/*
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
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.checkers()
- && !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
+ + pos.count<PAWN>(strongerSide) * 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;
- }
+ 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 bishopSq = 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
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 us;
{
wksq = pos.king_square(WHITE);
bksq = pos.king_square(BLACK);
- wpsq = pos.piece_list(WHITE, PAWN)[0];
+ wpsq = pos.list<PAWN>(WHITE)[0];
us = pos.side_to_move();
}
else
{
wksq = ~pos.king_square(BLACK);
bksq = ~pos.king_square(WHITE);
- wpsq = ~pos.piece_list(BLACK, PAWN)[0];
+ wpsq = ~pos.list<PAWN>(BLACK)[0];
us = ~pos.side_to_move();
}
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);
+ assert(pos.count<PAWN>(strongerSide) == 0);
+ assert(pos.count<PAWN>(weakerSide ) == 1);
Square wksq, wrsq, bksq, bpsq;
int tempo = (pos.side_to_move() == strongerSide);
wksq = pos.king_square(strongerSide);
- wrsq = pos.piece_list(strongerSide, ROOK)[0];
bksq = pos.king_square(weakerSide);
- bpsq = pos.piece_list(weakerSide, PAWN)[0];
+ wrsq = pos.list<ROOK>(strongerSide)[0];
+ bpsq = pos.list<PAWN>(weakerSide)[0];
if (strongerSide == BLACK)
{
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)]);
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);
+ 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);
const int penalty[8] = { 0, 10, 14, 20, 30, 42, 58, 80 };
Square bksq = pos.king_square(weakerSide);
- Square bnsq = pos.piece_list(weakerSide, KNIGHT)[0];
+ Square bnsq = pos.list<KNIGHT>(weakerSide)[0];
Value result = Value(MateTable[bksq] + penalty[square_distance(bksq, bnsq)]);
return strongerSide == pos.side_to_move() ? result : -result;
}
Value Endgame<KQKP>::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) == 0);
- assert(pos.piece_count(weakerSide, PAWN) == 1);
+ 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.piece_list(weakerSide, PAWN)[0];
+ Square pawnSq = pos.list<PAWN>(weakerSide)[0];
Value result = QueenValueEg
- PawnValueEg
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);
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];
+ Square nsq = pos.list<KNIGHT>(weakerSide)[0];
// Bonus for attacking king close to defending king
result += Value(DistanceBonus[square_distance(wksq, bksq)]);
}
-/// 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);
- }
+ Rank rank = relative_rank(strongerSide, lsb(weakerSide, 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
if ( (pawnFile == FILE_B || pawnFile == FILE_G)
&& !(pos.pieces(PAWN) & ~file_bb(pawnFile))
&& pos.non_pawn_material(weakerSide) == 0
- && pos.piece_count(weakerSide, PAWN) >= 1)
+ && pos.count<PAWN>(weakerSide) >= 1)
{
- // Get weaker pawn closest to opponent's queening square
- Bitboard wkPawns = pos.pieces(weakerSide, PAWN);
- Square weakerPawnSq = strongerSide == WHITE ? msb(wkPawns) : lsb(wkPawns);
+ // Get weakerSide pawn that is closest to home rank
+ Square weakerPawnSq = lsb(weakerSide, pos.pieces(weakerSide, PAWN));
Square strongerKingSq = pos.king_square(strongerSide);
Square weakerKingSq = pos.king_square(weakerSide);
- Square bishopSq = pos.piece_list(strongerSide, BISHOP)[0];
+ 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.
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
+ 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];
+ Square rsq = pos.list<ROOK>(weakerSide)[0];
if (pos.attacks_from<PAWN>(rsq, strongerSide) & pos.pieces(weakerSide, PAWN))
return SCALE_FACTOR_DRAW;
}
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.
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];
+ Square wpsq = pos.list<PAWN>(strongerSide)[0];
Color us = pos.side_to_move();
if (strongerSide == BLACK)
projects / stockfish / blobdiff