#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'.
QUEEN_SIDE
};
- template<CastlingSide Side>
+ template<CastlingSide>
MoveStack* generate_castle_moves(const Position&, MoveStack*, Color us);
- template<Color Us, MoveType Type>
+ template<Color, MoveType>
MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square);
- template<PieceType Piece>
+ template<PieceType Pt>
inline MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) {
- assert(Piece != QUEEN);
+ assert(Pt != QUEEN);
+ assert(Pt != PAWN);
+
+ Bitboard b = pos.attacks_from<Pt>(from) & pos.empty_squares();
+
+ if (Pt == KING)
+ b &= ~QueenPseudoAttacks[pos.king_square(opposite_color(pos.side_to_move()))];
- Bitboard b = pos.attacks_from<Piece>(from) & pos.empty_squares();
- if (Piece == KING)
- {
- Square ksq = pos.king_square(opposite_color(pos.side_to_move()));
- b &= ~QueenPseudoAttacks[ksq];
- }
SERIALIZE_MOVES(b);
return mlist;
}
- template<PieceType Piece>
+ template<PieceType Pt>
inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us,
Bitboard dc, Square ksq) {
- assert(Piece != KING);
+ assert(Pt != KING);
+ assert(Pt != PAWN);
Bitboard checkSqs, b;
Square from;
- const Square* ptr = pos.piece_list_begin(us, Piece);
+ const Square* pl = pos.piece_list(us, Pt);
- if ((from = *ptr++) == SQ_NONE)
+ if ((from = *pl++) == SQ_NONE)
return mlist;
- checkSqs = pos.attacks_from<Piece>(ksq) & pos.empty_squares();
+ checkSqs = pos.attacks_from<Pt>(ksq) & pos.empty_squares();
do
{
- if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs))
- || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs))
- || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
+ if ( (Pt == QUEEN && !(QueenPseudoAttacks[from] & checkSqs))
+ || (Pt == ROOK && !(RookPseudoAttacks[from] & checkSqs))
+ || (Pt == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
continue;
if (dc && bit_is_set(dc, from))
continue;
- b = pos.attacks_from<Piece>(from) & checkSqs;
+ b = pos.attacks_from<Pt>(from) & checkSqs;
SERIALIZE_MOVES(b);
- } while ((from = *ptr++) != SQ_NONE);
+ } while ((from = *pl++) != SQ_NONE);
return mlist;
}
: generate_pawn_moves<BLACK, MV_CHECK>(p, m, dc, ksq));
}
- template<PieceType Piece, MoveType Type>
+ template<PieceType Pt, MoveType Type>
FORCE_INLINE MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) {
- assert(Piece == PAWN);
+ assert(Pt == PAWN);
assert(Type == MV_CAPTURE || Type == MV_NON_CAPTURE || Type == MV_EVASION);
return (us == WHITE ? generate_pawn_moves<WHITE, Type>(p, m, t, SQ_NONE)
: generate_pawn_moves<BLACK, Type>(p, m, t, SQ_NONE));
}
- template<PieceType Piece>
+ template<PieceType Pt>
FORCE_INLINE MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
Bitboard b;
Square from;
- const Square* ptr = pos.piece_list_begin(us, Piece);
+ const Square* pl = pos.piece_list(us, Pt);
- if (*ptr != SQ_NONE)
+ if (*pl != SQ_NONE)
{
do {
- from = *ptr;
- b = pos.attacks_from<Piece>(from) & target;
+ from = *pl;
+ b = pos.attacks_from<Pt>(from) & target;
SERIALIZE_MOVES(b);
- } while (*++ptr != SQ_NONE);
+ } while (*++pl != SQ_NONE);
}
return mlist;
}
}
-////
-//// Functions
-////
-
/// generate<MV_CAPTURE> generates all pseudo-legal captures and queen
/// promotions. Returns a pointer to the end of the move list.
template<MoveType Type>
MoveStack* generate(const Position& pos, MoveStack* mlist) {
- assert(pos.is_ok());
- assert(!pos.is_check());
+ assert(!pos.in_check());
Color us = pos.side_to_move();
Bitboard target;
if (Type == MV_CAPTURE || Type == MV_NON_EVASION)
- target = pos.pieces_of_color(opposite_color(us));
+ target = pos.pieces(opposite_color(us));
else if (Type == MV_NON_CAPTURE)
target = pos.empty_squares();
else
mlist = generate_piece_moves<QUEEN>(pos, mlist, us, target);
mlist = generate_piece_moves<KING>(pos, mlist, us, target);
- if (Type != MV_CAPTURE)
+ if (Type != MV_CAPTURE && pos.can_castle(us))
{
- if (pos.can_castle_kingside(us))
+ if (pos.can_castle(us == WHITE ? WHITE_OO : BLACK_OO))
mlist = generate_castle_moves<KING_SIDE>(pos, mlist, us);
- if (pos.can_castle_queenside(us))
+ if (pos.can_castle(us == WHITE ? WHITE_OOO : BLACK_OOO))
mlist = generate_castle_moves<QUEEN_SIDE>(pos, mlist, us);
}
return mlist;
}
-// Explicit template instantiation
+// 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);
template<>
MoveStack* generate<MV_NON_CAPTURE_CHECK>(const Position& pos, MoveStack* mlist) {
- assert(pos.is_ok());
- assert(!pos.is_check());
+ assert(!pos.in_check());
Bitboard b, dc;
Square from;
assert(pos.piece_on(ksq) == make_piece(opposite_color(us), KING));
// Discovered non-capture checks
- b = dc = pos.discovered_check_candidates(us);
+ b = dc = pos.discovered_check_candidates();
while (b)
{
from = pop_1st_bit(&b);
- switch (pos.type_of_piece_on(from))
+ switch (piece_type(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;
template<>
MoveStack* generate<MV_EVASION>(const Position& pos, MoveStack* mlist) {
- assert(pos.is_ok());
- assert(pos.is_check());
+ assert(pos.in_check());
Bitboard b, target;
Square from, checksq;
checkersCnt++;
checksq = pop_1st_bit(&b);
- assert(pos.color_of_piece_on(checksq) == opposite_color(us));
+ assert(piece_color(pos.piece_on(checksq)) == opposite_color(us));
- switch (pos.type_of_piece_on(checksq))
+ switch (piece_type(pos.piece_on(checksq)))
{
case BISHOP: sliderAttacks |= BishopPseudoAttacks[checksq]; break;
case ROOK: sliderAttacks |= RookPseudoAttacks[checksq]; break;
case QUEEN:
- // In case of a queen remove also squares attacked in the other direction to
- // avoid possible illegal moves when queen and king are on adjacent squares.
- if (RookPseudoAttacks[checksq] & (1ULL << ksq))
- sliderAttacks |= RookPseudoAttacks[checksq] | pos.attacks_from<BISHOP>(checksq);
+ // 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_of_color(us) & ~sliderAttacks;
+ b = pos.attacks_from<KING>(ksq) & ~pos.pieces(us) & ~sliderAttacks;
from = ksq;
SERIALIZE_MOVES(b);
}
-/// generate<MV_LEGAL / MV_PSEUDO_LEGAL> computes a complete list of legal
-/// or pseudo-legal moves in the current position.
-template<>
-inline MoveStack* generate<MV_PSEUDO_LEGAL>(const Position& pos, MoveStack* mlist) {
-
- assert(pos.is_ok());
-
- return pos.is_check() ? generate<MV_EVASION>(pos, mlist)
- : generate<MV_NON_EVASION>(pos, mlist);
-}
+/// generate<MV_LEGAL> computes a complete list of legal moves in the current position
template<>
MoveStack* generate<MV_LEGAL>(const Position& pos, MoveStack* mlist) {
- assert(pos.is_ok());
-
MoveStack *last, *cur = mlist;
- Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
+ Bitboard pinned = pos.pinned_pieces();
- last = generate<MV_PSEUDO_LEGAL>(pos, mlist);
+ 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++;
- else
+ if (!pos.pl_move_is_legal(cur->move, pinned))
cur->move = (--last)->move;
+ else
+ cur++;
return last;
}
-/// move_is_legal() takes a position and a (not necessarily pseudo-legal)
-/// move and tests whether the move is legal. This version is not very fast
-/// and should be used only in non time-critical paths.
-
-bool move_is_legal(const Position& pos, const Move m) {
-
- MoveStack mlist[MOVES_MAX];
- MoveStack *cur, *last = generate<MV_PSEUDO_LEGAL>(pos, mlist);
-
- for (cur = mlist; cur != last; cur++)
- if (cur->move == m)
- return pos.pl_move_is_legal(m, pos.pinned_pieces(pos.side_to_move()));
-
- return false;
-}
-
-
-/// Fast version of move_is_legal() that takes a position a move and a
-/// bitboard of pinned pieces as input, and tests whether the move is legal.
-
-bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
-
- assert(pos.is_ok());
- assert(pinned == pos.pinned_pieces(pos.side_to_move()));
-
- Color us = pos.side_to_move();
- Color them = opposite_color(us);
- Square from = move_from(m);
- Square to = move_to(m);
- Piece pc = pos.piece_on(from);
-
- // Use a slower but simpler function for uncommon cases
- if (move_is_special(m))
- return move_is_legal(pos, m);
-
- // If the from square is not occupied by a piece belonging to the side to
- // move, the move is obviously not legal.
- if (color_of_piece(pc) != us)
- return false;
-
- // The destination square cannot be occupied by a friendly piece
- if (pos.color_of_piece_on(to) == us)
- return false;
-
- // Handle the special case of a pawn move
- if (type_of_piece(pc) == PAWN)
- {
- // Move direction must be compatible with pawn color
- int direction = to - from;
- if ((us == WHITE) != (direction > 0))
- return false;
-
- // We have already handled promotion moves, so destination
- // cannot be on the 8/1th rank.
- if (square_rank(to) == RANK_8 || square_rank(to) == RANK_1)
- return false;
-
- // Proceed according to the square delta between the origin and
- // destination squares.
- switch (direction)
- {
- case DELTA_NW:
- case DELTA_NE:
- case DELTA_SW:
- case DELTA_SE:
- // Capture. The destination square must be occupied by an enemy
- // piece (en passant captures was handled earlier).
- if (pos.color_of_piece_on(to) != them)
- return false;
- break;
-
- case DELTA_N:
- case DELTA_S:
- // Pawn push. The destination square must be empty.
- if (!pos.square_is_empty(to))
- return false;
- break;
-
- case DELTA_NN:
- // Double white pawn push. The destination square must be on the fourth
- // rank, and both the destination square and the square between the
- // source and destination squares must be empty.
- if ( square_rank(to) != RANK_4
- || !pos.square_is_empty(to)
- || !pos.square_is_empty(from + DELTA_N))
- return false;
- break;
-
- case DELTA_SS:
- // Double black pawn push. The destination square must be on the fifth
- // rank, and both the destination square and the square between the
- // source and destination squares must be empty.
- if ( square_rank(to) != RANK_5
- || !pos.square_is_empty(to)
- || !pos.square_is_empty(from + DELTA_S))
- return false;
- break;
-
- default:
- return false;
- }
- }
- else if (!bit_is_set(pos.attacks_from(pc, from), to))
- return false;
-
- // The move is pseudo-legal, check if it is also legal
- return pos.is_check() ? pos.pl_move_is_evasion(m, pinned) : pos.pl_move_is_legal(m, pinned);
-}
-
-
namespace {
template<Square Delta>
return mlist;
}
- template<Color Us, MoveType Type, Square Delta>
+ 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);
// 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(opposite_color(Us))))
+ && bit_is_set(pos.attacks_from<KNIGHT>(to), pos.king_square(Delta > 0 ? BLACK : WHITE)))
(*mlist++).move = make_promotion_move(to - Delta, to, KNIGHT);
else (void)pos; // Silence a warning under MSVC
}
const Color Them = (Us == WHITE ? BLACK : WHITE);
const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
- const Square TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
- const Square TDELTA_NE = (Us == WHITE ? DELTA_NE : DELTA_SE);
- const Square TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW);
+ 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_of_color(Them));
+ 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<TDELTA_N>(pawns & ~TRank7BB) & emptySquares;
+ pawnPushes = move_pawns<UP>(pawns & ~TRank7BB) & emptySquares;
}
if (Type == MV_EVASION)
emptySquares = pos.empty_squares();
pawns &= ~TRank7BB;
- mlist = generate_promotions<Us, Type, TDELTA_NE>(pos, mlist, pawnsOn7, enemyPieces);
- mlist = generate_promotions<Us, Type, TDELTA_NW>(pos, mlist, pawnsOn7, enemyPieces);
- mlist = generate_promotions<Us, Type, TDELTA_N >(pos, mlist, pawnsOn7, emptySquares);
+ 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);
}
// Standard captures
if (Type == MV_CAPTURE || Type == MV_EVASION)
{
- mlist = generate_pawn_captures<Type, TDELTA_NE>(mlist, pawns, enemyPieces);
- mlist = generate_pawn_captures<Type, TDELTA_NW>(mlist, pawns, enemyPieces);
+ mlist = generate_pawn_captures<Type, RIGHT_UP>(mlist, pawns, enemyPieces);
+ mlist = generate_pawn_captures<Type, LEFT_UP>(mlist, pawns, enemyPieces);
}
// Single and double pawn pushes
if (Type != MV_CAPTURE)
{
- b1 = pawnPushes & emptySquares;
- b2 = move_pawns<TDELTA_N>(pawnPushes & TRank3BB) & emptySquares;
+ b1 = (Type != MV_EVASION ? pawnPushes : pawnPushes & emptySquares);
+ b2 = move_pawns<UP>(pawnPushes & TRank3BB) & emptySquares;
if (Type == MV_CHECK)
{
// don't generate captures.
if (pawns & target) // For CHECK type target is dc bitboard
{
- dc1 = move_pawns<TDELTA_N>(pawns & target & ~file_bb(ksq)) & emptySquares;
- dc2 = move_pawns<TDELTA_N>(dc1 & TRank3BB) & emptySquares;
+ dc1 = move_pawns<UP>(pawns & target & ~file_bb(ksq)) & emptySquares;
+ dc2 = move_pawns<UP>(dc1 & TRank3BB) & emptySquares;
b1 |= dc1;
b2 |= dc2;
}
}
- SERIALIZE_MOVES_D(b1, -TDELTA_N);
- SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N);
+ SERIALIZE_MOVES_D(b1, -UP);
+ SERIALIZE_MOVES_D(b2, -UP -UP);
}
// En passant captures
// 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() - TDELTA_N))
+ if (Type == MV_EVASION && !bit_is_set(target, pos.ep_square() - UP))
return mlist;
b1 = pawns & pos.attacks_from<PAWN>(pos.ep_square(), Them);
template<CastlingSide Side>
MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist, Color us) {
+ CastleRight f = CastleRight((Side == KING_SIDE ? WHITE_OO : WHITE_OOO) << us);
Color them = opposite_color(us);
- Square ksq = pos.king_square(us);
-
- assert(pos.piece_on(ksq) == make_piece(us, KING));
- Square rsq = (Side == KING_SIDE ? pos.initial_kr_square(us) : pos.initial_qr_square(us));
- Square s1 = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1);
- Square s2 = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1);
- Square s;
- bool illegal = false;
-
- assert(pos.piece_on(rsq) == make_piece(us, ROOK));
-
- // It is a bit complicated to correctly handle Chess960
- for (s = Min(ksq, s1); s <= Max(ksq, s1); s++)
- if ( (s != ksq && s != rsq && pos.square_is_occupied(s))
- ||(pos.attackers_to(s) & pos.pieces_of_color(them)))
- illegal = true;
+ // 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 = Min(kfrom, kto); s <= Max(kfrom, kto); s++)
+ if ( (s != kfrom && s != rfrom && !pos.square_is_empty(s))
+ ||(pos.attackers_to(s) & pos.pieces(them)))
+ return mlist;
- for (s = Min(rsq, s2); s <= Max(rsq, s2); s++)
- if (s != ksq && s != rsq && pos.square_is_occupied(s))
- illegal = true;
+ for (Square s = Min(rfrom, rto); s <= Max(rfrom, rto); s++)
+ if (s != kfrom && s != rfrom && !pos.square_is_empty(s))
+ return mlist;
- if ( Side == QUEEN_SIDE
- && square_file(rsq) == FILE_B
- && ( pos.piece_on(relative_square(us, SQ_A1)) == make_piece(them, ROOK)
- || pos.piece_on(relative_square(us, SQ_A1)) == make_piece(them, QUEEN)))
- illegal = true;
+ // 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;
+ }
- if (!illegal)
- (*mlist++).move = make_castle_move(ksq, rsq);
+ (*mlist++).move = make_castle_move(kfrom, rfrom);
return mlist;
}
projects / stockfish / blobdiff