along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include "position.h"
+
#include <algorithm>
+#include <atomic>
#include <cassert>
-#include <cstddef> // For offsetof()
-#include <cstring> // For std::memset, std::memcmp
+#include <cctype>
+#include <cstddef>
+#include <cstring>
+#include <initializer_list>
#include <iomanip>
+#include <iostream>
#include <sstream>
#include <string_view>
+#include <utility>
#include "bitboard.h"
#include "misc.h"
#include "movegen.h"
-#include "position.h"
+#include "nnue/nnue_common.h"
+#include "syzygy/tbprobe.h"
#include "thread.h"
#include "tt.h"
#include "uci.h"
-#include "syzygy/tbprobe.h"
using std::string;
Key psq[PIECE_NB][SQUARE_NB];
Key enpassant[FILE_NB];
Key castling[CASTLING_RIGHT_NB];
- Key side, noPawns;
+ Key side;
}
namespace {
}
-// Marcel van Kervinck's cuckoo algorithm for fast detection of "upcoming repetition"
-// situations. Description of the algorithm in the following paper:
+// Implements Marcel van Kervinck's cuckoo algorithm to detect repetition of positions
+// for 3-fold repetition draws. The algorithm uses two hash tables with Zobrist hashes to
+// allow fast detection of recurring positions. For details see:
// http://web.archive.org/web/20201107002606/https://marcelk.net/2013-04-06/paper/upcoming-rep-v2.pdf
// First and second hash functions for indexing the cuckoo tables
Zobrist::castling[cr] = rng.rand<Key>();
Zobrist::side = rng.rand<Key>();
- Zobrist::noPawns = rng.rand<Key>();
// Prepare the cuckoo tables
std::memset(cuckoo, 0, sizeof(cuckoo));
void Position::set_check_info() const {
- st->blockersForKing[WHITE] = slider_blockers(pieces(BLACK), square<KING>(WHITE), st->pinners[BLACK]);
- st->blockersForKing[BLACK] = slider_blockers(pieces(WHITE), square<KING>(BLACK), st->pinners[WHITE]);
+ update_slider_blockers(WHITE);
+ update_slider_blockers(BLACK);
Square ksq = square<KING>(~sideToMove);
void Position::set_state() const {
st->key = st->materialKey = 0;
- st->pawnKey = Zobrist::noPawns;
st->nonPawnMaterial[WHITE] = st->nonPawnMaterial[BLACK] = VALUE_ZERO;
st->checkersBB = attackers_to(square<KING>(sideToMove)) & pieces(~sideToMove);
Piece pc = piece_on(s);
st->key ^= Zobrist::psq[pc][s];
- if (type_of(pc) == PAWN)
- st->pawnKey ^= Zobrist::psq[pc][s];
-
- else if (type_of(pc) != KING)
- st->nonPawnMaterial[color_of(pc)] += PieceValue[MG][pc];
+ if (type_of(pc) != KING && type_of(pc) != PAWN)
+ st->nonPawnMaterial[color_of(pc)] += PieceValue[pc];
}
if (st->epSquare != SQ_NONE)
return ss.str();
}
+/// update_slider_blockers() calculates st->blockersForKing[c] and st->pinners[~c],
+/// which store respectively the pieces preventing king of color c from being in check
+/// and the slider pieces of color ~c pinning pieces of color c to the king.
+void Position::update_slider_blockers(Color c) const {
-/// Position::slider_blockers() returns a bitboard of all the pieces (both colors)
-/// that are blocking attacks on the square 's' from 'sliders'. A piece blocks a
-/// slider if removing that piece from the board would result in a position where
-/// square 's' is attacked. For example, a king-attack blocking piece can be either
-/// a pinned or a discovered check piece, according if its color is the opposite
-/// or the same of the color of the slider.
-
-Bitboard Position::slider_blockers(Bitboard sliders, Square s, Bitboard& pinners) const {
+ Square ksq = square<KING>(c);
- Bitboard blockers = 0;
- pinners = 0;
+ st->blockersForKing[c] = 0;
+ st->pinners[~c] = 0;
// Snipers are sliders that attack 's' when a piece and other snipers are removed
- Bitboard snipers = ( (attacks_bb< ROOK>(s) & pieces(QUEEN, ROOK))
- | (attacks_bb<BISHOP>(s) & pieces(QUEEN, BISHOP))) & sliders;
+ Bitboard snipers = ( (attacks_bb< ROOK>(ksq) & pieces(QUEEN, ROOK))
+ | (attacks_bb<BISHOP>(ksq) & pieces(QUEEN, BISHOP))) & pieces(~c);
Bitboard occupancy = pieces() ^ snipers;
while (snipers)
{
Square sniperSq = pop_lsb(snipers);
- Bitboard b = between_bb(s, sniperSq) & occupancy;
+ Bitboard b = between_bb(ksq, sniperSq) & occupancy;
if (b && !more_than_one(b))
{
- blockers |= b;
- if (b & pieces(color_of(piece_on(s))))
- pinners |= sniperSq;
+ st->blockersForKing[c] |= b;
+ if (b & pieces(c))
+ st->pinners[~c] |= sniperSq;
}
}
- return blockers;
}
/// Position::pseudo_legal() takes a random move and tests whether the move is
-/// pseudo legal. It is used to validate moves from TT that can be corrupted
+/// pseudo-legal. It is used to validate moves from TT that can be corrupted
/// due to SMP concurrent access or hash position key aliasing.
bool Position::pseudo_legal(const Move m) const {
return checkers() ? MoveList< EVASIONS>(*this).contains(m)
: MoveList<NON_EVASIONS>(*this).contains(m);
- // Is not a promotion, so promotion piece must be empty
+ // Is not a promotion, so the promotion piece must be empty
assert(promotion_type(m) - KNIGHT == NO_PIECE_TYPE);
// If the 'from' square is not occupied by a piece belonging to the side to
{
if (type_of(pc) != KING)
{
- // Double check? In this case a king move is required
+ // Double check? In this case, a king move is required
if (more_than_one(checkers()))
return false;
if (!(between_bb(square<KING>(us), lsb(checkers())) & to))
return false;
}
- // In case of king moves under check we have to remove king so as to catch
+ // In case of king moves under check we have to remove the king so as to catch
// invalid moves like b1a1 when opposite queen is on c1.
else if (attackers_to(to, pieces() ^ from) & pieces(~us))
return false;
return true;
// Is there a discovered check?
- if ( (blockers_for_king(~sideToMove) & from)
- && !aligned(from, to, square<KING>(~sideToMove)))
- return true;
+ if (blockers_for_king(~sideToMove) & from)
+ return !aligned(from, to, square<KING>(~sideToMove))
+ || type_of(m) == CASTLING;
switch (type_of(m))
{
default: //CASTLING
{
// Castling is encoded as 'king captures the rook'
- Square ksq = square<KING>(~sideToMove);
Square rto = relative_square(sideToMove, to > from ? SQ_F1 : SQ_D1);
- return (attacks_bb<ROOK>(rto) & ksq)
- && (attacks_bb<ROOK>(rto, pieces() ^ from ^ to) & ksq);
+ return check_squares(ROOK) & rto;
}
}
}
assert(piece_on(to) == NO_PIECE);
assert(piece_on(capsq) == make_piece(them, PAWN));
}
-
- st->pawnKey ^= Zobrist::psq[captured][capsq];
}
else
- st->nonPawnMaterial[them] -= PieceValue[MG][captured];
+ st->nonPawnMaterial[them] -= PieceValue[captured];
- if (Eval::useNNUE)
- {
- dp.dirty_num = 2; // 1 piece moved, 1 piece captured
- dp.piece[1] = captured;
- dp.from[1] = capsq;
- dp.to[1] = SQ_NONE;
- }
+ dp.dirty_num = 2; // 1 piece moved, 1 piece captured
+ dp.piece[1] = captured;
+ dp.from[1] = capsq;
+ dp.to[1] = SQ_NONE;
// Update board and piece lists
remove_piece(capsq);
// Update material hash key and prefetch access to materialTable
k ^= Zobrist::psq[captured][capsq];
st->materialKey ^= Zobrist::psq[captured][pieceCount[captured]];
- prefetch(thisThread->materialTable[st->materialKey]);
// Reset rule 50 counter
st->rule50 = 0;
// Move the piece. The tricky Chess960 castling is handled earlier
if (type_of(m) != CASTLING)
{
- if (Eval::useNNUE)
- {
- dp.piece[0] = pc;
- dp.from[0] = from;
- dp.to[0] = to;
- }
+ dp.piece[0] = pc;
+ dp.from[0] = from;
+ dp.to[0] = to;
move_piece(from, to);
}
remove_piece(to);
put_piece(promotion, to);
- if (Eval::useNNUE)
- {
- // Promoting pawn to SQ_NONE, promoted piece from SQ_NONE
- dp.to[0] = SQ_NONE;
- dp.piece[dp.dirty_num] = promotion;
- dp.from[dp.dirty_num] = SQ_NONE;
- dp.to[dp.dirty_num] = to;
- dp.dirty_num++;
- }
+ // Promoting pawn to SQ_NONE, promoted piece from SQ_NONE
+ dp.to[0] = SQ_NONE;
+ dp.piece[dp.dirty_num] = promotion;
+ dp.from[dp.dirty_num] = SQ_NONE;
+ dp.to[dp.dirty_num] = to;
+ dp.dirty_num++;
// Update hash keys
k ^= Zobrist::psq[pc][to] ^ Zobrist::psq[promotion][to];
- st->pawnKey ^= Zobrist::psq[pc][to];
st->materialKey ^= Zobrist::psq[promotion][pieceCount[promotion]-1]
^ Zobrist::psq[pc][pieceCount[pc]];
// Update material
- st->nonPawnMaterial[us] += PieceValue[MG][promotion];
+ st->nonPawnMaterial[us] += PieceValue[promotion];
}
- // Update pawn hash key
- st->pawnKey ^= Zobrist::psq[pc][from] ^ Zobrist::psq[pc][to];
-
// Reset rule 50 draw counter
st->rule50 = 0;
}
rto = relative_square(us, kingSide ? SQ_F1 : SQ_D1);
to = relative_square(us, kingSide ? SQ_G1 : SQ_C1);
- if (Do && Eval::useNNUE)
+ if (Do)
{
auto& dp = st->dirtyPiece;
dp.piece[0] = make_piece(us, KING);
/// SEE value of move is greater or equal to the given threshold. We'll use an
/// algorithm similar to alpha-beta pruning with a null window.
-bool Position::see_ge(Move m, Bitboard& occupied, Value threshold) const {
+bool Position::see_ge(Move m, Value threshold) const {
assert(is_ok(m));
Square from = from_sq(m), to = to_sq(m);
- int swap = PieceValue[MG][piece_on(to)] - threshold;
+ int swap = PieceValue[piece_on(to)] - threshold;
if (swap < 0)
return false;
- swap = PieceValue[MG][piece_on(from)] - swap;
+ swap = PieceValue[piece_on(from)] - swap;
if (swap <= 0)
return true;
assert(color_of(piece_on(from)) == sideToMove);
- occupied = pieces() ^ from ^ to; // xoring to is important for pinned piece logic
+ Bitboard occupied = pieces() ^ from ^ to; // xoring to is important for pinned piece logic
Color stm = sideToMove;
Bitboard attackers = attackers_to(to, occupied);
Bitboard stmAttackers, bb;
// the bitboard 'attackers' any X-ray attackers behind it.
if ((bb = stmAttackers & pieces(PAWN)))
{
- occupied ^= least_significant_square_bb(bb);
- if ((swap = PawnValueMg - swap) < res)
+ if ((swap = PawnValue - swap) < res)
break;
+ occupied ^= least_significant_square_bb(bb);
attackers |= attacks_bb<BISHOP>(to, occupied) & pieces(BISHOP, QUEEN);
}
else if ((bb = stmAttackers & pieces(KNIGHT)))
{
- occupied ^= least_significant_square_bb(bb);
- if ((swap = KnightValueMg - swap) < res)
+ if ((swap = KnightValue - swap) < res)
break;
+ occupied ^= least_significant_square_bb(bb);
}
else if ((bb = stmAttackers & pieces(BISHOP)))
{
- occupied ^= least_significant_square_bb(bb);
- if ((swap = BishopValueMg - swap) < res)
+ if ((swap = BishopValue - swap) < res)
break;
+ occupied ^= least_significant_square_bb(bb);
attackers |= attacks_bb<BISHOP>(to, occupied) & pieces(BISHOP, QUEEN);
}
else if ((bb = stmAttackers & pieces(ROOK)))
{
- occupied ^= least_significant_square_bb(bb);
- if ((swap = RookValueMg - swap) < res)
+ if ((swap = RookValue - swap) < res)
break;
+ occupied ^= least_significant_square_bb(bb);
attackers |= attacks_bb<ROOK>(to, occupied) & pieces(ROOK, QUEEN);
}
else if ((bb = stmAttackers & pieces(QUEEN)))
{
- occupied ^= least_significant_square_bb(bb);
- if ((swap = QueenValueMg - swap) < res)
+ if ((swap = QueenValue - swap) < res)
break;
+ occupied ^= least_significant_square_bb(bb);
attackers |= (attacks_bb<BISHOP>(to, occupied) & pieces(BISHOP, QUEEN))
| (attacks_bb<ROOK >(to, occupied) & pieces(ROOK , QUEEN));
}
else // KING
- // If we "capture" with the king but opponent still has attackers,
+ // If we "capture" with the king but the opponent still has attackers,
// reverse the result.
return (attackers & ~pieces(stm)) ? res ^ 1 : res;
}
return bool(res);
}
-bool Position::see_ge(Move m, Value threshold) const {
- Bitboard occupied;
- return see_ge(m, occupied, threshold);
-}
-
-
/// Position::is_draw() tests whether the position is drawn by 50-move rule
/// or by repetition. It does not detect stalemates.
/// Position::pos_is_ok() performs some consistency checks for the
-/// position object and raises an asserts if something wrong is detected.
+/// position object and raise an assert if something wrong is detected.
/// This is meant to be helpful when debugging.
bool Position::pos_is_ok() const {
projects / stockfish / blobdiff