/*
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) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2004-2021 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
#include "movegen.h"
#include "position.h"
+namespace Stockfish {
+
namespace {
template<GenType Type, Direction D>
ExtMove* make_promotions(ExtMove* moveList, Square to, Square ksq) {
if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
+ {
*moveList++ = make<PROMOTION>(to - D, to, QUEEN);
+ if (attacks_bb<KNIGHT>(to) & ksq)
+ *moveList++ = make<PROMOTION>(to - D, to, KNIGHT);
+ }
if (Type == QUIETS || Type == EVASIONS || Type == NON_EVASIONS)
{
*moveList++ = make<PROMOTION>(to - D, to, ROOK);
*moveList++ = make<PROMOTION>(to - D, to, BISHOP);
- *moveList++ = make<PROMOTION>(to - D, to, KNIGHT);
+ if (!(attacks_bb<KNIGHT>(to) & ksq))
+ *moveList++ = make<PROMOTION>(to - D, to, KNIGHT);
}
- // 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, GenType Type>
ExtMove* generate_pawn_moves(const Position& pos, ExtMove* moveList, Bitboard target) {
- // Compute some compile time parameters relative to the white side
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Color Them = ~Us;
constexpr Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
constexpr Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
- constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH);
+ constexpr Direction Up = pawn_push(Us);
constexpr Direction UpRight = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
constexpr Direction UpLeft = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
+ const Square ksq = pos.square<KING>(Them);
Bitboard emptySquares;
Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB;
if (Type == QUIET_CHECKS)
{
- Square ksq = pos.square<KING>(Them);
-
- b1 &= pos.attacks_from<PAWN>(ksq, Them);
- b2 &= pos.attacks_from<PAWN>(ksq, Them);
+ b1 &= pawn_attacks_bb(Them, ksq);
+ b2 &= pawn_attacks_bb(Them, ksq);
// 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
+ // don't generate captures. Note that a possible discovered check
// promotion has been already generated amongst the captures.
- Bitboard dcCandidates = pos.blockers_for_king(Them);
- if (pawnsNotOn7 & dcCandidates)
+ Bitboard dcCandidateQuiets = pos.blockers_for_king(Them) & pawnsNotOn7;
+ if (dcCandidateQuiets)
{
- Bitboard dc1 = shift<Up>(pawnsNotOn7 & dcCandidates) & emptySquares & ~file_bb(ksq);
+ Bitboard dc1 = shift<Up>(dcCandidateQuiets) & emptySquares & ~file_bb(ksq);
Bitboard dc2 = shift<Up>(dc1 & TRank3BB) & emptySquares;
b1 |= dc1;
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);
moveList = make_promotions<Type, Up >(moveList, pop_lsb(&b3), ksq);
}
- // Standard and en-passant captures
+ // Standard and en passant captures
if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
{
Bitboard b1 = shift<UpRight>(pawnsNotOn7) & enemies;
{
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 == EVASIONS && !(target & (pos.ep_square() - Up)))
+ // 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)
- *moveList++ = make<ENPASSANT>(pop_lsb(&b1), pos.ep_square());
+ *moveList++ = make<EN_PASSANT>(pop_lsb(&b1), pos.ep_square());
}
}
template<PieceType Pt, bool Checks>
- ExtMove* generate_moves(const Position& pos, ExtMove* moveList, Color us,
- Bitboard target) {
+ ExtMove* generate_moves(const Position& pos, ExtMove* moveList, Bitboard piecesToMove, Bitboard target) {
- assert(Pt != KING && Pt != PAWN);
+ static_assert(Pt != KING && Pt != PAWN, "Unsupported piece type in generate_moves()");
- const Square* pl = pos.squares<Pt>(us);
+ Bitboard bb = piecesToMove & pos.pieces(Pt);
- for (Square from = *pl; from != SQ_NONE; from = *++pl)
- {
- if (Checks)
- {
- if ( (Pt == BISHOP || Pt == ROOK || Pt == QUEEN)
- && !(PseudoAttacks[Pt][from] & target & pos.check_squares(Pt)))
- continue;
+ if (!bb)
+ return moveList;
- if (pos.blockers_for_king(~us) & from)
- continue;
- }
+ [[maybe_unused]] const Bitboard checkSquares = pos.check_squares(Pt);
- Bitboard b = pos.attacks_from<Pt>(from) & target;
+ while (bb) {
+ Square from = pop_lsb(&bb);
- if (Checks)
- b &= pos.check_squares(Pt);
+ Bitboard b = attacks_bb<Pt>(from, pos.pieces()) & target;
+ if constexpr (Checks)
+ b &= checkSquares;
while (b)
*moveList++ = make_move(from, pop_lsb(&b));
template<Color Us, GenType Type>
- ExtMove* generate_all(const Position& pos, ExtMove* moveList, Bitboard target) {
+ ExtMove* generate_all(const Position& pos, ExtMove* moveList) {
+
+ static_assert(Type != LEGAL, "Unsupported type in generate_all()");
+
+ constexpr bool Checks = Type == QUIET_CHECKS; // Reduce template instantiations
+ Bitboard target, piecesToMove = pos.pieces(Us);
+
+ if(Type == QUIET_CHECKS)
+ piecesToMove &= ~pos.blockers_for_king(~Us);
- constexpr CastlingRight OO = Us | KING_SIDE;
- constexpr CastlingRight OOO = Us | QUEEN_SIDE;
- constexpr bool Checks = Type == QUIET_CHECKS; // Reduce template instantations
+ switch (Type)
+ {
+ case CAPTURES:
+ target = pos.pieces(~Us);
+ break;
+ case QUIETS:
+ case QUIET_CHECKS:
+ target = ~pos.pieces();
+ break;
+ case EVASIONS:
+ target = between_bb(pos.square<KING>(Us), lsb(pos.checkers())) | pos.checkers();
+ break;
+ case NON_EVASIONS:
+ target = ~pos.pieces(Us);
+ break;
+ }
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);
+ moveList = generate_moves<KNIGHT, Checks>(pos, moveList, piecesToMove, target);
+ moveList = generate_moves<BISHOP, Checks>(pos, moveList, piecesToMove, target);
+ moveList = generate_moves< ROOK, Checks>(pos, moveList, piecesToMove, target);
+ moveList = generate_moves< QUEEN, Checks>(pos, moveList, piecesToMove, target);
if (Type != QUIET_CHECKS && Type != EVASIONS)
{
Square ksq = pos.square<KING>(Us);
- Bitboard b = pos.attacks_from<KING>(ksq) & target;
+ Bitboard b = attacks_bb<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));
- }
+ if ((Type != CAPTURES) && 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 moveList;
} // namespace
-/// 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.
+/// <CAPTURES> Generates all pseudo-legal captures plus queen and checking knight promotions
+/// <QUIETS> Generates all pseudo-legal non-captures and underpromotions (except checking knight)
+/// <NON_EVASIONS> Generates all pseudo-legal captures and non-captures
///
-/// generate<NON_EVASIONS> 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<GenType Type>
ExtMove* generate(const Position& pos, ExtMove* moveList) {
- assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS);
+ static_assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS, "Unsupported type in generate()");
assert(!pos.checkers());
Color us = pos.side_to_move();
- Bitboard target = Type == CAPTURES ? pos.pieces(~us)
- : Type == QUIETS ? ~pos.pieces()
- : Type == NON_EVASIONS ? ~pos.pieces(us) : 0;
-
- return us == WHITE ? generate_all<WHITE, Type>(pos, moveList, target)
- : generate_all<BLACK, Type>(pos, moveList, target);
+ return us == WHITE ? generate_all<WHITE, Type>(pos, moveList)
+ : generate_all<BLACK, Type>(pos, moveList);
}
// Explicit template instantiations
template ExtMove* generate<NON_EVASIONS>(const Position&, ExtMove*);
-/// 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.
+/// generate<QUIET_CHECKS> generates all pseudo-legal non-captures giving check,
+/// except castling. Returns a pointer to the end of the move list.
template<>
ExtMove* generate<QUIET_CHECKS>(const Position& pos, ExtMove* moveList) {
assert(!pos.checkers());
Color us = pos.side_to_move();
- Bitboard dc = pos.blockers_for_king(~us) & pos.pieces(us);
+ Bitboard dc = pos.blockers_for_king(~us) & pos.pieces(us) & ~pos.pieces(PAWN);
while (dc)
{
Square from = pop_lsb(&dc);
PieceType pt = type_of(pos.piece_on(from));
- if (pt == PAWN)
- continue; // Will be generated together with direct checks
-
- Bitboard b = pos.attacks_from(pt, from) & ~pos.pieces();
+ Bitboard b = attacks_bb(pt, from, pos.pieces()) & ~pos.pieces();
if (pt == KING)
- b &= ~PseudoAttacks[QUEEN][pos.square<KING>(~us)];
+ b &= ~attacks_bb<QUEEN>(pos.square<KING>(~us));
while (b)
*moveList++ = make_move(from, pop_lsb(&b));
}
- return us == WHITE ? generate_all<WHITE, QUIET_CHECKS>(pos, moveList, ~pos.pieces())
- : generate_all<BLACK, QUIET_CHECKS>(pos, moveList, ~pos.pieces());
+ return us == WHITE ? generate_all<WHITE, QUIET_CHECKS>(pos, moveList)
+ : generate_all<BLACK, QUIET_CHECKS>(pos, moveList);
}
// 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;
- }
+ sliderAttacks |= line_bb(ksq, pop_lsb(&sliders)) & ~pos.checkers();
// Generate evasions for king, capture and non capture moves
- Bitboard b = pos.attacks_from<KING>(ksq) & ~pos.pieces(us) & ~sliderAttacks;
+ Bitboard b = attacks_bb<KING>(ksq) & ~pos.pieces(us) & ~sliderAttacks;
while (b)
*moveList++ = make_move(ksq, pop_lsb(&b));
return moveList; // Double check, only a king move can save the day
// Generate blocking evasions or captures of the checking piece
- Square checksq = lsb(pos.checkers());
- Bitboard target = between_bb(checksq, ksq) | checksq;
-
- return us == WHITE ? generate_all<WHITE, EVASIONS>(pos, moveList, target)
- : generate_all<BLACK, EVASIONS>(pos, moveList, target);
+ return us == WHITE ? generate_all<WHITE, EVASIONS>(pos, moveList)
+ : generate_all<BLACK, EVASIONS>(pos, 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)
+ if ( ((pinned && pinned & from_sq(*cur)) || from_sq(*cur) == ksq || type_of(*cur) == EN_PASSANT)
&& !pos.legal(*cur))
*cur = (--moveList)->move;
else
return moveList;
}
+
+} // namespace Stockfish
projects / stockfish / blobdiff