/*
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 : 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;
+ }
+};
////
-//// Variables
+//// Constants and variables
////
-int Position::castleRightsMask[64];
+/// Bonus for having the side to move (modified by Joona Kiiski)
+
+static const Score TempoValue = make_score(48, 22);
+
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;
Score Position::PieceSquareTable[16][64];
-static bool RequestPending = false;
+static PieceLetters pieceLetters;
+
+// Material values used by SEE, indexed by PieceType
+const Value Position::seeValues[] = {
+ VALUE_ZERO, PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
+ RookValueMidgame, QueenValueMidgame, QueenValueMidgame*10
+};
/// Constructors
checkSq[KING] = EmptyBoardBB;
}
-Position::Position(const Position& pos) {
- copy(pos);
+
+/// 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++;
-
- // En passant square -- ignore if no capture is possible
- if ( i <= fen.length() - 2
- && (fen[i] >= 'a' && fen[i] <= 'h')
- && (fen[i+1] == '3' || fen[i+1] == '6'))
+ // 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 = square_from_string(fen.substr(i, 2));
+ Square fenEpSquare = make_square(file_from_char(col), rank_from_char(row));
Color them = opposite_color(sideToMove);
- if (attacks_from<PAWN>(fenEpSquare, them) & this->pieces(PAWN, sideToMove))
- 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;
castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO;
+ isChess960 = initialKFile != FILE_E
+ || initialQRFile != FILE_A
+ || initialKRFile != FILE_H;
+
find_checkers();
st->key = compute_key();
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 += '-';
+ if (can_castle_kingside(WHITE))
+ fen += isChess960 ? char(toupper(file_to_char(initialKRFile))) : 'K';
- fen += ' ';
- if (ep_square() != SQ_NONE)
- fen += square_to_string(ep_square());
- else
+ if (can_castle_queenside(WHITE))
+ fen += isChess960 ? char(toupper(file_to_char(initialQRFile))) : 'Q';
+
+ if (can_castle_kingside(BLACK))
+ fen += isChess960 ? file_to_char(initialKRFile) : 'k';
+
+ if (can_castle_queenside(BLACK))
+ fen += isChess960 ? 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.
+/// the standard output. If a move is given then also the san is printed.
-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;
}
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);
}
}
- // En passant capture with check? We have already handled the case
+ // 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.
+ // 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));
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 pawnKey, materialKey;
- int castleRights, rule50, pliesFromNull;
+ 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;
}
// 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;
+ 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
// Reset rule 50 draw counter
st->rule50 = 0;
- // Update pawn hash key
+ // 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)
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] += PieceValueMidgame[promotion];
+ }
}
// Update incremental scores
st->value += pst_delta(piece, from, to);
// Set capture piece
- st->capture = capture;
-
- 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 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;
- 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);
- }
+ st->capturedType = capture;
// Update the key with the final value
st->key = key;
/// 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] -= PieceValueMidgame[capture];
// Remove captured piece
clear_bit(&(byColorBB[them]), capsq);
// Update incremental scores
st->value -= pst(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]];
-
// 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
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);
// 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;
assert(is_ok());
assert(move_is_ok(m));
- gamePly--;
sideToMove = opposite_color(sideToMove);
if (move_is_castle(m))
pieceList[us][PAWN][index[to]] = to;
}
-
// 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[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
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);
// 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++;
st->pliesFromNull = 0;
st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue;
- gamePly++;
}
// Update the necessary information
sideToMove = opposite_color(sideToMove);
st->rule50--;
- gamePly--;
+ st->gamePly--;
}
/// move, and one which takes a 'from' and a 'to' square. The function does
/// not yet understand promotions captures.
-int Position::see(Square to) const {
-
- assert(square_is_ok(to));
- return see(SQ_NONE, to);
-}
-
int Position::see(Move m) const {
assert(move_is_ok(m));
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);
}
int Position::see(Square from, Square to) const {
- // Material values
- static const int seeValues[18] = {
- 0, PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
- RookValueMidgame, QueenValueMidgame, QueenValueMidgame*10, 0,
- 0, PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
- RookValueMidgame, QueenValueMidgame, QueenValueMidgame*10, 0,
- 0, 0
- };
-
- Bitboard attackers, stmAttackers, b;
+ Bitboard occ, attackers, stmAttackers, b;
+ int swapList[32], slIndex = 1;
+ PieceType capturedType, pt;
+ Color stm;
- assert(square_is_ok(from) || from == SQ_NONE);
+ assert(square_is_ok(from));
assert(square_is_ok(to));
- // Initialize colors
- Color us = (from != SQ_NONE ? color_of_piece_on(from) : opposite_color(color_of_piece_on(to)));
- Color them = opposite_color(us);
-
- // Initialize pieces
- Piece piece = piece_on(from);
- Piece capture = piece_on(to);
- Bitboard occ = occupied_squares();
+ capturedType = type_of_piece_on(to);
// King cannot be recaptured
- if (type_of_piece(piece) == KING)
- return seeValues[capture];
+ if (capturedType == KING)
+ return seeValues[capturedType];
+
+ occ = occupied_squares();
// Handle en passant moves
if (st->epSquare == to && type_of_piece_on(from) == PAWN)
{
- assert(capture == EMPTY);
+ Square capQq = (side_to_move() == WHITE) ? (to - DELTA_N) : (to - DELTA_S);
- Square capQq = (side_to_move() == WHITE)? (to - DELTA_N) : (to - DELTA_S);
- capture = piece_on(capQq);
+ assert(capturedType == PIECE_TYPE_NONE);
assert(type_of_piece_on(capQq) == PAWN);
// Remove the captured pawn
clear_bit(&occ, capQq);
+ capturedType = PAWN;
}
- 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))
- | (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;
-
- // If we don't have any attacker we are finished
- if ((attackers & pieces_of_color(us)) == EmptyBoardBB)
- return 0;
-
- // Locate the least valuable attacker to the destination square
- // and use it to initialize from square.
- stmAttackers = attackers & pieces_of_color(us);
- PieceType pt;
- for (pt = PAWN; !(stmAttackers & pieces(pt)); pt++)
- assert(pt < KING);
-
- from = first_1(stmAttackers & pieces(pt));
- piece = piece_on(from);
- }
+ // 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))
+ | (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 the opponent has no attackers we are finished
- stmAttackers = attackers & pieces_of_color(them);
+ stm = opposite_color(color_of_piece_on(from));
+ stmAttackers = attackers & pieces_of_color(stm);
if (!stmAttackers)
- return seeValues[capture];
-
- attackers &= occ; // Remove the moving piece
+ return seeValues[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.
- int lastCapturingPieceValue = seeValues[piece];
- int swapList[32], n = 1;
- Color c = them;
- PieceType pt;
-
- swapList[0] = seeValues[capture];
+ swapList[0] = seeValues[capturedType];
+ capturedType = type_of_piece_on(from);
do {
// Locate the least valuable attacker for the side to move. The loop
// and scan for new X-ray attacks behind the attacker.
b = stmAttackers & pieces(pt);
occ ^= (b & (~b + 1));
- attackers |= (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN))
+ attackers |= (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN))
| (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN));
- attackers &= occ;
+ attackers &= occ; // Cut out pieces we've already done
// Add the new entry to the swap list
- assert(n < 32);
- swapList[n] = -swapList[n - 1] + lastCapturingPieceValue;
- n++;
+ assert(slIndex < 32);
+ swapList[slIndex] = -swapList[slIndex - 1] + seeValues[capturedType];
+ slIndex++;
// Remember the value of the capturing piece, and change the side to move
// before beginning the next iteration
- lastCapturingPieceValue = seeValues[pt];
- c = opposite_color(c);
- stmAttackers = attackers & pieces_of_color(c);
+ capturedType = pt;
+ stm = opposite_color(stm);
+ stmAttackers = attackers & pieces_of_color(stm);
// Stop after a king capture
if (pt == KING && stmAttackers)
{
- assert(n < 32);
- swapList[n++] = QueenValueMidgame*10;
+ assert(slIndex < 32);
+ swapList[slIndex++] = QueenValueMidgame*10;
break;
}
} while (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 (--n)
- swapList[n-1] = Min(-swapList[n], swapList[n-1]);
+ while (--slIndex)
+ swapList[slIndex-1] = Min(-swapList[slIndex], swapList[slIndex-1]);
return swapList[0];
}
-/// 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 < 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.
Key Position::compute_key() const {
- Key result = Key(0ULL);
+ Key result = 0;
for (Square s = SQ_A1; s <= SQ_H8; s++)
if (square_is_occupied(s))
Key Position::compute_pawn_key() const {
- Key result = Key(0ULL);
+ Key result = 0;
Bitboard b;
Square 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];
Key Position::compute_material_key() const {
- Key result = Key(0ULL);
+ Key result = 0;
for (Color c = WHITE; c <= BLACK; c++)
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;
}
/// updated by do_move and undo_move when the program is running in debug mode.
Score Position::compute_value() const {
- Score result = make_score(0, 0);
+ Score result = SCORE_ZERO;
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));
Value Position::compute_non_pawn_material(Color c) const {
- Value result = Value(0);
+ Value result = VALUE_ZERO;
for (PieceType pt = KNIGHT; pt <= QUEEN; pt++)
{
while (b)
{
assert(piece_on(first_1(b)) == piece_of_color_and_type(c, pt));
+
pop_1st_bit(&b);
- result += piece_value_midgame(pt);
+ result += PieceValueMidgame[pt];
}
}
return result;
return true;
// Draw by the 50 moves rule?
- if (st->rule50 > 100 || (st->rule50 == 100 && !is_check()))
+ if (st->rule50 > 99 && (st->rule50 > 100 || !is_mate()))
return true;
// Draw by repetition?
- for (int i = 2; i < Min(Min(gamePly, st->rule50), st->pliesFromNull); 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_moves(*this, moves, false) == moves);
+ MoveStack moves[MOVES_MAX];
+ 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[MOVES_MAX], *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 pinned = pinned_pieces(sideToMove);
-
- // Generate pseudo-legal non-capture and capture check moves
- MoveStack* last = generate_non_capture_checks(*this, mlist);
+ // 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());
-
- for (int i = 0; i < 64; i++)
- zobEp[i] = Key(genrand_int64());
+ int i,j, k;
- for (int i = 0; i < 16; i++)
- zobCastle[i] = 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());
- zobSideToMove = 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 < 64; i++)
+ zobEp[i] = Key(genrand_int64());
- for (int i = 0; i < 16; i++)
- zobMaterial[0][KING][i] = zobMaterial[1][KING][i] = Key(0ULL);
+ for (i = 0; i < 16; i++)
+ zobCastle[i] = Key(genrand_int64());
- zobExclusion = genrand_int64();
+ 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);
- PieceSquareTable[p][s] = make_score(MgPST[p][s] + i, 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++)
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;
static const bool debugNonPawnMaterial = false;
static const bool debugPieceCounts = false;
static const bool debugPieceList = false;
+ static const bool debugCastleSquares = false;
if (failedStep) *failedStep = 1;
// Is there more than 2 checkers?
if (failedStep) (*failedStep)++;
- if (debugCheckerCount && count_1s(st->checkersBB) > 2)
+ if (debugCheckerCount && count_1s<CNT32>(st->checkersBB) > 2)
return false;
// Bitboards OK?
if (debugPieceCounts)
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= KING; pt++)
- if (pieceCount[c][pt] != count_1s(pieces(pt, c)))
+ if (pieceCount[c][pt] != count_1s<CNT32>(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++)
+ 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))
return false;
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