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) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, 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 {
// There are 24 possible pawn squares: the first 4 files and ranks from 2 to 7
- const unsigned MAX_INDEX = 2*24*64*64; // stm * psq * wksq * bksq = 196608
+ constexpr unsigned MAX_INDEX = 2*24*64*64; // stm * psq * wksq * bksq = 196608
// Each uint32_t stores results of 32 positions, one per bit
uint32_t KPKBitbase[MAX_INDEX / 32];
ksq[WHITE] = Square((idx >> 0) & 0x3F);
ksq[BLACK] = Square((idx >> 6) & 0x3F);
us = Color ((idx >> 12) & 0x01);
- psq = make_square(File((idx >> 13) & 0x3), RANK_7 - Rank((idx >> 15) & 0x7));
+ 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
if ( distance(ksq[WHITE], ksq[BLACK]) <= 1
|| ksq[WHITE] == psq
|| ksq[BLACK] == psq
- || (us == WHITE && (StepAttacksBB[PAWN][psq] & ksq[BLACK])))
+ || (us == WHITE && (PawnAttacks[WHITE][psq] & ksq[BLACK])))
result = INVALID;
// Immediate win if a pawn can be promoted without getting captured
&& rank_of(psq) == RANK_7
&& ksq[us] != psq + NORTH
&& ( distance(ksq[~us], psq + NORTH) > 1
- || (StepAttacksBB[KING][ksq[us]] & (psq + NORTH))))
+ || (PseudoAttacks[KING][ksq[us]] & (psq + NORTH))))
result = WIN;
// Immediate draw if it is a stalemate or a king captures undefended pawn
else if ( us == BLACK
- && ( !(StepAttacksBB[KING][ksq[us]] & ~(StepAttacksBB[KING][ksq[~us]] | StepAttacksBB[PAWN][psq]))
- || (StepAttacksBB[KING][ksq[us]] & psq & ~StepAttacksBB[KING][ksq[~us]])))
+ && ( !(PseudoAttacks[KING][ksq[us]] & ~(PseudoAttacks[KING][ksq[~us]] | PawnAttacks[~us][psq]))
+ || (PseudoAttacks[KING][ksq[us]] & psq & ~PseudoAttacks[KING][ksq[~us]])))
result = DRAW;
// Position will be classified later
// as WIN, the position is classified as WIN, otherwise the current position is
// classified as UNKNOWN.
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Result Good = (Us == WHITE ? WIN : DRAW);
- const Result Bad = (Us == WHITE ? DRAW : WIN);
+ constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Result Good = (Us == WHITE ? WIN : DRAW);
+ constexpr Result Bad = (Us == WHITE ? DRAW : WIN);
Result r = INVALID;
- Bitboard b = StepAttacksBB[KING][ksq[Us]];
+ Bitboard b = PseudoAttacks[KING][ksq[Us]];
while (b)
r |= Us == WHITE ? db[index(Them, ksq[Them] , pop_lsb(&b), psq)]