZERO;
+ const Square* pl = pos.piece_list(Us, PAWN);
+
+ // Loop through all pawns of the current color and score each pawn
+ while ((s = *pl++) != SQ_NONE)
+ {
+ assert(pos.piece_on(s) == make_piece(Us, PAWN));
+
+ f = file_of(s);
+ r = rank_of(s);
+
+ // This file cannot be half open
+ e->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));
+
+ // Flag the pawn as passed, isolated, doubled or member of a pawn
+ // chain (but not the backward one).
+ chain = ourPawns & adjacent_files_bb(f) & b;
+ isolated = !(ourPawns & adjacent_files_bb(f));
+ doubled = ourPawns & forward_bb(Us, s);
+ opposed = theirPawns & forward_bb(Us, s);
+ passed = !(theirPawns & passed_pawn_mask(Us, s));
+
+ // Test for backward pawn
+ backward = false;
+
+ // If the pawn is passed, isolated, or member of a pawn chain it cannot
+ // be backward. If there are friendly pawns behind on adjacent files
+ // or if can capture an enemy pawn it cannot be backward either.
+ if ( !(passed | isolated | chain)
+ && !(ourPawns & attack_span_mask(Them, s))
+ && !(pos.attacks_from<PAWN>(s, Us) & theirPawns))
+ {
+ // We now know that there are no friendly pawns beside or behind this
+ // pawn on adjacent files. We now check whether the pawn is
+ // backward by looking in the forward direction on the adjacent
+ // files, and seeing whether we meet a friendly or an enemy pawn first.
+ b = pos.attacks_from<PAWN>(s, Us);
+
+ // Note that we are sure to find something because pawn is not passed
+ // nor isolated, so loop is potentially infinite, but it isn't.
+ while (!(b & (ourPawns | theirPawns)))
+ Us == WHITE ? b <<= 8 : b >>= 8;
+
+ // The friendly pawn needs to be at least two ranks closer than the
+ // enemy pawn in order to help the potentially backward pawn advance.
+ backward = (b | (Us == WHITE ? b << 8 : b >> 8)) & theirPawns;
+ }
+
+ assert(opposed | passed | (attack_span_mask(Us, s) & theirPawns));
+
+ // A not passed pawn is a candidate to become passed if it is free to
+ // advance and if the number of friendly pawns beside or behind this
+ // pawn on adjacent files is higher or equal than the number of
+ // enemy pawns in the forward direction on the adjacent files.
+ candidate = !(opposed | passed | backward | isolated)
+ && (b = attack_span_mask(Them, s + pawn_push(Us)) & ourPawns) != 0
+ && popcount<Max15>(b) >= popcount<Max15>(attack_span_mask(Us, s) & theirPawns);
+
+ // Passed pawns will be properly scored in evaluation 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)
+ e->passedPawns[Us] |= s;
+
+ // Score this pawn
+ if (isolated)
+ value -= IsolatedPawnPenalty[opposed][f];
+
+ if (doubled)
+ value -= DoubledPawnPenalty[opposed][f];
+
+ if (backward)
+ value -= BackwardPawnPenalty[opposed][f];
+
+ if (chain)
+ value += ChainBonus[f];
+
+ if (candidate)
+ value += CandidateBonus[relative_rank(Us, s)];
+ }
+
+ return value;
+ }
}
+namespace Pawns {
-/// PawnTable::probe() takes a position object as input, computes a PawnEntry
-/// object, and returns a pointer to it. The result is also stored in a hash
-/// table, so we don't have to recompute everything when the same pawn structure
-/// occurs again.
+/// probe() takes a position object as input, computes a Entry object, and returns
+/// a pointer to it. The result is also stored in a hash table, so we don't have
+/// to recompute everything when the same pawn structure occurs again.
-PawnEntry* PawnTable::probe(const Position& pos) {
+Entry* probe(const Position& pos, Table& entries) {
Key key = pos.pawn_key();
- PawnEntry* e = entries[key];
+ Entry* e = entries[key];
// If e->key matches the position's pawn hash key, it means that we
// have analysed this pawn structure before, and we can simply return
}
-/// PawnTable::evaluate_pawns() evaluates each pawn of the given color
-
-template<Color Us>
-Score PawnTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
- Bitboard theirPawns, PawnEntry* e) {
-
- const Color Them = (Us == WHITE ? BLACK : WHITE);
-
- Bitboard b;
- Square s;
- File f;
- Rank r;
- bool passed, isolated, doubled, opposed, chain, backward, candidate;
- Score value = SCORE_ZERO;
- const Square* pl = pos.piece_list(Us, PAWN);
-
- // Loop through all pawns of the current color and score each pawn
- while ((s = *pl++) != SQ_NONE)
- {
- assert(pos.piece_on(s) == make_piece(Us, PAWN));
-
- f = file_of(s);
- r = rank_of(s);
-
- // This file cannot be half open
- e->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));
-
- // Flag the pawn as passed, isolated, doubled or member of a pawn
- // chain (but not the backward one).
- chain = ourPawns & adjacent_files_bb(f) & b;
- isolated = !(ourPawns & adjacent_files_bb(f));
- doubled = ourPawns & forward_bb(Us, s);
- opposed = theirPawns & forward_bb(Us, s);
- passed = !(theirPawns & passed_pawn_mask(Us, s));
-
- // Test for backward pawn
- backward = false;
-
- // If the pawn is passed, isolated, or member of a pawn chain it cannot
- // be backward. If there are friendly pawns behind on adjacent files
- // or if can capture an enemy pawn it cannot be backward either.
- if ( !(passed | isolated | chain)
- && !(ourPawns & attack_span_mask(Them, s))
- && !(pos.attacks_from<PAWN>(s, Us) & theirPawns))
- {
- // We now know that there are no friendly pawns beside or behind this
- // pawn on adjacent files. We now check whether the pawn is
- // backward by looking in the forward direction on the adjacent
- // files, and seeing whether we meet a friendly or an enemy pawn first.
- b = pos.attacks_from<PAWN>(s, Us);
-
- // Note that we are sure to find something because pawn is not passed
- // nor isolated, so loop is potentially infinite, but it isn't.
- while (!(b & (ourPawns | theirPawns)))
- Us == WHITE ? b <<= 8 : b >>= 8;
-
- // The friendly pawn needs to be at least two ranks closer than the
- // enemy pawn in order to help the potentially backward pawn advance.
- backward = (b | (Us == WHITE ? b << 8 : b >> 8)) & theirPawns;
- }
-
- assert(opposed | passed | (attack_span_mask(Us, s) & theirPawns));
-
- // A not passed pawn is a candidate to become passed if it is free to
- // advance and if the number of friendly pawns beside or behind this
- // pawn on adjacent files is higher or equal than the number of
- // enemy pawns in the forward direction on the adjacent files.
- candidate = !(opposed | passed | backward | isolated)
- && (b = attack_span_mask(Them, s + pawn_push(Us)) & ourPawns) != 0
- && popcount<Max15>(b) >= popcount<Max15>(attack_span_mask(Us, s) & theirPawns);
-
- // Passed pawns will be properly scored in evaluation 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)
- e->passedPawns[Us] |= s;
-
- // Score this pawn
- if (isolated)
- value -= IsolatedPawnPenalty[opposed][f];
-
- if (doubled)
- value -= DoubledPawnPenalty[opposed][f];
-
- if (backward)
- value -= BackwardPawnPenalty[opposed][f];
-
- if (chain)
- value += ChainBonus[f];
-
- if (candidate)
- value += CandidateBonus[relative_rank(Us, s)];
- }
-
- return value;
-}
-
-
-/// PawnEntry::shelter_storm() calculates shelter and storm penalties for the file
+/// Entry::shelter_storm() calculates shelter and storm penalties for the file
/// the king is on, as well as the two adjacent files.
template<Color Us>
-Value PawnEntry::shelter_storm(const Position& pos, Square ksq) {
+Value Entry::shelter_storm(const Position& pos, Square ksq) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
}
-/// PawnEntry::update_safety() calculates and caches a bonus for king safety. It is
+/// Entry::update_safety() calculates and caches a bonus for king safety. It is
/// called only when king square changes, about 20% of total king_safety() calls.
template<Color Us>
-Score PawnEntry::update_safety(const Position& pos, Square ksq) {
+Score Entry::update_safety(const Position& pos, Square ksq) {
kingSquares[Us] = ksq;
castleRights[Us] = pos.can_castle(Us);
}
// Explicit template instantiation
-template Score PawnEntry::update_safety<WHITE>(const Position& pos, Square ksq);
-template Score PawnEntry::update_safety<BLACK>(const Position& pos, Square ksq);
+template Score Entry::update_safety<WHITE>(const Position& pos, Square ksq);
+template Score Entry::update_safety<BLACK>(const Position& pos, Square ksq);
+
+} // namespace Pawns
#include "position.h"
#include "types.h"
-const int PawnTableSize = 16384;
+namespace Pawns {
-/// PawnEntry 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 probe method in a PawnTable object)
-/// returns a pointer to a PawnEntry object.
+/// Pawns::Entry contains various information about a pawn structure. Currently,
+/// it only includes a middle game and 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 probe function)
+/// returns a pointer to an Entry object.
-class PawnEntry {
+struct Entry {
- friend struct PawnTable;
-
-public:
- Score pawns_value() const;
- Bitboard pawn_attacks(Color c) 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;
+ Score pawns_value() const { return value; }
+ Bitboard pawn_attacks(Color c) const { return pawnAttacks[c]; }
+ Bitboard passed_pawns(Color c) const { return passedPawns[c]; }
+ int file_is_half_open(Color c, File f) const { return halfOpenFiles[c] & (1 << int(f)); }
+ int has_open_file_to_left(Color c, File f) const { return halfOpenFiles[c] & ((1 << int(f)) - 1); }
+ int has_open_file_to_right(Color c, File f) const { return halfOpenFiles[c] & ~((1 << int(f+1)) - 1); }
template<Color Us>
- Score king_safety(const Position& pos, Square ksq);
+ Score king_safety(const Position& pos, Square ksq) {
+
+ return kingSquares[Us] == ksq && castleRights[Us] == pos.can_castle(Us)
+ ? kingSafety[Us] : update_safety<Us>(pos, ksq);
+ }
-private:
template<Color Us>
Score update_safety(const Position& pos, Square ksq);
Score kingSafety[COLOR_NB];
};
+typedef HashTable<Entry, 16384> Table;
-/// The PawnTable class represents a pawn hash table. The most important
-/// method is probe, which returns a pointer to a PawnEntry object.
-
-struct PawnTable {
-
- PawnEntry* probe(const Position& pos);
-
- template<Color Us>
- static Score evaluate_pawns(const Position& pos, Bitboard ourPawns,
- Bitboard theirPawns, PawnEntry* e);
-
- HashTable<PawnEntry, PawnTableSize> entries;
-};
-
-
-inline Score PawnEntry::pawns_value() const {
- return value;
-}
-
-inline Bitboard PawnEntry::pawn_attacks(Color c) const {
- return pawnAttacks[c];
-}
-
-inline Bitboard PawnEntry::passed_pawns(Color c) const {
- return passedPawns[c];
-}
-
-inline int PawnEntry::file_is_half_open(Color c, File f) const {
- return halfOpenFiles[c] & (1 << int(f));
-}
-
-inline int PawnEntry::has_open_file_to_left(Color c, File f) const {
- return halfOpenFiles[c] & ((1 << int(f)) - 1);
-}
-
-inline int PawnEntry::has_open_file_to_right(Color c, File f) const {
- return halfOpenFiles[c] & ~((1 << int(f+1)) - 1);
-}
+Entry* probe(const Position& pos, Table& entries);
-template<Color Us>
-inline Score PawnEntry::king_safety(const Position& pos, Square ksq) {
- return kingSquares[Us] == ksq && castleRights[Us] == pos.can_castle(Us)
- ? kingSafety[Us] : update_safety<Us>(pos, ksq);
}
#endif // !defined(PAWNS_H_INCLUDED)