/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2013 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
namespace {
- // Table used to drive the defending king towards the edge of the board
+ // Table used to drive the king towards the edge of the board
// in KX vs K and KQ vs KR endgames.
- const int MateTable[SQUARE_NB] = {
+ const int PushToEdges[SQUARE_NB] = {
100, 90, 80, 70, 70, 80, 90, 100,
90, 70, 60, 50, 50, 60, 70, 90,
80, 60, 40, 30, 30, 40, 60, 80,
100, 90, 80, 70, 70, 80, 90, 100,
};
- // Table used to drive the defending king towards a corner square of the
+ // Table used to drive the king towards a corner square of the
// right color in KBN vs K endgames.
- const int KBNKMateTable[SQUARE_NB] = {
+ const int PushToCorners[SQUARE_NB] = {
200, 190, 180, 170, 160, 150, 140, 130,
190, 180, 170, 160, 150, 140, 130, 140,
180, 170, 155, 140, 140, 125, 140, 150,
130, 140, 150, 160, 170, 180, 190, 200
};
- // The attacking side is given a descending bonus based on distance between
- // the two kings in basic endgames.
- const int DistanceBonus[8] = { 0, 0, 100, 80, 60, 40, 20, 10 };
+ // Tables used to drive a piece towards or away from another piece
+ const int PushClose[8] = { 0, 0, 100, 80, 60, 40, 20, 10 };
+ const int PushAway [8] = { 0, 5, 20, 40, 60, 80, 90, 100 };
// Get the material key of a Position out of the given endgame key code
// like "KBPKN". The trick here is to first forge an ad-hoc fen string
add<KRKP>("KRKP");
add<KRKB>("KRKB");
add<KRKN>("KRKN");
+ add<KQKP>("KQKP");
add<KQKR>("KQKR");
add<KBBKN>("KBBKN");
add<KNPK>("KNPK");
+ add<KNPKB>("KNPKB");
add<KRPKR>("KRPKR");
add<KBPKB>("KBPKB");
add<KBPKN>("KBPKN");
Value Endgame<KXK>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
- assert(pos.piece_count(weakerSide, PAWN) == VALUE_ZERO);
+ assert(!pos.count<PAWN>(weakerSide));
+ assert(!pos.checkers()); // Eval is never called when in check
// Stalemate detection with lone king
- if ( pos.side_to_move() == weakerSide
- && !pos.in_check()
- && !MoveList<LEGAL>(pos).size()) {
- return VALUE_DRAW;
- }
+ if (pos.side_to_move() == weakerSide && !MoveList<LEGAL>(pos).size())
+ return VALUE_DRAW;
Square winnerKSq = pos.king_square(strongerSide);
Square loserKSq = pos.king_square(weakerSide);
Value result = pos.non_pawn_material(strongerSide)
- + pos.piece_count(strongerSide, PAWN) * PawnValueEg
- + MateTable[loserKSq]
- + DistanceBonus[square_distance(winnerKSq, loserKSq)];
-
- if ( pos.piece_count(strongerSide, QUEEN)
- || pos.piece_count(strongerSide, ROOK)
- || pos.bishop_pair(strongerSide)) {
- result += VALUE_KNOWN_WIN;
- }
+ + pos.count<PAWN>(strongerSide) * PawnValueEg
+ + PushToEdges[loserKSq]
+ + PushClose[square_distance(winnerKSq, loserKSq)];
+
+ if ( pos.count<QUEEN>(strongerSide)
+ || pos.count<ROOK>(strongerSide)
+ || pos.bishop_pair(strongerSide))
+ result += VALUE_KNOWN_WIN;
return strongerSide == pos.side_to_move() ? result : -result;
}
template<>
Value Endgame<KBNK>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
- assert(pos.piece_count(weakerSide, PAWN) == VALUE_ZERO);
assert(pos.non_pawn_material(strongerSide) == KnightValueMg + BishopValueMg);
- assert(pos.piece_count(strongerSide, BISHOP) == 1);
- assert(pos.piece_count(strongerSide, KNIGHT) == 1);
- assert(pos.piece_count(strongerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
+ assert(pos.count<BISHOP>(strongerSide) == 1);
+ assert(pos.count<KNIGHT>(strongerSide) == 1);
+ assert(pos.count< PAWN>(strongerSide) == 0);
+ assert(pos.count< PAWN>(weakerSide ) == 0);
Square winnerKSq = pos.king_square(strongerSide);
Square loserKSq = pos.king_square(weakerSide);
- Square bishopSquare = pos.piece_list(strongerSide, BISHOP)[0];
+ Square bishopSq = pos.list<BISHOP>(strongerSide)[0];
// kbnk_mate_table() tries to drive toward corners A1 or H8,
// if we have a bishop that cannot reach the above squares we
// mirror the kings so to drive enemy toward corners A8 or H1.
- if (opposite_colors(bishopSquare, SQ_A1))
+ if (opposite_colors(bishopSq, SQ_A1))
{
winnerKSq = mirror(winnerKSq);
loserKSq = mirror(loserKSq);
}
Value result = VALUE_KNOWN_WIN
- + DistanceBonus[square_distance(winnerKSq, loserKSq)]
- + KBNKMateTable[loserKSq];
+ + PushClose[square_distance(winnerKSq, loserKSq)]
+ + PushToCorners[loserKSq];
return strongerSide == pos.side_to_move() ? result : -result;
}
assert(pos.non_pawn_material(strongerSide) == VALUE_ZERO);
assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
- assert(pos.piece_count(strongerSide, PAWN) == 1);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.count<PAWN>(strongerSide) == 1);
+ assert(pos.count<PAWN>(weakerSide ) == 0);
- Square wksq, bksq, wpsq;
- Color stm;
+ Square wksq = pos.king_square(strongerSide);
+ Square bksq = pos.king_square(weakerSide);
+ Square psq = pos.list<PAWN>(strongerSide)[0];
+ Color us = pos.side_to_move();
- if (strongerSide == WHITE)
- {
- wksq = pos.king_square(WHITE);
- bksq = pos.king_square(BLACK);
- wpsq = pos.piece_list(WHITE, PAWN)[0];
- stm = pos.side_to_move();
- }
- else
+ if (strongerSide == BLACK)
{
- wksq = ~pos.king_square(BLACK);
- bksq = ~pos.king_square(WHITE);
- wpsq = ~pos.piece_list(BLACK, PAWN)[0];
- stm = ~pos.side_to_move();
+ wksq = ~wksq;
+ bksq = ~bksq;
+ psq = ~psq;
+ us = ~us;
}
- if (file_of(wpsq) >= FILE_E)
+ if (file_of(psq) >= FILE_E)
{
wksq = mirror(wksq);
bksq = mirror(bksq);
- wpsq = mirror(wpsq);
+ psq = mirror(psq);
}
- if (!Bitbases::probe_kpk(wksq, wpsq, bksq, stm))
+ if (!Bitbases::probe_kpk(wksq, psq, bksq, us))
return VALUE_DRAW;
- Value result = VALUE_KNOWN_WIN + PawnValueEg + Value(rank_of(wpsq));
+ Value result = VALUE_KNOWN_WIN + PawnValueEg + Value(rank_of(psq));
return strongerSide == pos.side_to_move() ? result : -result;
}
Value Endgame<KRKP>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == RookValueMg);
- assert(pos.piece_count(strongerSide, PAWN) == 0);
assert(pos.non_pawn_material(weakerSide) == 0);
- assert(pos.piece_count(weakerSide, PAWN) == 1);
-
- Square wksq, wrsq, bksq, bpsq;
- int tempo = (pos.side_to_move() == strongerSide);
+ assert(pos.count<PAWN>(strongerSide) == 0);
+ assert(pos.count<PAWN>(weakerSide ) == 1);
- wksq = pos.king_square(strongerSide);
- wrsq = pos.piece_list(strongerSide, ROOK)[0];
- bksq = pos.king_square(weakerSide);
- bpsq = pos.piece_list(weakerSide, PAWN)[0];
+ Square wksq = pos.king_square(strongerSide);
+ Square bksq = pos.king_square(weakerSide);
+ Square rsq = pos.list<ROOK>(strongerSide)[0];
+ Square psq = pos.list<PAWN>(weakerSide)[0];
if (strongerSide == BLACK)
{
wksq = ~wksq;
- wrsq = ~wrsq;
bksq = ~bksq;
- bpsq = ~bpsq;
+ rsq = ~rsq;
+ psq = ~psq;
}
- Square queeningSq = file_of(bpsq) | RANK_1;
+ Square queeningSq = file_of(psq) | RANK_1;
Value result;
// If the stronger side's king is in front of the pawn, it's a win
- if (wksq < bpsq && file_of(wksq) == file_of(bpsq))
- result = RookValueEg - Value(square_distance(wksq, bpsq));
+ if (wksq < psq && file_of(wksq) == file_of(psq))
+ result = RookValueEg - Value(square_distance(wksq, psq));
// If the weaker side's king is too far from the pawn and the rook,
- // it's a win
- else if ( square_distance(bksq, bpsq) - (tempo ^ 1) >= 3
- && square_distance(bksq, wrsq) >= 3)
- result = RookValueEg - Value(square_distance(wksq, bpsq));
+ // it's a win.
+ else if ( square_distance(bksq, psq) >= 3 + (pos.side_to_move() == weakerSide)
+ && square_distance(bksq, rsq) >= 3)
+ result = RookValueEg - Value(square_distance(wksq, psq));
// If the pawn is far advanced and supported by the defending king,
// the position is drawish
else if ( rank_of(bksq) <= RANK_3
- && square_distance(bksq, bpsq) == 1
+ && square_distance(bksq, psq) == 1
&& rank_of(wksq) >= RANK_4
- && square_distance(wksq, bpsq) - tempo > 2)
- result = Value(80 - square_distance(wksq, bpsq) * 8);
+ && square_distance(wksq, psq) > 2 + (pos.side_to_move() == strongerSide))
+ result = Value(80 - square_distance(wksq, psq) * 8);
else
result = Value(200)
- - Value(square_distance(wksq, bpsq + DELTA_S) * 8)
- + Value(square_distance(bksq, bpsq + DELTA_S) * 8)
- + Value(square_distance(bpsq, queeningSq) * 8);
+ - Value(square_distance(wksq, psq + DELTA_S) * 8)
+ + Value(square_distance(bksq, psq + DELTA_S) * 8)
+ + Value(square_distance(psq, queeningSq) * 8);
return strongerSide == pos.side_to_move() ? result : -result;
}
Value Endgame<KRKB>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == RookValueMg);
- assert(pos.piece_count(strongerSide, PAWN) == 0);
- assert(pos.non_pawn_material(weakerSide) == BishopValueMg);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
- assert(pos.piece_count(weakerSide, BISHOP) == 1);
+ assert(pos.non_pawn_material(weakerSide ) == BishopValueMg);
+ assert(pos.count<BISHOP>(weakerSide ) == 1);
+ assert(pos.count< PAWN>(weakerSide ) == 0);
+ assert(pos.count< PAWN>(strongerSide) == 0);
- Value result = Value(MateTable[pos.king_square(weakerSide)]);
+ Value result = Value(PushToEdges[pos.king_square(weakerSide)]);
return strongerSide == pos.side_to_move() ? result : -result;
}
Value Endgame<KRKN>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == RookValueMg);
- assert(pos.piece_count(strongerSide, PAWN) == 0);
- assert(pos.non_pawn_material(weakerSide) == KnightValueMg);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
- assert(pos.piece_count(weakerSide, KNIGHT) == 1);
-
- const int penalty[8] = { 0, 10, 14, 20, 30, 42, 58, 80 };
+ assert(pos.non_pawn_material(weakerSide ) == KnightValueMg);
+ assert(pos.count<KNIGHT>(weakerSide ) == 1);
+ assert(pos.count< PAWN>(weakerSide ) == 0);
+ assert(pos.count< PAWN>(strongerSide) == 0);
Square bksq = pos.king_square(weakerSide);
- Square bnsq = pos.piece_list(weakerSide, KNIGHT)[0];
- Value result = Value(MateTable[bksq] + penalty[square_distance(bksq, bnsq)]);
+ Square bnsq = pos.list<KNIGHT>(weakerSide)[0];
+ Value result = Value(PushToEdges[bksq] + PushAway[square_distance(bksq, bnsq)]);
+ return strongerSide == pos.side_to_move() ? result : -result;
+}
+
+
+/// KQ vs KP. In general, a win for the stronger side, however, there are a few
+/// important exceptions. Pawn on 7th rank, A,C,F or H file, with king next can
+/// be a draw, so we scale down to distance between kings only.
+template<>
+Value Endgame<KQKP>::operator()(const Position& pos) const {
+
+ assert(pos.non_pawn_material(strongerSide) == QueenValueMg);
+ assert(pos.non_pawn_material(weakerSide ) == VALUE_ZERO);
+ assert(pos.count<PAWN>(strongerSide) == 0);
+ assert(pos.count<PAWN>(weakerSide ) == 1);
+
+ Square winnerKSq = pos.king_square(strongerSide);
+ Square loserKSq = pos.king_square(weakerSide);
+ Square pawnSq = pos.list<PAWN>(weakerSide)[0];
+
+ Value result = Value(PushClose[square_distance(winnerKSq, loserKSq)]);
+
+ if ( relative_rank(weakerSide, pawnSq) != RANK_7
+ || square_distance(loserKSq, pawnSq) != 1
+ || !((FileABB | FileCBB | FileFBB | FileHBB) & pawnSq))
+ result += QueenValueEg - PawnValueEg;
+
return strongerSide == pos.side_to_move() ? result : -result;
}
Value Endgame<KQKR>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == QueenValueMg);
- assert(pos.piece_count(strongerSide, PAWN) == 0);
- assert(pos.non_pawn_material(weakerSide) == RookValueMg);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(weakerSide ) == RookValueMg);
+ assert(pos.count<PAWN>(strongerSide) == 0);
+ assert(pos.count<PAWN>(weakerSide ) == 0);
Square winnerKSq = pos.king_square(strongerSide);
Square loserKSq = pos.king_square(weakerSide);
Value result = QueenValueEg
- RookValueEg
- + MateTable[loserKSq]
- + DistanceBonus[square_distance(winnerKSq, loserKSq)];
+ + PushToEdges[loserKSq]
+ + PushClose[square_distance(winnerKSq, loserKSq)];
return strongerSide == pos.side_to_move() ? result : -result;
}
+
+/// KBB vs KN. This is almost always a win. We try to push enemy king to a corner
+/// and away from his knight. For a reference of this difficult endgame see:
+/// en.wikipedia.org/wiki/Chess_endgame#Effect_of_tablebases_on_endgame_theory
+
template<>
Value Endgame<KBBKN>::operator()(const Position& pos) const {
- assert(pos.piece_count(strongerSide, BISHOP) == 2);
- assert(pos.non_pawn_material(strongerSide) == 2*BishopValueMg);
- assert(pos.piece_count(weakerSide, KNIGHT) == 1);
- assert(pos.non_pawn_material(weakerSide) == KnightValueMg);
+ assert(pos.non_pawn_material(strongerSide) == 2 * BishopValueMg);
+ assert(pos.non_pawn_material(weakerSide ) == KnightValueMg);
+ assert(pos.count<BISHOP>(strongerSide) == 2);
+ assert(pos.count<KNIGHT>(weakerSide ) == 1);
assert(!pos.pieces(PAWN));
- Value result = BishopValueEg;
- Square wksq = pos.king_square(strongerSide);
- Square bksq = pos.king_square(weakerSide);
- Square nsq = pos.piece_list(weakerSide, KNIGHT)[0];
-
- // Bonus for attacking king close to defending king
- result += Value(DistanceBonus[square_distance(wksq, bksq)]);
-
- // Bonus for driving the defending king and knight apart
- result += Value(square_distance(bksq, nsq) * 32);
+ Square winnerKSq = pos.king_square(strongerSide);
+ Square loserKSq = pos.king_square(weakerSide);
+ Square knightSq = pos.list<KNIGHT>(weakerSide)[0];
- // Bonus for restricting the knight's mobility
- result += Value((8 - popcount<Max15>(pos.attacks_from<KNIGHT>(nsq))) * 8);
+ Value result = VALUE_KNOWN_WIN
+ + PushToCorners[loserKSq]
+ + PushClose[square_distance(winnerKSq, loserKSq)]
+ + PushAway[square_distance(loserKSq, knightSq)];
return strongerSide == pos.side_to_move() ? result : -result;
}
-/// K and two minors vs K and one or two minors or K and two knights against
-/// king alone are always draw.
-template<>
-Value Endgame<KmmKm>::operator()(const Position&) const {
- return VALUE_DRAW;
-}
+/// Some cases of trivial draws
+template<> Value Endgame<KNNK>::operator()(const Position&) const { return VALUE_DRAW; }
+template<> Value Endgame<KmmKm>::operator()(const Position&) const { return VALUE_DRAW; }
-template<>
-Value Endgame<KNNK>::operator()(const Position&) const {
- return VALUE_DRAW;
-}
/// K, bishop and one or more pawns vs K. It checks for draws with rook pawns and
/// a bishop of the wrong color. If such a draw is detected, SCALE_FACTOR_DRAW
ScaleFactor Endgame<KBPsK>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == BishopValueMg);
- assert(pos.piece_count(strongerSide, BISHOP) == 1);
- assert(pos.piece_count(strongerSide, PAWN) >= 1);
+ assert(pos.count<BISHOP>(strongerSide) == 1);
+ assert(pos.count< PAWN>(strongerSide) >= 1);
// No assertions about the material of weakerSide, because we want draws to
// be detected even when the weaker side has some pawns.
Bitboard pawns = pos.pieces(strongerSide, PAWN);
- File pawnFile = file_of(pos.piece_list(strongerSide, PAWN)[0]);
+ File pawnFile = file_of(pos.list<PAWN>(strongerSide)[0]);
// All pawns are on a single rook file ?
if ( (pawnFile == FILE_A || pawnFile == FILE_H)
&& !(pawns & ~file_bb(pawnFile)))
{
- Square bishopSq = pos.piece_list(strongerSide, BISHOP)[0];
+ Square bishopSq = pos.list<BISHOP>(strongerSide)[0];
Square queeningSq = relative_square(strongerSide, pawnFile | RANK_8);
Square kingSq = pos.king_square(weakerSide);
// The bishop has the wrong color, and the defending king is on the
// file of the pawn(s) or the adjacent file. Find the rank of the
// frontmost pawn.
- Rank rank;
- if (strongerSide == WHITE)
- {
- for (rank = RANK_7; !(rank_bb(rank) & pawns); rank--) {}
- assert(rank >= RANK_2 && rank <= RANK_7);
- }
- else
- {
- for (rank = RANK_2; !(rank_bb(rank) & pawns); rank++) {}
- rank = Rank(rank ^ 7); // HACK to get the relative rank
- assert(rank >= RANK_2 && rank <= RANK_7);
- }
+ Square pawnSq = frontmost_sq(strongerSide, pawns);
+
// If the defending king has distance 1 to the promotion square or
// is placed somewhere in front of the pawn, it's a draw.
if ( square_distance(kingSq, queeningSq) <= 1
- || relative_rank(strongerSide, kingSq) >= rank)
+ || relative_rank(weakerSide, kingSq) <= relative_rank(weakerSide, pawnSq))
return SCALE_FACTOR_DRAW;
}
}
+
+ // All pawns on same B or G file? Then potential draw
+ if ( (pawnFile == FILE_B || pawnFile == FILE_G)
+ && !(pos.pieces(PAWN) & ~file_bb(pawnFile))
+ && pos.non_pawn_material(weakerSide) == 0
+ && pos.count<PAWN>(weakerSide) >= 1)
+ {
+ // Get weakerSide pawn that is closest to home rank
+ Square weakerPawnSq = backmost_sq(weakerSide, pos.pieces(weakerSide, PAWN));
+
+ Square strongerKingSq = pos.king_square(strongerSide);
+ Square weakerKingSq = pos.king_square(weakerSide);
+ Square bishopSq = pos.list<BISHOP>(strongerSide)[0];
+
+ // Draw if weaker pawn is on rank 7, bishop can't attack the pawn, and
+ // weaker king can stop opposing opponent's king from penetrating.
+ if ( relative_rank(strongerSide, weakerPawnSq) == RANK_7
+ && opposite_colors(bishopSq, weakerPawnSq)
+ && square_distance(weakerPawnSq, weakerKingSq) <= square_distance(weakerPawnSq, strongerKingSq))
+ return SCALE_FACTOR_DRAW;
+ }
+
return SCALE_FACTOR_NONE;
}
ScaleFactor Endgame<KQKRPs>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == QueenValueMg);
- assert(pos.piece_count(strongerSide, QUEEN) == 1);
- assert(pos.piece_count(strongerSide, PAWN) == 0);
- assert(pos.piece_count(weakerSide, ROOK) == 1);
- assert(pos.piece_count(weakerSide, PAWN) >= 1);
+ assert(pos.count<QUEEN>(strongerSide) == 1);
+ assert(pos.count< PAWN>(strongerSide) == 0);
+ assert(pos.count< ROOK>(weakerSide ) == 1);
+ assert(pos.count< PAWN>(weakerSide ) >= 1);
Square kingSq = pos.king_square(weakerSide);
- if ( relative_rank(weakerSide, kingSq) <= RANK_2
- && relative_rank(weakerSide, pos.king_square(strongerSide)) >= RANK_4
+ Square rsq = pos.list<ROOK>(weakerSide)[0];
+
+ if ( relative_rank(weakerSide, kingSq) <= RANK_2
+ && relative_rank(weakerSide, pos.king_square(strongerSide)) >= RANK_4
&& (pos.pieces(weakerSide, ROOK) & rank_bb(relative_rank(weakerSide, RANK_3)))
&& (pos.pieces(weakerSide, PAWN) & rank_bb(relative_rank(weakerSide, RANK_2)))
- && (pos.attacks_from<KING>(kingSq) & pos.pieces(weakerSide, PAWN)))
- {
- Square rsq = pos.piece_list(weakerSide, ROOK)[0];
- if (pos.attacks_from<PAWN>(rsq, strongerSide) & pos.pieces(weakerSide, PAWN))
+ && (pos.attacks_from<KING>(kingSq) & pos.pieces(weakerSide, PAWN))
+ && (pos.attacks_from<PAWN>(rsq, strongerSide) & pos.pieces(weakerSide, PAWN)))
return SCALE_FACTOR_DRAW;
- }
+
return SCALE_FACTOR_NONE;
}
ScaleFactor Endgame<KRPKR>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == RookValueMg);
- assert(pos.piece_count(strongerSide, PAWN) == 1);
- assert(pos.non_pawn_material(weakerSide) == RookValueMg);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(weakerSide) == RookValueMg);
+ assert(pos.count<PAWN>(strongerSide) == 1);
+ assert(pos.count<PAWN>(weakerSide ) == 0);
Square wksq = pos.king_square(strongerSide);
- Square wrsq = pos.piece_list(strongerSide, ROOK)[0];
- Square wpsq = pos.piece_list(strongerSide, PAWN)[0];
Square bksq = pos.king_square(weakerSide);
- Square brsq = pos.piece_list(weakerSide, ROOK)[0];
+ Square wrsq = pos.list<ROOK>(strongerSide)[0];
+ Square wpsq = pos.list<PAWN>(strongerSide)[0];
+ Square brsq = pos.list<ROOK>(weakerSide)[0];
// Orient the board in such a way that the stronger side is white, and the
// pawn is on the left half of the board.
bksq = ~bksq;
brsq = ~brsq;
}
+
if (file_of(wpsq) > FILE_D)
{
wksq = mirror(wksq);
ScaleFactor Endgame<KRPPKRP>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == RookValueMg);
- assert(pos.piece_count(strongerSide, PAWN) == 2);
- assert(pos.non_pawn_material(weakerSide) == RookValueMg);
- assert(pos.piece_count(weakerSide, PAWN) == 1);
+ assert(pos.non_pawn_material(weakerSide) == RookValueMg);
+ assert(pos.count<PAWN>(strongerSide) == 2);
+ assert(pos.count<PAWN>(weakerSide ) == 1);
- Square wpsq1 = pos.piece_list(strongerSide, PAWN)[0];
- Square wpsq2 = pos.piece_list(strongerSide, PAWN)[1];
+ Square wpsq1 = pos.list<PAWN>(strongerSide)[0];
+ Square wpsq2 = pos.list<PAWN>(strongerSide)[1];
Square bksq = pos.king_square(weakerSide);
// Does the stronger side have a passed pawn?
ScaleFactor Endgame<KPsK>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == VALUE_ZERO);
- assert(pos.piece_count(strongerSide, PAWN) >= 2);
- assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
+ assert(pos.count<PAWN>(strongerSide) >= 2);
+ assert(pos.count<PAWN>(weakerSide ) == 0);
Square ksq = pos.king_square(weakerSide);
Bitboard pawns = pos.pieces(strongerSide, PAWN);
// Does the defending king block the pawns?
if ( square_distance(ksq, relative_square(strongerSide, SQ_A8)) <= 1
|| ( file_of(ksq) == FILE_A
- && !(in_front_bb(strongerSide, ksq) & pawns)))
+ && !(in_front_bb(strongerSide, rank_of(ksq)) & pawns)))
return SCALE_FACTOR_DRAW;
}
// Are all pawns on the 'h' file?
// Does the defending king block the pawns?
if ( square_distance(ksq, relative_square(strongerSide, SQ_H8)) <= 1
|| ( file_of(ksq) == FILE_H
- && !(in_front_bb(strongerSide, ksq) & pawns)))
+ && !(in_front_bb(strongerSide, rank_of(ksq)) & pawns)))
return SCALE_FACTOR_DRAW;
}
return SCALE_FACTOR_NONE;
ScaleFactor Endgame<KBPKB>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == BishopValueMg);
- assert(pos.piece_count(strongerSide, BISHOP) == 1);
- assert(pos.piece_count(strongerSide, PAWN) == 1);
- assert(pos.non_pawn_material(weakerSide) == BishopValueMg);
- assert(pos.piece_count(weakerSide, BISHOP) == 1);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
-
- Square pawnSq = pos.piece_list(strongerSide, PAWN)[0];
- Square strongerBishopSq = pos.piece_list(strongerSide, BISHOP)[0];
- Square weakerBishopSq = pos.piece_list(weakerSide, BISHOP)[0];
+ assert(pos.non_pawn_material(weakerSide ) == BishopValueMg);
+ assert(pos.count<BISHOP>(strongerSide) == 1);
+ assert(pos.count<BISHOP>(weakerSide ) == 1);
+ assert(pos.count< PAWN>(strongerSide) == 1);
+ assert(pos.count< PAWN>(weakerSide ) == 0);
+
+ Square pawnSq = pos.list<PAWN>(strongerSide)[0];
+ Square strongerBishopSq = pos.list<BISHOP>(strongerSide)[0];
+ Square weakerBishopSq = pos.list<BISHOP>(weakerSide)[0];
Square weakerKingSq = pos.king_square(weakerSide);
// Case 1: Defending king blocks the pawn, and cannot be driven away
ScaleFactor Endgame<KBPPKB>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == BishopValueMg);
- assert(pos.piece_count(strongerSide, BISHOP) == 1);
- assert(pos.piece_count(strongerSide, PAWN) == 2);
- assert(pos.non_pawn_material(weakerSide) == BishopValueMg);
- assert(pos.piece_count(weakerSide, BISHOP) == 1);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(weakerSide ) == BishopValueMg);
+ assert(pos.count<BISHOP>(strongerSide) == 1);
+ assert(pos.count<BISHOP>(weakerSide ) == 1);
+ assert(pos.count< PAWN>(strongerSide) == 2);
+ assert(pos.count< PAWN>(weakerSide ) == 0);
- Square wbsq = pos.piece_list(strongerSide, BISHOP)[0];
- Square bbsq = pos.piece_list(weakerSide, BISHOP)[0];
+ Square wbsq = pos.list<BISHOP>(strongerSide)[0];
+ Square bbsq = pos.list<BISHOP>(weakerSide)[0];
if (!opposite_colors(wbsq, bbsq))
return SCALE_FACTOR_NONE;
Square ksq = pos.king_square(weakerSide);
- Square psq1 = pos.piece_list(strongerSide, PAWN)[0];
- Square psq2 = pos.piece_list(strongerSide, PAWN)[1];
+ Square psq1 = pos.list<PAWN>(strongerSide)[0];
+ Square psq2 = pos.list<PAWN>(strongerSide)[1];
Rank r1 = rank_of(psq1);
Rank r2 = rank_of(psq2);
Square blockSq1, blockSq2;
ScaleFactor Endgame<KBPKN>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == BishopValueMg);
- assert(pos.piece_count(strongerSide, BISHOP) == 1);
- assert(pos.piece_count(strongerSide, PAWN) == 1);
- assert(pos.non_pawn_material(weakerSide) == KnightValueMg);
- assert(pos.piece_count(weakerSide, KNIGHT) == 1);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
-
- Square pawnSq = pos.piece_list(strongerSide, PAWN)[0];
- Square strongerBishopSq = pos.piece_list(strongerSide, BISHOP)[0];
+ assert(pos.non_pawn_material(weakerSide ) == KnightValueMg);
+ assert(pos.count<BISHOP>(strongerSide) == 1);
+ assert(pos.count<KNIGHT>(weakerSide ) == 1);
+ assert(pos.count< PAWN>(strongerSide) == 1);
+ assert(pos.count< PAWN>(weakerSide ) == 0);
+
+ Square pawnSq = pos.list<PAWN>(strongerSide)[0];
+ Square strongerBishopSq = pos.list<BISHOP>(strongerSide)[0];
Square weakerKingSq = pos.king_square(weakerSide);
if ( file_of(weakerKingSq) == file_of(pawnSq)
ScaleFactor Endgame<KNPK>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == KnightValueMg);
- assert(pos.piece_count(strongerSide, KNIGHT) == 1);
- assert(pos.piece_count(strongerSide, PAWN) == 1);
- assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(weakerSide ) == VALUE_ZERO);
+ assert(pos.count<KNIGHT>(strongerSide) == 1);
+ assert(pos.count< PAWN>(strongerSide) == 1);
+ assert(pos.count< PAWN>(weakerSide ) == 0);
- Square pawnSq = pos.piece_list(strongerSide, PAWN)[0];
+ Square pawnSq = pos.list<PAWN>(strongerSide)[0];
Square weakerKingSq = pos.king_square(weakerSide);
if ( pawnSq == relative_square(strongerSide, SQ_A7)
}
+/// K, knight and a pawn vs K and bishop. If knight can block bishop from taking
+/// pawn, it's a win. Otherwise, drawn.
+template<>
+ScaleFactor Endgame<KNPKB>::operator()(const Position& pos) const {
+
+ Square pawnSq = pos.list<PAWN>(strongerSide)[0];
+ Square bishopSq = pos.list<BISHOP>(weakerSide)[0];
+ Square weakerKingSq = pos.king_square(weakerSide);
+
+ // King needs to get close to promoting pawn to prevent knight from blocking.
+ // Rules for this are very tricky, so just approximate.
+ if (forward_bb(strongerSide, pawnSq) & pos.attacks_from<BISHOP>(bishopSq))
+ return ScaleFactor(square_distance(weakerKingSq, pawnSq));
+
+ return SCALE_FACTOR_NONE;
+}
+
+
/// K and a pawn vs K and a pawn. This is done by removing the weakest side's
/// pawn and probing the KP vs K bitbase: If the weakest side has a draw without
/// the pawn, she probably has at least a draw with the pawn as well. The exception
ScaleFactor Endgame<KPKP>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == VALUE_ZERO);
- assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
- assert(pos.piece_count(WHITE, PAWN) == 1);
- assert(pos.piece_count(BLACK, PAWN) == 1);
+ assert(pos.non_pawn_material(weakerSide ) == VALUE_ZERO);
+ assert(pos.count<PAWN>(WHITE) == 1);
+ assert(pos.count<PAWN>(BLACK) == 1);
Square wksq = pos.king_square(strongerSide);
Square bksq = pos.king_square(weakerSide);
- Square wpsq = pos.piece_list(strongerSide, PAWN)[0];
- Color stm = pos.side_to_move();
+ Square psq = pos.list<PAWN>(strongerSide)[0];
+ Color us = pos.side_to_move();
if (strongerSide == BLACK)
{
wksq = ~wksq;
bksq = ~bksq;
- wpsq = ~wpsq;
- stm = ~stm;
+ psq = ~psq;
+ us = ~us;
}
- if (file_of(wpsq) >= FILE_E)
+ if (file_of(psq) >= FILE_E)
{
wksq = mirror(wksq);
bksq = mirror(bksq);
- wpsq = mirror(wpsq);
+ psq = mirror(psq);
}
// If the pawn has advanced to the fifth rank or further, and is not a
// rook pawn, it's too dangerous to assume that it's at least a draw.
- if ( rank_of(wpsq) >= RANK_5
- && file_of(wpsq) != FILE_A)
+ if (rank_of(psq) >= RANK_5 && file_of(psq) != FILE_A)
return SCALE_FACTOR_NONE;
// Probe the KPK bitbase with the weakest side's pawn removed. If it's a draw,
// it's probably at least a draw even with the pawn.
- return Bitbases::probe_kpk(wksq, wpsq, bksq, stm) ? SCALE_FACTOR_NONE : SCALE_FACTOR_DRAW;
+ return Bitbases::probe_kpk(wksq, psq, bksq, us) ? SCALE_FACTOR_NONE : SCALE_FACTOR_DRAW;
}
projects / stockfish / blobdiff