/*
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) 2004-2023 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
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#include <algorithm>
+#include "movegen.h"
+
#include <cassert>
+#include <initializer_list>
-#include "movegen.h"
+#include "bitboard.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))
+namespace Stockfish {
-/// 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_moves(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(flip(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();
- clear_bit(&occ, rfrom);
- if (pos.attackers_to(kto, occ) & enemies)
- return mlist;
- }
-
- (*mlist++).move = make_castle(kfrom, rfrom);
-
- if (OnlyChecks && !pos.move_gives_check((mlist - 1)->move, CheckInfo(pos)))
- mlist--;
-
- return mlist;
- }
-
-
- template<Square Delta>
- inline Bitboard move_pawns(Bitboard p) {
+template<GenType Type, Direction D, bool Enemy>
+ExtMove* make_promotions(ExtMove* moveList, [[maybe_unused]] Square to) {
- return Delta == DELTA_N ? p << 8 : Delta == DELTA_S ? p >> 8 :
- Delta == DELTA_NE ? p << 9 : Delta == DELTA_SE ? p >> 7 :
- Delta == DELTA_NW ? p << 7 : Delta == DELTA_SW ? p >> 9 : p;
- }
+ constexpr bool all = Type == EVASIONS || Type == NON_EVASIONS;
+ if constexpr (Type == CAPTURES || all)
+ *moveList++ = make<PROMOTION>(to - D, to, QUEEN);
- template<Square Delta>
- inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard target) {
-
- const Bitboard TFileABB = ( Delta == DELTA_NE
- || Delta == DELTA_SE ? FileABB : FileHBB);
-
- Bitboard b = move_pawns<Delta>(pawns) & target & ~TFileABB;
- SERIALIZE_PAWNS(b, -Delta);
- return mlist;
- }
-
-
- template<MoveType Type, Square Delta>
- inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7, Bitboard target, Square ksq) {
-
- const Bitboard TFileABB = ( Delta == DELTA_NE
- || Delta == DELTA_SE ? FileABB : FileHBB);
-
- Bitboard b = move_pawns<Delta>(pawnsOn7) & target;
-
- if (Delta != DELTA_N && Delta != DELTA_S)
- b &= ~TFileABB;
-
- while (b)
+ if constexpr ((Type == CAPTURES && Enemy) || (Type == QUIETS && !Enemy) || all)
{
- 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_NON_CAPTURE || 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 check (direct or
- // discovered) not already included in the queen-promotion.
- if (Type == MV_NON_CAPTURE_CHECK && bit_is_set(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;
- }
+ return moveList;
+}
- template<Color Us, MoveType Type>
- MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, Square ksq) {
- // Calculate 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 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);
+template<Color Us, GenType Type>
+ExtMove* generate_pawn_moves(const Position& pos, ExtMove* moveList, Bitboard target) {
- Bitboard b1, b2, dc1, dc2, emptySquares;
+ constexpr Color Them = ~Us;
+ constexpr Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
+ constexpr Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
+ constexpr Direction Up = pawn_push(Us);
+ constexpr Direction UpRight = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
+ constexpr Direction UpLeft = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
- Bitboard pawnsOn7 = pos.pieces(PAWN, Us) & TRank7BB;
- Bitboard pawnsNotOn7 = pos.pieces(PAWN, Us) & ~TRank7BB;
+ const Bitboard emptySquares = ~pos.pieces();
+ const Bitboard enemies = Type == EVASIONS ? pos.checkers() : pos.pieces(Them);
- Bitboard enemies = (Type == MV_EVASION ? pos.pieces(Them) & target:
- Type == MV_CAPTURE ? target : pos.pieces(Them));
+ Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB;
+ Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB;
// Single and double pawn pushes, no promotions
- if (Type != MV_CAPTURE)
+ if constexpr (Type != CAPTURES)
{
- emptySquares = (Type == MV_NON_CAPTURE ? target : pos.empty_squares());
+ Bitboard b1 = shift<Up>(pawnsNotOn7) & emptySquares;
+ Bitboard b2 = shift<Up>(b1 & TRank3BB) & emptySquares;
- b1 = move_pawns<UP>(pawnsNotOn7) & emptySquares;
- b2 = move_pawns<UP>(b1 & TRank3BB) & emptySquares;
-
- if (Type == MV_EVASION) // Consider only blocking squares
+ if constexpr (Type == EVASIONS) // Consider only blocking squares
{
b1 &= target;
b2 &= target;
}
- if (Type == MV_NON_CAPTURE_CHECK)
+ if constexpr (Type == QUIET_CHECKS)
{
- // Consider only direct checks
- 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
- {
- dc1 = move_pawns<UP>(pawnsNotOn7 & target) & emptySquares & ~file_bb(ksq);
- dc2 = move_pawns<UP>(dc1 & TRank3BB) & emptySquares;
-
- b1 |= dc1;
- b2 |= dc2;
- }
+ // To make a quiet check, you either make a direct check by pushing a pawn
+ // or push a blocker pawn that is not on the same file as the enemy king.
+ // Discovered check promotion has been already generated amongst the captures.
+ Square ksq = pos.square<KING>(Them);
+ Bitboard dcCandidatePawns = pos.blockers_for_king(Them) & ~file_bb(ksq);
+ b1 &= pawn_attacks_bb(Them, ksq) | shift<Up>(dcCandidatePawns);
+ b2 &= pawn_attacks_bb(Them, ksq) | shift<Up + Up>(dcCandidatePawns);
}
- 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)
{
- if (Type == MV_CAPTURE)
- emptySquares = pos.empty_squares();
+ Bitboard b1 = shift<UpRight>(pawnsOn7) & enemies;
+ Bitboard b2 = shift<UpLeft>(pawnsOn7) & enemies;
+ Bitboard b3 = shift<Up>(pawnsOn7) & emptySquares;
+
+ if constexpr (Type == EVASIONS)
+ b3 &= target;
+
+ while (b1)
+ moveList = make_promotions<Type, UpRight, true>(moveList, pop_lsb(b1));
- if (Type == MV_EVASION)
- emptySquares &= target;
+ while (b2)
+ moveList = make_promotions<Type, UpLeft, true>(moveList, pop_lsb(b2));
- 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);
+ while (b3)
+ moveList = make_promotions<Type, Up, false>(moveList, pop_lsb(b3));
}
- // Standard and en-passant captures
- if (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION)
+ // Standard and en passant captures
+ if constexpr (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
{
- mlist = generate_pawn_captures<RIGHT>(mlist, pawnsNotOn7, enemies);
- mlist = generate_pawn_captures<LEFT >(mlist, pawnsNotOn7, enemies);
+ Bitboard b1 = shift<UpRight>(pawnsNotOn7) & enemies;
+ Bitboard b2 = shift<UpLeft>(pawnsNotOn7) & enemies;
+
+ 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)
{
- assert(rank_of(pos.ep_square()) == (Us == WHITE ? RANK_6 : RANK_3));
+ assert(rank_of(pos.ep_square()) == relative_rank(Us, RANK_6));
- // 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 && !bit_is_set(target, pos.ep_square() - UP))
- return mlist;
+ // An en passant capture cannot resolve a discovered check
+ if (Type == EVASIONS && (target & (pos.ep_square() + Up)))
+ return moveList;
- b1 = pawnsNotOn7 & pos.attacks_from<PAWN>(pos.ep_square(), Them);
+ b1 = pawnsNotOn7 & pawn_attacks_bb(Them, pos.ep_square());
assert(b1);
while (b1)
- (*mlist++).move = make_enpassant(pop_1st_bit(&b1), pos.ep_square());
+ *moveList++ = make<EN_PASSANT>(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) {
- assert(Pt != KING && Pt != PAWN);
- Bitboard checkSqs, b;
- Square from;
- const Square* pl = pos.piece_list(us, Pt);
+template<Color Us, PieceType Pt, bool Checks>
+ExtMove* generate_moves(const Position& pos, ExtMove* moveList, Bitboard target) {
- if ((from = *pl++) == SQ_NONE)
- return mlist;
+ static_assert(Pt != KING && Pt != PAWN, "Unsupported piece type in generate_moves()");
- checkSqs = ci.checkSq[Pt] & pos.empty_squares();
+ Bitboard bb = pos.pieces(Us, Pt);
- do
+ while (bb)
{
- if ( (Pt == QUEEN && !(QueenPseudoAttacks[from] & checkSqs))
- || (Pt == ROOK && !(RookPseudoAttacks[from] & checkSqs))
- || (Pt == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
- continue;
-
- if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
- continue;
-
- b = pos.attacks_from<Pt>(from) & checkSqs;
- SERIALIZE(b);
-
- } while ((from = *pl++) != SQ_NONE);
-
- return mlist;
- }
+ Square from = pop_lsb(bb);
+ Bitboard b = attacks_bb<Pt>(from, pos.pieces()) & target;
+ // To check, you either move freely a blocker or make a direct check.
+ if (Checks && (Pt == QUEEN || !(pos.blockers_for_king(~Us) & from)))
+ b &= pos.check_squares(Pt);
- template<>
- FORCE_INLINE MoveStack* generate_direct_checks<PAWN>(const Position& p, MoveStack* m,
- Color us, const CheckInfo& ci) {
-
- return us == WHITE ? generate_pawn_moves<WHITE, MV_NON_CAPTURE_CHECK>(p, m, ci.dcCandidates, ci.ksq)
- : generate_pawn_moves<BLACK, MV_NON_CAPTURE_CHECK>(p, m, ci.dcCandidates, ci.ksq);
- }
-
+ while (b)
+ *moveList++ = make_move(from, pop_lsb(b));
+ }
- template<PieceType Pt, MoveType Type>
- FORCE_INLINE MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) {
+ return moveList;
+}
- assert(Pt == PAWN);
- return us == WHITE ? generate_pawn_moves<WHITE, Type>(p, m, t, SQ_NONE)
- : generate_pawn_moves<BLACK, Type>(p, m, t, SQ_NONE);
- }
+template<Color Us, GenType Type>
+ExtMove* generate_all(const Position& pos, ExtMove* moveList) {
- template<PieceType Pt>
- FORCE_INLINE MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
+ static_assert(Type != LEGAL, "Unsupported type in generate_all()");
- Bitboard b;
- Square from;
- const Square* pl = pos.piece_list(us, Pt);
+ constexpr bool Checks = Type == QUIET_CHECKS; // Reduce template instantiations
+ const Square ksq = pos.square<KING>(Us);
+ Bitboard target;
- if (*pl != SQ_NONE)
+ // Skip generating non-king moves when in double check
+ if (Type != EVASIONS || !more_than_one(pos.checkers()))
{
- do {
- from = *pl;
- b = pos.attacks_from<Pt>(from) & target;
- SERIALIZE(b);
- } while (*++pl != SQ_NONE);
+ target = Type == EVASIONS ? between_bb(ksq, lsb(pos.checkers()))
+ : Type == NON_EVASIONS ? ~pos.pieces(Us)
+ : Type == CAPTURES ? pos.pieces(~Us)
+ : ~pos.pieces(); // QUIETS || QUIET_CHECKS
+
+ moveList = generate_pawn_moves<Us, Type>(pos, moveList, target);
+ moveList = generate_moves<Us, KNIGHT, Checks>(pos, moveList, target);
+ moveList = generate_moves<Us, BISHOP, Checks>(pos, moveList, target);
+ moveList = generate_moves<Us, ROOK, Checks>(pos, moveList, target);
+ moveList = generate_moves<Us, QUEEN, Checks>(pos, moveList, target);
}
- return mlist;
- }
-
-
- template<>
- FORCE_INLINE MoveStack* generate_piece_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;
- }
-
-} // namespace
-
-
-/// generate<MV_CAPTURE> generates all pseudo-legal captures and queen
-/// promotions. Returns a pointer to the end of the move list.
-///
-/// generate<MV_NON_CAPTURE> 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.
-
-template<MoveType Type>
-MoveStack* generate(const Position& pos, MoveStack* mlist) {
-
- assert(Type == MV_CAPTURE || Type == MV_NON_CAPTURE || Type == MV_NON_EVASION);
- assert(!pos.in_check());
-
- Color us = pos.side_to_move();
- Bitboard target;
-
- if (Type == MV_CAPTURE)
- target = pos.pieces(flip(us));
-
- else if (Type == MV_NON_CAPTURE)
- target = pos.empty_squares();
- else if (Type == MV_NON_EVASION)
- target = pos.pieces(flip(us)) | pos.empty_squares();
+ if (!Checks || pos.blockers_for_king(~Us) & ksq)
+ {
+ Bitboard b = attacks_bb<KING>(ksq) & (Type == EVASIONS ? ~pos.pieces(Us) : target);
+ if (Checks)
+ b &= ~attacks_bb<QUEEN>(pos.square<KING>(~Us));
- mlist = generate_piece_moves<PAWN, Type>(pos, mlist, us, target);
- mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, target);
- mlist = generate_piece_moves<BISHOP>(pos, mlist, us, target);
- mlist = generate_piece_moves<ROOK>(pos, mlist, us, target);
- mlist = generate_piece_moves<QUEEN>(pos, mlist, us, target);
- mlist = generate_piece_moves<KING>(pos, mlist, us, target);
+ while (b)
+ *moveList++ = make_move(ksq, pop_lsb(b));
- if (Type != MV_CAPTURE && pos.can_castle(us))
- {
- mlist = generate_castle_moves<KING_SIDE, false>(pos, mlist, us);
- mlist = generate_castle_moves<QUEEN_SIDE, false>(pos, mlist, us);
- }
+ if ((Type == QUIETS || Type == NON_EVASIONS) && pos.can_castle(Us & ANY_CASTLING))
+ for (CastlingRights cr : {Us & KING_SIDE, Us & QUEEN_SIDE})
+ if (!pos.castling_impeded(cr) && pos.can_castle(cr))
+ *moveList++ = make<CASTLING>(ksq, pos.castling_rook_square(cr));
+ }
- return mlist;
+ return moveList;
}
-// Explicit template instantiations
-template MoveStack* generate<MV_CAPTURE>(const Position& pos, MoveStack* mlist);
-template MoveStack* generate<MV_NON_CAPTURE>(const Position& pos, MoveStack* mlist);
-template MoveStack* generate<MV_NON_EVASION>(const Position& pos, MoveStack* mlist);
-
-
-/// generate<MV_NON_CAPTURE_CHECK> 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_NON_CAPTURE_CHECK>(const Position& pos, MoveStack* mlist) {
-
- assert(!pos.in_check());
-
- Color us = pos.side_to_move();
- CheckInfo ci(pos);
- Bitboard dc = ci.dcCandidates;
-
- while (dc)
- {
- Square from = pop_1st_bit(&dc);
- PieceType pt = type_of(pos.piece_on(from));
-
- if (pt == PAWN)
- continue; // Will be generated togheter with direct checks
+} // namespace
- Bitboard b = pos.attacks_from(Piece(pt), from) & pos.empty_squares();
- if (pt == KING)
- b &= ~QueenPseudoAttacks[ci.ksq];
+// <CAPTURES> Generates all pseudo-legal captures plus queen promotions
+// <QUIETS> Generates all pseudo-legal non-captures and underpromotions
+// <EVASIONS> Generates all pseudo-legal check evasions
+// <NON_EVASIONS> Generates all pseudo-legal captures and non-captures
+// <QUIET_CHECKS> Generates all pseudo-legal non-captures giving check,
+// except castling and promotions
+//
+// Returns a pointer to the end of the move list.
+template<GenType Type>
+ExtMove* generate(const Position& pos, ExtMove* moveList) {
- SERIALIZE(b);
- }
+ static_assert(Type != LEGAL, "Unsupported type in generate()");
+ assert((Type == EVASIONS) == bool(pos.checkers()));
- mlist = generate_direct_checks<PAWN>(pos, mlist, us, ci);
- 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);
+ Color us = pos.side_to_move();
- if (pos.can_castle(us))
- {
- mlist = generate_castle_moves<KING_SIDE, true>(pos, mlist, us);
- mlist = generate_castle_moves<QUEEN_SIDE, true>(pos, mlist, us);
- }
-
- return mlist;
+ return us == WHITE ? generate_all<WHITE, Type>(pos, moveList)
+ : generate_all<BLACK, Type>(pos, moveList);
}
-
-/// generate<MV_EVASION> 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) {
-
- assert(pos.in_check());
-
- Bitboard b, target;
- Square from, checksq;
- int checkersCnt = 0;
- Color us = pos.side_to_move();
- Square ksq = pos.king_square(us);
- Bitboard checkers = pos.checkers();
- Bitboard sliderAttacks = 0;
-
- assert(pos.piece_on(ksq) == make_piece(us, KING));
- assert(checkers);
-
- // Find squares attacked by slider checkers, we will remove them from the king
- // evasions set so to skip known illegal moves and avoid to do legality check later.
- b = checkers;
- do
- {
- checkersCnt++;
- checksq = pop_1st_bit(&b);
-
- assert(color_of(pos.piece_on(checksq)) == flip(us));
-
- switch (type_of(pos.piece_on(checksq)))
- {
- case BISHOP: sliderAttacks |= BishopPseudoAttacks[checksq]; break;
- case ROOK: sliderAttacks |= RookPseudoAttacks[checksq]; break;
- case QUEEN:
- // If queen and king are far 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) || (RookPseudoAttacks[checksq] & (1ULL << ksq)))
- sliderAttacks |= QueenPseudoAttacks[checksq];
-
- // Otherwise, if king and queen are adjacent and on a diagonal line, 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 |= BishopPseudoAttacks[checksq] | pos.attacks_from<ROOK>(checksq);
-
- default:
- break;
- }
- } while (b);
-
- // 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;
-
- // Target for blocking evasions or captures of the checking piece
- target = squares_between(checksq, ksq) | checkers;
-
- mlist = generate_piece_moves<PAWN, MV_EVASION>(pos, mlist, us, target);
- mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, target);
- mlist = generate_piece_moves<BISHOP>(pos, mlist, us, target);
- mlist = generate_piece_moves<ROOK>(pos, mlist, us, target);
- return generate_piece_moves<QUEEN>(pos, mlist, us, target);
-}
+// Explicit template instantiations
+template ExtMove* generate<CAPTURES>(const Position&, ExtMove*);
+template ExtMove* generate<QUIETS>(const Position&, ExtMove*);
+template ExtMove* generate<EVASIONS>(const Position&, ExtMove*);
+template ExtMove* generate<QUIET_CHECKS>(const Position&, ExtMove*);
+template ExtMove* generate<NON_EVASIONS>(const Position&, ExtMove*);
-/// 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) {
-
- 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;
- else
- cur++;
+ExtMove* generate<LEGAL>(const Position& pos, ExtMove* moveList) {
+
+ 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)) || from_sq(*cur) == ksq || type_of(*cur) == EN_PASSANT)
+ && !pos.legal(*cur))
+ *cur = (--moveList)->move;
+ else
+ ++cur;
- return last;
+ return moveList;
}
+
+} // namespace Stockfish
projects / stockfish / blobdiff