/*
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
#include <algorithm>
#include <cassert>
+#include "bitboard.h"
#include "bitcount.h"
#include "endgame.h"
#include "movegen.h"
using std::string;
-extern uint32_t probe_kpk_bitbase(Square wksq, Square wpsq, Square bksq, Color stm);
-
namespace {
// Table used to drive the defending king towards the edge of the board
// in KX vs K and KQ vs KR endgames.
- const int MateTable[64] = {
+ const int MateTable[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,
// Table used to drive the defending king towards a corner square of the
// right color in KBN vs K endgames.
- const int KBNKMateTable[64] = {
+ const int KBNKMateTable[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,
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));
// Stalemate detection with lone king
if ( pos.side_to_move() == weakerSide
- && !pos.in_check()
+ && !pos.checkers()
&& !MoveList<LEGAL>(pos).size()) {
return VALUE_DRAW;
}
Square loserKSq = pos.king_square(weakerSide);
Value result = pos.non_pawn_material(strongerSide)
- + pos.piece_count(strongerSide, PAWN) * PawnValueEndgame
+ + pos.count<PAWN>(strongerSide) * PawnValueEg
+ MateTable[loserKSq]
+ DistanceBonus[square_distance(winnerKSq, loserKSq)];
- if ( pos.piece_count(strongerSide, QUEEN)
- || pos.piece_count(strongerSide, ROOK)
+ if ( pos.count<QUEEN>(strongerSide)
+ || pos.count<ROOK>(strongerSide)
|| pos.bishop_pair(strongerSide)) {
result += VALUE_KNOWN_WIN;
}
template<>
Value Endgame<KBNK>::operator()(const Position& pos) const {
+ assert(pos.non_pawn_material(strongerSide) == KnightValueMg + BishopValueMg);
assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
- assert(pos.piece_count(weakerSide, PAWN) == VALUE_ZERO);
- assert(pos.non_pawn_material(strongerSide) == KnightValueMidgame + BishopValueMidgame);
- assert(pos.piece_count(strongerSide, BISHOP) == 1);
- assert(pos.piece_count(strongerSide, KNIGHT) == 1);
- assert(pos.piece_count(strongerSide, PAWN) == 0);
+ 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);
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;
+ Color us;
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();
+ 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];
- stm = ~pos.side_to_move();
+ wpsq = ~pos.list<PAWN>(BLACK)[0];
+ us = ~pos.side_to_move();
}
if (file_of(wpsq) >= FILE_E)
wpsq = mirror(wpsq);
}
- if (!probe_kpk_bitbase(wksq, wpsq, bksq, stm))
+ if (!Bitbases::probe_kpk(wksq, wpsq, bksq, us))
return VALUE_DRAW;
- Value result = VALUE_KNOWN_WIN
- + PawnValueEndgame
- + Value(rank_of(wpsq));
+ Value result = VALUE_KNOWN_WIN + PawnValueEg + Value(rank_of(wpsq));
return strongerSide == pos.side_to_move() ? result : -result;
}
template<>
Value Endgame<KRKP>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
- assert(pos.piece_count(strongerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(strongerSide) == RookValueMg);
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)
{
// 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 = RookValueEndgame - Value(square_distance(wksq, bpsq));
+ result = RookValueEg - Value(square_distance(wksq, bpsq));
// 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 = RookValueEndgame - Value(square_distance(wksq, bpsq));
+ result = RookValueEg - Value(square_distance(wksq, bpsq));
// If the pawn is far advanced and supported by the defending king,
// the position is drawish
template<>
Value Endgame<KRKB>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
- assert(pos.piece_count(strongerSide, PAWN) == 0);
- assert(pos.non_pawn_material(weakerSide) == BishopValueMidgame);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
- assert(pos.piece_count(weakerSide, BISHOP) == 1);
+ assert(pos.non_pawn_material(strongerSide) == RookValueMg);
+ 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;
template<>
Value Endgame<KRKN>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
- assert(pos.piece_count(strongerSide, PAWN) == 0);
- assert(pos.non_pawn_material(weakerSide) == KnightValueMidgame);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
- assert(pos.piece_count(weakerSide, KNIGHT) == 1);
+ assert(pos.non_pawn_material(strongerSide) == RookValueMg);
+ 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;
}
+/// 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 = QueenValueEg
+ - PawnValueEg
+ + DistanceBonus[square_distance(winnerKSq, loserKSq)];
+
+ if ( square_distance(loserKSq, pawnSq) == 1
+ && relative_rank(weakerSide, pawnSq) == RANK_7)
+ {
+ File f = file_of(pawnSq);
+
+ if (f == FILE_A || f == FILE_C || f == FILE_F || f == FILE_H)
+ result = Value(DistanceBonus[square_distance(winnerKSq, loserKSq)]);
+ }
+ return strongerSide == pos.side_to_move() ? result : -result;
+}
+
+
/// KQ vs KR. This is almost identical to KX vs K: We give the attacking
/// king a bonus for having the kings close together, and for forcing the
/// defending king towards the edge. If we also take care to avoid null move
template<>
Value Endgame<KQKR>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == QueenValueMidgame);
- assert(pos.piece_count(strongerSide, PAWN) == 0);
- assert(pos.non_pawn_material(weakerSide) == RookValueMidgame);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(strongerSide) == QueenValueMg);
+ 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 = QueenValueEndgame
- - RookValueEndgame
+ Value result = QueenValueEg
+ - RookValueEg
+ MateTable[loserKSq]
+ DistanceBonus[square_distance(winnerKSq, loserKSq)];
template<>
Value Endgame<KBBKN>::operator()(const Position& pos) const {
- assert(pos.piece_count(strongerSide, BISHOP) == 2);
- assert(pos.non_pawn_material(strongerSide) == 2*BishopValueMidgame);
- assert(pos.piece_count(weakerSide, KNIGHT) == 1);
- assert(pos.non_pawn_material(weakerSide) == KnightValueMidgame);
+ 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 = BishopValueEndgame;
+ 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)]);
template<>
ScaleFactor Endgame<KBPsK>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
- assert(pos.piece_count(strongerSide, BISHOP) == 1);
- assert(pos.piece_count(strongerSide, PAWN) >= 1);
+ assert(pos.non_pawn_material(strongerSide) == BishopValueMg);
+ 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);
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 weaker pawn closest to opponent's queening square
+ Bitboard wkPawns = pos.pieces(weakerSide, PAWN);
+ Square weakerPawnSq = strongerSide == WHITE ? msb(wkPawns) : lsb(wkPawns);
+
+ 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;
}
template<>
ScaleFactor Endgame<KQKRPs>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == QueenValueMidgame);
- 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.non_pawn_material(strongerSide) == QueenValueMg);
+ 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;
}
template<>
ScaleFactor Endgame<KRPKR>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
- assert(pos.piece_count(strongerSide, PAWN) == 1);
- assert(pos.non_pawn_material(weakerSide) == RookValueMidgame);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(strongerSide) == RookValueMg);
+ 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.
template<>
ScaleFactor Endgame<KRPPKRP>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
- assert(pos.piece_count(strongerSide, PAWN) == 2);
- assert(pos.non_pawn_material(weakerSide) == RookValueMidgame);
- assert(pos.piece_count(weakerSide, PAWN) == 1);
+ assert(pos.non_pawn_material(strongerSide) == RookValueMg);
+ 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;
template<>
ScaleFactor Endgame<KBPKB>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
- assert(pos.piece_count(strongerSide, BISHOP) == 1);
- assert(pos.piece_count(strongerSide, PAWN) == 1);
- assert(pos.non_pawn_material(weakerSide) == BishopValueMidgame);
- assert(pos.piece_count(weakerSide, BISHOP) == 1);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(strongerSide) == BishopValueMg);
+ 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.piece_list(strongerSide, PAWN)[0];
- Square strongerBishopSq = pos.piece_list(strongerSide, BISHOP)[0];
- Square weakerBishopSq = pos.piece_list(weakerSide, BISHOP)[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
template<>
ScaleFactor Endgame<KBPPKB>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
- assert(pos.piece_count(strongerSide, BISHOP) == 1);
- assert(pos.piece_count(strongerSide, PAWN) == 2);
- assert(pos.non_pawn_material(weakerSide) == BishopValueMidgame);
- assert(pos.piece_count(weakerSide, BISHOP) == 1);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(strongerSide) == BishopValueMg);
+ 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;
template<>
ScaleFactor Endgame<KBPKN>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
- assert(pos.piece_count(strongerSide, BISHOP) == 1);
- assert(pos.piece_count(strongerSide, PAWN) == 1);
- assert(pos.non_pawn_material(weakerSide) == KnightValueMidgame);
- assert(pos.piece_count(weakerSide, KNIGHT) == 1);
- assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(strongerSide) == BishopValueMg);
+ 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.piece_list(strongerSide, PAWN)[0];
- Square strongerBishopSq = pos.piece_list(strongerSide, BISHOP)[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)
template<>
ScaleFactor Endgame<KNPK>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == KnightValueMidgame);
- 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(strongerSide) == KnightValueMg);
+ 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 wpsq = pos.list<PAWN>(strongerSide)[0];
+ Color us = pos.side_to_move();
if (strongerSide == BLACK)
{
wksq = ~wksq;
bksq = ~bksq;
wpsq = ~wpsq;
- stm = ~stm;
+ us = ~us;
}
if (file_of(wpsq) >= FILE_E)
// 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 probe_kpk_bitbase(wksq, wpsq, bksq, stm) ? SCALE_FACTOR_NONE : SCALE_FACTOR_DRAW;
+ return Bitbases::probe_kpk(wksq, wpsq, bksq, us) ? SCALE_FACTOR_NONE : SCALE_FACTOR_DRAW;
}