/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2014 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 "movegen.h"
#include "position.h"
-/// Simple macro to wrap a very common while loop, no facny, no flexibility,
+/// Simple macro to wrap a very common while loop, no fancy, no flexibility,
/// hardcoded names 'mlist' and 'from'.
#define SERIALIZE(b) while (b) (mlist++)->move = make_move(from, pop_lsb(&b))
(mlist++)->move = make_move(to - (d), to); }
namespace {
- template<CastlingSide Side, bool Checks, bool Chess960>
- ExtMove* generate_castle(const Position& pos, ExtMove* mlist, Color us) {
+ template<CastlingRight Cr, bool Checks, bool Chess960>
+ ExtMove* generate_castling(const Position& pos, ExtMove* mlist, Color us, const CheckInfo* ci) {
- if (pos.castle_impeded(us, Side) || !pos.can_castle(make_castle_right(us, Side)))
+ static const bool KingSide = (Cr == WHITE_OO || Cr == BLACK_OO);
+
+ if (pos.castling_impeded(Cr) || !pos.can_castle(Cr))
return mlist;
// After castling, the rook and king final positions are the same in Chess960
// as they would be in standard chess.
Square kfrom = pos.king_square(us);
- Square rfrom = pos.castle_rook_square(us, Side);
- Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1);
+ Square rfrom = pos.castling_rook_square(Cr);
+ Square kto = relative_square(us, KingSide ? SQ_G1 : SQ_C1);
Bitboard enemies = pos.pieces(~us);
assert(!pos.checkers());
- const int K = Chess960 ? kto > kfrom ? -1 : 1
- : Side == KING_SIDE ? -1 : 1;
+ const Square K = Chess960 ? kto > kfrom ? DELTA_W : DELTA_E
+ : KingSide ? DELTA_W : DELTA_E;
- for (Square s = kto; s != kfrom; s += (Square)K)
+ for (Square s = kto; s != kfrom; s += K)
if (pos.attackers_to(s) & enemies)
return mlist;
// Because we generate only legal castling moves we need to verify that
// when moving the castling rook we do not discover some hidden checker.
// For instance an enemy queen in SQ_A1 when castling rook is in SQ_B1.
- if (Chess960 && (pos.attackers_to(kto, pos.pieces() ^ rfrom) & enemies))
+ if (Chess960 && (attacks_bb<ROOK>(kto, pos.pieces() ^ rfrom) & pos.pieces(~us, ROOK, QUEEN)))
return mlist;
- (mlist++)->move = make<CASTLE>(kfrom, rfrom);
+ Move m = make<CASTLING>(kfrom, rfrom);
+
+ if (Checks && !pos.gives_check(m, *ci))
+ return mlist;
- if (Checks && !pos.gives_check((mlist - 1)->move, CheckInfo(pos)))
- --mlist;
+ (mlist++)->move = m;
return mlist;
}
(mlist++)->move = make<PROMOTION>(to - Delta, to, KNIGHT);
}
- // Knight-promotion is the only one that can give a direct check not
- // already included in the queen-promotion.
+ // Knight promotion is the only promotion that can give a direct check
+ // that's not already included in the queen promotion.
if (Type == QUIET_CHECKS && (StepAttacksBB[W_KNIGHT][to] & ci->ksq))
(mlist++)->move = make<PROMOTION>(to - Delta, to, KNIGHT);
else
// Add pawn pushes which give discovered check. This is possible only
// if the pawn is not on the same file as the enemy king, because we
// don't generate captures. Note that a possible discovery check
- // promotion has been already generated among captures.
+ // promotion has been already generated amongst the captures.
if (pawnsNotOn7 & ci->dcCandidates)
{
dc1 = shift_bb<Up>(pawnsNotOn7 & ci->dcCandidates) & emptySquares & ~file_bb(ci->ksq);
{
if (pos.is_chess960())
{
- mlist = generate_castle< KING_SIDE, Checks, true>(pos, mlist, Us);
- mlist = generate_castle<QUEEN_SIDE, Checks, true>(pos, mlist, Us);
+ mlist = generate_castling<MakeCastling<Us, KING_SIDE>::right, Checks, true>(pos, mlist, Us, ci);
+ mlist = generate_castling<MakeCastling<Us, QUEEN_SIDE>::right, Checks, true>(pos, mlist, Us, ci);
}
else
{
- mlist = generate_castle< KING_SIDE, Checks, false>(pos, mlist, Us);
- mlist = generate_castle<QUEEN_SIDE, Checks, false>(pos, mlist, Us);
+ mlist = generate_castling<MakeCastling<Us, KING_SIDE>::right, Checks, false>(pos, mlist, Us, ci);
+ mlist = generate_castling<MakeCastling<Us, QUEEN_SIDE>::right, Checks, false>(pos, mlist, Us, ci);
}
}
PieceType pt = type_of(pos.piece_on(from));
if (pt == PAWN)
- continue; // Will be generated togheter with direct checks
+ continue; // Will be generated together with direct checks
Bitboard b = pos.attacks_from(Piece(pt), from) & ~pos.pieces();
assert(pos.checkers());
- // Find squares attacked by slider checkers, we will remove them from the king
- // evasions so to skip known illegal moves avoiding useless legality check later.
+ // Find all the squares attacked by slider checkers. We will remove them from
+ // the king evasions in order to skip known illegal moves, which avoids any
+ // useless legality checks later on.
do
{
++checkersCnt;
assert(color_of(pos.piece_on(checksq)) == ~us);
- switch (type_of(pos.piece_on(checksq)))
- {
- case BISHOP: sliderAttacks |= PseudoAttacks[BISHOP][checksq]; break;
- case ROOK: sliderAttacks |= PseudoAttacks[ROOK][checksq]; break;
- case QUEEN:
- // If queen and king are far or not on a diagonal line we can safely
- // remove all the squares attacked in the other direction becuase are
- // not reachable by the king anyway.
- if (between_bb(ksq, checksq) || !(PseudoAttacks[BISHOP][checksq] & ksq))
- sliderAttacks |= PseudoAttacks[QUEEN][checksq];
-
- // Otherwise we need to use real rook attacks to check if king is safe
- // to move in the other direction. For example: king in B2, queen in A1
- // a knight in B1, and we can safely move to C1.
- else
- sliderAttacks |= PseudoAttacks[BISHOP][checksq] | pos.attacks_from<ROOK>(checksq);
-
- default:
- break;
- }
+ if (type_of(pos.piece_on(checksq)) > KNIGHT) // A slider
+ sliderAttacks |= LineBB[checksq][ksq] ^ checksq;
+
} while (b);
// Generate evasions for king, capture and non capture moves