along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
-////
-//// Includes
-////
-
#include <cassert>
#include "bitcount.h"
#include "movegen.h"
-#include "types.h"
// Simple macro to wrap a very common while loop, no facny, no flexibility,
// hardcoded list name 'mlist' and from square 'from'.
// 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); }
-////
-//// Local definitions
-////
-
namespace {
enum CastlingSide {
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);
- Bitboard b = pos.attacks_from<Piece>(from) & pos.empty_squares();
- if (Piece == KING)
+ Bitboard b = pos.attacks_from<Pt>(from) & pos.empty_squares();
+ if (Pt == KING)
{
Square ksq = pos.king_square(opposite_color(pos.side_to_move()));
b &= ~QueenPseudoAttacks[ksq];
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);
Bitboard checkSqs, b;
Square from;
- const Square* ptr = pos.piece_list_begin(us, Piece);
+ const Square* ptr = pos.piece_list_begin(us, Pt);
if ((from = *ptr++) == 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);
: 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* ptr = pos.piece_list_begin(us, Pt);
if (*ptr != SQ_NONE)
{
do {
from = *ptr;
- b = pos.attacks_from<Piece>(from) & target;
+ b = pos.attacks_from<Pt>(from) & target;
SERIALIZE_MOVES(b);
} while (*++ptr != SQ_NONE);
}
}
-////
-//// Functions
-////
-
/// generate<MV_CAPTURE> generates all pseudo-legal captures and queen
/// promotions. Returns a pointer to the end of the move list.
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;
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);
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;
Color us = pos.side_to_move();
Square ksq = pos.king_square(opposite_color(us));
- assert(pos.piece_on(ksq) == piece_of_color_and_type(opposite_color(us), KING));
+ assert(pos.piece_on(ksq) == make_piece(opposite_color(us), KING));
// Discovered non-capture checks
b = dc = pos.discovered_check_candidates(us);
while (b)
{
from = pop_1st_bit(&b);
- switch (pos.type_of_piece_on(from))
+ switch (type_of_piece(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;
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;
Bitboard checkers = pos.checkers();
Bitboard sliderAttacks = EmptyBoardBB;
- assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
+ assert(pos.piece_on(ksq) == make_piece(us, KING));
assert(checkers);
// Find squares attacked by slider checkers, we will remove
assert(pos.color_of_piece_on(checksq) == opposite_color(us));
- switch (pos.type_of_piece_on(checksq))
+ switch (type_of_piece(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;
}
}
-/// 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) {
MoveStack *last, *cur = mlist;
Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
- 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<SquareDelta Delta>
+ template<Square Delta>
inline Bitboard move_pawns(Bitboard p) {
return Delta == DELTA_N ? p << 8 : Delta == DELTA_S ? p >> 8 :
Delta == DELTA_NW ? p << 7 : Delta == DELTA_SW ? p >> 9 : p;
}
- template<MoveType Type, SquareDelta Delta>
+ 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);
return mlist;
}
- template<Color Us, MoveType Type, SquareDelta Delta>
+ template<Color Us, 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);
// 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 SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
- const SquareDelta TDELTA_NE = (Us == WHITE ? DELTA_NE : DELTA_SE);
- const SquareDelta TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW);
+ 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);
Square to;
Bitboard b1, b2, dc1, dc2, pawnPushes, emptySquares;
// Single and double pawn pushes
if (Type != MV_CAPTURE)
{
- b1 = pawnPushes & emptySquares;
+ b1 = (Type != MV_EVASION ? pawnPushes : pawnPushes & emptySquares);
b2 = move_pawns<TDELTA_N>(pawnPushes & TRank3BB) & emptySquares;
if (Type == MV_CHECK)
Color them = opposite_color(us);
Square ksq = pos.king_square(us);
- assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
+ 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 s;
bool illegal = false;
- assert(pos.piece_on(rsq) == piece_of_color_and_type(us, ROOK));
+ 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 ( Side == QUEEN_SIDE
&& square_file(rsq) == FILE_B
- && ( pos.piece_on(relative_square(us, SQ_A1)) == piece_of_color_and_type(them, ROOK)
- || pos.piece_on(relative_square(us, SQ_A1)) == piece_of_color_and_type(them, QUEEN)))
+ && ( 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;
if (!illegal)