/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ Copyright (C) 2008-2010 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
//// Includes
////
+#include <algorithm>
#include <cassert>
#include <cstring>
#include <fstream>
+#include <map>
#include <iostream>
+#include <sstream>
#include "bitcount.h"
#include "mersenne.h"
#include "ucioption.h"
using std::string;
+using std::cout;
+using std::endl;
+static inline bool isZero(char c) { return c == '0'; }
+
+struct PieceLetters : 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;
+ }
+};
////
//// Variables
////
-int Position::castleRightsMask[64];
-
Key Position::zobrist[2][8][64];
Key Position::zobEp[64];
Key Position::zobCastle[16];
-Key Position::zobMaterial[2][8][16];
Key Position::zobSideToMove;
+Key Position::zobExclusion;
-Value Position::MgPieceSquareTable[16][64];
-Value Position::EgPieceSquareTable[16][64];
+Score Position::PieceSquareTable[16][64];
-static bool RequestPending = false;
+static PieceLetters pieceLetters;
-////
-//// Functions
-////
/// Constructors
-Position::Position(const Position& pos) {
- copy(pos);
+CheckInfo::CheckInfo(const Position& pos) {
+
+ Color us = pos.side_to_move();
+ Color them = opposite_color(us);
+
+ ksq = pos.king_square(them);
+ dcCandidates = pos.discovered_check_candidates(us);
+
+ 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;
+}
+
+
+/// Position c'tors. Here we always create a copy of the original position
+/// 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(int th) : threadID(th) {}
+
+Position::Position(const Position& pos, int th) {
+
+ memcpy(this, &pos, sizeof(Position));
+ detach(); // Always detach() in copy c'tor to avoid surprises
+ threadID = th;
}
-Position::Position(const string& fen) {
+Position::Position(const string& fen, int th) {
+
from_fen(fen);
+ threadID = 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
}
/// correct (this is assumed to be the responsibility of the GUI).
void Position::from_fen(const string& fen) {
+/*
+ A FEN string defines a particular position using only the ASCII character set.
- static const string pieceLetters = "KQRBNPkqrbnp";
- static const Piece pieces[] = { WK, WQ, WR, WB, WN, WP, BK, BQ, BR, BB, BN, BP };
+ A FEN string contains six fields. The separator between fields is a space. The fields are:
- clear();
+ 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.
- // Board
+ 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).
+
+ 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.
+
+ 6) Fullmove number: The number of the full move. It starts at 1, and is incremented after Black's move.
+*/
+
+ char token;
+ std::istringstream ss(fen);
Rank rank = RANK_8;
File file = FILE_A;
- size_t i = 0;
- for ( ; fen[i] != ' '; i++)
+
+ clear();
+
+ // 1. Piece placement field
+ while (ss.get(token) && token != ' ')
{
- if (isdigit(fen[i]))
+ if (isdigit(token))
{
- // Skip the given number of files
- file += (fen[i] - '1' + 1);
+ file += File(token - '0'); // Skip the given number of files
continue;
}
- else if (fen[i] == '/')
+ else if (token == '/')
{
file = FILE_A;
rank--;
continue;
}
- size_t idx = pieceLetters.find(fen[i]);
- if (idx == string::npos)
- {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
- Square square = make_square(file, rank);
- put_piece(pieces[idx], square);
+
+ if (pieceLetters.find(token) == pieceLetters.end())
+ goto incorrect_fen;
+
+ put_piece(pieceLetters[token], make_square(file, rank));
file++;
}
- // Side to move
- i++;
- if (fen[i] != 'w' && fen[i] != 'b')
- {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
- sideToMove = (fen[i] == 'w' ? WHITE : BLACK);
+ // 2. Active color
+ if (!ss.get(token) || (token != 'w' && token != 'b'))
+ goto incorrect_fen;
- // Castling rights
- i++;
- if (fen[i] != ' ')
+ sideToMove = (token == 'w' ? WHITE : BLACK);
+
+ if (!ss.get(token) || token != ' ')
+ goto incorrect_fen;
+
+ // 3. Castling availability
+ while (ss.get(token) && token != ' ')
{
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
+ if (token == '-')
+ continue;
- i++;
- while(strchr("KQkqabcdefghABCDEFGH-", fen[i])) {
- if (fen[i] == '-')
- {
- i++;
- break;
- }
- else if(fen[i] == 'K') allow_oo(WHITE);
- else if(fen[i] == 'Q') allow_ooo(WHITE);
- else if(fen[i] == 'k') allow_oo(BLACK);
- else if(fen[i] == 'q') allow_ooo(BLACK);
- else if(fen[i] >= 'A' && fen[i] <= 'H') {
- File rookFile, kingFile = FILE_NONE;
- for(Square square = SQ_B1; square <= SQ_G1; square++)
- if(piece_on(square) == WK)
- kingFile = square_file(square);
- if(kingFile == FILE_NONE) {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
- initialKFile = kingFile;
- rookFile = File(fen[i] - 'A') + FILE_A;
- if(rookFile < initialKFile) {
- allow_ooo(WHITE);
- initialQRFile = rookFile;
- }
- else {
- allow_oo(WHITE);
- initialKRFile = rookFile;
- }
- }
- else if(fen[i] >= 'a' && fen[i] <= 'h') {
- File rookFile, kingFile = FILE_NONE;
- for(Square square = SQ_B8; square <= SQ_G8; square++)
- if(piece_on(square) == BK)
- kingFile = square_file(square);
- if(kingFile == FILE_NONE) {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
- initialKFile = kingFile;
- rookFile = File(fen[i] - 'a') + FILE_A;
- if(rookFile < initialKFile) {
- allow_ooo(BLACK);
- initialQRFile = rookFile;
- }
- else {
- allow_oo(BLACK);
- initialKRFile = rookFile;
- }
- }
- else {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
- i++;
+ if (!set_castling_rights(token))
+ goto incorrect_fen;
}
- // Skip blanks
- while (fen[i] == ' ')
- i++;
+ // 4. En passant square -- ignore if no capture is possible
+ char col, row;
+ if ( (ss.get(col) && (col >= 'a' && col <= 'h'))
+ && (ss.get(row) && (row == '3' || row == '6')))
+ {
+ Square fenEpSquare = make_square(file_from_char(col), rank_from_char(row));
+ Color them = opposite_color(sideToMove);
- // En passant square
- if ( i <= fen.length() - 2
- && (fen[i] >= 'a' && fen[i] <= 'h')
- && (fen[i+1] == '3' || fen[i+1] == '6'))
- st->epSquare = square_from_string(fen.substr(i, 2));
+ if (attacks_from<PAWN>(fenEpSquare, them) & pieces(PAWN, sideToMove))
+ st->epSquare = fenEpSquare;
+ }
- // Various initialisation
- for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
- castleRightsMask[sq] = ALL_CASTLES;
+ // 5-6. Halfmove clock and fullmove number are not parsed
- castleRightsMask[make_square(initialKFile, RANK_1)] ^= (WHITE_OO|WHITE_OOO);
- castleRightsMask[make_square(initialKFile, RANK_8)] ^= (BLACK_OO|BLACK_OOO);
+ // 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;
st->key = compute_key();
st->pawnKey = compute_pawn_key();
st->materialKey = compute_material_key();
- st->mgValue = compute_value<MidGame>();
- st->egValue = compute_value<EndGame>();
+ st->value = compute_value();
st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
+ return;
+
+incorrect_fen:
+ cout << "Error in FEN string: " << fen << endl;
+}
+
+
+/// 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)
+ {
+ allow_oo(c);
+ initialKRFile = square_file(sq);
+ break;
+ }
+ }
+ else if (token == 'Q')
+ {
+ for (Square sq = sqA; sq <= sqH; sq++)
+ if (piece_on(sq) == rook)
+ {
+ allow_ooo(c);
+ initialQRFile = square_file(sq);
+ break;
+ }
+ }
+ else if (token >= 'A' && token <= 'H')
+ {
+ File rookFile = File(token - 'A') + FILE_A;
+ if (rookFile < initialKFile)
+ {
+ allow_ooo(c);
+ initialQRFile = rookFile;
+ }
+ else
+ {
+ allow_oo(c);
+ initialKRFile = rookFile;
+ }
+ }
+ else return false;
+
+ return true;
}
-/// Position::to_fen() converts the position object to a FEN string. This is
-/// probably only useful for debugging.
+/// Position::to_fen() returns a FEN representation of the position. In case
+/// of Chess960 the Shredder-FEN notation is used. Mainly a debugging function.
const string Position::to_fen() const {
- static const string pieceLetters = " PNBRQK pnbrqk";
string fen;
- int skip;
+ Square sq;
+ char emptyCnt = '0';
for (Rank rank = RANK_8; rank >= RANK_1; rank--)
{
- skip = 0;
for (File file = FILE_A; file <= FILE_H; file++)
{
- Square sq = make_square(file, rank);
- if (!square_is_occupied(sq))
- { skip++;
- continue;
- }
- if (skip > 0)
+ sq = make_square(file, rank);
+
+ if (square_is_occupied(sq))
{
- fen += (char)skip + '0';
- skip = 0;
- }
- fen += pieceLetters[piece_on(sq)];
+ fen += emptyCnt;
+ fen += pieceLetters.from_piece(piece_on(sq));
+ emptyCnt = '0';
+ } else
+ emptyCnt++;
}
- if (skip > 0)
- fen += (char)skip + '0';
-
- fen += (rank > RANK_1 ? '/' : ' ');
+ fen += emptyCnt;
+ fen += '/';
+ emptyCnt = '0';
}
- fen += (sideToMove == WHITE ? "w " : "b ");
- if (st->castleRights != NO_CASTLES)
+
+ fen.erase(std::remove_if(fen.begin(), fen.end(), isZero), fen.end());
+ fen.erase(--fen.end());
+ fen += (sideToMove == WHITE ? " w " : " b ");
+
+ if (st->castleRights != CASTLES_NONE)
{
- if (can_castle_kingside(WHITE)) fen += 'K';
- if (can_castle_queenside(WHITE)) fen += 'Q';
- if (can_castle_kingside(BLACK)) fen += 'k';
- if (can_castle_queenside(BLACK)) fen += 'q';
- } else
- fen += '-';
+ const bool Chess960 = initialKFile != FILE_E
+ || initialQRFile != FILE_A
+ || initialKRFile != FILE_H;
- fen += ' ';
- if (ep_square() != SQ_NONE)
- fen += square_to_string(ep_square());
- else
+ if (can_castle_kingside(WHITE))
+ fen += Chess960 ? char(toupper(file_to_char(initialKRFile))) : 'K';
+
+ if (can_castle_queenside(WHITE))
+ fen += Chess960 ? char(toupper(file_to_char(initialQRFile))) : 'Q';
+
+ if (can_castle_kingside(BLACK))
+ fen += Chess960 ? file_to_char(initialKRFile) : 'k';
+
+ if (can_castle_queenside(BLACK))
+ fen += Chess960 ? file_to_char(initialQRFile) : 'q';
+ } else
fen += '-';
+ fen += (ep_square() == SQ_NONE ? " -" : " " + square_to_string(ep_square()));
return fen;
}
/// Position::print() prints an ASCII representation of the position to
/// the standard output. If a move is given then also the san is print.
-void Position::print(Move m) const {
+void Position::print(Move move) const {
- static const string pieceLetters = " PNBRQK PNBRQK .";
+ const char* dottedLine = "\n+---+---+---+---+---+---+---+---+\n";
+ static bool requestPending = false;
// Check for reentrancy, as example when called from inside
// MovePicker that is used also here in move_to_san()
- if (RequestPending)
+ if (requestPending)
return;
- RequestPending = true;
+ requestPending = true;
- std::cout << std::endl;
- if (m != MOVE_NONE)
+ if (move)
{
- string col = (color_of_piece_on(move_from(m)) == BLACK ? ".." : "");
- std::cout << "Move is: " << col << move_to_san(*this, m) << std::endl;
+ Position p(*this, thread());
+ string dd = (color_of_piece_on(move_from(move)) == BLACK ? ".." : "");
+ cout << "\nMove is: " << dd << move_to_san(p, move);
}
+
for (Rank rank = RANK_8; rank >= RANK_1; rank--)
{
- std::cout << "+---+---+---+---+---+---+---+---+" << std::endl;
+ cout << dottedLine << '|';
for (File file = FILE_A; file <= FILE_H; file++)
{
Square sq = make_square(file, rank);
+ char c = (color_of_piece_on(sq) == BLACK ? '=' : ' ');
Piece piece = piece_on(sq);
- if (piece == EMPTY && square_color(sq) == WHITE)
- piece = NO_PIECE;
- char col = (color_of_piece_on(sq) == BLACK ? '=' : ' ');
- std::cout << '|' << col << pieceLetters[piece] << col;
+ if (piece == PIECE_NONE && square_color(sq) == DARK)
+ piece = PIECE_NONE_DARK_SQ;
+
+ cout << c << pieceLetters.from_piece(piece) << c << '|';
}
- std::cout << '|' << std::endl;
}
- std::cout << "+---+---+---+---+---+---+---+---+" << std::endl
- << "Fen is: " << to_fen() << std::endl
- << "Key is: " << st->key << std::endl;
-
- RequestPending = false;
-}
-
-
-/// Position::copy() creates a copy of the input position.
-
-void Position::copy(const Position& pos) {
-
- memcpy(this, &pos, sizeof(Position));
- saveState(); // detach and copy state info
+ cout << dottedLine << "Fen is: " << to_fen() << "\nKey is: " << st->key << endl;
+ requestPending = false;
}
/// 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.
-/// Note that checkersBB bitboard must be already updated.
+/// Bitboard checkersBB must be already updated when looking for pinners.
template<bool FindPinned>
Bitboard Position::hidden_checkers(Color c) const {
- Bitboard pinners, result = EmptyBoardBB;
+ 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));
- // Pinners are sliders, not checkers, that give check when
- // candidate pinned is removed.
- pinners = (pieces(ROOK, QUEEN, FindPinned ? opposite_color(c) : c) & RookPseudoAttacks[ksq])
- | (pieces(BISHOP, QUEEN, FindPinned ? opposite_color(c) : c) & BishopPseudoAttacks[ksq]);
+ // Pinners are sliders, not checkers, that give check when candidate pinned is removed
+ pinners &= (pieces(ROOK, QUEEN) & RookPseudoAttacks[ksq]) | (pieces(BISHOP, QUEEN) & BishopPseudoAttacks[ksq]);
if (FindPinned && pinners)
pinners &= ~st->checkersBB;
/// Position:pinned_pieces() returns a bitboard of all pinned (against the
-/// king) pieces for the given color.
+/// king) pieces for the given color. Note that checkersBB bitboard must
+/// be already updated.
Bitboard Position::pinned_pieces(Color c) const {
/// Position:discovered_check_candidates() returns a bitboard containing all
/// pieces for the given side which are candidates for giving a discovered
-/// check.
+/// 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::attacks_to() computes a bitboard containing all pieces which
+/// Position::attackers_to() computes a bitboard containing all pieces which
/// attacks a given square.
-Bitboard Position::attacks_to(Square s) const {
+Bitboard Position::attackers_to(Square s) const {
- return (pawn_attacks(s, BLACK) & pieces(PAWN, WHITE))
- | (pawn_attacks(s, WHITE) & pieces(PAWN, BLACK))
- | (piece_attacks<KNIGHT>(s) & pieces(KNIGHT))
- | (piece_attacks<ROOK>(s) & pieces(ROOK, QUEEN))
- | (piece_attacks<BISHOP>(s) & pieces(BISHOP, QUEEN))
- | (piece_attacks<KING>(s) & pieces(KING));
+ 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))
+ | (attacks_from<KING>(s) & pieces(KING));
}
-/// Position::piece_attacks_square() tests whether the piece on square f
-/// attacks square t.
+/// Position::attacks_from() computes a bitboard of all attacks
+/// of a given piece put in a given square.
-bool Position::piece_attacks_square(Piece p, Square f, Square t) const {
+Bitboard Position::attacks_from(Piece p, Square s) const {
- assert(square_is_ok(f));
- assert(square_is_ok(t));
+ assert(square_is_ok(s));
switch (p)
{
- case WP: return pawn_attacks_square(f, t, WHITE);
- case BP: return pawn_attacks_square(f, t, BLACK);
- case WN: case BN: return piece_attacks_square<KNIGHT>(f, t);
- case WB: case BB: return piece_attacks_square<BISHOP>(f, t);
- case WR: case BR: return piece_attacks_square<ROOK>(f, t);
- case WQ: case BQ: return piece_attacks_square<QUEEN>(f, t);
- case WK: case BK: return piece_attacks_square<KING>(f, t);
+ case WP: return attacks_from<PAWN>(s, WHITE);
+ case BP: return attacks_from<PAWN>(s, BLACK);
+ case WN: case BN: return attacks_from<KNIGHT>(s);
+ 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);
+ case WK: case BK: return attacks_from<KING>(s);
default: break;
}
return false;
assert(square_is_occupied(f));
- if (piece_attacks_square(piece_on(f), t, s))
+ if (bit_is_set(attacks_from(piece_on(f), t), s))
return true;
// Move the piece and scan for X-ray attacks behind it
// If we have attacks we need to verify that are caused by our move
// and are not already existent ones.
- return xray && (xray ^ (xray & piece_attacks<QUEEN>(s)));
+ return xray && (xray ^ (xray & attacks_from<QUEEN>(s)));
}
/// 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::attacks_to, which is probably
+/// 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.
void Position::find_checkers() {
Color us = side_to_move();
- st->checkersBB = attacks_to(king_square(us), opposite_color(us));
+ st->checkersBB = attackers_to(king_square(us)) & pieces_of_color(opposite_color(us));
}
/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal
-bool Position::pl_move_is_legal(Move m) const {
-
- // If we're in check, all pseudo-legal moves are legal, because our
- // check evasion generator only generates true legal moves.
- return is_check() || pl_move_is_legal(m, pinned_pieces(side_to_move()));
-}
-
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_check());
// Castling moves are checked for legality during move generation.
if (move_is_castle(m))
assert(color_of_piece_on(from) == us);
assert(piece_on(king_square(us)) == piece_of_color_and_type(us, KING));
- // En passant captures are a tricky special case. Because they are
+ // 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(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) == EMPTY);
+ assert(piece_on(to) == PIECE_NONE);
clear_bit(&b, from);
clear_bit(&b, capsq);
// 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 !attacks_to(move_to(m), opposite_color(us));
+ return !(attackers_to(move_to(m)) & pieces_of_color(opposite_color(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.
}
+/// Position::pl_move_is_evasion() tests whether a pseudo-legal move is a legal evasion
+
+bool Position::pl_move_is_evasion(Move m, Bitboard pinned) const
+{
+ assert(is_check());
+
+ Color us = side_to_move();
+ Square from = move_from(m);
+ Square to = move_to(m);
+
+ // 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);
+
+ Bitboard target = checkers();
+ Square checksq = pop_1st_bit(&target);
+
+ if (target) // double check ?
+ 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);
+}
+
+
/// Position::move_is_check() tests whether a pseudo-legal move is a check
bool Position::move_is_check(Move m) const {
- Bitboard dc = discovered_check_candidates(side_to_move());
- return move_is_check(m, dc);
+ return move_is_check(m, CheckInfo(*this));
}
-bool Position::move_is_check(Move m, Bitboard dcCandidates) const {
+bool Position::move_is_check(Move m, const CheckInfo& ci) const {
assert(is_ok());
assert(move_is_ok(m));
- assert(dcCandidates == discovered_check_candidates(side_to_move()));
+ 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));
- Color us = side_to_move();
- Color them = opposite_color(us);
Square from = move_from(m);
Square to = move_to(m);
- Square ksq = king_square(them);
+ PieceType pt = type_of_piece_on(from);
- assert(color_of_piece_on(from) == us);
- assert(piece_on(ksq) == piece_of_color_and_type(them, KING));
+ // Direct check ?
+ if (bit_is_set(ci.checkSq[pt], to))
+ return true;
- // Proceed according to the type of the moving piece
- switch (type_of_piece_on(from))
+ // Discovery check ?
+ if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
{
- case PAWN:
-
- if (bit_is_set(pawn_attacks(ksq, them), to)) // Normal check?
+ // For pawn and king moves we need to verify also direction
+ if ( (pt != PAWN && pt != KING)
+ ||(direction_between_squares(from, ci.ksq) != direction_between_squares(to, ci.ksq)))
return true;
+ }
- if ( dcCandidates // Discovered check?
- && bit_is_set(dcCandidates, from)
- && (direction_between_squares(from, ksq) != direction_between_squares(to, ksq)))
- return true;
-
- if (move_is_promotion(m)) // Promotion with check?
- {
- Bitboard b = occupied_squares();
- clear_bit(&b, from);
-
- switch (move_promotion_piece(m))
- {
- case KNIGHT:
- return bit_is_set(piece_attacks<KNIGHT>(to), ksq);
- case BISHOP:
- return bit_is_set(bishop_attacks_bb(to, b), ksq);
- case ROOK:
- return bit_is_set(rook_attacks_bb(to, b), ksq);
- case QUEEN:
- return bit_is_set(queen_attacks_bb(to, b), ksq);
- default:
- assert(false);
- }
- }
- // 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.
- else if (move_is_ep(m))
- {
- Square capsq = make_square(square_file(to), square_rank(from));
- Bitboard b = occupied_squares();
- clear_bit(&b, from);
- clear_bit(&b, capsq);
- set_bit(&b, to);
- return (rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, us))
- ||(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, us));
- }
+ // Can we skip the ugly special cases ?
+ if (!move_is_special(m))
return false;
- // Test discovered check and normal check according to piece type
- case KNIGHT:
- return (dcCandidates && bit_is_set(dcCandidates, from))
- || bit_is_set(piece_attacks<KNIGHT>(ksq), to);
-
- case BISHOP:
- return (dcCandidates && bit_is_set(dcCandidates, from))
- || (direction_is_diagonal(ksq, to) && bit_is_set(piece_attacks<BISHOP>(ksq), to));
-
- case ROOK:
- return (dcCandidates && bit_is_set(dcCandidates, from))
- || (direction_is_straight(ksq, to) && bit_is_set(piece_attacks<ROOK>(ksq), to));
-
- case QUEEN:
- // Discovered checks are impossible!
- assert(!bit_is_set(dcCandidates, from));
- return ( (direction_is_straight(ksq, to) && bit_is_set(piece_attacks<ROOK>(ksq), to))
- || (direction_is_diagonal(ksq, to) && bit_is_set(piece_attacks<BISHOP>(ksq), to)));
-
- case KING:
- // Discovered check?
- if ( bit_is_set(dcCandidates, from)
- && (direction_between_squares(from, ksq) != direction_between_squares(to, ksq)))
- return true;
+ Color us = side_to_move();
+ Bitboard b = occupied_squares();
- // Castling with check?
- if (move_is_castle(m))
- {
- Square kfrom, kto, rfrom, rto;
- Bitboard b = occupied_squares();
- kfrom = from;
- rfrom = to;
+ // Promotion with check ?
+ if (move_is_promotion(m))
+ {
+ clear_bit(&b, from);
- if (rfrom > kfrom)
- {
- kto = relative_square(us, SQ_G1);
- rto = relative_square(us, SQ_F1);
- } else {
- kto = relative_square(us, SQ_C1);
- rto = relative_square(us, SQ_D1);
- }
- clear_bit(&b, kfrom);
- clear_bit(&b, rfrom);
- set_bit(&b, rto);
- set_bit(&b, kto);
- return bit_is_set(rook_attacks_bb(rto, b), ksq);
+ 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 false;
-
- default: // NO_PIECE_TYPE
- break;
}
- assert(false);
- return false;
-}
-
-
-/// Position::update_checkers() udpates chekers info given the move. It is called
-/// in do_move() and is faster then find_checkers().
-
-template<PieceType Piece>
-inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square from,
- Square to, Bitboard dcCandidates) {
-
- const bool Bishop = (Piece == QUEEN || Piece == BISHOP);
- const bool Rook = (Piece == QUEEN || Piece == ROOK);
- const bool Slider = Bishop || Rook;
- // Direct checks
- if ( ( (Bishop && bit_is_set(BishopPseudoAttacks[ksq], to))
- || (Rook && bit_is_set(RookPseudoAttacks[ksq], to)))
- && bit_is_set(piece_attacks<Piece>(ksq), to)) // slow, try to early skip
- set_bit(pCheckersBB, to);
-
- else if ( Piece != KING
- && !Slider
- && bit_is_set(Piece == PAWN ? pawn_attacks(ksq, opposite_color(sideToMove)) : piece_attacks<Piece>(ksq), to))
- set_bit(pCheckersBB, to);
+ // 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))
+ {
+ Square capsq = make_square(square_file(to), square_rank(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));
+ }
- // Discovery checks
- if (Piece != QUEEN && bit_is_set(dcCandidates, from))
+ // Castling with check ?
+ if (move_is_castle(m))
{
- if (Piece != ROOK)
- (*pCheckersBB) |= (piece_attacks<ROOK>(ksq) & pieces(ROOK, QUEEN, side_to_move()));
+ Square kfrom, kto, rfrom, rto;
+ kfrom = from;
+ rfrom = to;
- if (Piece != BISHOP)
- (*pCheckersBB) |= (piece_attacks<BISHOP>(ksq) & pieces(BISHOP, QUEEN, side_to_move()));
+ if (rfrom > kfrom)
+ {
+ kto = relative_square(us, SQ_G1);
+ rto = relative_square(us, SQ_F1);
+ } else {
+ kto = relative_square(us, SQ_C1);
+ rto = relative_square(us, SQ_D1);
+ }
+ clear_bit(&b, kfrom);
+ clear_bit(&b, rfrom);
+ set_bit(&b, rto);
+ set_bit(&b, kto);
+ return bit_is_set(rook_attacks_bb(rto, b), ci.ksq);
}
+
+ return false;
}
void Position::do_move(Move m, StateInfo& newSt) {
- do_move(m, newSt, discovered_check_candidates(side_to_move()));
+ CheckInfo ci(*this);
+ do_move(m, newSt, ci, move_is_check(m, ci));
}
-void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) {
+void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveIsCheck) {
assert(is_ok());
assert(move_is_ok(m));
- Bitboard key = st->key;
+ Key key = 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.
struct ReducedStateInfo {
- Key key, pawnKey, materialKey;
- int castleRights, rule50;
- Square kingSquare[2], epSquare;
- Value mgValue, egValue;
+ Key pawnKey, materialKey;
+ int castleRights, rule50, gamePly, pliesFromNull;
+ Square epSquare;
+ Score value;
Value npMaterial[2];
};
// Save the current key to the history[] array, in order to be able to
// detect repetition draws.
- history[gamePly] = key;
- gamePly++;
+ history[st->gamePly++] = key;
// Update side to move
key ^= 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))
{
Piece piece = piece_on(from);
PieceType pt = type_of_piece(piece);
+ PieceType capture = ep ? 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);
- st->capture = ep ? PAWN : type_of_piece_on(to);
-
- if (st->capture)
- do_capture_move(key, st->capture, them, to, ep);
+ if (capture)
+ do_capture_move(key, capture, them, to, ep);
// Update hash key
key ^= zobrist[us][pt][from] ^ zobrist[us][pt][to];
}
// Prefetch TT access as soon as we know key is updated
- TT.prefetch(key);
+ prefetch((char*)TT.first_entry(key));
// Move the piece
Bitboard move_bb = make_move_bb(from, to);
do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares
board[to] = board[from];
- board[from] = EMPTY;
-
- // If the moving piece was a king, update the king square
- if (pt == KING)
- st->kingSquare[us] = to;
+ board[from] = PIECE_NONE;
// Update piece lists, note that index[from] is not updated and
// becomes stale. This works as long as index[] is accessed just
st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
// Set en passant square, only if moved pawn can be captured
- if (abs(int(to) - int(from)) == 16)
+ if ((to ^ from) == 16)
{
- if (pawn_attacks(from + (us == WHITE ? DELTA_N : DELTA_S), 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];
}
}
+
+ if (pm) // promotion ?
+ {
+ PieceType promotion = move_promotion_piece(m);
+
+ 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];
+
+ // 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;
+ pieceList[us][PAWN][pieceCount[us][PAWN]] = SQ_NONE;
+ index[to] = pieceCount[us][promotion] - 1;
+ pieceList[us][promotion][index[to]] = to;
+
+ // Partially revert hash keys update
+ key ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to];
+ st->pawnKey ^= zobrist[us][PAWN][to];
+
+ // Partially revert and update incremental scores
+ st->value -= pst(us, PAWN, to);
+ st->value += pst(us, promotion, to);
+
+ // Update material
+ st->npMaterial[us] += piece_value_midgame(promotion);
+ }
}
// Update incremental scores
- st->mgValue += pst_delta<MidGame>(piece, from, to);
- st->egValue += pst_delta<EndGame>(piece, from, to);
-
- if (pm) // promotion ?
- {
- PieceType promotion = move_promotion_piece(m);
-
- 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);
+ st->value += pst_delta(piece, from, to);
- // Update material key
- st->materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]];
- st->materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1];
-
- // Update piece counts
- pieceCount[us][PAWN]--;
- pieceCount[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;
- index[to] = pieceCount[us][promotion] - 1;
- pieceList[us][promotion][index[to]] = to;
-
- // Partially revert hash keys update
- key ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to];
- st->pawnKey ^= zobrist[us][PAWN][to];
-
- // Partially revert and update incremental scores
- st->mgValue -= pst<MidGame>(us, PAWN, to);
- st->mgValue += pst<MidGame>(us, promotion, to);
- st->egValue -= pst<EndGame>(us, PAWN, to);
- st->egValue += pst<EndGame>(us, promotion, to);
-
- // Update material
- st->npMaterial[us] += piece_value_midgame(promotion);
- }
+ // Set capture piece
+ st->capturedType = capture;
// Update the key with the final value
st->key = key;
// Update checkers bitboard, piece must be already moved
- if (ep | pm)
- st->checkersBB = attacks_to(king_square(them), us);
- else
+ st->checkersBB = EmptyBoardBB;
+
+ if (moveIsCheck)
{
- st->checkersBB = EmptyBoardBB;
- Square ksq = king_square(them);
- switch (pt)
+ if (ep | pm)
+ st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us);
+ else
{
- case PAWN: update_checkers<PAWN>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
- case KNIGHT: update_checkers<KNIGHT>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
- case BISHOP: update_checkers<BISHOP>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
- case ROOK: update_checkers<ROOK>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
- case QUEEN: update_checkers<QUEEN>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
- case KING: update_checkers<KING>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
- default: assert(false); break;
+ // Direct checks
+ if (bit_is_set(ci.checkSq[pt], to))
+ st->checkersBB = SetMaskBB[to];
+
+ // Discovery checks
+ if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
+ {
+ if (pt != ROOK)
+ st->checkersBB |= (attacks_from<ROOK>(ci.ksq) & pieces(ROOK, QUEEN, us));
+
+ if (pt != BISHOP)
+ st->checkersBB |= (attacks_from<BISHOP>(ci.ksq) & pieces(BISHOP, QUEEN, us));
+ }
}
}
// Finish
sideToMove = opposite_color(sideToMove);
-
- st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
- st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
+ 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(Bitboard& key, PieceType capture, Color them, Square to, bool ep) {
+void Position::do_capture_move(Key& key, PieceType capture, Color them, Square to, bool ep) {
assert(capture != KING);
Square capsq = to;
- if (ep) // en passant ?
+ // If the captured piece was a pawn, update pawn hash key,
+ // otherwise update non-pawn material.
+ if (capture == PAWN)
{
- capsq = (them == BLACK)? (to - DELTA_N) : (to - DELTA_S);
+ 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) == EMPTY);
- assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN));
+ 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] = EMPTY;
+ board[capsq] = PIECE_NONE;
+ }
+ st->pawnKey ^= zobrist[them][PAWN][capsq];
}
+ else
+ st->npMaterial[them] -= piece_value_midgame(capture);
// Remove captured piece
clear_bit(&(byColorBB[them]), capsq);
key ^= zobrist[them][capture][capsq];
// Update incremental scores
- st->mgValue -= pst<MidGame>(them, capture, capsq);
- st->egValue -= pst<EndGame>(them, capture, capsq);
-
- // If the captured piece was a pawn, update pawn hash key,
- // otherwise update non-pawn material.
- if (capture == PAWN)
- st->pawnKey ^= zobrist[them][PAWN][capsq];
- else
- st->npMaterial[them] -= piece_value_midgame(capture);
-
- // Update material hash key
- st->materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]];
+ 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
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;
Color them = opposite_color(us);
// Reset capture field
- st->capture = NO_PIECE_TYPE;
+ st->capturedType = PIECE_TYPE_NONE;
// Find source squares for king and rook
Square kfrom = move_from(m);
rto = relative_square(us, SQ_D1);
}
- // Move the pieces
- Bitboard kmove_bb = make_move_bb(kfrom, kto);
- do_move_bb(&(byColorBB[us]), kmove_bb);
- do_move_bb(&(byTypeBB[KING]), kmove_bb);
- do_move_bb(&(byTypeBB[0]), kmove_bb); // HACK: byTypeBB[0] == occupied squares
-
- Bitboard rmove_bb = make_move_bb(rfrom, rto);
- do_move_bb(&(byColorBB[us]), rmove_bb);
- do_move_bb(&(byTypeBB[ROOK]), rmove_bb);
- do_move_bb(&(byTypeBB[0]), rmove_bb); // HACK: byTypeBB[0] == occupied squares
+ // 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] = EMPTY;
+ board[kfrom] = board[rfrom] = PIECE_NONE;
board[kto] = king;
board[rto] = rook;
- // Update king square
- st->kingSquare[us] = kto;
-
// Update piece lists
pieceList[us][KING][index[kfrom]] = kto;
pieceList[us][ROOK][index[rfrom]] = rto;
index[rto] = tmp;
// Update incremental scores
- st->mgValue += pst_delta<MidGame>(king, kfrom, kto);
- st->egValue += pst_delta<EndGame>(king, kfrom, kto);
- st->mgValue += pst_delta<MidGame>(rook, rfrom, rto);
- st->egValue += pst_delta<EndGame>(rook, rfrom, rto);
+ 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->rule50 = 0;
// Update checkers BB
- st->checkersBB = attacks_to(king_square(them), us);
+ st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us);
// Finish
sideToMove = opposite_color(sideToMove);
-
- st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
- st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
+ st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
assert(is_ok());
}
assert(is_ok());
assert(move_is_ok(m));
- gamePly--;
sideToMove = opposite_color(sideToMove);
if (move_is_castle(m))
Square lastPromotionSquare = pieceList[us][promotion][pieceCount[us][promotion]];
index[lastPromotionSquare] = index[to];
pieceList[us][promotion][index[lastPromotionSquare]] = lastPromotionSquare;
+ pieceList[us][promotion][pieceCount[us][promotion]] = SQ_NONE;
index[to] = pieceCount[us][PAWN] - 1;
pieceList[us][PAWN][index[to]] = to;
}
do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares
board[from] = piece_of_color_and_type(us, pt);
- board[to] = EMPTY;
+ board[to] = PIECE_NONE;
// Update piece list
index[from] = index[to];
pieceList[us][pt][index[from]] = from;
- if (st->capture)
+ if (st->capturedType)
{
Square capsq = to;
if (ep)
capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
- assert(st->capture != KING);
+ assert(st->capturedType != KING);
assert(!ep || square_is_empty(capsq));
// Restore the captured piece
set_bit(&(byColorBB[them]), capsq);
- set_bit(&(byTypeBB[st->capture]), capsq);
+ set_bit(&(byTypeBB[st->capturedType]), capsq);
set_bit(&(byTypeBB[0]), capsq);
- board[capsq] = piece_of_color_and_type(them, st->capture);
+ board[capsq] = piece_of_color_and_type(them, st->capturedType);
// Update piece count
- pieceCount[them][st->capture]++;
+ pieceCount[them][st->capturedType]++;
// Update piece list, add a new captured piece in capsq square
- index[capsq] = pieceCount[them][st->capture] - 1;
- pieceList[them][st->capture][index[capsq]] = capsq;
+ index[capsq] = pieceCount[them][st->capturedType] - 1;
+ pieceList[them][st->capturedType][index[capsq]] = capsq;
}
// Finally point our state pointer back to the previous state
assert(piece_on(kto) == piece_of_color_and_type(us, KING));
assert(piece_on(rto) == piece_of_color_and_type(us, ROOK));
- // Put the pieces back at the source square
- Bitboard kmove_bb = make_move_bb(kto, kfrom);
- do_move_bb(&(byColorBB[us]), kmove_bb);
- do_move_bb(&(byTypeBB[KING]), kmove_bb);
- do_move_bb(&(byTypeBB[0]), kmove_bb); // HACK: byTypeBB[0] == occupied squares
-
- Bitboard rmove_bb = make_move_bb(rto, rfrom);
- do_move_bb(&(byColorBB[us]), rmove_bb);
- do_move_bb(&(byTypeBB[ROOK]), rmove_bb);
- do_move_bb(&(byTypeBB[0]), rmove_bb); // HACK: byTypeBB[0] == occupied squares
+ // 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
// Update board
- board[rto] = board[kto] = EMPTY;
+ board[rto] = board[kto] = PIECE_NONE;
board[rfrom] = piece_of_color_and_type(us, ROOK);
board[kfrom] = piece_of_color_and_type(us, KING);
// a backup storage not as a new state to be used.
backupSt.key = st->key;
backupSt.epSquare = st->epSquare;
- backupSt.mgValue = st->mgValue;
- backupSt.egValue = st->egValue;
+ 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[gamePly] = st->key;
+ history[st->gamePly++] = st->key;
// Update the necessary information
if (st->epSquare != SQ_NONE)
st->key ^= zobEp[st->epSquare];
st->key ^= zobSideToMove;
- TT.prefetch(st->key);
+ prefetch((char*)TT.first_entry(st->key));
sideToMove = opposite_color(sideToMove);
st->epSquare = SQ_NONE;
st->rule50++;
- gamePly++;
-
- st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
- st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
+ st->pliesFromNull = 0;
+ st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue;
}
StateInfo* backupSt = st->previous;
st->key = backupSt->key;
st->epSquare = backupSt->epSquare;
- st->mgValue = backupSt->mgValue;
- st->egValue = backupSt->egValue;
+ st->value = backupSt->value;
st->previous = backupSt->previous;
+ st->pliesFromNull = backupSt->pliesFromNull;
// Update the necessary information
sideToMove = opposite_color(sideToMove);
st->rule50--;
- gamePly--;
+ st->gamePly--;
}
Square from = move_from(m);
Square to = move_to(m);
- // Early return if SEE cannot be negative because capturing piece value
- // is not bigger then captured one.
- if ( midgame_value_of_piece_on(from) <= midgame_value_of_piece_on(to)
- && type_of_piece_on(from) != KING)
- return 1;
+ // 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))
+ return 1;
return see(from, to);
}
0, 0
};
- Bitboard attackers, stmAttackers, occ, b;
+ Bitboard attackers, stmAttackers, b;
assert(square_is_ok(from) || from == SQ_NONE);
assert(square_is_ok(to));
// Initialize pieces
Piece piece = piece_on(from);
Piece capture = piece_on(to);
+ Bitboard occ = occupied_squares();
- // Find all attackers to the destination square, with the moving piece
- // removed, but possibly an X-ray attacker added behind it.
- occ = occupied_squares();
+ // King cannot be recaptured
+ if (type_of_piece(piece) == KING)
+ return seeValues[capture];
// Handle en passant moves
if (st->epSquare == to && type_of_piece_on(from) == PAWN)
{
- assert(capture == EMPTY);
+ assert(capture == PIECE_NONE);
Square capQq = (side_to_move() == WHITE)? (to - DELTA_N) : (to - DELTA_S);
capture = piece_on(capQq);
while (true)
{
+ // Find all attackers to the destination square, with the moving piece
+ // removed, but possibly an X-ray attacker added behind it.
clear_bit(&occ, from);
- attackers = (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN))
- | (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN))
- | (piece_attacks<KNIGHT>(to) & pieces(KNIGHT))
- | (piece_attacks<KING>(to) & pieces(KING))
- | (pawn_attacks(to, WHITE) & pieces(PAWN, BLACK))
- | (pawn_attacks(to, BLACK) & pieces(PAWN, WHITE));
+ attackers = (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN))
+ | (bishop_attacks_bb(to, occ) & 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));
if (from != SQ_NONE)
break;
}
-/// Position::saveState() copies the content of the current state
-/// inside startState and makes st point to it. This is needed
-/// when the st pointee could become stale, as example because
-/// the caller is about to going out of scope.
-
-void Position::saveState() {
-
- startState = *st;
- st = &startState;
- st->previous = NULL; // as a safe guard
-}
-
-
/// Position::clear() erases the position object to a pristine state, with an
/// empty board, white to move, and no castling rights.
st = &startState;
memset(st, 0, sizeof(StateInfo));
st->epSquare = SQ_NONE;
+ startPosPlyCounter = 0;
memset(byColorBB, 0, sizeof(Bitboard) * 2);
memset(byTypeBB, 0, sizeof(Bitboard) * 8);
memset(index, 0, sizeof(int) * 64);
for (int i = 0; i < 64; i++)
- board[i] = EMPTY;
+ board[i] = PIECE_NONE;
- for (int i = 0; i < 7; i++)
- for (int j = 0; j < 8; j++)
+ 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++)
+ castleRightsMask[sq] = ALL_CASTLES;
+
sideToMove = WHITE;
- gamePly = 0;
initialKFile = FILE_E;
initialKRFile = FILE_H;
initialQRFile = FILE_A;
void Position::reset_game_ply() {
- gamePly = 0;
+ st->gamePly = 0;
}
+void Position::inc_startpos_ply_counter() {
+
+ startPosPlyCounter++;
+}
/// Position::put_piece() puts a piece on the given square of the board,
/// updating the board array, bitboards, and piece counts.
set_bit(&byTypeBB[0], s); // HACK: byTypeBB[0] contains all occupied squares.
pieceCount[c][pt]++;
-
- if (pt == KING)
- st->kingSquare[c] = s;
}
for (Color c = WHITE; c <= BLACK; c++)
{
b = pieces(PAWN, c);
- while(b)
+ while (b)
{
s = pop_1st_bit(&b);
result ^= zobrist[c][PAWN][s];
for (PieceType pt = PAWN; pt <= QUEEN; pt++)
{
int count = piece_count(c, pt);
- for (int i = 0; i <= count; i++)
- result ^= zobMaterial[c][pt][i];
+ for (int i = 0; i < count; i++)
+ result ^= zobrist[c][pt][i];
}
return result;
}
/// game and the endgame. These functions are used to initialize the incremental
/// scores when a new position is set up, and to verify that the scores are correctly
/// updated by do_move and undo_move when the program is running in debug mode.
-template<Position::GamePhase Phase>
-Value Position::compute_value() const {
+Score Position::compute_value() const {
- Value result = Value(0);
+ Score result = make_score(0, 0);
Bitboard b;
Square s;
for (PieceType pt = PAWN; pt <= KING; pt++)
{
b = pieces(pt, c);
- while(b)
+ while (b)
{
s = pop_1st_bit(&b);
assert(piece_on(s) == piece_of_color_and_type(c, pt));
- result += pst<Phase>(c, pt, s);
+ result += pst(c, pt, s);
}
}
- const Value TempoValue = (Phase == MidGame ? TempoValueMidgame : TempoValueEndgame);
- result += (side_to_move() == WHITE)? TempoValue / 2 : -TempoValue / 2;
+ result += (side_to_move() == WHITE ? TempoValue / 2 : -TempoValue / 2);
return result;
}
Value Position::compute_non_pawn_material(Color c) const {
- Value result = Value(0);
+ Value result = VALUE_ZERO;
for (PieceType pt = KNIGHT; pt <= QUEEN; pt++)
{
/// 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.
+// FIXME: Currently we are not handling 50 move rule correctly when in check
bool Position::is_draw() const {
return true;
// Draw by repetition?
- for (int i = 2; i < Min(gamePly, st->rule50); i += 2)
- if (history[gamePly - i] == st->key)
+ 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;
bool Position::is_mate() const {
MoveStack moves[256];
-
- return is_check() && (generate_evasions(*this, moves, pinned_pieces(sideToMove)) == moves);
+ return is_check() && (generate_moves(*this, moves) == moves);
}
-/// Position::has_mate_threat() tests whether a given color has a mate in one
-/// from the current position.
+/// 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(Color c) {
+bool Position::has_mate_threat() {
+ MoveStack mlist[256], *last, *cur;
StateInfo st1, st2;
- Color stm = side_to_move();
+ bool mateFound = false;
+ // If we are under check it's up to evasions to do the job
if (is_check())
return false;
- // If the input color is not equal to the side to move, do a null move
- if (c != stm)
- do_null_move(st1);
+ // First pass the move to our opponent doing a null move
+ do_null_move(st1);
- MoveStack mlist[120];
- bool result = false;
- Bitboard dc = discovered_check_candidates(sideToMove);
- Bitboard pinned = pinned_pieces(sideToMove);
-
- // Generate pseudo-legal non-capture and capture check moves
- MoveStack* last = generate_non_capture_checks(*this, mlist, dc);
+ // Then generate pseudo-legal moves that give check
+ last = generate_non_capture_checks(*this, mlist);
last = generate_captures(*this, last);
- // Loop through the moves, and see if one of them is mate
- for (MoveStack* cur = mlist; cur != last; cur++)
+ // 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))
+ if ( !pl_move_is_legal(move, pinned)
+ || !move_is_check(move, ci))
continue;
- do_move(move, st2);
+ do_move(move, st2, ci, true);
+
if (is_mate())
- result = true;
+ mateFound = true;
undo_move(move);
}
- // Undo null move, if necessary
- if (c != stm)
- undo_null_move();
-
- return result;
+ undo_null_move();
+ return mateFound;
}
-/// Position::init_zobrist() is a static member function which initializes the
-/// various arrays used to compute hash keys.
+/// Position::init_zobrist() is a static member function which initializes at
+/// startup the various arrays used to compute hash keys.
void Position::init_zobrist() {
- for (int i = 0; i < 2; i++)
- for (int j = 0; j < 8; j++)
- for (int k = 0; k < 64; k++)
- zobrist[i][j][k] = Key(genrand_int64());
+ int i,j, k;
- for (int i = 0; i < 64; i++)
- zobEp[i] = Key(genrand_int64());
+ for (i = 0; i < 2; i++) for (j = 0; j < 8; j++) for (k = 0; k < 64; k++)
+ zobrist[i][j][k] = Key(genrand_int64());
- for (int i = 0; i < 16; i++)
- zobCastle[i] = genrand_int64();
-
- zobSideToMove = genrand_int64();
+ for (i = 0; i < 64; i++)
+ zobEp[i] = Key(genrand_int64());
- for (int i = 0; i < 2; i++)
- for (int j = 0; j < 8; j++)
- for (int k = 0; k < 16; k++)
- zobMaterial[i][j][k] = (k > 0)? Key(genrand_int64()) : Key(0LL);
+ for (i = 0; i < 16; i++)
+ zobCastle[i] = Key(genrand_int64());
- for (int i = 0; i < 16; i++)
- zobMaterial[0][KING][i] = zobMaterial[1][KING][i] = Key(0ULL);
+ zobSideToMove = Key(genrand_int64());
+ zobExclusion = Key(genrand_int64());
}
/// 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, with a small random number
-/// added to each entry if the "Randomness" UCI parameter is non-zero.
-/// Second, the black halves of the tables are initialized by mirroring
-/// and changing the sign of the corresponding white scores.
+/// 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() {
- int r = get_option_value_int("Randomness"), i;
for (Square s = SQ_A1; s <= SQ_H8; s++)
for (Piece p = WP; p <= WK; p++)
- {
- i = (r == 0)? 0 : (genrand_int32() % (r*2) - r);
- MgPieceSquareTable[p][s] = Value(MgPST[p][s] + i);
- EgPieceSquareTable[p][s] = Value(EgPST[p][s] + i);
- }
+ 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++)
- {
- MgPieceSquareTable[p][s] = -MgPieceSquareTable[p-8][flip_square(s)];
- EgPieceSquareTable[p][s] = -EgPieceSquareTable[p-8][flip_square(s)];
- }
+ PieceSquareTable[p][s] = -PieceSquareTable[p-8][flip_square(s)];
}
assert(pos.is_ok());
clear();
+ threadID = pos.thread();
// Board
for (Square s = SQ_A1; s <= SQ_H8; s++)
initialKRFile = pos.initialKRFile;
initialQRFile = pos.initialQRFile;
- for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
- castleRightsMask[sq] = ALL_CASTLES;
-
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;
st->materialKey = compute_material_key();
// Incremental scores
- st->mgValue = compute_value<MidGame>();
- st->egValue = compute_value<EndGame>();
+ st->value = compute_value();
// Material
st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
static const bool debugNonPawnMaterial = false;
static const bool debugPieceCounts = false;
static const bool debugPieceList = false;
+ static const bool debugCastleSquares = false;
if (failedStep) *failedStep = 1;
Color us = side_to_move();
Color them = opposite_color(us);
Square ksq = king_square(them);
- if (attacks_to(ksq, us))
+ if (attackers_to(ksq) & pieces_of_color(us))
return false;
}
// Incremental eval OK?
if (failedStep) (*failedStep)++;
- if (debugIncrementalEval)
- {
- if (st->mgValue != compute_value<MidGame>())
- return false;
-
- if (st->egValue != compute_value<EndGame>())
- return false;
- }
+ if (debugIncrementalEval && st->value != compute_value())
+ return false;
// Non-pawn material OK?
if (failedStep) (*failedStep)++;
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++)
+ 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)) != (pieces(pt, c)))
+ if (piece_on(piece_list(c, pt, i)) != piece_of_color_and_type(c, pt))
return false;
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))
+ 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