/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#include <algorithm>
#include <cassert>
#include <cstring>
#include <fstream>
-#include <map>
#include <iostream>
#include <sstream>
+#include <algorithm>
#include "bitcount.h"
#include "movegen.h"
#include "position.h"
#include "psqtab.h"
#include "rkiss.h"
+#include "thread.h"
#include "tt.h"
-#include "ucioption.h"
using std::string;
using std::cout;
Key Position::zobSideToMove;
Key Position::zobExclusion;
-Score Position::PieceSquareTable[16][64];
+Score Position::pieceSquareTable[16][64];
// Material values arrays, indexed by Piece
-const Value Position::PieceValueMidgame[17] = {
+const Value PieceValueMidgame[17] = {
VALUE_ZERO,
PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
- RookValueMidgame, QueenValueMidgame, VALUE_ZERO,
- VALUE_ZERO, VALUE_ZERO,
+ RookValueMidgame, QueenValueMidgame,
+ VALUE_ZERO, VALUE_ZERO, VALUE_ZERO,
PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
RookValueMidgame, QueenValueMidgame
};
-const Value Position::PieceValueEndgame[17] = {
+const Value PieceValueEndgame[17] = {
VALUE_ZERO,
PawnValueEndgame, KnightValueEndgame, BishopValueEndgame,
- RookValueEndgame, QueenValueEndgame, VALUE_ZERO,
- VALUE_ZERO, VALUE_ZERO,
+ RookValueEndgame, QueenValueEndgame,
+ VALUE_ZERO, VALUE_ZERO, VALUE_ZERO,
PawnValueEndgame, KnightValueEndgame, BishopValueEndgame,
RookValueEndgame, QueenValueEndgame
};
-// Material values array used by SEE, indexed by PieceType
-const Value Position::seeValues[] = {
- VALUE_ZERO,
- PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
- RookValueMidgame, QueenValueMidgame, QueenValueMidgame*10
-};
-
namespace {
// Bonus for having the side to move (modified by Joona Kiiski)
const Score TempoValue = make_score(48, 22);
- bool isZero(char c) { return c == '0'; }
-
- struct PieceLetters : public std::map<char, Piece> {
-
- PieceLetters() {
-
- operator[]('K') = WK; operator[]('k') = BK;
- operator[]('Q') = WQ; operator[]('q') = BQ;
- operator[]('R') = WR; operator[]('r') = BR;
- operator[]('B') = WB; operator[]('b') = BB;
- operator[]('N') = WN; operator[]('n') = BN;
- operator[]('P') = WP; operator[]('p') = BP;
- operator[](' ') = PIECE_NONE;
- operator[]('.') = PIECE_NONE_DARK_SQ;
- }
-
- char from_piece(Piece p) const {
-
- std::map<char, Piece>::const_iterator it;
- for (it = begin(); it != end(); ++it)
- if (it->second == p)
- return it->first;
-
- assert(false);
- return 0;
- }
- };
-
- PieceLetters pieceLetters;
+ // To convert a Piece to and from a FEN char
+ const string PieceToChar(" PNBRQK pnbrqk .");
}
CheckInfo::CheckInfo(const Position& pos) {
- Color us = pos.side_to_move();
- Color them = opposite_color(us);
-
+ Color them = ~pos.side_to_move();
ksq = pos.king_square(them);
- dcCandidates = pos.discovered_check_candidates(us);
- checkSq[PAWN] = pos.attacks_from<PAWN>(ksq, them);
+ pinned = pos.pinned_pieces();
+ dcCandidates = pos.discovered_check_candidates();
+
+ checkSq[PAWN] = pos.attacks_from<PAWN>(ksq, them);
checkSq[KNIGHT] = pos.attacks_from<KNIGHT>(ksq);
checkSq[BISHOP] = pos.attacks_from<BISHOP>(ksq);
- checkSq[ROOK] = pos.attacks_from<ROOK>(ksq);
- checkSq[QUEEN] = checkSq[BISHOP] | checkSq[ROOK];
- checkSq[KING] = EmptyBoardBB;
+ checkSq[ROOK] = pos.attacks_from<ROOK>(ksq);
+ checkSq[QUEEN] = checkSq[BISHOP] | checkSq[ROOK];
+ checkSq[KING] = 0;
}
/// or the FEN string, we want the new born Position object do not depend
/// on any external data so we detach state pointer from the source one.
-Position::Position(const Position& pos, int th) {
+void Position::copy(const Position& pos, int th) {
memcpy(this, &pos, sizeof(Position));
- detach(); // Always detach() in copy c'tor to avoid surprises
+ startState = *st;
+ st = &startState;
threadID = th;
nodes = 0;
+
+ assert(pos_is_ok());
}
Position::Position(const string& fen, bool isChess960, int th) {
}
-/// Position::detach() copies the content of the current state and castling
-/// masks inside the position itself. This is needed when the st pointee could
-/// become stale, as example because the caller is about to going out of scope.
-
-void Position::detach() {
-
- startState = *st;
- st = &startState;
- st->previous = NULL; // as a safe guard
-}
-
-
/// Position::from_fen() initializes the position object with the given FEN
/// string. This function is not very robust - make sure that input FENs are
/// correct (this is assumed to be the responsibility of the GUI).
-void Position::from_fen(const string& fen, bool c960) {
+void Position::from_fen(const string& fenStr, bool isChess960) {
/*
A FEN string defines a particular position using only the ASCII character set.
- A FEN string contains six fields. The separator between fields is a space. The fields are:
+ A FEN string contains six fields separated by a space. The fields are:
- 1) Piece placement (from white's perspective). Each rank is described, starting with rank 8 and ending
- with rank 1; within each rank, the contents of each square are described from file A through file H.
- Following the Standard Algebraic Notation (SAN), each piece is identified by a single letter taken
- from the standard English names. White pieces are designated using upper-case letters ("PNBRQK")
- while Black take lowercase ("pnbrqk"). Blank squares are noted using digits 1 through 8 (the number
- of blank squares), and "/" separate ranks.
+ 1) Piece placement (from white's perspective). Each rank is described, starting
+ with rank 8 and ending with rank 1; within each rank, the contents of each
+ square are described from file A through file H. Following the Standard
+ Algebraic Notation (SAN), each piece is identified by a single letter taken
+ from the standard English names. White pieces are designated using upper-case
+ letters ("PNBRQK") while Black take lowercase ("pnbrqk"). Blank squares are
+ noted using digits 1 through 8 (the number of blank squares), and "/"
+ separates ranks.
2) Active color. "w" means white moves next, "b" means black.
- 3) Castling availability. If neither side can castle, this is "-". Otherwise, this has one or more
- letters: "K" (White can castle kingside), "Q" (White can castle queenside), "k" (Black can castle
- kingside), and/or "q" (Black can castle queenside).
+ 3) Castling availability. If neither side can castle, this is "-". Otherwise,
+ this has one or more letters: "K" (White can castle kingside), "Q" (White
+ can castle queenside), "k" (Black can castle kingside), and/or "q" (Black
+ can castle queenside).
- 4) En passant target square in algebraic notation. If there's no en passant target square, this is "-".
- If a pawn has just made a 2-square move, this is the position "behind" the pawn. This is recorded
- regardless of whether there is a pawn in position to make an en passant capture.
+ 4) En passant target square (in algebraic notation). If there's no en passant
+ target square, this is "-". If a pawn has just made a 2-square move, this
+ is the position "behind" the pawn. This is recorded regardless of whether
+ there is a pawn in position to make an en passant capture.
- 5) Halfmove clock: This is the number of halfmoves since the last pawn advance or capture. This is used
- to determine if a draw can be claimed under the fifty-move rule.
+ 5) Halfmove clock. This is the number of halfmoves since the last pawn advance
+ or capture. This is used to determine if a draw can be claimed under the
+ fifty-move rule.
- 6) Fullmove number: The number of the full move. It starts at 1, and is incremented after Black's move.
+ 6) Fullmove number. The number of the full move. It starts at 1, and is
+ incremented after Black's move.
*/
- char token;
- int hmc, fmn;
- std::istringstream ss(fen);
+ char col, row, token;
+ size_t p;
Square sq = SQ_A8;
+ std::istringstream fen(fenStr);
clear();
+ fen >> std::noskipws;
- // 1. Piece placement field
- while (ss.get(token) && token != ' ')
+ // 1. Piece placement
+ while ((fen >> token) && !isspace(token))
{
- if (pieceLetters.find(token) != pieceLetters.end())
+ if (isdigit(token))
+ sq += Square(token - '0'); // Advance the given number of files
+
+ else if (token == '/')
+ sq = make_square(FILE_A, rank_of(sq) - Rank(2));
+
+ else if ((p = PieceToChar.find(token)) != string::npos)
{
- put_piece(pieceLetters[token], sq);
+ put_piece(Piece(p), sq);
sq++;
}
- else if (isdigit(token))
- sq += Square(token - '0'); // Skip the given number of files
- else if (token == '/')
- sq -= SQ_A3; // Jump back of 2 rows
- else
- goto incorrect_fen;
}
// 2. Active color
- if (!ss.get(token) || (token != 'w' && token != 'b'))
- goto incorrect_fen;
-
+ fen >> token;
sideToMove = (token == 'w' ? WHITE : BLACK);
+ fen >> token;
+
+ // 3. Castling availability. Compatible with 3 standards: Normal FEN standard,
+ // Shredder-FEN that uses the letters of the columns on which the rooks began
+ // the game instead of KQkq and also X-FEN standard that, in case of Chess960,
+ // if an inner rook is associated with the castling right, the castling tag is
+ // replaced by the file letter of the involved rook, as for the Shredder-FEN.
+ while ((fen >> token) && !isspace(token))
+ {
+ Square rsq;
+ Color c = islower(token) ? BLACK : WHITE;
- if (!ss.get(token) || token != ' ')
- goto incorrect_fen;
+ token = char(toupper(token));
- // 3. Castling availability
- while (ss.get(token) && token != ' ')
- if (!set_castling_rights(token))
- goto incorrect_fen;
+ if (token == 'K')
+ for (rsq = relative_square(c, SQ_H1); type_of(piece_on(rsq)) != ROOK; rsq--) {}
- // 4. En passant square
- char col, row;
- if ( (ss.get(col) && (col >= 'a' && col <= 'h'))
- && (ss.get(row) && (row == '3' || row == '6')))
- {
- st->epSquare = make_square(file_from_char(col), rank_from_char(row));
+ else if (token == 'Q')
+ for (rsq = relative_square(c, SQ_A1); type_of(piece_on(rsq)) != ROOK; rsq++) {}
- // Ignore if no capture is possible
- Color them = opposite_color(sideToMove);
- if (!(attacks_from<PAWN>(st->epSquare, them) & pieces(PAWN, sideToMove)))
- st->epSquare = SQ_NONE;
+ else if (token >= 'A' && token <= 'H')
+ rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1));
+
+ else
+ continue;
+
+ set_castle_right(c, rsq);
}
- // 5. Halfmove clock
- if (ss >> hmc)
- st->rule50 = hmc;
+ // 4. En passant square. Ignore if no pawn capture is possible
+ if ( ((fen >> col) && (col >= 'a' && col <= 'h'))
+ && ((fen >> row) && (row == '3' || row == '6')))
+ {
+ st->epSquare = make_square(File(col - 'a'), Rank(row - '1'));
- // 6. Fullmove number
- if (ss >> fmn)
- startPosPlyCounter = (fmn - 1) * 2 + int(sideToMove == BLACK);
+ if (!(attackers_to(st->epSquare) & pieces(PAWN, sideToMove)))
+ st->epSquare = SQ_NONE;
+ }
- // Various initialisations
- castleRightsMask[make_square(initialKFile, RANK_1)] ^= WHITE_OO | WHITE_OOO;
- castleRightsMask[make_square(initialKFile, RANK_8)] ^= BLACK_OO | BLACK_OOO;
- castleRightsMask[make_square(initialKRFile, RANK_1)] ^= WHITE_OO;
- castleRightsMask[make_square(initialKRFile, RANK_8)] ^= BLACK_OO;
- castleRightsMask[make_square(initialQRFile, RANK_1)] ^= WHITE_OOO;
- castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO;
+ // 5-6. Halfmove clock and fullmove number
+ fen >> std::skipws >> st->rule50 >> startPosPly;
- isChess960 = c960;
- find_checkers();
+ // Convert from fullmove starting from 1 to ply starting from 0,
+ // handle also common incorrect FEN with fullmove = 0.
+ startPosPly = std::max(2 * (startPosPly - 1), 0) + int(sideToMove == BLACK);
st->key = compute_key();
st->pawnKey = compute_pawn_key();
st->value = compute_value();
st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
- return;
+ st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove);
+ chess960 = isChess960;
-incorrect_fen:
- cout << "Error in FEN string: " << fen << endl;
+ assert(pos_is_ok());
}
-/// Position::set_castling_rights() sets castling parameters castling avaiability.
-/// This function is compatible with 3 standards: Normal FEN standard, Shredder-FEN
-/// that uses the letters of the columns on which the rooks began the game instead
-/// of KQkq and also X-FEN standard that, in case of Chess960, if an inner Rook is
-/// associated with the castling right, the traditional castling tag will be replaced
-/// by the file letter of the involved rook as for the Shredder-FEN.
-
-bool Position::set_castling_rights(char token) {
-
- Color c = token >= 'a' ? BLACK : WHITE;
- Square sqA = (c == WHITE ? SQ_A1 : SQ_A8);
- Square sqH = (c == WHITE ? SQ_H1 : SQ_H8);
- Piece rook = (c == WHITE ? WR : BR);
-
- initialKFile = square_file(king_square(c));
- token = char(toupper(token));
-
- if (token == 'K')
- {
- for (Square sq = sqH; sq >= sqA; sq--)
- if (piece_on(sq) == rook)
- {
- do_allow_oo(c);
- initialKRFile = square_file(sq);
- break;
- }
- }
- else if (token == 'Q')
- {
- for (Square sq = sqA; sq <= sqH; sq++)
- if (piece_on(sq) == rook)
- {
- do_allow_ooo(c);
- initialQRFile = square_file(sq);
- break;
- }
- }
- else if (token >= 'A' && token <= 'H')
- {
- File rookFile = File(token - 'A') + FILE_A;
- if (rookFile < initialKFile)
- {
- do_allow_ooo(c);
- initialQRFile = rookFile;
- }
- else
- {
- do_allow_oo(c);
- initialKRFile = rookFile;
- }
- }
- else
- return token == '-';
+/// Position::set_castle_right() is an helper function used to set castling
+/// rights given the corresponding color and the rook starting square.
- return true;
+void Position::set_castle_right(Color c, Square rsq) {
+
+ int f = (rsq < king_square(c) ? WHITE_OOO : WHITE_OO) << c;
+
+ st->castleRights |= f;
+ castleRightsMask[king_square(c)] ^= f;
+ castleRightsMask[rsq] ^= f;
+ castleRookSquare[f] = rsq;
}
const string Position::to_fen() const {
- string fen;
+ std::ostringstream fen;
Square sq;
- char emptyCnt = '0';
+ int emptyCnt;
for (Rank rank = RANK_8; rank >= RANK_1; rank--)
{
+ emptyCnt = 0;
+
for (File file = FILE_A; file <= FILE_H; file++)
{
sq = make_square(file, rank);
- if (square_is_occupied(sq))
- {
- fen += emptyCnt;
- fen += pieceLetters.from_piece(piece_on(sq));
- emptyCnt = '0';
- } else
+ if (square_is_empty(sq))
emptyCnt++;
+ else
+ {
+ if (emptyCnt > 0)
+ {
+ fen << emptyCnt;
+ emptyCnt = 0;
+ }
+ fen << PieceToChar[piece_on(sq)];
+ }
}
- fen += emptyCnt;
- fen += '/';
- emptyCnt = '0';
+
+ if (emptyCnt > 0)
+ fen << emptyCnt;
+
+ if (rank > RANK_1)
+ fen << '/';
}
- fen.erase(std::remove_if(fen.begin(), fen.end(), isZero), fen.end());
- fen.erase(--fen.end());
- fen += (sideToMove == WHITE ? " w " : " b ");
+ fen << (sideToMove == WHITE ? " w " : " b ");
- if (st->castleRights != CASTLES_NONE)
- {
- if (can_castle_kingside(WHITE))
- fen += isChess960 ? char(toupper(file_to_char(initialKRFile))) : 'K';
+ if (can_castle(WHITE_OO))
+ fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OO))))) : 'K');
+
+ if (can_castle(WHITE_OOO))
+ fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OOO))))) : 'Q');
+
+ if (can_castle(BLACK_OO))
+ fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OO))) : 'k');
- if (can_castle_queenside(WHITE))
- fen += isChess960 ? char(toupper(file_to_char(initialQRFile))) : 'Q';
+ if (can_castle(BLACK_OOO))
+ fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OOO))) : 'q');
- if (can_castle_kingside(BLACK))
- fen += isChess960 ? file_to_char(initialKRFile) : 'k';
+ if (st->castleRights == CASTLES_NONE)
+ fen << '-';
- if (can_castle_queenside(BLACK))
- fen += isChess960 ? file_to_char(initialQRFile) : 'q';
- } else
- fen += '-';
+ fen << (ep_square() == SQ_NONE ? " - " : " " + square_to_string(ep_square()) + " ")
+ << st->rule50 << " " << 1 + (startPosPly - int(sideToMove == BLACK)) / 2;
- fen += (ep_square() == SQ_NONE ? " -" : " " + square_to_string(ep_square()));
- return fen;
+ return fen.str();
}
if (move)
{
Position p(*this, thread());
- string dd = (color_of_piece_on(move_from(move)) == BLACK ? ".." : "");
- cout << "\nMove is: " << dd << move_to_san(p, move);
+ cout << "\nMove is: " << (sideToMove == BLACK ? ".." : "") << move_to_san(p, move);
}
for (Rank rank = RANK_8; rank >= RANK_1; rank--)
{
Square sq = make_square(file, rank);
Piece piece = piece_on(sq);
+ char c = (color_of(piece) == BLACK ? '=' : ' ');
- if (piece == PIECE_NONE && square_color(sq) == DARK)
- piece = PIECE_NONE_DARK_SQ;
+ if (piece == NO_PIECE && !opposite_colors(sq, SQ_A1))
+ piece++; // Index the dot
- char c = (color_of_piece_on(sq) == BLACK ? '=' : ' ');
- cout << c << pieceLetters.from_piece(piece) << c << '|';
+ cout << c << PieceToChar[piece] << c << '|';
}
}
cout << dottedLine << "Fen is: " << to_fen() << "\nKey is: " << st->key << endl;
/// Position:hidden_checkers<>() returns a bitboard of all pinned (against the
-/// king) pieces for the given color and for the given pinner type. Or, when
-/// template parameter FindPinned is false, the pieces of the given color
-/// candidate for a discovery check against the enemy king.
-/// Bitboard checkersBB must be already updated when looking for pinners.
-
+/// king) pieces for the given color. Or, when template parameter FindPinned is
+/// false, the function return the pieces of the given color candidate for a
+/// discovery check against the enemy king.
template<bool FindPinned>
-Bitboard Position::hidden_checkers(Color c) const {
-
- Bitboard result = EmptyBoardBB;
- Bitboard pinners = pieces_of_color(FindPinned ? opposite_color(c) : c);
-
- // Pinned pieces protect our king, dicovery checks attack
- // the enemy king.
- Square ksq = king_square(FindPinned ? c : opposite_color(c));
+Bitboard Position::hidden_checkers() const {
- // Pinners are sliders, not checkers, that give check when candidate pinned is removed
- pinners &= (pieces(ROOK, QUEEN) & RookPseudoAttacks[ksq]) | (pieces(BISHOP, QUEEN) & BishopPseudoAttacks[ksq]);
+ // Pinned pieces protect our king, dicovery checks attack the enemy king
+ Bitboard b, result = 0;
+ Bitboard pinners = pieces(FindPinned ? ~sideToMove : sideToMove);
+ Square ksq = king_square(FindPinned ? sideToMove : ~sideToMove);
- if (FindPinned && pinners)
- pinners &= ~st->checkersBB;
+ // Pinners are sliders, that give check when candidate pinned is removed
+ pinners &= (pieces(ROOK, QUEEN) & PseudoAttacks[ROOK][ksq])
+ | (pieces(BISHOP, QUEEN) & PseudoAttacks[BISHOP][ksq]);
while (pinners)
{
- Square s = pop_1st_bit(&pinners);
- Bitboard b = squares_between(s, ksq) & occupied_squares();
+ b = squares_between(ksq, pop_1st_bit(&pinners)) & occupied_squares();
- assert(b);
-
- if ( !(b & (b - 1)) // Only one bit set?
- && (b & pieces_of_color(c))) // Is an our piece?
+ // Only one bit set and is an our piece?
+ if (b && !(b & (b - 1)) && (b & pieces(sideToMove)))
result |= b;
}
return result;
}
+// Explicit template instantiations
+template Bitboard Position::hidden_checkers<true>() const;
+template Bitboard Position::hidden_checkers<false>() const;
-/// Position:pinned_pieces() returns a bitboard of all pinned (against the
-/// king) pieces for the given color. Note that checkersBB bitboard must
-/// be already updated.
-
-Bitboard Position::pinned_pieces(Color c) const {
-
- return hidden_checkers<true>(c);
-}
-
-
-/// Position:discovered_check_candidates() returns a bitboard containing all
-/// pieces for the given side which are candidates for giving a discovered
-/// check. Contrary to pinned_pieces() here there is no need of checkersBB
-/// to be already updated.
-
-Bitboard Position::discovered_check_candidates(Color c) const {
-
- return hidden_checkers<false>(c);
-}
-/// Position::attackers_to() computes a bitboard containing all pieces which
-/// attacks a given square.
+/// Position::attackers_to() computes a bitboard of all pieces which attack a
+/// given square. Slider attacks use occ bitboard as occupancy.
-Bitboard Position::attackers_to(Square s) const {
+Bitboard Position::attackers_to(Square s, Bitboard occ) const {
return (attacks_from<PAWN>(s, BLACK) & pieces(PAWN, WHITE))
| (attacks_from<PAWN>(s, WHITE) & pieces(PAWN, BLACK))
| (attacks_from<KNIGHT>(s) & pieces(KNIGHT))
- | (attacks_from<ROOK>(s) & pieces(ROOK, QUEEN))
- | (attacks_from<BISHOP>(s) & pieces(BISHOP, QUEEN))
+ | (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN))
+ | (bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN))
| (attacks_from<KING>(s) & pieces(KING));
}
-/// Position::attacks_from() computes a bitboard of all attacks
-/// of a given piece put in a given square.
-
-Bitboard Position::attacks_from(Piece p, Square s) const {
- assert(square_is_ok(s));
-
- switch (p)
- {
- case WB: case BB: return attacks_from<BISHOP>(s);
- case WR: case BR: return attacks_from<ROOK>(s);
- case WQ: case BQ: return attacks_from<QUEEN>(s);
- default: return NonSlidingAttacksBB[p][s];
- }
-}
+/// Position::attacks_from() computes a bitboard of all attacks of a given piece
+/// put in a given square. Slider attacks use occ bitboard as occupancy.
Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) {
assert(square_is_ok(s));
- switch (p)
+ switch (type_of(p))
{
- case WB: case BB: return bishop_attacks_bb(s, occ);
- case WR: case BR: return rook_attacks_bb(s, occ);
- case WQ: case BQ: return bishop_attacks_bb(s, occ) | rook_attacks_bb(s, occ);
- default: return NonSlidingAttacksBB[p][s];
+ case BISHOP: return bishop_attacks_bb(s, occ);
+ case ROOK : return rook_attacks_bb(s, occ);
+ case QUEEN : return bishop_attacks_bb(s, occ) | rook_attacks_bb(s, occ);
+ default : return StepAttacksBB[p][s];
}
}
bool Position::move_attacks_square(Move m, Square s) const {
- assert(move_is_ok(m));
+ assert(is_ok(m));
assert(square_is_ok(s));
Bitboard occ, xray;
- Square f = move_from(m), t = move_to(m);
+ Square from = from_sq(m);
+ Square to = to_sq(m);
+ Piece piece = piece_on(from);
- assert(square_is_occupied(f));
+ assert(!square_is_empty(from));
- if (bit_is_set(attacks_from(piece_on(f), t), s))
- return true;
-
- // Move the piece and scan for X-ray attacks behind it
+ // Update occupancy as if the piece is moving
occ = occupied_squares();
- do_move_bb(&occ, make_move_bb(f, t));
- xray = ( (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN))
- |(bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN)))
- & pieces_of_color(color_of_piece_on(f));
-
- // If we have attacks we need to verify that are caused by our move
- // and are not already existent ones.
- return xray && (xray ^ (xray & attacks_from<QUEEN>(s)));
-}
-
+ do_move_bb(&occ, make_move_bb(from, to));
-/// Position::find_checkers() computes the checkersBB bitboard, which
-/// contains a nonzero bit for each checking piece (0, 1 or 2). It
-/// currently works by calling Position::attackers_to, which is probably
-/// inefficient. Consider rewriting this function to use the last move
-/// played, like in non-bitboard versions of Glaurung.
+ // The piece moved in 'to' attacks the square 's' ?
+ if (bit_is_set(attacks_from(piece, to, occ), s))
+ return true;
-void Position::find_checkers() {
+ // Scan for possible X-ray attackers behind the moved piece
+ xray = (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN, color_of(piece)))
+ |(bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN, color_of(piece)));
- Color us = side_to_move();
- st->checkersBB = attackers_to(king_square(us)) & pieces_of_color(opposite_color(us));
+ // Verify attackers are triggered by our move and not already existing
+ return xray && (xray ^ (xray & attacks_from<QUEEN>(s)));
}
bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
- assert(is_ok());
- assert(move_is_ok(m));
- assert(pinned == pinned_pieces(side_to_move()));
+ assert(is_ok(m));
+ assert(pinned == pinned_pieces());
- // Castling moves are checked for legality during move generation.
- if (move_is_castle(m))
- return true;
+ Color us = sideToMove;
+ Square from = from_sq(m);
- // En passant captures are a tricky special case. Because they are
- // rather uncommon, we do it simply by testing whether the king is attacked
- // after the move is made
- if (move_is_ep(m))
+ assert(color_of(piece_on(from)) == us);
+ assert(piece_on(king_square(us)) == make_piece(us, KING));
+
+ // En passant captures are a tricky special case. Because they are rather
+ // uncommon, we do it simply by testing whether the king is attacked after
+ // the move is made.
+ if (is_enpassant(m))
{
- Color us = side_to_move();
- Color them = opposite_color(us);
- Square from = move_from(m);
- Square to = move_to(m);
- Square capsq = make_square(square_file(to), square_rank(from));
+ Color them = ~us;
+ Square to = to_sq(m);
+ Square capsq = to + pawn_push(them);
Square ksq = king_square(us);
Bitboard b = occupied_squares();
assert(to == ep_square());
- assert(piece_on(from) == piece_of_color_and_type(us, PAWN));
- assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN));
- assert(piece_on(to) == PIECE_NONE);
+ assert(piece_on(from) == make_piece(us, PAWN));
+ assert(piece_on(capsq) == make_piece(them, PAWN));
+ assert(piece_on(to) == NO_PIECE);
clear_bit(&b, from);
clear_bit(&b, capsq);
&& !(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, them));
}
- Color us = side_to_move();
- Square from = move_from(m);
-
- assert(color_of_piece_on(from) == us);
- assert(piece_on(king_square(us)) == piece_of_color_and_type(us, KING));
-
// If the moving piece is a king, check whether the destination
- // square is attacked by the opponent.
- if (type_of_piece_on(from) == KING)
- return !(attackers_to(move_to(m)) & pieces_of_color(opposite_color(us)));
+ // square is attacked by the opponent. Castling moves are checked
+ // for legality during move generation.
+ if (type_of(piece_on(from)) == KING)
+ return is_castle(m) || !(attackers_to(to_sq(m)) & pieces(~us));
// A non-king move is legal if and only if it is not pinned or it
// is moving along the ray towards or away from the king.
return !pinned
|| !bit_is_set(pinned, from)
- || squares_aligned(from, move_to(m), king_square(us));
+ || squares_aligned(from, to_sq(m), king_square(us));
}
-/// Position::pl_move_is_evasion() tests whether a pseudo-legal move is a legal evasion
+/// Position::move_is_legal() takes a random 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 Position::pl_move_is_evasion(Move m, Bitboard pinned) const
-{
- assert(is_check());
+bool Position::move_is_legal(const Move m) const {
- Color us = side_to_move();
- Square from = move_from(m);
- Square to = move_to(m);
+ for (MoveList<MV_LEGAL> ml(*this); !ml.end(); ++ml)
+ if (ml.move() == m)
+ return true;
- // King moves and en-passant captures are verified in pl_move_is_legal()
- if (type_of_piece_on(from) == KING || move_is_ep(m))
- return pl_move_is_legal(m, pinned);
+ return false;
+}
+
+
+/// Position::is_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
+/// due to SMP concurrent access or hash position key aliasing.
- Bitboard target = checkers();
- Square checksq = pop_1st_bit(&target);
+bool Position::is_pseudo_legal(const Move m) const {
- if (target) // double check ?
+ Color us = sideToMove;
+ Color them = ~sideToMove;
+ Square from = from_sq(m);
+ Square to = to_sq(m);
+ Piece pc = piece_on(from);
+
+ // Use a slower but simpler function for uncommon cases
+ if (is_special(m))
+ return move_is_legal(m);
+
+ // Is not a promotion, so promotion piece must be empty
+ if (promotion_piece_type(m) - 2 != NO_PIECE_TYPE)
return false;
- // Our move must be a blocking evasion or a capture of the checking piece
- target = squares_between(checksq, king_square(us)) | checkers();
- return bit_is_set(target, to) && pl_move_is_legal(m, pinned);
-}
+ // If the from square is not occupied by a piece belonging to the side to
+ // move, the move is obviously not legal.
+ if (pc == NO_PIECE || color_of(pc) != us)
+ return false;
+
+ // The destination square cannot be occupied by a friendly piece
+ if (color_of(piece_on(to)) == us)
+ return false;
+
+ // Handle the special case of a pawn move
+ if (type_of(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 (rank_of(to) == RANK_8 || rank_of(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 (color_of(piece_on(to)) != them)
+ return false;
+
+ // From and to files must be one file apart, avoids a7h5
+ if (abs(file_of(from) - file_of(to)) != 1)
+ return false;
+ break;
+
+ case DELTA_N:
+ case DELTA_S:
+ // Pawn push. The destination square must be empty.
+ if (!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 ( rank_of(to) != RANK_4
+ || !square_is_empty(to)
+ || !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 ( rank_of(to) != RANK_5
+ || !square_is_empty(to)
+ || !square_is_empty(from + DELTA_S))
+ return false;
+ break;
+ default:
+ return false;
+ }
+ }
+ else if (!bit_is_set(attacks_from(pc, from), to))
+ return false;
+
+ // Evasions generator already takes care to avoid some kind of illegal moves
+ // and pl_move_is_legal() relies on this. So we have to take care that the
+ // same kind of moves are filtered out here.
+ if (in_check())
+ {
+ // In case of king moves under check we have to remove king so to catch
+ // as invalid moves like b1a1 when opposite queen is on c1.
+ if (type_of(piece_on(from)) == KING)
+ {
+ Bitboard b = occupied_squares();
+ clear_bit(&b, from);
+ if (attackers_to(to_sq(m), b) & pieces(~us))
+ return false;
+ }
+ else
+ {
+ Bitboard target = checkers();
+ Square checksq = pop_1st_bit(&target);
-/// Position::move_is_check() tests whether a pseudo-legal move is a check
+ if (target) // double check ? In this case a king move is required
+ return false;
-bool Position::move_is_check(Move m) const {
+ // Our move must be a blocking evasion or a capture of the checking piece
+ target = squares_between(checksq, king_square(us)) | checkers();
+ if (!bit_is_set(target, to_sq(m)))
+ return false;
+ }
+ }
- return move_is_check(m, CheckInfo(*this));
+ return true;
}
-bool Position::move_is_check(Move m, const CheckInfo& ci) const {
- assert(is_ok());
- assert(move_is_ok(m));
- assert(ci.dcCandidates == discovered_check_candidates(side_to_move()));
- assert(color_of_piece_on(move_from(m)) == side_to_move());
- assert(piece_on(ci.ksq) == piece_of_color_and_type(opposite_color(side_to_move()), KING));
+/// Position::move_gives_check() tests whether a pseudo-legal move gives a check
+
+bool Position::move_gives_check(Move m, const CheckInfo& ci) const {
+
+ assert(is_ok(m));
+ assert(ci.dcCandidates == discovered_check_candidates());
+ assert(color_of(piece_moved(m)) == sideToMove);
- Square from = move_from(m);
- Square to = move_to(m);
- PieceType pt = type_of_piece_on(from);
+ Square from = from_sq(m);
+ Square to = to_sq(m);
+ PieceType pt = type_of(piece_on(from));
// Direct check ?
if (bit_is_set(ci.checkSq[pt], to))
{
// For pawn and king moves we need to verify also direction
if ( (pt != PAWN && pt != KING)
- || !squares_aligned(from, to, ci.ksq))
+ || !squares_aligned(from, to, king_square(~sideToMove)))
return true;
}
// Can we skip the ugly special cases ?
- if (!move_is_special(m))
+ if (!is_special(m))
return false;
- Color us = side_to_move();
+ Color us = sideToMove;
Bitboard b = occupied_squares();
+ Square ksq = king_square(~us);
// Promotion with check ?
- if (move_is_promotion(m))
+ if (is_promotion(m))
{
clear_bit(&b, from);
-
- switch (move_promotion_piece(m))
- {
- case KNIGHT:
- return bit_is_set(attacks_from<KNIGHT>(to), ci.ksq);
- case BISHOP:
- return bit_is_set(bishop_attacks_bb(to, b), ci.ksq);
- case ROOK:
- return bit_is_set(rook_attacks_bb(to, b), ci.ksq);
- case QUEEN:
- return bit_is_set(queen_attacks_bb(to, b), ci.ksq);
- default:
- assert(false);
- }
+ return bit_is_set(attacks_from(Piece(promotion_piece_type(m)), to, b), ksq);
}
// En passant capture with check ? We have already handled the case
// of direct checks and ordinary discovered check, the only case we
// need to handle is the unusual case of a discovered check through
// the captured pawn.
- if (move_is_ep(m))
+ if (is_enpassant(m))
{
- Square capsq = make_square(square_file(to), square_rank(from));
+ Square capsq = make_square(file_of(to), rank_of(from));
clear_bit(&b, from);
clear_bit(&b, capsq);
set_bit(&b, to);
- return (rook_attacks_bb(ci.ksq, b) & pieces(ROOK, QUEEN, us))
- ||(bishop_attacks_bb(ci.ksq, b) & pieces(BISHOP, QUEEN, us));
+ return (rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, us))
+ ||(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, us));
}
// Castling with check ?
- if (move_is_castle(m))
+ if (is_castle(m))
{
Square kfrom, kto, rfrom, rto;
kfrom = from;
clear_bit(&b, rfrom);
set_bit(&b, rto);
set_bit(&b, kto);
- return bit_is_set(rook_attacks_bb(rto, b), ci.ksq);
+ return bit_is_set(rook_attacks_bb(rto, b), ksq);
}
return false;
}
-/// Position::do_setup_move() makes a permanent move on the board.
-/// It should be used when setting up a position on board.
-/// You can't undo the move.
-
-void Position::do_setup_move(Move m) {
-
- StateInfo newSt;
-
- do_move(m, newSt);
-
- // Reset "game ply" in case we made a non-reversible move.
- // "game ply" is used for repetition detection.
- if (st->rule50 == 0)
- st->gamePly = 0;
-
- // Update the number of plies played from the starting position
- startPosPlyCounter++;
-
- // Our StateInfo newSt is about going out of scope so copy
- // its content inside pos before it disappears.
- detach();
-}
-
/// Position::do_move() makes a move, and saves all information necessary
-/// to a StateInfo object. The move is assumed to be legal.
-/// Pseudo-legal moves should be filtered out before this function is called.
+/// to a StateInfo object. The move is assumed to be legal. Pseudo-legal
+/// moves should be filtered out before this function is called.
void Position::do_move(Move m, StateInfo& newSt) {
CheckInfo ci(*this);
- do_move(m, newSt, ci, move_is_check(m, ci));
+ do_move(m, newSt, ci, move_gives_check(m, ci));
}
void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveIsCheck) {
- assert(is_ok());
- assert(move_is_ok(m));
+ assert(is_ok(m));
assert(&newSt != st);
nodes++;
- Key key = st->key;
+ Key k = st->key;
- // Copy some fields of old state to our new StateInfo object except the
- // ones which are recalculated from scratch anyway, then switch our state
- // pointer to point to the new, ready to be updated, state.
+ // Copy some fields of old state to our new StateInfo object except the ones
+ // which are recalculated from scratch anyway, then switch our state pointer
+ // to point to the new, ready to be updated, state.
struct ReducedStateInfo {
Key pawnKey, materialKey;
- int castleRights, rule50, gamePly, pliesFromNull;
- Square epSquare;
- Score value;
Value npMaterial[2];
+ int castleRights, rule50, pliesFromNull;
+ Score value;
+ Square epSquare;
};
memcpy(&newSt, st, sizeof(ReducedStateInfo));
newSt.previous = st;
st = &newSt;
- // Save the current key to the history[] array, in order to be able to
- // detect repetition draws.
- history[st->gamePly++] = key;
-
// Update side to move
- key ^= zobSideToMove;
+ k ^= zobSideToMove;
// Increment the 50 moves rule draw counter. Resetting it to zero in the
// case of non-reversible moves is taken care of later.
st->rule50++;
st->pliesFromNull++;
- if (move_is_castle(m))
+ if (is_castle(m))
{
- st->key = key;
- do_castle_move(m);
+ st->key = k;
+ do_castle_move<true>(m);
return;
}
- Color us = side_to_move();
- Color them = opposite_color(us);
- Square from = move_from(m);
- Square to = move_to(m);
- bool ep = move_is_ep(m);
- bool pm = move_is_promotion(m);
-
+ Color us = sideToMove;
+ Color them = ~us;
+ Square from = from_sq(m);
+ Square to = to_sq(m);
Piece piece = piece_on(from);
- PieceType pt = type_of_piece(piece);
- PieceType capture = ep ? PAWN : type_of_piece_on(to);
+ PieceType pt = type_of(piece);
+ PieceType capture = is_enpassant(m) ? PAWN : type_of(piece_on(to));
- assert(color_of_piece_on(from) == us);
- assert(color_of_piece_on(to) == them || square_is_empty(to));
- assert(!(ep || pm) || piece == piece_of_color_and_type(us, PAWN));
- assert(!pm || relative_rank(us, to) == RANK_8);
+ assert(color_of(piece) == us);
+ assert(color_of(piece_on(to)) != us);
+ assert(capture != KING);
if (capture)
- do_capture_move(key, capture, them, to, ep);
+ {
+ Square capsq = to;
+
+ // If the captured piece is a pawn, update pawn hash key, otherwise
+ // update non-pawn material.
+ if (capture == PAWN)
+ {
+ if (is_enpassant(m))
+ {
+ capsq += pawn_push(them);
+
+ assert(pt == PAWN);
+ assert(to == st->epSquare);
+ assert(relative_rank(us, to) == RANK_6);
+ assert(piece_on(to) == NO_PIECE);
+ assert(piece_on(capsq) == make_piece(them, PAWN));
+
+ board[capsq] = NO_PIECE;
+ }
+
+ st->pawnKey ^= zobrist[them][PAWN][capsq];
+ }
+ else
+ st->npMaterial[them] -= PieceValueMidgame[capture];
+
+ // Remove the captured piece
+ clear_bit(&byColorBB[them], capsq);
+ clear_bit(&byTypeBB[capture], capsq);
+ clear_bit(&occupied, capsq);
+
+ // Update piece list, move the last piece at index[capsq] position and
+ // shrink the list.
+ //
+ // WARNING: This is a not revresible operation. When we will reinsert the
+ // captured piece in undo_move() we will put it at the end of the list and
+ // not in its original place, it means index[] and pieceList[] are not
+ // guaranteed to be invariant to a do_move() + undo_move() sequence.
+ Square lastSquare = pieceList[them][capture][--pieceCount[them][capture]];
+ index[lastSquare] = index[capsq];
+ pieceList[them][capture][index[lastSquare]] = lastSquare;
+ pieceList[them][capture][pieceCount[them][capture]] = SQ_NONE;
+
+ // Update hash keys
+ k ^= zobrist[them][capture][capsq];
+ st->materialKey ^= zobrist[them][capture][pieceCount[them][capture]];
+
+ // Update incremental scores
+ st->value -= pst(make_piece(them, capture), capsq);
+
+ // Reset rule 50 counter
+ st->rule50 = 0;
+ }
// Update hash key
- key ^= zobrist[us][pt][from] ^ zobrist[us][pt][to];
+ k ^= zobrist[us][pt][from] ^ zobrist[us][pt][to];
// Reset en passant square
if (st->epSquare != SQ_NONE)
{
- key ^= zobEp[st->epSquare];
+ k ^= zobEp[st->epSquare];
st->epSquare = SQ_NONE;
}
- // Update castle rights, try to shortcut a common case
- int cm = castleRightsMask[from] & castleRightsMask[to];
- if (cm != ALL_CASTLES && ((cm & st->castleRights) != st->castleRights))
+ // Update castle rights if needed
+ if ( st->castleRights != CASTLES_NONE
+ && (castleRightsMask[from] & castleRightsMask[to]) != ALL_CASTLES)
{
- key ^= zobCastle[st->castleRights];
- st->castleRights &= castleRightsMask[from];
- st->castleRights &= castleRightsMask[to];
- key ^= zobCastle[st->castleRights];
+ k ^= zobCastle[st->castleRights];
+ st->castleRights &= castleRightsMask[from] & castleRightsMask[to];
+ k ^= zobCastle[st->castleRights];
}
// Prefetch TT access as soon as we know key is updated
- prefetch((char*)TT.first_entry(key));
+ prefetch((char*)TT.first_entry(k));
// Move the piece
Bitboard move_bb = make_move_bb(from, to);
- do_move_bb(&(byColorBB[us]), move_bb);
- do_move_bb(&(byTypeBB[pt]), move_bb);
- do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares
+ do_move_bb(&byColorBB[us], move_bb);
+ do_move_bb(&byTypeBB[pt], move_bb);
+ do_move_bb(&occupied, move_bb);
board[to] = board[from];
- board[from] = PIECE_NONE;
+ board[from] = NO_PIECE;
- // Update piece lists, note that index[from] is not updated and
- // becomes stale. This works as long as index[] is accessed just
- // by known occupied squares.
+ // Update piece lists, index[from] is not updated and becomes stale. This
+ // works as long as index[] is accessed just by known occupied squares.
index[to] = index[from];
pieceList[us][pt][index[to]] = to;
- // If the moving piece was a pawn do some special extra work
+ // If the moving piece is a pawn do some special extra work
if (pt == PAWN)
{
- // Reset rule 50 draw counter
- st->rule50 = 0;
-
- // Update pawn hash key and prefetch in L1/L2 cache
- st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
- prefetchPawn(st->pawnKey, threadID);
-
- // Set en passant square, only if moved pawn can be captured
- if ((to ^ from) == 16)
+ // Set en-passant square, only if moved pawn can be captured
+ if ( (to ^ from) == 16
+ && (attacks_from<PAWN>(from + pawn_push(us), us) & pieces(PAWN, them)))
{
- if (attacks_from<PAWN>(from + (us == WHITE ? DELTA_N : DELTA_S), us) & pieces(PAWN, them))
- {
- st->epSquare = Square((int(from) + int(to)) / 2);
- key ^= zobEp[st->epSquare];
- }
+ st->epSquare = Square((from + to) / 2);
+ k ^= zobEp[st->epSquare];
}
- if (pm) // promotion ?
+ if (is_promotion(m))
{
- PieceType promotion = move_promotion_piece(m);
+ PieceType promotion = promotion_piece_type(m);
+ assert(relative_rank(us, to) == RANK_8);
assert(promotion >= KNIGHT && promotion <= QUEEN);
- // Insert promoted piece instead of pawn
- clear_bit(&(byTypeBB[PAWN]), to);
- set_bit(&(byTypeBB[promotion]), to);
- board[to] = piece_of_color_and_type(us, promotion);
-
- // Update piece counts
- pieceCount[us][promotion]++;
- pieceCount[us][PAWN]--;
-
- // Update material key
- st->materialKey ^= zobrist[us][PAWN][pieceCount[us][PAWN]];
- st->materialKey ^= zobrist[us][promotion][pieceCount[us][promotion]-1];
+ // Replace the pawn with the promoted piece
+ clear_bit(&byTypeBB[PAWN], to);
+ set_bit(&byTypeBB[promotion], to);
+ board[to] = make_piece(us, promotion);
// Update piece lists, move the last pawn at index[to] position
// and shrink the list. Add a new promotion piece to the list.
- Square lastPawnSquare = pieceList[us][PAWN][pieceCount[us][PAWN]];
- index[lastPawnSquare] = index[to];
- pieceList[us][PAWN][index[lastPawnSquare]] = lastPawnSquare;
+ Square lastSquare = pieceList[us][PAWN][--pieceCount[us][PAWN]];
+ index[lastSquare] = index[to];
+ pieceList[us][PAWN][index[lastSquare]] = lastSquare;
pieceList[us][PAWN][pieceCount[us][PAWN]] = SQ_NONE;
- index[to] = pieceCount[us][promotion] - 1;
+ index[to] = pieceCount[us][promotion];
pieceList[us][promotion][index[to]] = to;
- // Partially revert hash keys update
- key ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to];
+ // Update hash keys
+ k ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to];
st->pawnKey ^= zobrist[us][PAWN][to];
+ st->materialKey ^= zobrist[us][promotion][pieceCount[us][promotion]++]
+ ^ zobrist[us][PAWN][pieceCount[us][PAWN]];
- // Partially revert and update incremental scores
- st->value -= pst(us, PAWN, to);
- st->value += pst(us, promotion, to);
+ // Update incremental score
+ st->value += pst(make_piece(us, promotion), to)
+ - pst(make_piece(us, PAWN), to);
// Update material
st->npMaterial[us] += PieceValueMidgame[promotion];
}
+
+ // Update pawn hash key
+ st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
+
+ // Reset rule 50 draw counter
+ st->rule50 = 0;
}
+ // Prefetch pawn and material hash tables
+ Threads[threadID].pawnTable.prefetch(st->pawnKey);
+ Threads[threadID].materialTable.prefetch(st->materialKey);
+
// Update incremental scores
st->value += pst_delta(piece, from, to);
st->capturedType = capture;
// Update the key with the final value
- st->key = key;
+ st->key = k;
// Update checkers bitboard, piece must be already moved
- st->checkersBB = EmptyBoardBB;
+ st->checkersBB = 0;
if (moveIsCheck)
{
- if (ep | pm)
- st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us);
+ if (is_special(m))
+ st->checkersBB = attackers_to(king_square(them)) & pieces(us);
else
{
// Direct checks
if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
{
if (pt != ROOK)
- st->checkersBB |= (attacks_from<ROOK>(ci.ksq) & pieces(ROOK, QUEEN, us));
+ st->checkersBB |= attacks_from<ROOK>(king_square(them)) & pieces(ROOK, QUEEN, us);
if (pt != BISHOP)
- st->checkersBB |= (attacks_from<BISHOP>(ci.ksq) & pieces(BISHOP, QUEEN, us));
+ st->checkersBB |= attacks_from<BISHOP>(king_square(them)) & pieces(BISHOP, QUEEN, us);
}
}
}
// Finish
- sideToMove = opposite_color(sideToMove);
+ sideToMove = ~sideToMove;
st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
- assert(is_ok());
-}
-
-
-/// Position::do_capture_move() is a private method used to update captured
-/// piece info. It is called from the main Position::do_move function.
-
-void Position::do_capture_move(Key& key, PieceType capture, Color them, Square to, bool ep) {
-
- assert(capture != KING);
-
- Square capsq = to;
-
- // If the captured piece was a pawn, update pawn hash key,
- // otherwise update non-pawn material.
- if (capture == PAWN)
- {
- if (ep) // en passant ?
- {
- capsq = (them == BLACK)? (to - DELTA_N) : (to - DELTA_S);
-
- assert(to == st->epSquare);
- assert(relative_rank(opposite_color(them), to) == RANK_6);
- assert(piece_on(to) == PIECE_NONE);
- assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN));
-
- board[capsq] = PIECE_NONE;
- }
- st->pawnKey ^= zobrist[them][PAWN][capsq];
- }
- else
- st->npMaterial[them] -= PieceValueMidgame[capture];
-
- // Remove captured piece
- clear_bit(&(byColorBB[them]), capsq);
- clear_bit(&(byTypeBB[capture]), capsq);
- clear_bit(&(byTypeBB[0]), capsq);
-
- // Update hash key
- key ^= zobrist[them][capture][capsq];
-
- // Update incremental scores
- st->value -= pst(them, capture, capsq);
-
- // Update piece count
- pieceCount[them][capture]--;
-
- // Update material hash key
- st->materialKey ^= zobrist[them][capture][pieceCount[them][capture]];
-
- // Update piece list, move the last piece at index[capsq] position
- //
- // WARNING: This is a not perfectly revresible operation. When we
- // will reinsert the captured piece in undo_move() we will put it
- // at the end of the list and not in its original place, it means
- // index[] and pieceList[] are not guaranteed to be invariant to a
- // do_move() + undo_move() sequence.
- Square lastPieceSquare = pieceList[them][capture][pieceCount[them][capture]];
- index[lastPieceSquare] = index[capsq];
- pieceList[them][capture][index[lastPieceSquare]] = lastPieceSquare;
- pieceList[them][capture][pieceCount[them][capture]] = SQ_NONE;
-
- // Reset rule 50 counter
- st->rule50 = 0;
-}
-
-
-/// Position::do_castle_move() is a private method used to make a castling
-/// move. It is called from the main Position::do_move function. Note that
-/// castling moves are encoded as "king captures friendly rook" moves, for
-/// instance white short castling in a non-Chess960 game is encoded as e1h1.
-
-void Position::do_castle_move(Move m) {
-
- assert(move_is_ok(m));
- assert(move_is_castle(m));
-
- Color us = side_to_move();
- Color them = opposite_color(us);
-
- // Reset capture field
- st->capturedType = PIECE_TYPE_NONE;
-
- // Find source squares for king and rook
- Square kfrom = move_from(m);
- Square rfrom = move_to(m); // HACK: See comment at beginning of function
- Square kto, rto;
-
- assert(piece_on(kfrom) == piece_of_color_and_type(us, KING));
- assert(piece_on(rfrom) == piece_of_color_and_type(us, ROOK));
-
- // Find destination squares for king and rook
- if (rfrom > kfrom) // O-O
- {
- kto = relative_square(us, SQ_G1);
- rto = relative_square(us, SQ_F1);
- } else { // O-O-O
- kto = relative_square(us, SQ_C1);
- rto = relative_square(us, SQ_D1);
- }
-
- // Remove pieces from source squares:
- clear_bit(&(byColorBB[us]), kfrom);
- clear_bit(&(byTypeBB[KING]), kfrom);
- clear_bit(&(byTypeBB[0]), kfrom); // HACK: byTypeBB[0] == occupied squares
- clear_bit(&(byColorBB[us]), rfrom);
- clear_bit(&(byTypeBB[ROOK]), rfrom);
- clear_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares
-
- // Put pieces on destination squares:
- set_bit(&(byColorBB[us]), kto);
- set_bit(&(byTypeBB[KING]), kto);
- set_bit(&(byTypeBB[0]), kto); // HACK: byTypeBB[0] == occupied squares
- set_bit(&(byColorBB[us]), rto);
- set_bit(&(byTypeBB[ROOK]), rto);
- set_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares
-
- // Update board array
- Piece king = piece_of_color_and_type(us, KING);
- Piece rook = piece_of_color_and_type(us, ROOK);
- board[kfrom] = board[rfrom] = PIECE_NONE;
- board[kto] = king;
- board[rto] = rook;
-
- // Update piece lists
- pieceList[us][KING][index[kfrom]] = kto;
- pieceList[us][ROOK][index[rfrom]] = rto;
- int tmp = index[rfrom]; // In Chess960 could be rto == kfrom
- index[kto] = index[kfrom];
- index[rto] = tmp;
-
- // Update incremental scores
- st->value += pst_delta(king, kfrom, kto);
- st->value += pst_delta(rook, rfrom, rto);
-
- // Update hash key
- st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto];
- st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto];
-
- // Clear en passant square
- if (st->epSquare != SQ_NONE)
- {
- st->key ^= zobEp[st->epSquare];
- st->epSquare = SQ_NONE;
- }
-
- // Update castling rights
- st->key ^= zobCastle[st->castleRights];
- st->castleRights &= castleRightsMask[kfrom];
- st->key ^= zobCastle[st->castleRights];
-
- // Reset rule 50 counter
- st->rule50 = 0;
-
- // Update checkers BB
- st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us);
-
- // Finish
- sideToMove = opposite_color(sideToMove);
- st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
-
- assert(is_ok());
+ assert(pos_is_ok());
}
void Position::undo_move(Move m) {
- assert(is_ok());
- assert(move_is_ok(m));
+ assert(is_ok(m));
- sideToMove = opposite_color(sideToMove);
+ sideToMove = ~sideToMove;
- if (move_is_castle(m))
+ if (is_castle(m))
{
- undo_castle_move(m);
+ do_castle_move<false>(m);
return;
}
- Color us = side_to_move();
- Color them = opposite_color(us);
- Square from = move_from(m);
- Square to = move_to(m);
- bool ep = move_is_ep(m);
- bool pm = move_is_promotion(m);
-
- PieceType pt = type_of_piece_on(to);
+ Color us = sideToMove;
+ Color them = ~us;
+ Square from = from_sq(m);
+ Square to = to_sq(m);
+ Piece piece = piece_on(to);
+ PieceType pt = type_of(piece);
+ PieceType capture = st->capturedType;
assert(square_is_empty(from));
- assert(color_of_piece_on(to) == us);
- assert(!pm || relative_rank(us, to) == RANK_8);
- assert(!ep || to == st->previous->epSquare);
- assert(!ep || relative_rank(us, to) == RANK_6);
- assert(!ep || piece_on(to) == piece_of_color_and_type(us, PAWN));
+ assert(color_of(piece) == us);
+ assert(capture != KING);
- if (pm) // promotion ?
+ if (is_promotion(m))
{
- PieceType promotion = move_promotion_piece(m);
- pt = PAWN;
+ PieceType promotion = promotion_piece_type(m);
+ assert(promotion == pt);
+ assert(relative_rank(us, to) == RANK_8);
assert(promotion >= KNIGHT && promotion <= QUEEN);
- assert(piece_on(to) == piece_of_color_and_type(us, promotion));
-
- // Replace promoted piece with a pawn
- clear_bit(&(byTypeBB[promotion]), to);
- set_bit(&(byTypeBB[PAWN]), to);
- // Update piece counts
- pieceCount[us][promotion]--;
- pieceCount[us][PAWN]++;
+ // Replace the promoted piece with the pawn
+ clear_bit(&byTypeBB[promotion], to);
+ set_bit(&byTypeBB[PAWN], to);
+ board[to] = make_piece(us, PAWN);
- // Update piece list replacing promotion piece with a pawn
- Square lastPromotionSquare = pieceList[us][promotion][pieceCount[us][promotion]];
- index[lastPromotionSquare] = index[to];
- pieceList[us][promotion][index[lastPromotionSquare]] = lastPromotionSquare;
+ // Update piece lists, move the last promoted piece at index[to] position
+ // and shrink the list. Add a new pawn to the list.
+ Square lastSquare = pieceList[us][promotion][--pieceCount[us][promotion]];
+ index[lastSquare] = index[to];
+ pieceList[us][promotion][index[lastSquare]] = lastSquare;
pieceList[us][promotion][pieceCount[us][promotion]] = SQ_NONE;
- index[to] = pieceCount[us][PAWN] - 1;
+ index[to] = pieceCount[us][PAWN]++;
pieceList[us][PAWN][index[to]] = to;
+
+ pt = PAWN;
}
// Put the piece back at the source square
Bitboard move_bb = make_move_bb(to, from);
- do_move_bb(&(byColorBB[us]), move_bb);
- do_move_bb(&(byTypeBB[pt]), move_bb);
- do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares
+ do_move_bb(&byColorBB[us], move_bb);
+ do_move_bb(&byTypeBB[pt], move_bb);
+ do_move_bb(&occupied, move_bb);
- board[from] = piece_of_color_and_type(us, pt);
- board[to] = PIECE_NONE;
+ board[from] = board[to];
+ board[to] = NO_PIECE;
- // Update piece list
+ // Update piece lists, index[to] is not updated and becomes stale. This
+ // works as long as index[] is accessed just by known occupied squares.
index[from] = index[to];
pieceList[us][pt][index[from]] = from;
- if (st->capturedType)
+ if (capture)
{
Square capsq = to;
- if (ep)
- capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
+ if (is_enpassant(m))
+ {
+ capsq -= pawn_push(us);
- assert(st->capturedType != KING);
- assert(!ep || square_is_empty(capsq));
+ assert(pt == PAWN);
+ assert(to == st->previous->epSquare);
+ assert(relative_rank(us, to) == RANK_6);
+ assert(piece_on(capsq) == NO_PIECE);
+ }
// Restore the captured piece
- set_bit(&(byColorBB[them]), capsq);
- set_bit(&(byTypeBB[st->capturedType]), capsq);
- set_bit(&(byTypeBB[0]), capsq);
-
- board[capsq] = piece_of_color_and_type(them, st->capturedType);
+ set_bit(&byColorBB[them], capsq);
+ set_bit(&byTypeBB[capture], capsq);
+ set_bit(&occupied, capsq);
- // Update piece count
- pieceCount[them][st->capturedType]++;
+ board[capsq] = make_piece(them, capture);
// Update piece list, add a new captured piece in capsq square
- index[capsq] = pieceCount[them][st->capturedType] - 1;
- pieceList[them][st->capturedType][index[capsq]] = capsq;
+ index[capsq] = pieceCount[them][capture]++;
+ pieceList[them][capture][index[capsq]] = capsq;
}
// Finally point our state pointer back to the previous state
st = st->previous;
- assert(is_ok());
+ assert(pos_is_ok());
}
-/// Position::undo_castle_move() is a private method used to unmake a castling
-/// move. It is called from the main Position::undo_move function. Note that
-/// castling moves are encoded as "king captures friendly rook" moves, for
-/// instance white short castling in a non-Chess960 game is encoded as e1h1.
-
-void Position::undo_castle_move(Move m) {
+/// Position::do_castle_move() is a private method used to do/undo a castling
+/// move. Note that castling moves are encoded as "king captures friendly rook"
+/// moves, for instance white short castling in a non-Chess960 game is encoded
+/// as e1h1.
+template<bool Do>
+void Position::do_castle_move(Move m) {
- assert(move_is_ok(m));
- assert(move_is_castle(m));
+ assert(is_ok(m));
+ assert(is_castle(m));
- // When we have arrived here, some work has already been done by
- // Position::undo_move. In particular, the side to move has been switched,
- // so the code below is correct.
- Color us = side_to_move();
+ Square kto, kfrom, rfrom, rto, kAfter, rAfter;
- // Find source squares for king and rook
- Square kfrom = move_from(m);
- Square rfrom = move_to(m); // HACK: See comment at beginning of function
- Square kto, rto;
+ Color us = sideToMove;
+ Square kBefore = from_sq(m);
+ Square rBefore = to_sq(m);
- // Find destination squares for king and rook
- if (rfrom > kfrom) // O-O
+ // Find after-castle squares for king and rook
+ if (rBefore > kBefore) // O-O
{
- kto = relative_square(us, SQ_G1);
- rto = relative_square(us, SQ_F1);
- } else { // O-O-O
- kto = relative_square(us, SQ_C1);
- rto = relative_square(us, SQ_D1);
+ kAfter = relative_square(us, SQ_G1);
+ rAfter = relative_square(us, SQ_F1);
}
+ else // O-O-O
+ {
+ kAfter = relative_square(us, SQ_C1);
+ rAfter = relative_square(us, SQ_D1);
+ }
+
+ kfrom = Do ? kBefore : kAfter;
+ rfrom = Do ? rBefore : rAfter;
+
+ kto = Do ? kAfter : kBefore;
+ rto = Do ? rAfter : rBefore;
+
+ assert(piece_on(kfrom) == make_piece(us, KING));
+ assert(piece_on(rfrom) == make_piece(us, ROOK));
+
+ // Remove pieces from source squares
+ clear_bit(&byColorBB[us], kfrom);
+ clear_bit(&byTypeBB[KING], kfrom);
+ clear_bit(&occupied, kfrom);
+ clear_bit(&byColorBB[us], rfrom);
+ clear_bit(&byTypeBB[ROOK], rfrom);
+ clear_bit(&occupied, rfrom);
- assert(piece_on(kto) == piece_of_color_and_type(us, KING));
- assert(piece_on(rto) == piece_of_color_and_type(us, ROOK));
-
- // Remove pieces from destination squares:
- clear_bit(&(byColorBB[us]), kto);
- clear_bit(&(byTypeBB[KING]), kto);
- clear_bit(&(byTypeBB[0]), kto); // HACK: byTypeBB[0] == occupied squares
- clear_bit(&(byColorBB[us]), rto);
- clear_bit(&(byTypeBB[ROOK]), rto);
- clear_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares
-
- // Put pieces on source squares:
- set_bit(&(byColorBB[us]), kfrom);
- set_bit(&(byTypeBB[KING]), kfrom);
- set_bit(&(byTypeBB[0]), kfrom); // HACK: byTypeBB[0] == occupied squares
- set_bit(&(byColorBB[us]), rfrom);
- set_bit(&(byTypeBB[ROOK]), rfrom);
- set_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares
+ // Put pieces on destination squares
+ set_bit(&byColorBB[us], kto);
+ set_bit(&byTypeBB[KING], kto);
+ set_bit(&occupied, kto);
+ set_bit(&byColorBB[us], rto);
+ set_bit(&byTypeBB[ROOK], rto);
+ set_bit(&occupied, rto);
// Update board
- board[rto] = board[kto] = PIECE_NONE;
- board[rfrom] = piece_of_color_and_type(us, ROOK);
- board[kfrom] = piece_of_color_and_type(us, KING);
+ Piece king = make_piece(us, KING);
+ Piece rook = make_piece(us, ROOK);
+ board[kfrom] = board[rfrom] = NO_PIECE;
+ board[kto] = king;
+ board[rto] = rook;
// Update piece lists
- pieceList[us][KING][index[kto]] = kfrom;
- pieceList[us][ROOK][index[rto]] = rfrom;
- int tmp = index[rto]; // In Chess960 could be rto == kfrom
- index[kfrom] = index[kto];
- index[rfrom] = tmp;
+ pieceList[us][KING][index[kfrom]] = kto;
+ pieceList[us][ROOK][index[rfrom]] = rto;
+ int tmp = index[rfrom]; // In Chess960 could be kto == rfrom
+ index[kto] = index[kfrom];
+ index[rto] = tmp;
- // Finally point our state pointer back to the previous state
- st = st->previous;
+ if (Do)
+ {
+ // Reset capture field
+ st->capturedType = NO_PIECE_TYPE;
- assert(is_ok());
-}
+ // Update incremental scores
+ st->value += pst_delta(king, kfrom, kto);
+ st->value += pst_delta(rook, rfrom, rto);
+ // Update hash key
+ st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto];
+ st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto];
-/// Position::do_null_move makes() a "null move": It switches the side to move
-/// and updates the hash key without executing any move on the board.
+ // Clear en passant square
+ if (st->epSquare != SQ_NONE)
+ {
+ st->key ^= zobEp[st->epSquare];
+ st->epSquare = SQ_NONE;
+ }
-void Position::do_null_move(StateInfo& backupSt) {
+ // Update castling rights
+ st->key ^= zobCastle[st->castleRights];
+ st->castleRights &= castleRightsMask[kfrom];
+ st->key ^= zobCastle[st->castleRights];
- assert(is_ok());
- assert(!is_check());
+ // Reset rule 50 counter
+ st->rule50 = 0;
- // Back up the information necessary to undo the null move to the supplied
- // StateInfo object.
- // Note that differently from normal case here backupSt is actually used as
- // a backup storage not as a new state to be used.
- backupSt.key = st->key;
- backupSt.epSquare = st->epSquare;
- backupSt.value = st->value;
- backupSt.previous = st->previous;
- backupSt.pliesFromNull = st->pliesFromNull;
- st->previous = &backupSt;
-
- // Save the current key to the history[] array, in order to be able to
- // detect repetition draws.
- history[st->gamePly++] = st->key;
-
- // Update the necessary information
- if (st->epSquare != SQ_NONE)
- st->key ^= zobEp[st->epSquare];
+ // Update checkers BB
+ st->checkersBB = attackers_to(king_square(~us)) & pieces(us);
- st->key ^= zobSideToMove;
- prefetch((char*)TT.first_entry(st->key));
+ // Finish
+ sideToMove = ~sideToMove;
+ st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
+ }
+ else
+ // Undo: point our state pointer back to the previous state
+ st = st->previous;
- sideToMove = opposite_color(sideToMove);
- st->epSquare = SQ_NONE;
- st->rule50++;
- st->pliesFromNull = 0;
- st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue;
+ assert(pos_is_ok());
}
-/// Position::undo_null_move() unmakes a "null move".
+/// Position::do_null_move() is used to do/undo a "null move": It flips the side
+/// to move and updates the hash key without executing any move on the board.
+template<bool Do>
+void Position::do_null_move(StateInfo& backupSt) {
+
+ assert(!in_check());
+
+ // Back up the information necessary to undo the null move to the supplied
+ // StateInfo object. Note that differently from normal case here backupSt
+ // is actually used as a backup storage not as the new state. This reduces
+ // the number of fields to be copied.
+ StateInfo* src = Do ? st : &backupSt;
+ StateInfo* dst = Do ? &backupSt : st;
+
+ dst->key = src->key;
+ dst->epSquare = src->epSquare;
+ dst->value = src->value;
+ dst->rule50 = src->rule50;
+ dst->pliesFromNull = src->pliesFromNull;
+
+ sideToMove = ~sideToMove;
-void Position::undo_null_move() {
+ if (Do)
+ {
+ if (st->epSquare != SQ_NONE)
+ st->key ^= zobEp[st->epSquare];
- assert(is_ok());
- assert(!is_check());
+ st->key ^= zobSideToMove;
+ prefetch((char*)TT.first_entry(st->key));
- // Restore information from the our backup StateInfo object
- StateInfo* backupSt = st->previous;
- st->key = backupSt->key;
- st->epSquare = backupSt->epSquare;
- st->value = backupSt->value;
- st->previous = backupSt->previous;
- st->pliesFromNull = backupSt->pliesFromNull;
+ st->epSquare = SQ_NONE;
+ st->rule50++;
+ st->pliesFromNull = 0;
+ st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue;
+ }
- // Update the necessary information
- sideToMove = opposite_color(sideToMove);
- st->rule50--;
- st->gamePly--;
+ assert(pos_is_ok());
}
+// Explicit template instantiations
+template void Position::do_null_move<false>(StateInfo& backupSt);
+template void Position::do_null_move<true>(StateInfo& backupSt);
+
/// Position::see() is a static exchange evaluator: It tries to estimate the
/// material gain or loss resulting from a move. There are three versions of
/// move, and one which takes a 'from' and a 'to' square. The function does
/// not yet understand promotions captures.
-int Position::see(Move m) const {
-
- assert(move_is_ok(m));
- return see(move_from(m), move_to(m));
-}
-
int Position::see_sign(Move m) const {
- assert(move_is_ok(m));
+ assert(is_ok(m));
- Square from = move_from(m);
- Square to = move_to(m);
+ Square from = from_sq(m);
+ Square to = to_sq(m);
// Early return if SEE cannot be negative because captured piece value
// is not less then capturing one. Note that king moves always return
// here because king midgame value is set to 0.
- if (midgame_value_of_piece_on(to) >= midgame_value_of_piece_on(from))
+ if (PieceValueMidgame[piece_on(to)] >= PieceValueMidgame[piece_on(from)])
return 1;
- return see(from, to);
+ return see(m);
}
-int Position::see(Square from, Square to) const {
+int Position::see(Move m) const {
- Bitboard occupied, attackers, stmAttackers, b;
+ Square from, to;
+ Bitboard occ, attackers, stmAttackers, b;
int swapList[32], slIndex = 1;
PieceType capturedType, pt;
Color stm;
- assert(square_is_ok(from));
- assert(square_is_ok(to));
+ assert(is_ok(m));
- capturedType = type_of_piece_on(to);
-
- // King cannot be recaptured
- if (capturedType == KING)
- return seeValues[capturedType];
+ // As castle moves are implemented as capturing the rook, they have
+ // SEE == RookValueMidgame most of the times (unless the rook is under
+ // attack).
+ if (is_castle(m))
+ return 0;
- occupied = occupied_squares();
+ from = from_sq(m);
+ to = to_sq(m);
+ capturedType = type_of(piece_on(to));
+ occ = occupied_squares();
// Handle en passant moves
- if (st->epSquare == to && type_of_piece_on(from) == PAWN)
+ if (is_enpassant(m))
{
- Square capQq = (side_to_move() == WHITE ? to - DELTA_N : to - DELTA_S);
+ Square capQq = to - pawn_push(sideToMove);
- assert(capturedType == PIECE_TYPE_NONE);
- assert(type_of_piece_on(capQq) == PAWN);
+ assert(!capturedType);
+ assert(type_of(piece_on(capQq)) == PAWN);
// Remove the captured pawn
- clear_bit(&occupied, capQq);
+ clear_bit(&occ, capQq);
capturedType = PAWN;
}
// Find all attackers to the destination square, with the moving piece
// removed, but possibly an X-ray attacker added behind it.
- clear_bit(&occupied, from);
- attackers = (rook_attacks_bb(to, occupied) & pieces(ROOK, QUEEN))
- | (bishop_attacks_bb(to, occupied)& pieces(BISHOP, QUEEN))
- | (attacks_from<KNIGHT>(to) & pieces(KNIGHT))
- | (attacks_from<KING>(to) & pieces(KING))
- | (attacks_from<PAWN>(to, WHITE) & pieces(PAWN, BLACK))
- | (attacks_from<PAWN>(to, BLACK) & pieces(PAWN, WHITE));
+ clear_bit(&occ, from);
+ attackers = attackers_to(to, occ);
// If the opponent has no attackers we are finished
- stm = opposite_color(color_of_piece_on(from));
- stmAttackers = attackers & pieces_of_color(stm);
+ stm = ~color_of(piece_on(from));
+ stmAttackers = attackers & pieces(stm);
if (!stmAttackers)
- return seeValues[capturedType];
+ return PieceValueMidgame[capturedType];
// The destination square is defended, which makes things rather more
// difficult to compute. We proceed by building up a "swap list" containing
// destination square, where the sides alternately capture, and always
// capture with the least valuable piece. After each capture, we look for
// new X-ray attacks from behind the capturing piece.
- swapList[0] = seeValues[capturedType];
- capturedType = type_of_piece_on(from);
+ swapList[0] = PieceValueMidgame[capturedType];
+ capturedType = type_of(piece_on(from));
do {
// Locate the least valuable attacker for the side to move. The loop
// Remove the attacker we just found from the 'occupied' bitboard,
// and scan for new X-ray attacks behind the attacker.
b = stmAttackers & pieces(pt);
- occupied ^= (b & (~b + 1));
- attackers |= (rook_attacks_bb(to, occupied) & pieces(ROOK, QUEEN))
- | (bishop_attacks_bb(to, occupied) & pieces(BISHOP, QUEEN));
+ occ ^= (b & (~b + 1));
+ attackers |= (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN))
+ | (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN));
- attackers &= occupied; // Cut out pieces we've already done
+ attackers &= occ; // Cut out pieces we've already done
// Add the new entry to the swap list
assert(slIndex < 32);
- swapList[slIndex] = -swapList[slIndex - 1] + seeValues[capturedType];
+ swapList[slIndex] = -swapList[slIndex - 1] + PieceValueMidgame[capturedType];
slIndex++;
// Remember the value of the capturing piece, and change the side to
// move before beginning the next iteration.
capturedType = pt;
- stm = opposite_color(stm);
- stmAttackers = attackers & pieces_of_color(stm);
+ stm = ~stm;
+ stmAttackers = attackers & pieces(stm);
// Stop before processing a king capture
if (capturedType == KING && stmAttackers)
// Having built the swap list, we negamax through it to find the best
// achievable score from the point of view of the side to move.
while (--slIndex)
- swapList[slIndex-1] = Min(-swapList[slIndex], swapList[slIndex-1]);
+ swapList[slIndex-1] = std::min(-swapList[slIndex], swapList[slIndex-1]);
return swapList[0];
}
st = &startState;
memset(st, 0, sizeof(StateInfo));
st->epSquare = SQ_NONE;
- startPosPlyCounter = 0;
- nodes = 0;
memset(byColorBB, 0, sizeof(Bitboard) * 2);
memset(byTypeBB, 0, sizeof(Bitboard) * 8);
memset(pieceCount, 0, sizeof(int) * 2 * 8);
memset(index, 0, sizeof(int) * 64);
- for (int i = 0; i < 64; i++)
- board[i] = PIECE_NONE;
-
for (int i = 0; i < 8; i++)
for (int j = 0; j < 16; j++)
pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
+ {
+ board[sq] = NO_PIECE;
castleRightsMask[sq] = ALL_CASTLES;
-
+ }
sideToMove = WHITE;
- initialKFile = FILE_E;
- initialKRFile = FILE_H;
- initialQRFile = FILE_A;
+ nodes = 0;
+ occupied = 0;
}
void Position::put_piece(Piece p, Square s) {
- Color c = color_of_piece(p);
- PieceType pt = type_of_piece(p);
+ Color c = color_of(p);
+ PieceType pt = type_of(p);
board[s] = p;
index[s] = pieceCount[c][pt]++;
pieceList[c][pt][index[s]] = s;
- set_bit(&(byTypeBB[pt]), s);
- set_bit(&(byColorBB[c]), s);
- set_bit(&(byTypeBB[0]), s); // HACK: byTypeBB[0] contains all occupied squares.
+ set_bit(&byTypeBB[pt], s);
+ set_bit(&byColorBB[c], s);
+ set_bit(&occupied, s);
}
Key result = zobCastle[st->castleRights];
for (Square s = SQ_A1; s <= SQ_H8; s++)
- if (square_is_occupied(s))
- result ^= zobrist[color_of_piece_on(s)][type_of_piece_on(s)][s];
+ if (!square_is_empty(s))
+ result ^= zobrist[color_of(piece_on(s))][type_of(piece_on(s))][s];
if (ep_square() != SQ_NONE)
result ^= zobEp[ep_square()];
- if (side_to_move() == BLACK)
+ if (sideToMove == BLACK)
result ^= zobSideToMove;
return result;
Key Position::compute_material_key() const {
- int count;
Key result = 0;
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= QUEEN; pt++)
- {
- count = piece_count(c, pt);
- for (int i = 0; i < count; i++)
+ for (int i = 0; i < piece_count(c, pt); i++)
result ^= zobrist[c][pt][i];
- }
+
return result;
}
{
b = pieces(pt, c);
while (b)
- result += pst(c, pt, pop_1st_bit(&b));
+ result += pst(make_piece(c, pt), pop_1st_bit(&b));
}
- result += (side_to_move() == WHITE ? TempoValue / 2 : -TempoValue / 2);
+ result += (sideToMove == WHITE ? TempoValue / 2 : -TempoValue / 2);
return result;
}
/// Position::is_draw() tests whether the position is drawn by material,
/// repetition, or the 50 moves rule. It does not detect stalemates, this
/// must be done by the search.
-
+template<bool SkipRepetition>
bool Position::is_draw() const {
// Draw by material?
return true;
// Draw by the 50 moves rule?
- if (st->rule50 > 99 && !is_mate())
+ if (st->rule50 > 99 && (!in_check() || MoveList<MV_LEGAL>(*this).size()))
return true;
// Draw by repetition?
- for (int i = 4, e = Min(Min(st->gamePly, st->rule50), st->pliesFromNull); i <= e; i += 2)
- if (history[st->gamePly - i] == st->key)
- return true;
-
- return false;
-}
-
-
-/// Position::is_mate() returns true or false depending on whether the
-/// side to move is checkmated.
-
-bool Position::is_mate() const {
-
- MoveStack moves[MOVES_MAX];
- return is_check() && generate<MV_LEGAL>(*this, moves) == moves;
-}
-
-
-/// Position::has_mate_threat() tests whether the side to move is under
-/// a threat of being mated in one from the current position.
-
-bool Position::has_mate_threat() {
-
- MoveStack mlist[MOVES_MAX], *last, *cur;
- StateInfo st1, st2;
- bool mateFound = false;
-
- // If we are under check it's up to evasions to do the job
- if (is_check())
- return false;
-
- // First pass the move to our opponent doing a null move
- do_null_move(st1);
+ if (!SkipRepetition)
+ {
+ int i = 4, e = std::min(st->rule50, st->pliesFromNull);
- // Then generate pseudo-legal moves that could give check
- last = generate<MV_NON_CAPTURE_CHECK>(*this, mlist);
- last = generate<MV_CAPTURE>(*this, last);
+ if (i <= e)
+ {
+ StateInfo* stp = st->previous->previous;
- // Loop through the moves, and see if one of them gives mate
- Bitboard pinned = pinned_pieces(sideToMove);
- CheckInfo ci(*this);
- for (cur = mlist; cur != last && !mateFound; cur++)
- {
- Move move = cur->move;
- if ( !pl_move_is_legal(move, pinned)
- || !move_is_check(move, ci))
- continue;
+ do {
+ stp = stp->previous->previous;
- do_move(move, st2, ci, true);
+ if (stp->key == st->key)
+ return true;
- if (is_mate())
- mateFound = true;
+ i +=2;
- undo_move(move);
+ } while (i <= e);
+ }
}
- undo_null_move();
- return mateFound;
+ return false;
}
+// Explicit template instantiations
+template bool Position::is_draw<false>() const;
+template bool Position::is_draw<true>() const;
+
-/// Position::init_zobrist() is a static member function which initializes at
-/// startup the various arrays used to compute hash keys.
+/// Position::init() is a static member function which initializes at startup
+/// the various arrays used to compute hash keys and the piece square tables.
+/// The latter is a two-step operation: First, the white halves of the tables
+/// are copied from PSQT[] tables. Second, the black halves of the tables are
+/// initialized by flipping and changing the sign of the white scores.
-void Position::init_zobrist() {
+void Position::init() {
- int i,j, k;
RKISS rk;
- for (i = 0; i < 2; i++) for (j = 0; j < 8; j++) for (k = 0; k < 64; k++)
- zobrist[i][j][k] = rk.rand<Key>();
+ for (Color c = WHITE; c <= BLACK; c++)
+ for (PieceType pt = PAWN; pt <= KING; pt++)
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ zobrist[c][pt][s] = rk.rand<Key>();
- for (i = 0; i < 64; i++)
- zobEp[i] = rk.rand<Key>();
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ zobEp[s] = rk.rand<Key>();
- for (i = 0; i < 16; i++)
+ for (int i = 0; i < 16; i++)
zobCastle[i] = rk.rand<Key>();
zobSideToMove = rk.rand<Key>();
zobExclusion = rk.rand<Key>();
-}
+ for (Piece p = W_PAWN; p <= W_KING; p++)
+ {
+ Score ps = make_score(PieceValueMidgame[p], PieceValueEndgame[p]);
-/// Position::init_piece_square_tables() initializes the piece square tables.
-/// This is a two-step operation: First, the white halves of the tables are
-/// copied from the MgPST[][] and EgPST[][] arrays. Second, the black halves
-/// of the tables are initialized by mirroring and changing the sign of the
-/// corresponding white scores.
-
-void Position::init_piece_square_tables() {
-
- for (Square s = SQ_A1; s <= SQ_H8; s++)
- for (Piece p = WP; p <= WK; p++)
- PieceSquareTable[p][s] = make_score(MgPST[p][s], EgPST[p][s]);
-
- for (Square s = SQ_A1; s <= SQ_H8; s++)
- for (Piece p = BP; p <= BK; p++)
- PieceSquareTable[p][s] = -PieceSquareTable[p-8][flip_square(s)];
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ {
+ pieceSquareTable[p][s] = ps + PSQT[p][s];
+ pieceSquareTable[p+8][~s] = -pieceSquareTable[p][s];
+ }
+ }
}
-/// Position::flipped_copy() makes a copy of the input position, but with
-/// the white and black sides reversed. This is only useful for debugging,
-/// especially for finding evaluation symmetry bugs.
+/// Position::flip_me() flips position with the white and black sides reversed. This
+/// is only useful for debugging especially for finding evaluation symmetry bugs.
-void Position::flipped_copy(const Position& pos) {
+void Position::flip_me() {
- assert(pos.is_ok());
+ // Make a copy of current position before to start changing
+ const Position pos(*this, threadID);
clear();
threadID = pos.thread();
// Board
for (Square s = SQ_A1; s <= SQ_H8; s++)
if (!pos.square_is_empty(s))
- put_piece(Piece(pos.piece_on(s) ^ 8), flip_square(s));
+ put_piece(Piece(pos.piece_on(s) ^ 8), ~s);
// Side to move
- sideToMove = opposite_color(pos.side_to_move());
+ sideToMove = ~pos.side_to_move();
// Castling rights
- if (pos.can_castle_kingside(WHITE)) do_allow_oo(BLACK);
- if (pos.can_castle_queenside(WHITE)) do_allow_ooo(BLACK);
- if (pos.can_castle_kingside(BLACK)) do_allow_oo(WHITE);
- if (pos.can_castle_queenside(BLACK)) do_allow_ooo(WHITE);
-
- initialKFile = pos.initialKFile;
- initialKRFile = pos.initialKRFile;
- initialQRFile = pos.initialQRFile;
-
- castleRightsMask[make_square(initialKFile, RANK_1)] ^= (WHITE_OO | WHITE_OOO);
- castleRightsMask[make_square(initialKFile, RANK_8)] ^= (BLACK_OO | BLACK_OOO);
- castleRightsMask[make_square(initialKRFile, RANK_1)] ^= WHITE_OO;
- castleRightsMask[make_square(initialKRFile, RANK_8)] ^= BLACK_OO;
- castleRightsMask[make_square(initialQRFile, RANK_1)] ^= WHITE_OOO;
- castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO;
+ if (pos.can_castle(WHITE_OO))
+ set_castle_right(BLACK, ~pos.castle_rook_square(WHITE_OO));
+ if (pos.can_castle(WHITE_OOO))
+ set_castle_right(BLACK, ~pos.castle_rook_square(WHITE_OOO));
+ if (pos.can_castle(BLACK_OO))
+ set_castle_right(WHITE, ~pos.castle_rook_square(BLACK_OO));
+ if (pos.can_castle(BLACK_OOO))
+ set_castle_right(WHITE, ~pos.castle_rook_square(BLACK_OOO));
// En passant square
if (pos.st->epSquare != SQ_NONE)
- st->epSquare = flip_square(pos.st->epSquare);
+ st->epSquare = ~pos.st->epSquare;
// Checkers
- find_checkers();
+ st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove);
// Hash keys
st->key = compute_key();
st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
- assert(is_ok());
+ assert(pos_is_ok());
}
-/// Position::is_ok() performs some consitency checks for the position object.
+/// Position::pos_is_ok() performs some consitency checks for the position object.
/// This is meant to be helpful when debugging.
-bool Position::is_ok(int* failedStep) const {
+bool Position::pos_is_ok(int* failedStep) const {
// What features of the position should be verified?
const bool debugAll = false;
if (failedStep) *failedStep = 1;
// Side to move OK?
- if (!color_is_ok(side_to_move()))
+ if (sideToMove != WHITE && sideToMove != BLACK)
return false;
// Are the king squares in the position correct?
if (failedStep) (*failedStep)++;
- if (piece_on(king_square(WHITE)) != WK)
+ if (piece_on(king_square(WHITE)) != W_KING)
return false;
if (failedStep) (*failedStep)++;
- if (piece_on(king_square(BLACK)) != BK)
- return false;
-
- // Castle files OK?
- if (failedStep) (*failedStep)++;
- if (!file_is_ok(initialKRFile))
- return false;
-
- if (!file_is_ok(initialQRFile))
+ if (piece_on(king_square(BLACK)) != B_KING)
return false;
// Do both sides have exactly one king?
{
int kingCount[2] = {0, 0};
for (Square s = SQ_A1; s <= SQ_H8; s++)
- if (type_of_piece_on(s) == KING)
- kingCount[color_of_piece_on(s)]++;
+ if (type_of(piece_on(s)) == KING)
+ kingCount[color_of(piece_on(s))]++;
if (kingCount[0] != 1 || kingCount[1] != 1)
return false;
if (failedStep) (*failedStep)++;
if (debugKingCapture)
{
- Color us = side_to_move();
- Color them = opposite_color(us);
+ Color us = sideToMove;
+ Color them = ~us;
Square ksq = king_square(them);
- if (attackers_to(ksq) & pieces_of_color(us))
+ if (attackers_to(ksq) & pieces(us))
return false;
}
// Is there more than 2 checkers?
if (failedStep) (*failedStep)++;
- if (debugCheckerCount && count_1s<CNT32>(st->checkersBB) > 2)
+ if (debugCheckerCount && popcount<Full>(st->checkersBB) > 2)
return false;
// Bitboards OK?
if (debugBitboards)
{
// The intersection of the white and black pieces must be empty
- if ((pieces_of_color(WHITE) & pieces_of_color(BLACK)) != EmptyBoardBB)
+ if (!(pieces(WHITE) & pieces(BLACK)))
return false;
// The union of the white and black pieces must be equal to all
// occupied squares
- if ((pieces_of_color(WHITE) | pieces_of_color(BLACK)) != occupied_squares())
+ if ((pieces(WHITE) | pieces(BLACK)) != occupied_squares())
return false;
// Separate piece type bitboards must have empty intersections
{
// The en passant square must be on rank 6, from the point of view of the
// side to move.
- if (relative_rank(side_to_move(), ep_square()) != RANK_6)
+ if (relative_rank(sideToMove, ep_square()) != RANK_6)
return false;
}
if (debugPieceCounts)
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= KING; pt++)
- if (pieceCount[c][pt] != count_1s<CNT32>(pieces(pt, c)))
+ if (pieceCount[c][pt] != popcount<Full>(pieces(pt, c)))
return false;
if (failedStep) (*failedStep)++;
if (debugPieceList)
- {
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= KING; pt++)
for (int i = 0; i < pieceCount[c][pt]; i++)
{
- if (piece_on(piece_list(c, pt, i)) != piece_of_color_and_type(c, pt))
+ if (piece_on(piece_list(c, pt)[i]) != make_piece(c, pt))
return false;
- if (index[piece_list(c, pt, i)] != i)
+ if (index[piece_list(c, pt)[i]] != i)
return false;
}
- }
if (failedStep) (*failedStep)++;
- if (debugCastleSquares) {
- for (Color c = WHITE; c <= BLACK; c++) {
- if (can_castle_kingside(c) && piece_on(initial_kr_square(c)) != piece_of_color_and_type(c, ROOK))
- return false;
- if (can_castle_queenside(c) && piece_on(initial_qr_square(c)) != piece_of_color_and_type(c, ROOK))
+ if (debugCastleSquares)
+ for (CastleRight f = WHITE_OO; f <= BLACK_OOO; f = CastleRight(f << 1))
+ {
+ if (!can_castle(f))
+ continue;
+
+ Piece rook = (f & (WHITE_OO | WHITE_OOO) ? W_ROOK : B_ROOK);
+
+ if ( castleRightsMask[castleRookSquare[f]] != (ALL_CASTLES ^ f)
+ || piece_on(castleRookSquare[f]) != rook)
return false;
}
- if (castleRightsMask[initial_kr_square(WHITE)] != (ALL_CASTLES ^ WHITE_OO))
- return false;
- if (castleRightsMask[initial_qr_square(WHITE)] != (ALL_CASTLES ^ WHITE_OOO))
- return false;
- if (castleRightsMask[initial_kr_square(BLACK)] != (ALL_CASTLES ^ BLACK_OO))
- return false;
- if (castleRightsMask[initial_qr_square(BLACK)] != (ALL_CASTLES ^ BLACK_OOO))
- return false;
- }
if (failedStep) *failedStep = 0;
return true;
projects / stockfish / blobdiff