/*
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
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 <cassert>
-#include <algorithm>
-#include "bitcount.h"
#include "movegen.h"
#include "position.h"
-// Simple macro to wrap a very common while loop, no facny, no flexibility,
-// hardcoded list name 'mlist' and from square 'from'.
-#define SERIALIZE_MOVES(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_MOVES_D(b, d) while (b) { to = pop_1st_bit(&b); (*mlist++).move = make_move(to + (d), to); }
-
namespace {
- enum CastlingSide {
- KING_SIDE,
- QUEEN_SIDE
- };
-
- template<CastlingSide>
- MoveStack* generate_castle_moves(const Position&, MoveStack*, Color us);
+ template<CastlingRight Cr, bool Checks, bool Chess960>
+ ExtMove* generate_castling(const Position& pos, ExtMove* moveList, Color us, const CheckInfo* ci) {
- template<Color, MoveType>
- MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square);
+ static const bool KingSide = (Cr == WHITE_OO || Cr == BLACK_OO);
- template<PieceType Pt>
- inline MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) {
+ if (pos.castling_impeded(Cr) || !pos.can_castle(Cr))
+ return moveList;
- assert(Pt != QUEEN && Pt != PAWN);
+ // 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.castling_rook_square(Cr);
+ Square kto = relative_square(us, KingSide ? SQ_G1 : SQ_C1);
+ Bitboard enemies = pos.pieces(~us);
- Bitboard b = pos.attacks_from<Pt>(from) & pos.empty_squares();
+ assert(!pos.checkers());
- if (Pt == KING)
- b &= ~QueenPseudoAttacks[pos.king_square(flip(pos.side_to_move()))];
+ const Square K = Chess960 ? kto > kfrom ? DELTA_W : DELTA_E
+ : KingSide ? DELTA_W : DELTA_E;
- SERIALIZE_MOVES(b);
- return mlist;
- }
+ for (Square s = kto; s != kfrom; s += K)
+ if (pos.attackers_to(s) & enemies)
+ return moveList;
- template<PieceType Pt>
- inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us,
- Bitboard dc, Square ksq) {
- assert(Pt != KING && Pt != PAWN);
+ // 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 && (attacks_bb<ROOK>(kto, pos.pieces() ^ rfrom) & pos.pieces(~us, ROOK, QUEEN)))
+ return moveList;
- Bitboard checkSqs, b;
- Square from;
- const Square* pl = pos.piece_list(us, Pt);
+ Move m = make<CASTLING>(kfrom, rfrom);
- if ((from = *pl++) == SQ_NONE)
- return mlist;
+ if (Checks && !pos.gives_check(m, *ci))
+ return moveList;
- checkSqs = pos.attacks_from<Pt>(ksq) & pos.empty_squares();
+ (moveList++)->move = m;
- do
- {
- if ( (Pt == QUEEN && !(QueenPseudoAttacks[from] & checkSqs))
- || (Pt == ROOK && !(RookPseudoAttacks[from] & checkSqs))
- || (Pt == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
- continue;
+ return moveList;
+ }
- if (dc && bit_is_set(dc, from))
- continue;
- b = pos.attacks_from<Pt>(from) & checkSqs;
- SERIALIZE_MOVES(b);
+ template<GenType Type, Square Delta>
+ inline ExtMove* make_promotions(ExtMove* moveList, Square to, const CheckInfo* ci) {
- } while ((from = *pl++) != SQ_NONE);
+ if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
+ (moveList++)->move = make<PROMOTION>(to - Delta, to, QUEEN);
- return mlist;
- }
+ if (Type == QUIETS || Type == EVASIONS || Type == NON_EVASIONS)
+ {
+ (moveList++)->move = make<PROMOTION>(to - Delta, to, ROOK);
+ (moveList++)->move = make<PROMOTION>(to - Delta, to, BISHOP);
+ (moveList++)->move = make<PROMOTION>(to - Delta, to, KNIGHT);
+ }
- template<>
- FORCE_INLINE MoveStack* generate_direct_checks<PAWN>(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) {
+ // 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))
+ (moveList++)->move = make<PROMOTION>(to - Delta, to, KNIGHT);
+ else
+ (void)ci; // Silence a warning under MSVC
- return (us == WHITE ? generate_pawn_moves<WHITE, MV_CHECK>(p, m, dc, ksq)
- : generate_pawn_moves<BLACK, MV_CHECK>(p, m, dc, ksq));
+ return moveList;
}
- template<PieceType Pt, MoveType Type>
- FORCE_INLINE MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) {
- assert(Pt == PAWN);
- assert(Type == MV_CAPTURE || Type == MV_NON_CAPTURE || Type == MV_EVASION);
+ template<Color Us, GenType Type>
+ ExtMove* generate_pawn_moves(const Position& pos, ExtMove* moveList,
+ Bitboard target, const CheckInfo* ci) {
- return (us == WHITE ? generate_pawn_moves<WHITE, Type>(p, m, t, SQ_NONE)
- : generate_pawn_moves<BLACK, Type>(p, m, t, SQ_NONE));
- }
+ // 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);
- template<PieceType Pt>
- FORCE_INLINE MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
+ Bitboard emptySquares;
- Bitboard b;
- Square from;
- const Square* pl = pos.piece_list(us, Pt);
+ Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB;
+ Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB;
- if (*pl != SQ_NONE)
- {
- do {
- from = *pl;
- b = pos.attacks_from<Pt>(from) & target;
- SERIALIZE_MOVES(b);
- } while (*++pl != SQ_NONE);
- }
- return mlist;
- }
+ Bitboard enemies = (Type == EVASIONS ? pos.pieces(Them) & target:
+ Type == CAPTURES ? target : pos.pieces(Them));
- template<>
- FORCE_INLINE MoveStack* generate_piece_moves<KING>(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
+ // Single and double pawn pushes, no promotions
+ if (Type != CAPTURES)
+ {
+ emptySquares = (Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces());
- Bitboard b;
- Square from = pos.king_square(us);
+ Bitboard b1 = shift_bb<Up>(pawnsNotOn7) & emptySquares;
+ Bitboard b2 = shift_bb<Up>(b1 & TRank3BB) & emptySquares;
- b = pos.attacks_from<KING>(from) & target;
- SERIALIZE_MOVES(b);
- return mlist;
- }
+ if (Type == EVASIONS) // Consider only blocking squares
+ {
+ b1 &= target;
+ b2 &= target;
+ }
-}
+ if (Type == QUIET_CHECKS)
+ {
+ b1 &= pos.attacks_from<PAWN>(ci->ksq, Them);
+ b2 &= pos.attacks_from<PAWN>(ci->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 amongst the captures.
+ if (pawnsNotOn7 & ci->dcCandidates)
+ {
+ Bitboard dc1 = shift_bb<Up>(pawnsNotOn7 & ci->dcCandidates) & emptySquares & ~file_bb(ci->ksq);
+ Bitboard dc2 = shift_bb<Up>(dc1 & TRank3BB) & emptySquares;
-/// 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.
+ b1 |= dc1;
+ b2 |= dc2;
+ }
+ }
-template<MoveType Type>
-MoveStack* generate(const Position& pos, MoveStack* mlist) {
+ while (b1)
+ {
+ Square to = pop_lsb(&b1);
+ (moveList++)->move = make_move(to - Up, to);
+ }
- assert(!pos.in_check());
+ while (b2)
+ {
+ Square to = pop_lsb(&b2);
+ (moveList++)->move = make_move(to - Up - Up, to);
+ }
+ }
- Color us = pos.side_to_move();
- Bitboard target;
+ // Promotions and underpromotions
+ if (pawnsOn7 && (Type != EVASIONS || (target & TRank8BB)))
+ {
+ if (Type == CAPTURES)
+ emptySquares = ~pos.pieces();
- if (Type == MV_CAPTURE || Type == MV_NON_EVASION)
- target = pos.pieces(flip(us));
- else if (Type == MV_NON_CAPTURE)
- target = pos.empty_squares();
- else
- assert(false);
+ if (Type == EVASIONS)
+ emptySquares &= target;
- if (Type == MV_NON_EVASION)
- {
- mlist = generate_piece_moves<PAWN, MV_CAPTURE>(pos, mlist, us, target);
- mlist = generate_piece_moves<PAWN, MV_NON_CAPTURE>(pos, mlist, us, pos.empty_squares());
- target |= pos.empty_squares();
- }
- else
- mlist = generate_piece_moves<PAWN, Type>(pos, mlist, us, target);
+ Bitboard b1 = shift_bb<Right>(pawnsOn7) & enemies;
+ Bitboard b2 = shift_bb<Left >(pawnsOn7) & enemies;
+ Bitboard b3 = shift_bb<Up >(pawnsOn7) & emptySquares;
- 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 (b1)
+ moveList = make_promotions<Type, Right>(moveList, pop_lsb(&b1), ci);
- if (Type != MV_CAPTURE && pos.can_castle(us))
- {
- if (pos.can_castle(us == WHITE ? WHITE_OO : BLACK_OO))
- mlist = generate_castle_moves<KING_SIDE>(pos, mlist, us);
+ while (b2)
+ moveList = make_promotions<Type, Left >(moveList, pop_lsb(&b2), ci);
- if (pos.can_castle(us == WHITE ? WHITE_OOO : BLACK_OOO))
- mlist = generate_castle_moves<QUEEN_SIDE>(pos, mlist, us);
- }
+ while (b3)
+ moveList = make_promotions<Type, Up >(moveList, pop_lsb(&b3), ci);
+ }
- return mlist;
-}
+ // Standard and en-passant captures
+ if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
+ {
+ Bitboard b1 = shift_bb<Right>(pawnsNotOn7) & enemies;
+ Bitboard b2 = shift_bb<Left >(pawnsNotOn7) & enemies;
-// 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);
+ while (b1)
+ {
+ Square to = pop_lsb(&b1);
+ (moveList++)->move = make_move(to - Right, to);
+ }
+ while (b2)
+ {
+ Square to = pop_lsb(&b2);
+ (moveList++)->move = make_move(to - Left, to);
+ }
-/// 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) {
+ if (pos.ep_square() != SQ_NONE)
+ {
+ assert(rank_of(pos.ep_square()) == relative_rank(Us, RANK_6));
- assert(!pos.in_check());
+ // 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 == EVASIONS && !(target & (pos.ep_square() - Up)))
+ return moveList;
- Bitboard b, dc;
- Square from;
- Color us = pos.side_to_move();
- Square ksq = pos.king_square(flip(us));
+ b1 = pawnsNotOn7 & pos.attacks_from<PAWN>(pos.ep_square(), Them);
- assert(pos.piece_on(ksq) == make_piece(flip(us), KING));
+ assert(b1);
- // Discovered non-capture checks
- b = dc = pos.discovered_check_candidates();
+ while (b1)
+ (moveList++)->move = make<ENPASSANT>(pop_lsb(&b1), pos.ep_square());
+ }
+ }
- while (b)
- {
- from = pop_1st_bit(&b);
- switch (type_of(pos.piece_on(from)))
- {
- case PAWN: /* Will be generated togheter with pawns direct checks */ break;
- case KNIGHT: mlist = generate_discovered_checks<KNIGHT>(pos, mlist, from); break;
- case BISHOP: mlist = generate_discovered_checks<BISHOP>(pos, mlist, from); break;
- case ROOK: mlist = generate_discovered_checks<ROOK>(pos, mlist, from); break;
- case KING: mlist = generate_discovered_checks<KING>(pos, mlist, from); break;
- default: assert(false); break;
- }
+ return moveList;
}
- // Direct non-capture checks
- mlist = generate_direct_checks<PAWN>(pos, mlist, us, dc, ksq);
- mlist = generate_direct_checks<KNIGHT>(pos, mlist, us, dc, ksq);
- mlist = generate_direct_checks<BISHOP>(pos, mlist, us, dc, ksq);
- mlist = generate_direct_checks<ROOK>(pos, mlist, us, dc, ksq);
- return generate_direct_checks<QUEEN>(pos, mlist, us, dc, ksq);
-}
-
-/// 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) {
+ template<PieceType Pt, bool Checks> FORCE_INLINE
+ ExtMove* generate_moves(const Position& pos, ExtMove* moveList, Color us,
+ Bitboard target, const CheckInfo* ci) {
- 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(Pt != KING && Pt != PAWN);
- assert(pos.piece_on(ksq) == make_piece(us, KING));
- assert(checkers);
+ const Square* pl = pos.list<Pt>(us);
- // Find squares attacked by slider checkers, we will remove
- // them from the king evasions set so to early skip known
- // illegal moves and avoid an useless 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);
+ for (Square from = *pl; from != SQ_NONE; from = *++pl)
+ {
+ if (Checks)
+ {
+ if ( (Pt == BISHOP || Pt == ROOK || Pt == QUEEN)
+ && !(PseudoAttacks[Pt][from] & target & ci->checkSq[Pt]))
+ continue;
- // Generate evasions for king, capture and non capture moves
- b = pos.attacks_from<KING>(ksq) & ~pos.pieces(us) & ~sliderAttacks;
- from = ksq;
- SERIALIZE_MOVES(b);
-
- // Generate evasions for other pieces only if not double check
- if (checkersCnt > 1)
- return mlist;
-
- // Find squares where a blocking evasion or a capture of the
- // checker piece is possible.
- 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);
-}
+ if (ci->dcCandidates && (ci->dcCandidates & from))
+ continue;
+ }
+ Bitboard b = pos.attacks_from<Pt>(from) & target;
-/// generate<MV_LEGAL> computes a complete list of legal moves in the current position
+ if (Checks)
+ b &= ci->checkSq[Pt];
-template<>
-MoveStack* generate<MV_LEGAL>(const Position& pos, MoveStack* mlist) {
+ while (b)
+ (moveList++)->move = make_move(from, pop_lsb(&b));
+ }
- MoveStack *last, *cur = mlist;
- Bitboard pinned = pos.pinned_pieces();
+ return moveList;
+ }
- last = pos.in_check() ? generate<MV_EVASION>(pos, mlist)
- : generate<MV_NON_EVASION>(pos, mlist);
- // Remove illegal moves from the list
- while (cur != last)
- if (!pos.pl_move_is_legal(cur->move, pinned))
- cur->move = (--last)->move;
- else
- cur++;
+ template<Color Us, GenType Type> FORCE_INLINE
+ ExtMove* generate_all(const Position& pos, ExtMove* moveList, Bitboard target,
+ const CheckInfo* ci = NULL) {
- return last;
-}
+ const bool Checks = Type == QUIET_CHECKS;
+ moveList = generate_pawn_moves<Us, Type>(pos, moveList, target, ci);
+ moveList = generate_moves<KNIGHT, Checks>(pos, moveList, Us, target, ci);
+ moveList = generate_moves<BISHOP, Checks>(pos, moveList, Us, target, ci);
+ moveList = generate_moves< ROOK, Checks>(pos, moveList, Us, target, ci);
+ moveList = generate_moves< QUEEN, Checks>(pos, moveList, Us, target, ci);
-namespace {
+ if (Type != QUIET_CHECKS && Type != EVASIONS)
+ {
+ Square ksq = pos.king_square(Us);
+ Bitboard b = pos.attacks_from<KING>(ksq) & target;
+ while (b)
+ (moveList++)->move = make_move(ksq, pop_lsb(&b));
+ }
- template<Square Delta>
- inline Bitboard move_pawns(Bitboard p) {
+ if (Type != CAPTURES && Type != EVASIONS && pos.can_castle(Us))
+ {
+ if (pos.is_chess960())
+ {
+ moveList = generate_castling<MakeCastling<Us, KING_SIDE>::right, Checks, true>(pos, moveList, Us, ci);
+ moveList = generate_castling<MakeCastling<Us, QUEEN_SIDE>::right, Checks, true>(pos, moveList, Us, ci);
+ }
+ else
+ {
+ moveList = generate_castling<MakeCastling<Us, KING_SIDE>::right, Checks, false>(pos, moveList, Us, ci);
+ moveList = generate_castling<MakeCastling<Us, QUEEN_SIDE>::right, Checks, false>(pos, moveList, Us, ci);
+ }
+ }
- 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;
+ return moveList;
}
- template<MoveType Type, 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;
- Square to;
-
- // Captures in the a1-h8 (a8-h1 for black) diagonal or in the h1-a8 (h8-a1 for black)
- b = move_pawns<Delta>(pawns) & target & ~TFileABB;
- SERIALIZE_MOVES_D(b, -Delta);
- return mlist;
- }
+} // namespace
- template<MoveType Type, Square Delta>
- inline MoveStack* generate_promotions(const Position& pos, MoveStack* mlist, Bitboard pawnsOn7, Bitboard target) {
- const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB);
+/// generate<CAPTURES> generates all pseudo-legal captures and queen
+/// promotions. Returns a pointer to the end of the move list.
+///
+/// generate<QUIETS> generates all pseudo-legal non-captures and
+/// underpromotions. Returns a pointer to the end of the move list.
+///
+/// generate<NON_EVASIONS> generates all pseudo-legal captures and
+/// non-captures. Returns a pointer to the end of the move list.
- Bitboard b;
- Square to;
+template<GenType Type>
+ExtMove* generate(const Position& pos, ExtMove* moveList) {
- // Promotions and under-promotions, both captures and non-captures
- b = move_pawns<Delta>(pawnsOn7) & target;
+ assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS);
+ assert(!pos.checkers());
- if (Delta != DELTA_N && Delta != DELTA_S)
- b &= ~TFileABB;
+ Color us = pos.side_to_move();
- while (b)
- {
- to = pop_1st_bit(&b);
+ Bitboard target = Type == CAPTURES ? pos.pieces(~us)
+ : Type == QUIETS ? ~pos.pieces()
+ : Type == NON_EVASIONS ? ~pos.pieces(us) : 0;
- if (Type == MV_CAPTURE || Type == MV_EVASION)
- (*mlist++).move = make_promotion(to - Delta, to, QUEEN);
+ return us == WHITE ? generate_all<WHITE, Type>(pos, moveList, target)
+ : generate_all<BLACK, Type>(pos, moveList, target);
+}
- if (Type == MV_NON_CAPTURE || Type == MV_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);
- }
+// Explicit template instantiations
+template ExtMove* generate<CAPTURES>(const Position&, ExtMove*);
+template ExtMove* generate<QUIETS>(const Position&, ExtMove*);
+template ExtMove* generate<NON_EVASIONS>(const Position&, ExtMove*);
- // This is the only possible under promotion that can give a check
- // not already included in the queen-promotion.
- if ( Type == MV_CHECK
- && bit_is_set(pos.attacks_from<KNIGHT>(to), pos.king_square(Delta > 0 ? BLACK : WHITE)))
- (*mlist++).move = make_promotion(to - Delta, to, KNIGHT);
- else (void)pos; // Silence a warning under MSVC
- }
- return mlist;
- }
- 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_UP = (Us == WHITE ? DELTA_NE : DELTA_SW);
- const Square LEFT_UP = (Us == WHITE ? DELTA_NW : DELTA_SE);
-
- Square to;
- Bitboard b1, b2, dc1, dc2, pawnPushes, emptySquares;
- Bitboard pawns = pos.pieces(PAWN, Us);
- Bitboard pawnsOn7 = pawns & TRank7BB;
- Bitboard enemyPieces = (Type == MV_CAPTURE ? target : pos.pieces(Them));
-
- // Pre-calculate pawn pushes before changing emptySquares definition
- if (Type != MV_CAPTURE)
- {
- emptySquares = (Type == MV_NON_CAPTURE ? target : pos.empty_squares());
- pawnPushes = move_pawns<UP>(pawns & ~TRank7BB) & emptySquares;
- }
+/// 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<>
+ExtMove* generate<QUIET_CHECKS>(const Position& pos, ExtMove* moveList) {
- if (Type == MV_EVASION)
- {
- emptySquares &= target; // Only blocking squares
- enemyPieces &= target; // Capture only the checker piece
- }
+ assert(!pos.checkers());
- // Promotions and underpromotions
- if (pawnsOn7)
- {
- if (Type == MV_CAPTURE)
- emptySquares = pos.empty_squares();
+ Color us = pos.side_to_move();
+ CheckInfo ci(pos);
+ Bitboard dc = ci.dcCandidates;
- pawns &= ~TRank7BB;
- mlist = generate_promotions<Type, RIGHT_UP>(pos, mlist, pawnsOn7, enemyPieces);
- mlist = generate_promotions<Type, LEFT_UP>(pos, mlist, pawnsOn7, enemyPieces);
- mlist = generate_promotions<Type, UP>(pos, mlist, pawnsOn7, emptySquares);
- }
+ while (dc)
+ {
+ Square from = pop_lsb(&dc);
+ PieceType pt = type_of(pos.piece_on(from));
- // Standard captures
- if (Type == MV_CAPTURE || Type == MV_EVASION)
- {
- mlist = generate_pawn_captures<Type, RIGHT_UP>(mlist, pawns, enemyPieces);
- mlist = generate_pawn_captures<Type, LEFT_UP>(mlist, pawns, enemyPieces);
- }
+ if (pt == PAWN)
+ continue; // Will be generated together with direct checks
- // Single and double pawn pushes
- if (Type != MV_CAPTURE)
- {
- b1 = (Type != MV_EVASION ? pawnPushes : pawnPushes & emptySquares);
- b2 = move_pawns<UP>(pawnPushes & TRank3BB) & emptySquares;
+ Bitboard b = pos.attacks_from(Piece(pt), from) & ~pos.pieces();
- if (Type == MV_CHECK)
- {
- // Consider only pawn moves which give direct checks
- b1 &= pos.attacks_from<PAWN>(ksq, Them);
- b2 &= pos.attacks_from<PAWN>(ksq, Them);
+ if (pt == KING)
+ b &= ~PseudoAttacks[QUEEN][ci.ksq];
- // Add pawn moves which gives 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.
- if (pawns & target) // For CHECK type target is dc bitboard
- {
- dc1 = move_pawns<UP>(pawns & target & ~file_bb(ksq)) & emptySquares;
- dc2 = move_pawns<UP>(dc1 & TRank3BB) & emptySquares;
+ while (b)
+ (moveList++)->move = make_move(from, pop_lsb(&b));
+ }
- b1 |= dc1;
- b2 |= dc2;
- }
- }
- SERIALIZE_MOVES_D(b1, -UP);
- SERIALIZE_MOVES_D(b2, -UP -UP);
- }
+ return us == WHITE ? generate_all<WHITE, QUIET_CHECKS>(pos, moveList, ~pos.pieces(), &ci)
+ : generate_all<BLACK, QUIET_CHECKS>(pos, moveList, ~pos.pieces(), &ci);
+}
- // En passant captures
- if ((Type == MV_CAPTURE || Type == MV_EVASION) && pos.ep_square() != SQ_NONE)
- {
- assert(Us != WHITE || rank_of(pos.ep_square()) == RANK_6);
- assert(Us != BLACK || rank_of(pos.ep_square()) == RANK_3);
- // 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;
+/// 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<>
+ExtMove* generate<EVASIONS>(const Position& pos, ExtMove* moveList) {
- b1 = pawns & pos.attacks_from<PAWN>(pos.ep_square(), Them);
+ assert(pos.checkers());
- assert(b1);
+ Color us = pos.side_to_move();
+ Square ksq = pos.king_square(us);
+ Bitboard sliderAttacks = 0;
+ Bitboard sliders = pos.checkers() & ~pos.pieces(KNIGHT, PAWN);
- while (b1)
- {
- to = pop_1st_bit(&b1);
- (*mlist++).move = make_enpassant(to, pos.ep_square());
- }
- }
- return mlist;
+ // 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)
+ {
+ Square checksq = pop_lsb(&sliders);
+ sliderAttacks |= LineBB[checksq][ksq] ^ checksq;
}
- template<CastlingSide Side>
- MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist, Color us) {
+ // Generate evasions for king, capture and non capture moves
+ Bitboard b = pos.attacks_from<KING>(ksq) & ~pos.pieces(us) & ~sliderAttacks;
+ while (b)
+ (moveList++)->move = make_move(ksq, pop_lsb(&b));
- CastleRight f = CastleRight((Side == KING_SIDE ? WHITE_OO : WHITE_OOO) << us);
- Color them = flip(us);
+ if (more_than_one(pos.checkers()))
+ return moveList; // Double check, only a king move can save the day
- // After castling, the rook and king's final positions are exactly the same
- // in Chess960 as they would be in standard chess.
- Square kfrom = pos.king_square(us);
- Square rfrom = pos.castle_rook_square(f);
- Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1);
- Square rto = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1);
-
- 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(kfrom, kto); s <= std::max(kfrom, kto); s++)
- if ( (s != kfrom && s != rfrom && !pos.square_is_empty(s))
- ||(pos.attackers_to(s) & pos.pieces(them)))
- return mlist;
-
- for (Square s = std::min(rfrom, rto); s <= std::max(rfrom, rto); s++)
- if (s != kfrom && s != rfrom && !pos.square_is_empty(s))
- return mlist;
+ // Generate blocking evasions or captures of the checking piece
+ Square checksq = lsb(pos.checkers());
+ Bitboard target = between_bb(checksq, ksq) | checksq;
- // 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) & pos.pieces(them))
- return mlist;
- }
+ return us == WHITE ? generate_all<WHITE, EVASIONS>(pos, moveList, target)
+ : generate_all<BLACK, EVASIONS>(pos, moveList, target);
+}
- (*mlist++).move = make_castle(kfrom, rfrom);
- return mlist;
- }
+/// generate<LEGAL> generates all the legal moves in the given position
-} // namespace
+template<>
+ExtMove* generate<LEGAL>(const Position& pos, ExtMove* moveList) {
+
+ Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
+ Square ksq = pos.king_square(pos.side_to_move());
+ ExtMove* cur = moveList;
+
+ moveList = pos.checkers() ? generate<EVASIONS >(pos, moveList)
+ : generate<NON_EVASIONS>(pos, moveList);
+ while (cur != moveList)
+ if ( (pinned || from_sq(cur->move) == ksq || type_of(cur->move) == ENPASSANT)
+ && !pos.legal(cur->move, pinned))
+ cur->move = (--moveList)->move;
+ else
+ ++cur;
+
+ return moveList;
+}
projects / stockfish / blobdiff