#include <algorithm>
#include <cassert>
+#include "bitboard.h"
#include "bitcount.h"
#include "endgame.h"
-#include "pawns.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,
string sides[] = { code.substr(code.find('K', 1)), // Weaker
code.substr(0, code.find('K', 1)) }; // Stronger
- transform(sides[c].begin(), sides[c].end(), sides[c].begin(), tolower);
+ std::transform(sides[c].begin(), sides[c].end(), sides[c].begin(), tolower);
string fen = sides[0] + char('0' + int(8 - code.length()))
+ sides[1] + "/8/8/8/8/8/8/8 w - - 0 10";
- return Position(fen, false, 0).material_key();
+ return Position(fen, false, NULL).material_key();
}
template<typename M>
add<KRKP>("KRKP");
add<KRKB>("KRKB");
add<KRKN>("KRKN");
+ add<KQKP>("KQKP");
add<KQKR>("KQKR");
add<KBBKN>("KBBKN");
template<EndgameType E>
void Endgames::add(const string& code) {
- typedef typename eg_family<E>::type T;
-
- map((T*)0)[key(code, WHITE)] = new Endgame<E>(WHITE);
- map((T*)0)[key(code, BLACK)] = new Endgame<E>(BLACK);
+ map((Endgame<E>*)0)[key(code, WHITE)] = new Endgame<E>(WHITE);
+ map((Endgame<E>*)0)[key(code, BLACK)] = new Endgame<E>(BLACK);
}
assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
assert(pos.piece_count(weakerSide, PAWN) == VALUE_ZERO);
+ // Stalemate detection with lone king
+ if ( pos.side_to_move() == weakerSide
+ && !pos.checkers()
+ && !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) * PawnValueEndgame
+ + 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.piece_count(strongerSide, BISHOP) > 1)
- // TODO: check for two equal-colored bishops!
- result += VALUE_KNOWN_WIN;
+ || pos.bishop_pair(strongerSide)) {
+ result += VALUE_KNOWN_WIN;
+ }
return strongerSide == pos.side_to_move() ? result : -result;
}
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.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);
Square winnerKSq = pos.king_square(strongerSide);
Square loserKSq = pos.king_square(weakerSide);
- Square bishopSquare = pos.piece_list(strongerSide, BISHOP)[0];
+ Square bishopSq = pos.piece_list(strongerSide, BISHOP)[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.piece_count(weakerSide, PAWN) == 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();
+ us = pos.side_to_move();
}
else
{
- wksq = flip(pos.king_square(BLACK));
- bksq = flip(pos.king_square(WHITE));
- wpsq = flip(pos.piece_list(BLACK, PAWN)[0]);
- stm = flip(pos.side_to_move());
+ wksq = ~pos.king_square(BLACK);
+ bksq = ~pos.king_square(WHITE);
+ wpsq = ~pos.piece_list(BLACK, PAWN)[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.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);
if (strongerSide == BLACK)
{
- wksq = flip(wksq);
- wrsq = flip(wrsq);
- bksq = flip(bksq);
- bpsq = flip(bpsq);
+ wksq = ~wksq;
+ wrsq = ~wrsq;
+ bksq = ~bksq;
+ bpsq = ~bpsq;
}
- Square queeningSq = make_square(file_of(bpsq), RANK_1);
+ Square queeningSq = file_of(bpsq) | 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 = 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.non_pawn_material(strongerSide) == RookValueMg);
assert(pos.piece_count(strongerSide, PAWN) == 0);
- assert(pos.non_pawn_material(weakerSide) == BishopValueMidgame);
+ assert(pos.non_pawn_material(weakerSide) == BishopValueMg);
assert(pos.piece_count(weakerSide, PAWN) == 0);
assert(pos.piece_count(weakerSide, BISHOP) == 1);
template<>
Value Endgame<KRKN>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
+ assert(pos.non_pawn_material(strongerSide) == RookValueMg);
assert(pos.piece_count(strongerSide, PAWN) == 0);
- assert(pos.non_pawn_material(weakerSide) == KnightValueMidgame);
+ assert(pos.non_pawn_material(weakerSide) == KnightValueMg);
assert(pos.piece_count(weakerSide, PAWN) == 0);
assert(pos.piece_count(weakerSide, KNIGHT) == 1);
}
+/// 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.piece_count(strongerSide, PAWN) == 0);
+ assert(pos.non_pawn_material(weakerSide) == 0);
+ assert(pos.piece_count(weakerSide, PAWN) == 1);
+
+ Square winnerKSq = pos.king_square(strongerSide);
+ Square loserKSq = pos.king_square(weakerSide);
+ Square pawnSq = pos.piece_list(weakerSide, PAWN)[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.non_pawn_material(strongerSide) == QueenValueMg);
assert(pos.piece_count(strongerSide, PAWN) == 0);
- assert(pos.non_pawn_material(weakerSide) == RookValueMidgame);
+ assert(pos.non_pawn_material(weakerSide) == RookValueMg);
assert(pos.piece_count(weakerSide, PAWN) == 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)];
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.non_pawn_material(strongerSide) == 2*BishopValueMg);
assert(pos.piece_count(weakerSide, KNIGHT) == 1);
- assert(pos.non_pawn_material(weakerSide) == KnightValueMidgame);
+ assert(pos.non_pawn_material(weakerSide) == KnightValueMg);
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];
result += Value(square_distance(bksq, nsq) * 32);
// Bonus for restricting the knight's mobility
- result += Value((8 - count_1s<CNT32_MAX15>(pos.attacks_from<KNIGHT>(nsq))) * 8);
+ result += Value((8 - popcount<Max15>(pos.attacks_from<KNIGHT>(nsq))) * 8);
return strongerSide == pos.side_to_move() ? result : -result;
}
template<>
ScaleFactor Endgame<KBPsK>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
+ assert(pos.non_pawn_material(strongerSide) == BishopValueMg);
assert(pos.piece_count(strongerSide, BISHOP) == 1);
assert(pos.piece_count(strongerSide, PAWN) >= 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(PAWN, strongerSide);
+ Bitboard pawns = pos.pieces(strongerSide, PAWN);
File pawnFile = file_of(pos.piece_list(strongerSide, PAWN)[0]);
// All pawns are on a single rook file ?
- if ( (pawnFile == FILE_A || pawnFile == FILE_H)
+ if ( (pawnFile == FILE_A || pawnFile == FILE_H)
&& !(pawns & ~file_bb(pawnFile)))
{
Square bishopSq = pos.piece_list(strongerSide, BISHOP)[0];
- Square queeningSq = relative_square(strongerSide, make_square(pawnFile, RANK_8));
+ Square queeningSq = relative_square(strongerSide, pawnFile | RANK_8);
Square kingSq = pos.king_square(weakerSide);
if ( opposite_colors(queeningSq, bishopSq)
&& abs(file_of(kingSq) - pawnFile) <= 1)
{
// The bishop has the wrong color, and the defending king is on the
- // file of the pawn(s) or the neighboring file. Find the rank of the
+ // file of the pawn(s) or the adjacent file. Find the rank of the
// frontmost pawn.
Rank rank;
if (strongerSide == WHITE)
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.piece_count(weakerSide, PAWN) >= 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.piece_list(strongerSide, BISHOP)[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.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);
Square kingSq = pos.king_square(weakerSide);
if ( relative_rank(weakerSide, kingSq) <= RANK_2
&& relative_rank(weakerSide, pos.king_square(strongerSide)) >= RANK_4
- && (pos.pieces(ROOK, weakerSide) & rank_bb(relative_rank(weakerSide, RANK_3)))
- && (pos.pieces(PAWN, weakerSide) & rank_bb(relative_rank(weakerSide, RANK_2)))
- && (pos.attacks_from<KING>(kingSq) & pos.pieces(PAWN, weakerSide)))
+ && (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(PAWN, weakerSide))
+ if (pos.attacks_from<PAWN>(rsq, strongerSide) & pos.pieces(weakerSide, PAWN))
return SCALE_FACTOR_DRAW;
}
return SCALE_FACTOR_NONE;
template<>
ScaleFactor Endgame<KRPKR>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
+ assert(pos.non_pawn_material(strongerSide) == RookValueMg);
assert(pos.piece_count(strongerSide, PAWN) == 1);
- assert(pos.non_pawn_material(weakerSide) == RookValueMidgame);
+ assert(pos.non_pawn_material(weakerSide) == RookValueMg);
assert(pos.piece_count(weakerSide, PAWN) == 0);
Square wksq = pos.king_square(strongerSide);
// pawn is on the left half of the board.
if (strongerSide == BLACK)
{
- wksq = flip(wksq);
- wrsq = flip(wrsq);
- wpsq = flip(wpsq);
- bksq = flip(bksq);
- brsq = flip(brsq);
+ wksq = ~wksq;
+ wrsq = ~wrsq;
+ wpsq = ~wpsq;
+ bksq = ~bksq;
+ brsq = ~brsq;
}
if (file_of(wpsq) > FILE_D)
{
File f = file_of(wpsq);
Rank r = rank_of(wpsq);
- Square queeningSq = make_square(f, RANK_8);
+ Square queeningSq = f | RANK_8;
int tempo = (pos.side_to_move() == strongerSide);
// If the pawn is not too far advanced and the defending king defends the
template<>
ScaleFactor Endgame<KRPPKRP>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
+ assert(pos.non_pawn_material(strongerSide) == RookValueMg);
assert(pos.piece_count(strongerSide, PAWN) == 2);
- assert(pos.non_pawn_material(weakerSide) == RookValueMidgame);
+ assert(pos.non_pawn_material(weakerSide) == RookValueMg);
assert(pos.piece_count(weakerSide, PAWN) == 1);
Square wpsq1 = pos.piece_list(strongerSide, PAWN)[0];
assert(pos.piece_count(weakerSide, PAWN) == 0);
Square ksq = pos.king_square(weakerSide);
- Bitboard pawns = pos.pieces(PAWN, strongerSide);
+ Bitboard pawns = pos.pieces(strongerSide, PAWN);
// Are all pawns on the 'a' file?
if (!(pawns & ~FileABB))
{
// 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))
+ || ( file_of(ksq) == FILE_A
+ && !(in_front_bb(strongerSide, 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))
+ || ( file_of(ksq) == FILE_H
+ && !(in_front_bb(strongerSide, 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.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) == BishopValueMidgame);
+ assert(pos.non_pawn_material(weakerSide) == BishopValueMg);
assert(pos.piece_count(weakerSide, BISHOP) == 1);
assert(pos.piece_count(weakerSide, PAWN) == 0);
return SCALE_FACTOR_DRAW;
else
{
- Bitboard path = squares_in_front_of(strongerSide, pawnSq);
+ Bitboard path = forward_bb(strongerSide, pawnSq);
- if (path & pos.pieces(KING, weakerSide))
+ if (path & pos.pieces(weakerSide, KING))
return SCALE_FACTOR_DRAW;
if ( (pos.attacks_from<BISHOP>(weakerBishopSq) & path)
template<>
ScaleFactor Endgame<KBPPKB>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
+ 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) == BishopValueMidgame);
+ assert(pos.non_pawn_material(weakerSide) == BishopValueMg);
assert(pos.piece_count(weakerSide, BISHOP) == 1);
assert(pos.piece_count(weakerSide, PAWN) == 0);
if (relative_rank(strongerSide, psq1) > relative_rank(strongerSide, psq2))
{
blockSq1 = psq1 + pawn_push(strongerSide);
- blockSq2 = make_square(file_of(psq2), rank_of(psq1));
+ blockSq2 = file_of(psq2) | rank_of(psq1);
}
else
{
blockSq1 = psq2 + pawn_push(strongerSide);
- blockSq2 = make_square(file_of(psq1), rank_of(psq2));
+ blockSq2 = file_of(psq1) | rank_of(psq2);
}
switch (file_distance(psq1, psq2))
return SCALE_FACTOR_NONE;
case 1:
- // Pawns on neighboring files. Draw if defender firmly controls the square
+ // Pawns on adjacent files. Draw if defender firmly controls the square
// in front of the frontmost pawn's path, and the square diagonally behind
// this square on the file of the other pawn.
if ( ksq == blockSq1
&& opposite_colors(ksq, wbsq)
&& ( bbsq == blockSq2
- || (pos.attacks_from<BISHOP>(blockSq2) & pos.pieces(BISHOP, weakerSide))
+ || (pos.attacks_from<BISHOP>(blockSq2) & pos.pieces(weakerSide, BISHOP))
|| abs(r1 - r2) >= 2))
return SCALE_FACTOR_DRAW;
else if ( ksq == blockSq2
&& opposite_colors(ksq, wbsq)
&& ( bbsq == blockSq1
- || (pos.attacks_from<BISHOP>(blockSq1) & pos.pieces(BISHOP, weakerSide))))
+ || (pos.attacks_from<BISHOP>(blockSq1) & pos.pieces(weakerSide, BISHOP))))
return SCALE_FACTOR_DRAW;
else
return SCALE_FACTOR_NONE;
template<>
ScaleFactor Endgame<KBPKN>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
+ 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) == KnightValueMidgame);
+ assert(pos.non_pawn_material(weakerSide) == KnightValueMg);
assert(pos.piece_count(weakerSide, KNIGHT) == 1);
assert(pos.piece_count(weakerSide, PAWN) == 0);
template<>
ScaleFactor Endgame<KNPK>::operator()(const Position& pos) const {
- assert(pos.non_pawn_material(strongerSide) == KnightValueMidgame);
+ 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);
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();
+ Color us = pos.side_to_move();
if (strongerSide == BLACK)
{
- wksq = flip(wksq);
- bksq = flip(bksq);
- wpsq = flip(wpsq);
- stm = flip(stm);
+ wksq = ~wksq;
+ bksq = ~bksq;
+ wpsq = ~wpsq;
+ 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;
}
projects / stockfish / blobdiff