Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB;
Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB;
- Bitboard enemies = (Type == EVASIONS ? pos.pieces(Them) & target:
+ Bitboard enemies = (Type == EVASIONS ? pos.checkers():
Type == CAPTURES ? target : pos.pieces(Them));
// Single and double pawn pushes, no promotions
while (b1)
{
- Square to = pop_lsb(&b1);
+ Square to = pop_lsb(b1);
*moveList++ = make_move(to - Up, to);
}
while (b2)
{
- Square to = pop_lsb(&b2);
+ Square to = pop_lsb(b2);
*moveList++ = make_move(to - Up - Up, to);
}
}
Bitboard b3 = shift<Up >(pawnsOn7) & emptySquares;
while (b1)
- moveList = make_promotions<Type, UpRight>(moveList, pop_lsb(&b1), ksq);
+ moveList = make_promotions<Type, UpRight>(moveList, pop_lsb(b1), ksq);
while (b2)
- moveList = make_promotions<Type, UpLeft >(moveList, pop_lsb(&b2), ksq);
+ moveList = make_promotions<Type, UpLeft >(moveList, pop_lsb(b2), ksq);
while (b3)
- moveList = make_promotions<Type, Up >(moveList, pop_lsb(&b3), ksq);
+ moveList = make_promotions<Type, Up >(moveList, pop_lsb(b3), ksq);
}
// Standard and en passant captures
while (b1)
{
- Square to = pop_lsb(&b1);
+ Square to = pop_lsb(b1);
*moveList++ = make_move(to - UpRight, to);
}
while (b2)
{
- Square to = pop_lsb(&b2);
+ Square to = pop_lsb(b2);
*moveList++ = make_move(to - UpLeft, to);
}
{
assert(rank_of(pos.ep_square()) == relative_rank(Us, RANK_6));
- // An en passant capture cannot resolve a discovered check.
+ // An en passant capture cannot resolve a discovered check
if (Type == EVASIONS && (target & (pos.ep_square() + Up)))
return moveList;
assert(b1);
while (b1)
- *moveList++ = make<EN_PASSANT>(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, Bitboard piecesToMove, Bitboard target) {
+ template<Color Us, PieceType Pt, bool Checks>
+ ExtMove* generate_moves(const Position& pos, ExtMove* moveList, Bitboard target) {
static_assert(Pt != KING && Pt != PAWN, "Unsupported piece type in generate_moves()");
- Bitboard bb = piecesToMove & pos.pieces(Pt);
+ Bitboard bb = pos.pieces(Us, Pt);
- if (!bb)
- return moveList;
-
- [[maybe_unused]] const Bitboard checkSquares = pos.check_squares(Pt);
-
- while (bb) {
- Square from = pop_lsb(&bb);
+ while (bb)
+ {
+ Square from = pop_lsb(bb);
Bitboard b = attacks_bb<Pt>(from, pos.pieces()) & target;
- if constexpr (Checks)
- b &= checkSquares;
+ if (Checks && (Pt == QUEEN || !(pos.blockers_for_king(~Us) & from)))
+ b &= pos.check_squares(Pt);
while (b)
- *moveList++ = make_move(from, pop_lsb(&b));
+ *moveList++ = make_move(from, pop_lsb(b));
}
return 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);
+ const Square ksq = pos.square<KING>(Us);
+ Bitboard target;
+
+ if (Type == EVASIONS && more_than_one(pos.checkers()))
+ goto kingMoves; // Double check, only a king move can save the day
switch (Type)
{
target = ~pos.pieces();
break;
case EVASIONS:
- {
- Square checksq = lsb(pos.checkers());
- target = between_bb(pos.square<KING>(Us), checksq) | checksq;
+ target = between_bb(ksq, lsb(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, 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);
+ 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);
- if (Type != QUIET_CHECKS && Type != EVASIONS)
+kingMoves:
+ if (!Checks || pos.blockers_for_king(~Us) & ksq)
{
- Square ksq = pos.square<KING>(Us);
- Bitboard b = attacks_bb<KING>(ksq) & target;
+ Bitboard b = attacks_bb<KING>(ksq) & (Type == EVASIONS ? ~pos.pieces(Us) : target);
+ if (Checks)
+ b &= ~attacks_bb<QUEEN>(pos.square<KING>(~Us));
+
while (b)
- *moveList++ = make_move(ksq, pop_lsb(&b));
+ *moveList++ = make_move(ksq, pop_lsb(b));
- if ((Type != CAPTURES) && pos.can_castle(Us & ANY_CASTLING))
+ 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));
/// <CAPTURES> Generates all pseudo-legal captures plus queen and checking knight promotions
/// <QUIETS> Generates all pseudo-legal non-captures and underpromotions (except checking knight)
+/// <EVASIONS> Generates all pseudo-legal check evasions when the side to move is in check
+/// <QUIET_CHECKS> Generates all pseudo-legal non-captures giving check, except castling
/// <NON_EVASIONS> Generates all pseudo-legal captures and non-captures
///
/// Returns a pointer to the end of the move list.
template<GenType Type>
ExtMove* generate(const Position& pos, ExtMove* moveList) {
- static_assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS, "Unsupported type in generate()");
- assert(!pos.checkers());
+ static_assert(Type != LEGAL, "Unsupported type in generate()");
+ assert((Type == EVASIONS) == (bool)pos.checkers());
Color us = pos.side_to_move();
// 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<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) & ~pos.pieces(PAWN);
-
- while (dc)
- {
- Square from = pop_lsb(&dc);
- PieceType pt = type_of(pos.piece_on(from));
-
- Bitboard b = attacks_bb(pt, from, pos.pieces()) & ~pos.pieces();
-
- if (pt == KING)
- 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)
- : generate_all<BLACK, QUIET_CHECKS>(pos, moveList);
-}
-
-
-/// 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) {
-
- assert(pos.checkers());
-
- Color us = pos.side_to_move();
- Square ksq = pos.square<KING>(us);
- Bitboard sliderAttacks = 0;
- Bitboard sliders = pos.checkers() & ~pos.pieces(KNIGHT, PAWN);
-
- // 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)
- sliderAttacks |= line_bb(ksq, pop_lsb(&sliders)) & ~pos.checkers();
-
- // Generate evasions for king, capture and non capture moves
- Bitboard b = attacks_bb<KING>(ksq) & ~pos.pieces(us) & ~sliderAttacks;
- while (b)
- *moveList++ = make_move(ksq, pop_lsb(&b));
-
- if (more_than_one(pos.checkers()))
- return moveList; // Double check, only a king move can save the day
-
- // Generate blocking evasions or captures of the checking piece
- return us == WHITE ? generate_all<WHITE, EVASIONS>(pos, moveList)
- : generate_all<BLACK, EVASIONS>(pos, moveList);
-}
-
-
/// generate<LEGAL> generates all the legal moves in the given position
template<>