/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
- Copyright (C) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2004-2022 The Stockfish developers (see AUTHORS file)
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 "bitboard.h"
#include "types.h"
+namespace Stockfish {
+
namespace {
// There are 24 possible pawn squares: files A to D and ranks from 2 to 7.
} // namespace
-
bool Bitbases::probe(Square wksq, Square wpsq, Square bksq, Color stm) {
assert(file_of(wpsq) <= FILE_D);
KPKBitbase.set(idx);
}
-
namespace {
KPKPosition::KPKPosition(unsigned idx) {
stm = Color ((idx >> 12) & 0x01);
psq = make_square(File((idx >> 13) & 0x3), Rank(RANK_7 - ((idx >> 15) & 0x7)));
- // Check if two pieces are on the same square or if a king can be captured
+ // Invalid if two pieces are on the same square or if a king can be captured
if ( distance(ksq[WHITE], ksq[BLACK]) <= 1
|| ksq[WHITE] == psq
|| ksq[BLACK] == psq
|| (stm == WHITE && (pawn_attacks_bb(WHITE, psq) & ksq[BLACK])))
result = INVALID;
- // Immediate win if a pawn can be promoted without getting captured
+ // Win if the pawn can be promoted without getting captured
else if ( stm == WHITE
&& rank_of(psq) == RANK_7
- && ksq[stm] != psq + NORTH
- && ( distance(ksq[~stm], psq + NORTH) > 1
- || (attacks_bb<KING>(ksq[stm]) & (psq + NORTH))))
+ && ksq[WHITE] != psq + NORTH
+ && ( distance(ksq[BLACK], psq + NORTH) > 1
+ || (distance(ksq[WHITE], psq + NORTH) == 1)))
result = WIN;
- // Immediate draw if it is a stalemate or a king captures undefended pawn
+ // Draw if it is stalemate or the black king can capture the pawn
else if ( stm == BLACK
- && ( !(attacks_bb<KING>(ksq[stm]) & ~(attacks_bb<KING>(ksq[~stm]) | pawn_attacks_bb(~stm, psq)))
- || (attacks_bb<KING>(ksq[stm]) & psq & ~attacks_bb<KING>(ksq[~stm]))))
+ && ( !(attacks_bb<KING>(ksq[BLACK]) & ~(attacks_bb<KING>(ksq[WHITE]) | pawn_attacks_bb(WHITE, psq)))
+ || (attacks_bb<KING>(ksq[BLACK]) & ~attacks_bb<KING>(ksq[WHITE]) & psq)))
result = DRAW;
// Position will be classified later
Bitboard b = attacks_bb<KING>(ksq[stm]);
while (b)
- r |= stm == WHITE ? db[index(BLACK, ksq[BLACK] , pop_lsb(&b), psq)]
- : db[index(WHITE, pop_lsb(&b), ksq[WHITE], psq)];
+ r |= stm == WHITE ? db[index(BLACK, ksq[BLACK], pop_lsb(b), psq)]
+ : db[index(WHITE, pop_lsb(b), ksq[WHITE], psq)];
if (stm == WHITE)
{
}
} // namespace
+
+} // namespace Stockfish