/*
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) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2019 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
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#include <algorithm>
#include <cassert>
#include "movegen.h"
#include "position.h"
-/// Simple macro to wrap a very common while loop, no facny, no flexibility,
-/// hardcoded names 'mlist' and 'from'.
-#define SERIALIZE(b) while (b) (*mlist++).move = make_move(from, pop_1st_bit(&b))
-
-/// Version used for pawns, where the 'from' square is given as a delta from the 'to' square
-#define SERIALIZE_PAWNS(b, d) while (b) { Square to = pop_1st_bit(&b); \
- (*mlist++).move = make_move(to - (d), to); }
namespace {
- enum CastlingSide { KING_SIDE, QUEEN_SIDE };
-
- template<CastlingSide Side, bool OnlyChecks>
- MoveStack* generate_castle(const Position& pos, MoveStack* mlist, Color us) {
-
- const CastleRight CR[] = { Side ? WHITE_OOO : WHITE_OO,
- Side ? BLACK_OOO : BLACK_OO };
-
- if (!pos.can_castle(CR[us]))
- 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(CR[us]);
- Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1);
- Square rto = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1);
- Bitboard enemies = pos.pieces(~us);
-
- assert(!pos.in_check());
- assert(pos.piece_on(kfrom) == make_piece(us, KING));
- assert(pos.piece_on(rfrom) == make_piece(us, ROOK));
-
- // Unimpeded rule: All the squares between the king's initial and final squares
- // (including the final square), and all the squares between the rook's initial
- // and final squares (including the final square), must be vacant except for
- // the king and castling rook.
- for (Square s = std::min(rfrom, rto), e = std::max(rfrom, rto); s <= e; s++)
- if (s != kfrom && s != rfrom && !pos.square_is_empty(s))
- return mlist;
-
- for (Square s = std::min(kfrom, kto), e = std::max(kfrom, kto); s <= e; s++)
- if ( (s != kfrom && s != rfrom && !pos.square_is_empty(s))
- ||(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 (pos.is_chess960())
- {
- Bitboard occ = pos.occupied_squares();
- occ ^= rfrom;
- if (pos.attackers_to(kto, occ) & enemies)
- return mlist;
- }
+ template<GenType Type, Direction D>
+ ExtMove* make_promotions(ExtMove* moveList, Square to, Square ksq) {
- (*mlist++).move = make_castle(kfrom, rfrom);
+ if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
+ *moveList++ = make<PROMOTION>(to - D, to, QUEEN);
- if (OnlyChecks && !pos.move_gives_check((mlist - 1)->move, CheckInfo(pos)))
- mlist--;
-
- return mlist;
- }
-
-
- template<Square Delta>
- inline Bitboard move_pawns(Bitboard p) {
-
- return Delta == DELTA_N ? p << 8
- : Delta == DELTA_S ? p >> 8
- : Delta == DELTA_NE ? (p & ~FileHBB) << 9
- : Delta == DELTA_SE ? (p & ~FileHBB) >> 7
- : Delta == DELTA_NW ? (p & ~FileABB) << 7
- : Delta == DELTA_SW ? (p & ~FileABB) >> 9 : 0;
- }
-
-
- template<MoveType Type, Square Delta>
- inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7, Bitboard target, Square ksq) {
-
- Bitboard b = move_pawns<Delta>(pawnsOn7) & target;
-
- while (b)
+ if (Type == QUIETS || Type == EVASIONS || Type == NON_EVASIONS)
{
- Square to = pop_1st_bit(&b);
-
- if (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION)
- (*mlist++).move = make_promotion(to - Delta, to, QUEEN);
-
- if (Type == MV_QUIET || Type == MV_EVASION || Type == MV_NON_EVASION)
- {
- (*mlist++).move = make_promotion(to - Delta, to, ROOK);
- (*mlist++).move = make_promotion(to - Delta, to, BISHOP);
- (*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.
- if (Type == MV_QUIET_CHECK && (StepAttacksBB[W_KNIGHT][to] & ksq))
- (*mlist++).move = make_promotion(to - Delta, to, KNIGHT);
- else
- (void)ksq; // Silence a warning under MSVC
+ *moveList++ = make<PROMOTION>(to - D, to, ROOK);
+ *moveList++ = make<PROMOTION>(to - D, to, BISHOP);
+ *moveList++ = make<PROMOTION>(to - D, to, KNIGHT);
}
- return mlist;
+ // 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 && (PseudoAttacks[KNIGHT][to] & ksq))
+ *moveList++ = make<PROMOTION>(to - D, to, KNIGHT);
+ else
+ (void)ksq; // Silence a warning under MSVC
+
+ return moveList;
}
- template<Color Us, MoveType Type>
- MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, Square ksq = SQ_NONE) {
+ template<Color Us, GenType Type>
+ ExtMove* generate_pawn_moves(const Position& pos, ExtMove* moveList, Bitboard target) {
- // Compute our parametrized parameters at compile time, named according to
- // the point of view of white side.
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
- const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
- const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
- const Square UP = (Us == WHITE ? DELTA_N : DELTA_S);
- const Square RIGHT = (Us == WHITE ? DELTA_NE : DELTA_SW);
- const Square LEFT = (Us == WHITE ? DELTA_NW : DELTA_SE);
+ // Compute some compile time parameters relative to the white side
+ constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
+ constexpr Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
+ constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH);
+ constexpr Direction UpRight = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
+ constexpr Direction UpLeft = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
- Bitboard b1, b2, dc1, dc2, emptySquares;
+ Bitboard emptySquares;
- Bitboard pawnsOn7 = pos.pieces(PAWN, Us) & TRank7BB;
- Bitboard pawnsNotOn7 = pos.pieces(PAWN, Us) & ~TRank7BB;
+ Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB;
+ Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB;
- Bitboard enemies = (Type == MV_EVASION ? pos.pieces(Them) & target:
- Type == MV_CAPTURE ? target : pos.pieces(Them));
+ Bitboard enemies = (Type == EVASIONS ? pos.pieces(Them) & target:
+ Type == CAPTURES ? target : pos.pieces(Them));
// Single and double pawn pushes, no promotions
- if (Type != MV_CAPTURE)
+ if (Type != CAPTURES)
{
- emptySquares = (Type == MV_QUIET ? target : ~pos.occupied_squares());
+ emptySquares = (Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces());
- b1 = move_pawns<UP>(pawnsNotOn7) & emptySquares;
- b2 = move_pawns<UP>(b1 & TRank3BB) & emptySquares;
+ Bitboard b1 = shift<Up>(pawnsNotOn7) & emptySquares;
+ Bitboard b2 = shift<Up>(b1 & TRank3BB) & emptySquares;
- if (Type == MV_EVASION) // Consider only blocking squares
+ if (Type == EVASIONS) // Consider only blocking squares
{
b1 &= target;
b2 &= target;
}
- if (Type == MV_QUIET_CHECK)
+ if (Type == QUIET_CHECKS)
{
+ Square ksq = pos.square<KING>(Them);
+
b1 &= pos.attacks_from<PAWN>(ksq, Them);
b2 &= pos.attacks_from<PAWN>(ksq, Them);
// 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.
- if (pawnsNotOn7 & target) // Target is dc bitboard
+ // promotion has been already generated amongst the captures.
+ Bitboard dcCandidateQuiets = pos.blockers_for_king(Them) & pawnsNotOn7;
+ if (dcCandidateQuiets)
{
- dc1 = move_pawns<UP>(pawnsNotOn7 & target) & emptySquares & ~file_bb(ksq);
- dc2 = move_pawns<UP>(dc1 & TRank3BB) & emptySquares;
+ Bitboard dc1 = shift<Up>(dcCandidateQuiets) & emptySquares & ~file_bb(ksq);
+ Bitboard dc2 = shift<Up>(dc1 & TRank3BB) & emptySquares;
b1 |= dc1;
b2 |= dc2;
}
}
- SERIALIZE_PAWNS(b1, UP);
- SERIALIZE_PAWNS(b2, UP + UP);
+ while (b1)
+ {
+ Square to = pop_lsb(&b1);
+ *moveList++ = make_move(to - Up, to);
+ }
+
+ while (b2)
+ {
+ Square to = pop_lsb(&b2);
+ *moveList++ = make_move(to - Up - Up, to);
+ }
}
// Promotions and underpromotions
- if (pawnsOn7 && (Type != MV_EVASION || (target & TRank8BB)))
+ if (pawnsOn7)
{
- if (Type == MV_CAPTURE)
- emptySquares = ~pos.occupied_squares();
+ if (Type == CAPTURES)
+ emptySquares = ~pos.pieces();
- if (Type == MV_EVASION)
+ if (Type == EVASIONS)
emptySquares &= target;
- mlist = generate_promotions<Type, RIGHT>(mlist, pawnsOn7, enemies, ksq);
- mlist = generate_promotions<Type, LEFT>(mlist, pawnsOn7, enemies, ksq);
- mlist = generate_promotions<Type, UP>(mlist, pawnsOn7, emptySquares, ksq);
+ Bitboard b1 = shift<UpRight>(pawnsOn7) & enemies;
+ Bitboard b2 = shift<UpLeft >(pawnsOn7) & enemies;
+ Bitboard b3 = shift<Up >(pawnsOn7) & emptySquares;
+
+ Square ksq = pos.square<KING>(Them);
+
+ while (b1)
+ moveList = make_promotions<Type, UpRight>(moveList, pop_lsb(&b1), ksq);
+
+ while (b2)
+ moveList = make_promotions<Type, UpLeft >(moveList, pop_lsb(&b2), ksq);
+
+ while (b3)
+ moveList = make_promotions<Type, Up >(moveList, pop_lsb(&b3), ksq);
}
// Standard and en-passant captures
- if (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION)
+ if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
{
- b1 = move_pawns<RIGHT>(pawnsNotOn7) & enemies;
- b2 = move_pawns<LEFT >(pawnsNotOn7) & enemies;
+ Bitboard b1 = shift<UpRight>(pawnsNotOn7) & enemies;
+ Bitboard b2 = shift<UpLeft >(pawnsNotOn7) & enemies;
- SERIALIZE_PAWNS(b1, RIGHT);
- SERIALIZE_PAWNS(b2, LEFT);
+ while (b1)
+ {
+ Square to = pop_lsb(&b1);
+ *moveList++ = make_move(to - UpRight, to);
+ }
+
+ while (b2)
+ {
+ Square to = pop_lsb(&b2);
+ *moveList++ = make_move(to - UpLeft, to);
+ }
if (pos.ep_square() != SQ_NONE)
{
// An en passant capture can be an evasion only if the checking piece
// is the double pushed pawn and so is in the target. Otherwise this
// is a discovery check and we are forced to do otherwise.
- if (Type == MV_EVASION && !(target & (pos.ep_square() - UP)))
- return mlist;
+ if (Type == EVASIONS && !(target & (pos.ep_square() - Up)))
+ return moveList;
b1 = pawnsNotOn7 & pos.attacks_from<PAWN>(pos.ep_square(), Them);
assert(b1);
while (b1)
- (*mlist++).move = make_enpassant(pop_1st_bit(&b1), pos.ep_square());
+ *moveList++ = make<ENPASSANT>(pop_lsb(&b1), pos.ep_square());
}
}
- return mlist;
+ return moveList;
}
- template<PieceType Pt>
- inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist,
- Color us, const CheckInfo& ci) {
+ template<PieceType Pt, bool Checks>
+ ExtMove* generate_moves(const Position& pos, ExtMove* moveList, Color us,
+ Bitboard target) {
+
assert(Pt != KING && Pt != PAWN);
- Bitboard b, target;
- Square from;
- const Square* pl = pos.piece_list(us, Pt);
+ const Square* pl = pos.squares<Pt>(us);
- if (*pl != SQ_NONE)
+ for (Square from = *pl; from != SQ_NONE; from = *++pl)
{
- target = ci.checkSq[Pt] & ~pos.occupied_squares(); // Non capture checks only
-
- do {
- from = *pl;
-
+ if (Checks)
+ {
if ( (Pt == BISHOP || Pt == ROOK || Pt == QUEEN)
- && !(PseudoAttacks[Pt][from] & target))
+ && !(PseudoAttacks[Pt][from] & target & pos.check_squares(Pt)))
continue;
- if (ci.dcCandidates && (ci.dcCandidates & from))
+ if (pos.blockers_for_king(~us) & from)
continue;
+ }
+
+ Bitboard b = pos.attacks_from<Pt>(from) & target;
- b = pos.attacks_from<Pt>(from) & target;
- SERIALIZE(b);
- } while (*++pl != SQ_NONE);
+ if (Checks)
+ b &= pos.check_squares(Pt);
+
+ while (b)
+ *moveList++ = make_move(from, pop_lsb(&b));
}
- return mlist;
+ return moveList;
}
- template<PieceType Pt>
- FORCE_INLINE MoveStack* generate_moves(const Position& pos, MoveStack* mlist,
- Color us, Bitboard target) {
- assert(Pt != KING && Pt != PAWN);
+ template<Color Us, GenType Type>
+ ExtMove* generate_all(const Position& pos, ExtMove* moveList, Bitboard target) {
- Bitboard b;
- Square from;
- const Square* pl = pos.piece_list(us, Pt);
+ constexpr CastlingRight OO = Us | KING_SIDE;
+ constexpr CastlingRight OOO = Us | QUEEN_SIDE;
+ constexpr bool Checks = Type == QUIET_CHECKS; // Reduce template instantations
- if (*pl != SQ_NONE)
- do {
- from = *pl;
- b = pos.attacks_from<Pt>(from) & target;
- SERIALIZE(b);
- } while (*++pl != SQ_NONE);
+ moveList = generate_pawn_moves<Us, Type>(pos, moveList, target);
+ moveList = generate_moves<KNIGHT, Checks>(pos, moveList, Us, target);
+ moveList = generate_moves<BISHOP, Checks>(pos, moveList, Us, target);
+ moveList = generate_moves< ROOK, Checks>(pos, moveList, Us, target);
+ moveList = generate_moves< QUEEN, Checks>(pos, moveList, Us, target);
- return mlist;
- }
+ if (Type != QUIET_CHECKS && Type != EVASIONS)
+ {
+ Square ksq = pos.square<KING>(Us);
+ Bitboard b = pos.attacks_from<KING>(ksq) & target;
+ while (b)
+ *moveList++ = make_move(ksq, pop_lsb(&b));
+
+ if (Type != CAPTURES && pos.can_castle(CastlingRight(OO | OOO)))
+ {
+ if (!pos.castling_impeded(OO) && pos.can_castle(OO))
+ *moveList++ = make<CASTLING>(ksq, pos.castling_rook_square(OO));
+ if (!pos.castling_impeded(OOO) && pos.can_castle(OOO))
+ *moveList++ = make<CASTLING>(ksq, pos.castling_rook_square(OOO));
+ }
+ }
- template<>
- FORCE_INLINE MoveStack* generate_moves<KING>(const Position& pos, MoveStack* mlist,
- Color us, Bitboard target) {
- Square from = pos.king_square(us);
- Bitboard b = pos.attacks_from<KING>(from) & target;
- SERIALIZE(b);
- return mlist;
+ return moveList;
}
} // namespace
-/// generate<MV_CAPTURE> generates all pseudo-legal captures and queen
-/// promotions. Returns a pointer to the end of the move list.
+/// <CAPTURES> Generates all pseudo-legal captures and queen promotions
+/// <QUIETS> Generates all pseudo-legal non-captures and underpromotions
+/// <NON_EVASIONS> Generates all pseudo-legal captures and non-captures
///
-/// generate<MV_QUIET> generates all pseudo-legal non-captures and
-/// underpromotions. Returns a pointer to the end of the move list.
-///
-/// generate<MV_NON_EVASION> generates all pseudo-legal captures and
-/// non-captures. Returns a pointer to the end of the move list.
+/// Returns a pointer to the end of the move list.
-template<MoveType Type>
-MoveStack* generate(const Position& pos, MoveStack* mlist) {
+template<GenType Type>
+ExtMove* generate(const Position& pos, ExtMove* moveList) {
- assert(Type == MV_CAPTURE || Type == MV_QUIET || Type == MV_NON_EVASION);
- assert(!pos.in_check());
+ assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS);
+ assert(!pos.checkers());
Color us = pos.side_to_move();
- Bitboard target;
-
- if (Type == MV_CAPTURE)
- target = pos.pieces(~us);
- else if (Type == MV_QUIET)
- target = ~pos.occupied_squares();
+ Bitboard target = Type == CAPTURES ? pos.pieces(~us)
+ : Type == QUIETS ? ~pos.pieces()
+ : Type == NON_EVASIONS ? ~pos.pieces(us) : 0;
- else if (Type == MV_NON_EVASION)
- target = pos.pieces(~us) | ~pos.occupied_squares();
-
- mlist = (us == WHITE ? generate_pawn_moves<WHITE, Type>(pos, mlist, target)
- : generate_pawn_moves<BLACK, Type>(pos, mlist, target));
-
- mlist = generate_moves<KNIGHT>(pos, mlist, us, target);
- mlist = generate_moves<BISHOP>(pos, mlist, us, target);
- mlist = generate_moves<ROOK>(pos, mlist, us, target);
- mlist = generate_moves<QUEEN>(pos, mlist, us, target);
- mlist = generate_moves<KING>(pos, mlist, us, target);
-
- if (Type != MV_CAPTURE && pos.can_castle(us))
- {
- mlist = generate_castle<KING_SIDE, false>(pos, mlist, us);
- mlist = generate_castle<QUEEN_SIDE, false>(pos, mlist, us);
- }
-
- return mlist;
+ return us == WHITE ? generate_all<WHITE, Type>(pos, moveList, target)
+ : generate_all<BLACK, Type>(pos, moveList, target);
}
// Explicit template instantiations
-template MoveStack* generate<MV_CAPTURE>(const Position& pos, MoveStack* mlist);
-template MoveStack* generate<MV_QUIET>(const Position& pos, MoveStack* mlist);
-template MoveStack* generate<MV_NON_EVASION>(const Position& pos, MoveStack* mlist);
+template ExtMove* generate<CAPTURES>(const Position&, ExtMove*);
+template ExtMove* generate<QUIETS>(const Position&, ExtMove*);
+template ExtMove* generate<NON_EVASIONS>(const Position&, ExtMove*);
-/// generate<MV_QUIET_CHECK> generates all pseudo-legal non-captures and knight
+/// generate<QUIET_CHECKS> generates all pseudo-legal non-captures and knight
/// underpromotions that give check. Returns a pointer to the end of the move list.
template<>
-MoveStack* generate<MV_QUIET_CHECK>(const Position& pos, MoveStack* mlist) {
+ExtMove* generate<QUIET_CHECKS>(const Position& pos, ExtMove* moveList) {
- assert(!pos.in_check());
+ assert(!pos.checkers());
Color us = pos.side_to_move();
- CheckInfo ci(pos);
- Bitboard dc = ci.dcCandidates;
+ Bitboard dc = pos.blockers_for_king(~us) & pos.pieces(us);
while (dc)
{
- Square from = pop_1st_bit(&dc);
+ Square from = pop_lsb(&dc);
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.occupied_squares();
+ Bitboard b = pos.attacks_from(pt, from) & ~pos.pieces();
if (pt == KING)
- b &= ~PseudoAttacks[QUEEN][ci.ksq];
-
- SERIALIZE(b);
- }
+ b &= ~PseudoAttacks[QUEEN][pos.square<KING>(~us)];
- mlist = (us == WHITE ? generate_pawn_moves<WHITE, MV_QUIET_CHECK>(pos, mlist, ci.dcCandidates, ci.ksq)
- : generate_pawn_moves<BLACK, MV_QUIET_CHECK>(pos, mlist, ci.dcCandidates, ci.ksq));
-
- mlist = generate_direct_checks<KNIGHT>(pos, mlist, us, ci);
- mlist = generate_direct_checks<BISHOP>(pos, mlist, us, ci);
- mlist = generate_direct_checks<ROOK>(pos, mlist, us, ci);
- mlist = generate_direct_checks<QUEEN>(pos, mlist, us, ci);
-
- if (pos.can_castle(us))
- {
- mlist = generate_castle<KING_SIDE, true>(pos, mlist, us);
- mlist = generate_castle<QUEEN_SIDE, true>(pos, mlist, us);
+ while (b)
+ *moveList++ = make_move(from, pop_lsb(&b));
}
- return mlist;
+ return us == WHITE ? generate_all<WHITE, QUIET_CHECKS>(pos, moveList, ~pos.pieces())
+ : generate_all<BLACK, QUIET_CHECKS>(pos, moveList, ~pos.pieces());
}
-/// generate<MV_EVASION> generates all pseudo-legal check evasions when the side
+/// generate<EVASIONS> generates all pseudo-legal check evasions when the side
/// to move is in check. Returns a pointer to the end of the move list.
template<>
-MoveStack* generate<MV_EVASION>(const Position& pos, MoveStack* mlist) {
+ExtMove* generate<EVASIONS>(const Position& pos, ExtMove* moveList) {
- assert(pos.in_check());
+ assert(pos.checkers());
- Bitboard b, target;
- Square from, checksq;
- int checkersCnt = 0;
Color us = pos.side_to_move();
- Square ksq = pos.king_square(us);
+ Square ksq = pos.square<KING>(us);
Bitboard sliderAttacks = 0;
- Bitboard checkers = pos.checkers();
-
- assert(checkers);
+ Bitboard sliders = pos.checkers() & ~pos.pieces(KNIGHT, PAWN);
- // 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.
- b = checkers;
- do
+ // 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.
+ while (sliders)
{
- checkersCnt++;
- checksq = pop_1st_bit(&b);
-
- 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 (squares_between(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;
- }
- } while (b);
+ Square checksq = pop_lsb(&sliders);
+ sliderAttacks |= LineBB[checksq][ksq] ^ checksq;
+ }
// Generate evasions for king, capture and non capture moves
- b = pos.attacks_from<KING>(ksq) & ~pos.pieces(us) & ~sliderAttacks;
- from = ksq;
- SERIALIZE(b);
-
- // Generate evasions for other pieces only if not under a double check
- if (checkersCnt > 1)
- return mlist;
+ Bitboard b = pos.attacks_from<KING>(ksq) & ~pos.pieces(us) & ~sliderAttacks;
+ while (b)
+ *moveList++ = make_move(ksq, pop_lsb(&b));
- // Blocking evasions or captures of the checking piece
- target = squares_between(checksq, ksq) | checkers;
+ if (more_than_one(pos.checkers()))
+ return moveList; // Double check, only a king move can save the day
- mlist = (us == WHITE ? generate_pawn_moves<WHITE, MV_EVASION>(pos, mlist, target)
- : generate_pawn_moves<BLACK, MV_EVASION>(pos, mlist, target));
+ // Generate blocking evasions or captures of the checking piece
+ Square checksq = lsb(pos.checkers());
+ Bitboard target = between_bb(checksq, ksq) | checksq;
- mlist = generate_moves<KNIGHT>(pos, mlist, us, target);
- mlist = generate_moves<BISHOP>(pos, mlist, us, target);
- mlist = generate_moves<ROOK>(pos, mlist, us, target);
- return generate_moves<QUEEN>(pos, mlist, us, target);
+ return us == WHITE ? generate_all<WHITE, EVASIONS>(pos, moveList, target)
+ : generate_all<BLACK, EVASIONS>(pos, moveList, target);
}
-/// generate<MV_LEGAL> generates all the legal moves in the given position
+/// generate<LEGAL> generates all the legal moves in the given position
template<>
-MoveStack* generate<MV_LEGAL>(const Position& pos, MoveStack* mlist) {
+ExtMove* generate<LEGAL>(const Position& pos, ExtMove* moveList) {
- MoveStack *last, *cur = mlist;
- Bitboard pinned = pos.pinned_pieces();
-
- last = pos.in_check() ? generate<MV_EVASION>(pos, mlist)
- : generate<MV_NON_EVASION>(pos, mlist);
- while (cur != last)
- if (!pos.pl_move_is_legal(cur->move, pinned))
- cur->move = (--last)->move;
+ Color us = pos.side_to_move();
+ Bitboard pinned = pos.blockers_for_king(us) & pos.pieces(us);
+ Square ksq = pos.square<KING>(us);
+ ExtMove* cur = moveList;
+
+ moveList = pos.checkers() ? generate<EVASIONS >(pos, moveList)
+ : generate<NON_EVASIONS>(pos, moveList);
+ while (cur != moveList)
+ if ( (pinned || from_sq(*cur) == ksq || type_of(*cur) == ENPASSANT)
+ && !pos.legal(*cur))
+ *cur = (--moveList)->move;
else
- cur++;
+ ++cur;
- return last;
+ return moveList;
}
projects / stockfish / blobdiff