/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#include <cassert>
#include <cstring>
-#include <fstream>
#include <iostream>
#include <sstream>
#include <algorithm>
#include "bitcount.h"
#include "movegen.h"
+#include "notation.h"
#include "position.h"
#include "psqtab.h"
#include "rkiss.h"
using std::cout;
using std::endl;
-Key Position::zobrist[2][8][64];
-Key Position::zobEp[64];
-Key Position::zobCastle[16];
-Key Position::zobSideToMove;
-Key Position::zobExclusion;
-
-Score Position::pieceSquareTable[16][64];
-
-// Material values arrays, indexed by Piece
-const Value PieceValueMidgame[17] = {
- VALUE_ZERO,
- PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
- RookValueMidgame, QueenValueMidgame,
- VALUE_ZERO, VALUE_ZERO, VALUE_ZERO,
- PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
- RookValueMidgame, QueenValueMidgame
-};
-
-const Value PieceValueEndgame[17] = {
- VALUE_ZERO,
- PawnValueEndgame, KnightValueEndgame, BishopValueEndgame,
- RookValueEndgame, QueenValueEndgame,
- VALUE_ZERO, VALUE_ZERO, VALUE_ZERO,
- PawnValueEndgame, KnightValueEndgame, BishopValueEndgame,
- RookValueEndgame, QueenValueEndgame
-};
+static const string PieceToChar(" PNBRQK pnbrqk");
+
+CACHE_LINE_ALIGNMENT
+
+Score pieceSquareTable[PIECE_NB][SQUARE_NB];
+Value PieceValue[PHASE_NB][PIECE_NB] = {
+{ VALUE_ZERO, PawnValueMg, KnightValueMg, BishopValueMg, RookValueMg, QueenValueMg },
+{ VALUE_ZERO, PawnValueEg, KnightValueEg, BishopValueEg, RookValueEg, QueenValueEg } };
+
+namespace Zobrist {
+
+Key psq[COLOR_NB][PIECE_TYPE_NB][SQUARE_NB];
+Key enpassant[FILE_NB];
+Key castle[CASTLE_RIGHT_NB];
+Key side;
+Key exclusion;
+
+/// init() initializes at startup the various arrays used to compute hash keys
+/// and the piece square tables. The latter is a two-step operation: First, the
+/// white halves of the tables are copied from PSQT[] tables. Second, the black
+/// halves of the tables are initialized by flipping and changing the sign of
+/// the white scores.
+
+void init() {
+
+ RKISS rk;
+
+ for (Color c = WHITE; c <= BLACK; c++)
+ for (PieceType pt = PAWN; pt <= KING; pt++)
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ psq[c][pt][s] = rk.rand<Key>();
+
+ for (File f = FILE_A; f <= FILE_H; f++)
+ enpassant[f] = rk.rand<Key>();
+
+ for (int cr = CASTLES_NONE; cr <= ALL_CASTLES; cr++)
+ {
+ Bitboard b = cr;
+ while (b)
+ {
+ Key k = castle[1ULL << pop_lsb(&b)];
+ castle[cr] ^= k ? k : rk.rand<Key>();
+ }
+ }
+
+ side = rk.rand<Key>();
+ exclusion = rk.rand<Key>();
+
+ for (PieceType pt = PAWN; pt <= KING; pt++)
+ {
+ PieceValue[MG][make_piece(BLACK, pt)] = PieceValue[MG][pt];
+ PieceValue[EG][make_piece(BLACK, pt)] = PieceValue[EG][pt];
+
+ Score v = make_score(PieceValue[MG][pt], PieceValue[EG][pt]);
+
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ {
+ pieceSquareTable[make_piece(WHITE, pt)][ s] = (v + PSQT[pt][s]);
+ pieceSquareTable[make_piece(BLACK, pt)][~s] = -(v + PSQT[pt][s]);
+ }
+ }
+}
+
+} // namespace Zobrist
namespace {
- // Bonus for having the side to move (modified by Joona Kiiski)
- const Score TempoValue = make_score(48, 22);
+/// next_attacker() is an helper function used by see() to locate the least
+/// valuable attacker for the side to move, remove the attacker we just found
+/// from the 'occupied' bitboard and scan for new X-ray attacks behind it.
+
+template<int Pt> FORCE_INLINE
+PieceType next_attacker(const Bitboard* bb, const Square& to, const Bitboard& stmAttackers,
+ Bitboard& occupied, Bitboard& attackers) {
+
+ if (stmAttackers & bb[Pt])
+ {
+ Bitboard b = stmAttackers & bb[Pt];
+ occupied ^= b & ~(b - 1);
+
+ if (Pt == PAWN || Pt == BISHOP || Pt == QUEEN)
+ attackers |= attacks_bb<BISHOP>(to, occupied) & (bb[BISHOP] | bb[QUEEN]);
+
+ if (Pt == ROOK || Pt == QUEEN)
+ attackers |= attacks_bb<ROOK>(to, occupied) & (bb[ROOK] | bb[QUEEN]);
+
+ return (PieceType)Pt;
+ }
+ return next_attacker<Pt+1>(bb, to, stmAttackers, occupied, attackers);
+}
- // To convert a Piece to and from a FEN char
- const string PieceToChar(".PNBRQK pnbrqk ");
+template<> FORCE_INLINE
+PieceType next_attacker<KING>(const Bitboard*, const Square&, const Bitboard&, Bitboard&, Bitboard&) {
+ return KING; // No need to update bitboards, it is the last cycle
}
+} // namespace
+
/// CheckInfo c'tor
CheckInfo::CheckInfo(const Position& pos) {
- Color them = flip(pos.side_to_move());
- Square ksq = pos.king_square(them);
+ Color them = ~pos.side_to_move();
+ ksq = pos.king_square(them);
pinned = pos.pinned_pieces();
dcCandidates = pos.discovered_check_candidates();
}
-/// 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::operator=() creates a copy of 'pos'. We want the new born Position
+/// object do not depend on any external data so we detach state pointer from
+/// the source one.
-void Position::copy(const Position& pos, int th) {
+Position& Position::operator=(const Position& pos) {
memcpy(this, &pos, sizeof(Position));
startState = *st;
st = &startState;
- threadID = th;
nodes = 0;
assert(pos_is_ok());
-}
-Position::Position(const string& fen, bool isChess960, int th) {
-
- from_fen(fen, isChess960);
- threadID = th;
+ return *this;
}
-/// Position::from_fen() initializes the position object with the given FEN
-/// string. This function is not very robust - make sure that input FENs are
-/// correct (this is assumed to be the responsibility of the GUI).
+/// Position::set() initializes the position object with the given FEN string.
+/// This function is not very robust - make sure that input FENs are correct,
+/// this is assumed to be the responsibility of the GUI.
-void Position::from_fen(const string& fenStr, bool isChess960) {
+void Position::set(const string& fenStr, bool isChess960, Thread* th) {
/*
A FEN string defines a particular position using only the ASCII character set.
char col, row, token;
size_t p;
Square sq = SQ_A8;
- std::istringstream fen(fenStr);
+ std::istringstream ss(fenStr);
clear();
- fen >> std::noskipws;
+ ss >> std::noskipws;
// 1. Piece placement
- while ((fen >> token) && !isspace(token))
+ while ((ss >> token) && !isspace(token))
{
- if (token == '/')
- sq -= Square(16); // Jump back of 2 rows
+ if (isdigit(token))
+ sq += Square(token - '0'); // Advance the given number of files
- else if (isdigit(token))
- sq += Square(token - '0'); // Skip the given number of files
+ else if (token == '/')
+ sq -= Square(16);
else if ((p = PieceToChar.find(token)) != string::npos)
{
}
// 2. Active color
- fen >> token;
+ ss >> token;
sideToMove = (token == 'w' ? WHITE : BLACK);
- fen >> token;
+ ss >> token;
// 3. Castling availability. Compatible with 3 standards: Normal FEN standard,
// Shredder-FEN that uses the letters of the columns on which the rooks began
// the game instead of KQkq and also X-FEN standard that, in case of Chess960,
// if an inner rook is associated with the castling right, the castling tag is
// replaced by the file letter of the involved rook, as for the Shredder-FEN.
- while ((fen >> token) && !isspace(token))
+ while ((ss >> token) && !isspace(token))
{
Square rsq;
Color c = islower(token) ? BLACK : WHITE;
- Piece rook = make_piece(c, ROOK);
token = char(toupper(token));
if (token == 'K')
- for (rsq = relative_square(c, SQ_H1); piece_on(rsq) != rook; rsq--) {}
+ for (rsq = relative_square(c, SQ_H1); type_of(piece_on(rsq)) != ROOK; rsq--) {}
else if (token == 'Q')
- for (rsq = relative_square(c, SQ_A1); piece_on(rsq) != rook; rsq++) {}
+ for (rsq = relative_square(c, SQ_A1); type_of(piece_on(rsq)) != ROOK; rsq++) {}
else if (token >= 'A' && token <= 'H')
- rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1));
+ rsq = File(token - 'A') | relative_rank(c, RANK_1);
else
continue;
- set_castle_right(king_square(c), rsq);
+ set_castle_right(c, rsq);
}
// 4. En passant square. Ignore if no pawn capture is possible
- if ( ((fen >> col) && (col >= 'a' && col <= 'h'))
- && ((fen >> row) && (row == '3' || row == '6')))
+ if ( ((ss >> col) && (col >= 'a' && col <= 'h'))
+ && ((ss >> row) && (row == '3' || row == '6')))
{
- st->epSquare = make_square(File(col - 'a'), Rank(row - '1'));
+ st->epSquare = File(col - 'a') | Rank(row - '1');
- if (!(attackers_to(st->epSquare) & pieces(PAWN, sideToMove)))
+ if (!(attackers_to(st->epSquare) & pieces(sideToMove, PAWN)))
st->epSquare = SQ_NONE;
}
// 5-6. Halfmove clock and fullmove number
- fen >> std::skipws >> st->rule50 >> startPosPly;
+ ss >> std::skipws >> st->rule50 >> startPosPly;
// Convert from fullmove starting from 1 to ply starting from 0,
// handle also common incorrect FEN with fullmove = 0.
st->key = compute_key();
st->pawnKey = compute_pawn_key();
st->materialKey = compute_material_key();
- st->value = compute_value();
+ st->psqScore = compute_psq_score();
st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
- st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(flip(sideToMove));
+ st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove);
chess960 = isChess960;
+ thisThread = th;
assert(pos_is_ok());
}
/// Position::set_castle_right() is an helper function used to set castling
-/// rights given the corresponding king and rook starting squares.
+/// rights given the corresponding color and the rook starting square.
+
+void Position::set_castle_right(Color c, Square rfrom) {
+
+ Square kfrom = king_square(c);
+ CastlingSide cs = kfrom < rfrom ? KING_SIDE : QUEEN_SIDE;
+ CastleRight cr = make_castle_right(c, cs);
-void Position::set_castle_right(Square ksq, Square rsq) {
+ st->castleRights |= cr;
+ castleRightsMask[kfrom] |= cr;
+ castleRightsMask[rfrom] |= cr;
+ castleRookSquare[c][cs] = rfrom;
- int f = (rsq < ksq ? WHITE_OOO : WHITE_OO) << color_of(piece_on(ksq));
+ Square kto = relative_square(c, cs == KING_SIDE ? SQ_G1 : SQ_C1);
+ Square rto = relative_square(c, cs == KING_SIDE ? SQ_F1 : SQ_D1);
- st->castleRights |= f;
- castleRightsMask[ksq] ^= f;
- castleRightsMask[rsq] ^= f;
- castleRookSquare[f] = rsq;
+ for (Square s = std::min(rfrom, rto); s <= std::max(rfrom, rto); s++)
+ if (s != kfrom && s != rfrom)
+ castlePath[c][cs] |= s;
+
+ for (Square s = std::min(kfrom, kto); s <= std::max(kfrom, kto); s++)
+ if (s != kfrom && s != rfrom)
+ castlePath[c][cs] |= s;
}
-/// Position::to_fen() returns a FEN representation of the position. In case
+/// Position::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 {
+const string Position::fen() const {
- std::ostringstream fen;
+ std::ostringstream ss;
Square sq;
int emptyCnt;
for (File file = FILE_A; file <= FILE_H; file++)
{
- sq = make_square(file, rank);
+ sq = file | rank;
- if (square_is_empty(sq))
+ if (is_empty(sq))
emptyCnt++;
else
{
if (emptyCnt > 0)
{
- fen << emptyCnt;
+ ss << emptyCnt;
emptyCnt = 0;
}
- fen << PieceToChar[piece_on(sq)];
+ ss << PieceToChar[piece_on(sq)];
}
}
if (emptyCnt > 0)
- fen << emptyCnt;
+ ss << emptyCnt;
if (rank > RANK_1)
- fen << '/';
+ ss << '/';
}
- fen << (sideToMove == WHITE ? " w " : " b ");
+ ss << (sideToMove == WHITE ? " w " : " b ");
if (can_castle(WHITE_OO))
- fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OO))))) : 'K');
+ ss << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE, KING_SIDE))))) : 'K');
if (can_castle(WHITE_OOO))
- fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OOO))))) : 'Q');
+ ss << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE, QUEEN_SIDE))))) : 'Q');
if (can_castle(BLACK_OO))
- fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OO))) : 'k');
+ ss << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK, KING_SIDE))) : 'k');
if (can_castle(BLACK_OOO))
- fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OOO))) : 'q');
+ ss << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK, QUEEN_SIDE))) : 'q');
if (st->castleRights == CASTLES_NONE)
- fen << '-';
+ ss << '-';
- fen << (ep_square() == SQ_NONE ? " - " : " " + square_to_string(ep_square()) + " ")
+ ss << (ep_square() == SQ_NONE ? " - " : " " + square_to_string(ep_square()) + " ")
<< st->rule50 << " " << 1 + (startPosPly - int(sideToMove == BLACK)) / 2;
- return fen.str();
+ return ss.str();
}
-/// Position::print() prints an ASCII representation of the position to
-/// the standard output. If a move is given then also the san is printed.
+/// Position::pretty() returns an ASCII representation of the position to be
+/// printed to the standard output together with the move's san notation.
+
+const string Position::pretty(Move move) const {
+
+ const string dottedLine = "\n+---+---+---+---+---+---+---+---+";
+ const string twoRows = dottedLine + "\n| | . | | . | | . | | . |"
+ + dottedLine + "\n| . | | . | | . | | . | |";
-void Position::print(Move move) const {
+ string brd = twoRows + twoRows + twoRows + twoRows + dottedLine;
- const char* dottedLine = "\n+---+---+---+---+---+---+---+---+\n";
+ std::ostringstream ss;
if (move)
- {
- Position p(*this, thread());
- cout << "\nMove is: " << (sideToMove == BLACK ? ".." : "") << move_to_san(p, move);
- }
+ ss << "\nMove: " << (sideToMove == BLACK ? ".." : "")
+ << move_to_san(*const_cast<Position*>(this), move);
- for (Rank rank = RANK_8; rank >= RANK_1; rank--)
- {
- cout << dottedLine << '|';
- for (File file = FILE_A; file <= FILE_H; file++)
- {
- Square sq = make_square(file, rank);
- Piece piece = piece_on(sq);
- char c = (color_of(piece) == BLACK ? '=' : ' ');
+ for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
+ if (piece_on(sq) != NO_PIECE)
+ brd[513 - 68*rank_of(sq) + 4*file_of(sq)] = PieceToChar[piece_on(sq)];
- if (piece == PIECE_NONE && color_of(sq) == DARK)
- piece = PIECE_NONE_DARK_SQ;
+ ss << brd << "\nFen: " << fen() << "\nKey: " << st->key;
- cout << c << PieceToChar[piece] << c << '|';
- }
+ if (checkers())
+ {
+ ss << "\nCheckers: ";
+ for (Bitboard b = checkers(); b; )
+ ss << square_to_string(pop_lsb(&b)) << " ";
}
- cout << dottedLine << "Fen is: " << to_fen() << "\nKey is: " << st->key << endl;
+ return ss.str();
}
// Pinned pieces protect our king, dicovery checks attack the enemy king
Bitboard b, result = 0;
- Bitboard pinners = pieces(FindPinned ? flip(sideToMove) : sideToMove);
- Square ksq = king_square(FindPinned ? sideToMove : flip(sideToMove));
+ Bitboard pinners = pieces(FindPinned ? ~sideToMove : sideToMove);
+ Square ksq = king_square(FindPinned ? sideToMove : ~sideToMove);
// Pinners are sliders, that give check when candidate pinned is removed
- pinners &= (pieces(ROOK, QUEEN) & RookPseudoAttacks[ksq])
- | (pieces(BISHOP, QUEEN) & BishopPseudoAttacks[ksq]);
+ pinners &= (pieces(ROOK, QUEEN) & PseudoAttacks[ROOK][ksq])
+ | (pieces(BISHOP, QUEEN) & PseudoAttacks[BISHOP][ksq]);
while (pinners)
{
- b = squares_between(ksq, pop_1st_bit(&pinners)) & occupied_squares();
+ b = between_bb(ksq, pop_lsb(&pinners)) & pieces();
- // Only one bit set and is an our piece?
- if (b && !(b & (b - 1)) && (b & pieces(sideToMove)))
+ if (b && !more_than_one(b) && (b & pieces(sideToMove)))
result |= b;
}
return result;
Bitboard Position::attackers_to(Square s, Bitboard occ) const {
- return (attacks_from<PAWN>(s, BLACK) & pieces(PAWN, WHITE))
- | (attacks_from<PAWN>(s, WHITE) & pieces(PAWN, BLACK))
+ return (attacks_from<PAWN>(s, BLACK) & pieces(WHITE, PAWN))
+ | (attacks_from<PAWN>(s, WHITE) & pieces(BLACK, PAWN))
| (attacks_from<KNIGHT>(s) & pieces(KNIGHT))
- | (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN))
- | (bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN))
+ | (attacks_bb<ROOK>(s, occ) & pieces(ROOK, QUEEN))
+ | (attacks_bb<BISHOP>(s, occ) & pieces(BISHOP, QUEEN))
| (attacks_from<KING>(s) & pieces(KING));
}
Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) {
- assert(square_is_ok(s));
+ assert(is_ok(s));
- switch (p)
+ switch (type_of(p))
{
- case WB: case BB: return bishop_attacks_bb(s, occ);
- case WR: case BR: return rook_attacks_bb(s, occ);
- case WQ: case BQ: return bishop_attacks_bb(s, occ) | rook_attacks_bb(s, occ);
- default: return StepAttacksBB[p][s];
+ case BISHOP: return attacks_bb<BISHOP>(s, occ);
+ case ROOK : return attacks_bb<ROOK>(s, occ);
+ case QUEEN : return attacks_bb<BISHOP>(s, occ) | attacks_bb<ROOK>(s, occ);
+ default : return StepAttacksBB[p][s];
}
}
-/// Position::move_attacks_square() tests whether a move from the current
-/// position attacks a given square.
-
-bool Position::move_attacks_square(Move m, Square s) const {
-
- assert(is_ok(m));
- assert(square_is_ok(s));
-
- Bitboard occ, xray;
- Square from = move_from(m);
- Square to = move_to(m);
- Piece piece = piece_on(from);
-
- assert(!square_is_empty(from));
-
- // Update occupancy as if the piece is moving
- occ = occupied_squares();
- do_move_bb(&occ, make_move_bb(from, to));
-
- // The piece moved in 'to' attacks the square 's' ?
- if (bit_is_set(attacks_from(piece, to, occ), s))
- return true;
-
- // Scan for possible X-ray attackers behind the moved piece
- xray = (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN, color_of(piece)))
- |(bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN, color_of(piece)));
-
- // Verify attackers are triggered by our move and not already existing
- return xray && (xray ^ (xray & attacks_from<QUEEN>(s)));
-}
-
-
/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal
bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
assert(is_ok(m));
assert(pinned == pinned_pieces());
- Color us = side_to_move();
- Square from = move_from(m);
+ Color us = sideToMove;
+ Square from = from_sq(m);
- assert(color_of(piece_on(from)) == us);
+ assert(color_of(piece_moved(m)) == us);
assert(piece_on(king_square(us)) == make_piece(us, KING));
// En passant captures are a tricky special case. Because they are rather
// uncommon, we do it simply by testing whether the king is attacked after
// the move is made.
- if (is_enpassant(m))
+ if (type_of(m) == ENPASSANT)
{
- Color them = flip(us);
- Square to = move_to(m);
+ Color them = ~us;
+ Square to = to_sq(m);
Square capsq = to + pawn_push(them);
Square ksq = king_square(us);
- Bitboard b = occupied_squares();
+ Bitboard b = (pieces() ^ from ^ capsq) | to;
assert(to == ep_square());
- assert(piece_on(from) == make_piece(us, PAWN));
+ assert(piece_moved(m) == make_piece(us, PAWN));
assert(piece_on(capsq) == make_piece(them, PAWN));
- assert(piece_on(to) == PIECE_NONE);
+ assert(piece_on(to) == NO_PIECE);
- clear_bit(&b, from);
- clear_bit(&b, capsq);
- set_bit(&b, to);
-
- return !(rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, them))
- && !(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, them));
+ return !(attacks_bb< ROOK>(ksq, b) & pieces(them, QUEEN, ROOK))
+ && !(attacks_bb<BISHOP>(ksq, b) & pieces(them, QUEEN, BISHOP));
}
// If the moving piece is a king, check whether the destination
// square is attacked by the opponent. Castling moves are checked
// for legality during move generation.
if (type_of(piece_on(from)) == KING)
- return is_castle(m) || !(attackers_to(move_to(m)) & pieces(flip(us)));
+ return type_of(m) == CASTLE || !(attackers_to(to_sq(m)) & pieces(~us));
// A non-king move is legal if and only if it is not pinned or it
// is moving along the ray towards or away from the king.
return !pinned
- || !bit_is_set(pinned, from)
- || squares_aligned(from, move_to(m), king_square(us));
-}
-
-
-/// Position::move_is_legal() takes a random move and tests whether the move
-/// is legal. This version is not very fast and should be used only in non
-/// time-critical paths.
-
-bool Position::move_is_legal(const Move m) const {
-
- for (MoveList<MV_LEGAL> ml(*this); !ml.end(); ++ml)
- if (ml.move() == m)
- return true;
-
- return false;
+ || !(pinned & from)
+ || squares_aligned(from, to_sq(m), king_square(us));
}
bool Position::is_pseudo_legal(const Move m) const {
Color us = sideToMove;
- Color them = flip(sideToMove);
- Square from = move_from(m);
- Square to = move_to(m);
- Piece pc = piece_on(from);
+ Square from = from_sq(m);
+ Square to = to_sq(m);
+ Piece pc = piece_moved(m);
// Use a slower but simpler function for uncommon cases
- if (is_special(m))
- return move_is_legal(m);
+ if (type_of(m) != NORMAL)
+ return MoveList<LEGAL>(*this).contains(m);
// Is not a promotion, so promotion piece must be empty
- if (promotion_piece_type(m) - 2 != PIECE_TYPE_NONE)
+ if (promotion_type(m) - 2 != NO_PIECE_TYPE)
return false;
// If the from square is not occupied by a piece belonging to the side to
// move, the move is obviously not legal.
- if (pc == PIECE_NONE || color_of(pc) != us)
+ if (pc == NO_PIECE || color_of(pc) != us)
return false;
// The destination square cannot be occupied by a friendly piece
- if (color_of(piece_on(to)) == us)
+ if (piece_on(to) != NO_PIECE && color_of(piece_on(to)) == us)
return false;
// Handle the special case of a pawn move
case DELTA_SE:
// Capture. The destination square must be occupied by an enemy
// piece (en passant captures was handled earlier).
- if (color_of(piece_on(to)) != them)
+ if (piece_on(to) == NO_PIECE || color_of(piece_on(to)) != ~us)
return false;
// From and to files must be one file apart, avoids a7h5
case DELTA_N:
case DELTA_S:
// Pawn push. The destination square must be empty.
- if (!square_is_empty(to))
+ if (!is_empty(to))
return false;
break;
// Double white pawn push. The destination square must be on the fourth
// rank, and both the destination square and the square between the
// source and destination squares must be empty.
- if ( rank_of(to) != RANK_4
- || !square_is_empty(to)
- || !square_is_empty(from + DELTA_N))
+ if ( rank_of(to) != RANK_4
+ || !is_empty(to)
+ || !is_empty(from + DELTA_N))
return false;
break;
// Double black pawn push. The destination square must be on the fifth
// rank, and both the destination square and the square between the
// source and destination squares must be empty.
- if ( rank_of(to) != RANK_5
- || !square_is_empty(to)
- || !square_is_empty(from + DELTA_S))
+ if ( rank_of(to) != RANK_5
+ || !is_empty(to)
+ || !is_empty(from + DELTA_S))
return false;
break;
return false;
}
}
- else if (!bit_is_set(attacks_from(pc, from), to))
+ else if (!(attacks_from(pc, from) & to))
return false;
// Evasions generator already takes care to avoid some kind of illegal moves
// and pl_move_is_legal() relies on this. So we have to take care that the
// same kind of moves are filtered out here.
- if (in_check())
+ if (checkers())
{
- // In case of king moves under check we have to remove king so to catch
- // as invalid moves like b1a1 when opposite queen is on c1.
- if (type_of(piece_on(from)) == KING)
- {
- Bitboard b = occupied_squares();
- clear_bit(&b, from);
- if (attackers_to(move_to(m), b) & pieces(flip(us)))
- return false;
- }
- else
+ if (type_of(pc) != KING)
{
- Bitboard target = checkers();
- Square checksq = pop_1st_bit(&target);
-
- if (target) // double check ? In this case a king move is required
+ // Double check? In this case a king move is required
+ if (more_than_one(checkers()))
return false;
// Our move must be a blocking evasion or a capture of the checking piece
- target = squares_between(checksq, king_square(us)) | checkers();
- if (!bit_is_set(target, move_to(m)))
+ if (!((between_bb(lsb(checkers()), king_square(us)) | checkers()) & to))
return false;
}
+ // In case of king moves under check we have to remove king so to catch
+ // as invalid moves like b1a1 when opposite queen is on c1.
+ else if (attackers_to(to, pieces() ^ from) & pieces(~us))
+ return false;
}
return true;
assert(is_ok(m));
assert(ci.dcCandidates == discovered_check_candidates());
- assert(color_of(piece_on(move_from(m))) == side_to_move());
+ assert(color_of(piece_moved(m)) == sideToMove);
- Square from = move_from(m);
- Square to = move_to(m);
+ Square from = from_sq(m);
+ Square to = to_sq(m);
PieceType pt = type_of(piece_on(from));
// Direct check ?
- if (bit_is_set(ci.checkSq[pt], to))
+ if (ci.checkSq[pt] & to)
return true;
// Discovery check ?
- if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
+ if (ci.dcCandidates && (ci.dcCandidates & from))
{
// For pawn and king moves we need to verify also direction
- if ( (pt != PAWN && pt != KING)
- || !squares_aligned(from, to, king_square(flip(side_to_move()))))
+ if ( (pt != PAWN && pt != KING)
+ || !squares_aligned(from, to, king_square(~sideToMove)))
return true;
}
// Can we skip the ugly special cases ?
- if (!is_special(m))
+ if (type_of(m) == NORMAL)
return false;
- Color us = side_to_move();
- Bitboard b = occupied_squares();
- Square ksq = king_square(flip(us));
+ Color us = sideToMove;
+ Square ksq = king_square(~us);
- // Promotion with check ?
- if (is_promotion(m))
+ switch (type_of(m))
{
- clear_bit(&b, from);
- return bit_is_set(attacks_from(Piece(promotion_piece_type(m)), to, b), ksq);
- }
+ case PROMOTION:
+ return attacks_from(Piece(promotion_type(m)), to, pieces() ^ from) & ksq;
// En passant capture with check ? We have already handled the case
// of direct checks and ordinary discovered check, the only case we
// need to handle is the unusual case of a discovered check through
// the captured pawn.
- if (is_enpassant(m))
+ case ENPASSANT:
{
- Square capsq = make_square(file_of(to), rank_of(from));
- clear_bit(&b, from);
- clear_bit(&b, capsq);
- set_bit(&b, to);
- return (rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, us))
- ||(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, us));
- }
+ Square capsq = file_of(to) | rank_of(from);
+ Bitboard b = (pieces() ^ from ^ capsq) | to;
- // Castling with check ?
- if (is_castle(m))
+ return (attacks_bb< ROOK>(ksq, b) & pieces(us, QUEEN, ROOK))
+ | (attacks_bb<BISHOP>(ksq, b) & pieces(us, QUEEN, BISHOP));
+ }
+ case CASTLE:
{
- Square kfrom, kto, rfrom, rto;
- kfrom = from;
- rfrom = to;
+ Square kfrom = from;
+ Square rfrom = to; // 'King captures the rook' notation
+ Square kto = relative_square(us, rfrom > kfrom ? SQ_G1 : SQ_C1);
+ Square rto = relative_square(us, rfrom > kfrom ? SQ_F1 : SQ_D1);
+ Bitboard b = (pieces() ^ kfrom ^ rfrom) | rto | kto;
- 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);
+ return attacks_bb<ROOK>(rto, b) & ksq;
+ }
+ default:
+ assert(false);
+ return false;
}
-
- return false;
}
assert(&newSt != st);
nodes++;
- Key key = st->key;
+ Key k = st->key;
// Copy some fields of old state to our new StateInfo object except the ones
- // which are recalculated from scratch anyway, then switch our state pointer
- // to point to the new, ready to be updated, state.
- struct ReducedStateInfo {
- Key pawnKey, materialKey;
- Value npMaterial[2];
- int castleRights, rule50, pliesFromNull;
- Score value;
- Square epSquare;
- };
-
- memcpy(&newSt, st, sizeof(ReducedStateInfo));
+ // which are going to be recalculated from scratch anyway, then switch our state
+ // pointer to point to the new, ready to be updated, state.
+ memcpy(&newSt, st, StateCopySize64 * sizeof(uint64_t));
newSt.previous = st;
st = &newSt;
// Update side to move
- key ^= zobSideToMove;
+ k ^= Zobrist::side;
// Increment the 50 moves rule draw counter. Resetting it to zero in the
- // case of non-reversible moves is taken care of later.
+ // case of a capture or a pawn move is taken care of later.
st->rule50++;
st->pliesFromNull++;
- if (is_castle(m))
+ if (type_of(m) == CASTLE)
{
- st->key = key;
+ st->key = k;
do_castle_move<true>(m);
return;
}
- Color us = side_to_move();
- Color them = flip(us);
- Square from = move_from(m);
- Square to = move_to(m);
+ Color us = sideToMove;
+ Color them = ~us;
+ Square from = from_sq(m);
+ Square to = to_sq(m);
Piece piece = piece_on(from);
PieceType pt = type_of(piece);
- PieceType capture = is_enpassant(m) ? PAWN : type_of(piece_on(to));
+ PieceType capture = type_of(m) == ENPASSANT ? PAWN : type_of(piece_on(to));
assert(color_of(piece) == us);
- assert(color_of(piece_on(to)) != us);
+ assert(piece_on(to) == NO_PIECE || color_of(piece_on(to)) == them);
assert(capture != KING);
if (capture)
// update non-pawn material.
if (capture == PAWN)
{
- if (is_enpassant(m))
+ if (type_of(m) == ENPASSANT)
{
capsq += pawn_push(them);
assert(pt == PAWN);
assert(to == st->epSquare);
assert(relative_rank(us, to) == RANK_6);
- assert(piece_on(to) == PIECE_NONE);
+ assert(piece_on(to) == NO_PIECE);
assert(piece_on(capsq) == make_piece(them, PAWN));
- board[capsq] = PIECE_NONE;
+ board[capsq] = NO_PIECE;
}
- st->pawnKey ^= zobrist[them][PAWN][capsq];
+ st->pawnKey ^= Zobrist::psq[them][PAWN][capsq];
}
else
- st->npMaterial[them] -= PieceValueMidgame[capture];
+ st->npMaterial[them] -= PieceValue[MG][capture];
// Remove the captured piece
- clear_bit(&byColorBB[them], capsq);
- clear_bit(&byTypeBB[capture], capsq);
- clear_bit(&occupied, capsq);
+ byTypeBB[ALL_PIECES] ^= capsq;
+ byTypeBB[capture] ^= capsq;
+ byColorBB[them] ^= capsq;
// Update piece list, move the last piece at index[capsq] position and
// shrink the list.
pieceList[them][capture][pieceCount[them][capture]] = SQ_NONE;
// Update hash keys
- key ^= zobrist[them][capture][capsq];
- st->materialKey ^= zobrist[them][capture][pieceCount[them][capture]];
+ k ^= Zobrist::psq[them][capture][capsq];
+ st->materialKey ^= Zobrist::psq[them][capture][pieceCount[them][capture]];
// Update incremental scores
- st->value -= pst(make_piece(them, capture), capsq);
+ st->psqScore -= pieceSquareTable[make_piece(them, capture)][capsq];
// Reset rule 50 counter
st->rule50 = 0;
}
// Update hash key
- key ^= zobrist[us][pt][from] ^ zobrist[us][pt][to];
+ k ^= Zobrist::psq[us][pt][from] ^ Zobrist::psq[us][pt][to];
// Reset en passant square
if (st->epSquare != SQ_NONE)
{
- key ^= zobEp[st->epSquare];
+ k ^= Zobrist::enpassant[file_of(st->epSquare)];
st->epSquare = SQ_NONE;
}
// Update castle rights if needed
- if ( st->castleRights != CASTLES_NONE
- && (castleRightsMask[from] & castleRightsMask[to]) != ALL_CASTLES)
+ if (st->castleRights && (castleRightsMask[from] | castleRightsMask[to]))
{
- key ^= zobCastle[st->castleRights];
- st->castleRights &= castleRightsMask[from] & castleRightsMask[to];
- key ^= zobCastle[st->castleRights];
+ int cr = castleRightsMask[from] | castleRightsMask[to];
+ k ^= Zobrist::castle[st->castleRights & cr];
+ st->castleRights &= ~cr;
}
// Prefetch TT access as soon as we know key is updated
- prefetch((char*)TT.first_entry(key));
+ prefetch((char*)TT.first_entry(k));
// Move the piece
- Bitboard move_bb = make_move_bb(from, to);
- do_move_bb(&byColorBB[us], move_bb);
- do_move_bb(&byTypeBB[pt], move_bb);
- do_move_bb(&occupied, move_bb);
+ Bitboard from_to_bb = SquareBB[from] ^ SquareBB[to];
+ byTypeBB[ALL_PIECES] ^= from_to_bb;
+ byTypeBB[pt] ^= from_to_bb;
+ byColorBB[us] ^= from_to_bb;
board[to] = board[from];
- board[from] = PIECE_NONE;
+ board[from] = NO_PIECE;
// Update piece lists, index[from] is not updated and becomes stale. This
// works as long as index[] is accessed just by known occupied squares.
if (pt == PAWN)
{
// Set en-passant square, only if moved pawn can be captured
- if ( (to ^ from) == 16
- && (attacks_from<PAWN>(from + pawn_push(us), us) & pieces(PAWN, them)))
+ if ( (int(to) ^ int(from)) == 16
+ && (attacks_from<PAWN>(from + pawn_push(us), us) & pieces(them, PAWN)))
{
st->epSquare = Square((from + to) / 2);
- key ^= zobEp[st->epSquare];
+ k ^= Zobrist::enpassant[file_of(st->epSquare)];
}
- if (is_promotion(m))
+ if (type_of(m) == PROMOTION)
{
- PieceType promotion = promotion_piece_type(m);
+ PieceType promotion = promotion_type(m);
assert(relative_rank(us, to) == RANK_8);
assert(promotion >= KNIGHT && promotion <= QUEEN);
// Replace the pawn with the promoted piece
- clear_bit(&byTypeBB[PAWN], to);
- set_bit(&byTypeBB[promotion], to);
+ byTypeBB[PAWN] ^= to;
+ byTypeBB[promotion] |= to;
board[to] = make_piece(us, promotion);
// Update piece lists, move the last pawn at index[to] position
pieceList[us][promotion][index[to]] = to;
// Update hash keys
- key ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to];
- st->pawnKey ^= zobrist[us][PAWN][to];
- st->materialKey ^= zobrist[us][promotion][pieceCount[us][promotion]++]
- ^ zobrist[us][PAWN][pieceCount[us][PAWN]];
+ k ^= Zobrist::psq[us][PAWN][to] ^ Zobrist::psq[us][promotion][to];
+ st->pawnKey ^= Zobrist::psq[us][PAWN][to];
+ st->materialKey ^= Zobrist::psq[us][promotion][pieceCount[us][promotion]++]
+ ^ Zobrist::psq[us][PAWN][pieceCount[us][PAWN]];
// Update incremental score
- st->value += pst(make_piece(us, promotion), to)
- - pst(make_piece(us, PAWN), to);
+ st->psqScore += pieceSquareTable[make_piece(us, promotion)][to]
+ - pieceSquareTable[make_piece(us, PAWN)][to];
// Update material
- st->npMaterial[us] += PieceValueMidgame[promotion];
+ st->npMaterial[us] += PieceValue[MG][promotion];
}
// Update pawn hash key
- st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
+ st->pawnKey ^= Zobrist::psq[us][PAWN][from] ^ Zobrist::psq[us][PAWN][to];
// Reset rule 50 draw counter
st->rule50 = 0;
}
// Prefetch pawn and material hash tables
- Threads[threadID].pawnTable.prefetch(st->pawnKey);
- Threads[threadID].materialTable.prefetch(st->materialKey);
+ prefetch((char*)thisThread->pawnsTable[st->pawnKey]);
+ prefetch((char*)thisThread->materialTable[st->materialKey]);
// Update incremental scores
- st->value += pst_delta(piece, from, to);
+ st->psqScore += psq_delta(piece, from, to);
// Set capture piece
st->capturedType = capture;
// Update the key with the final value
- st->key = key;
+ st->key = k;
// Update checkers bitboard, piece must be already moved
st->checkersBB = 0;
if (moveIsCheck)
{
- if (is_special(m))
+ if (type_of(m) != NORMAL)
st->checkersBB = attackers_to(king_square(them)) & pieces(us);
else
{
// Direct checks
- if (bit_is_set(ci.checkSq[pt], to))
- st->checkersBB = SetMaskBB[to];
+ if (ci.checkSq[pt] & to)
+ st->checkersBB |= to;
// Discovery checks
- if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
+ if (ci.dcCandidates && (ci.dcCandidates & from))
{
if (pt != ROOK)
- st->checkersBB |= attacks_from<ROOK>(king_square(them)) & pieces(ROOK, QUEEN, us);
+ st->checkersBB |= attacks_from<ROOK>(king_square(them)) & pieces(us, QUEEN, ROOK);
if (pt != BISHOP)
- st->checkersBB |= attacks_from<BISHOP>(king_square(them)) & pieces(BISHOP, QUEEN, us);
+ st->checkersBB |= attacks_from<BISHOP>(king_square(them)) & pieces(us, QUEEN, BISHOP);
}
}
}
- // Finish
- sideToMove = flip(sideToMove);
- st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
+ sideToMove = ~sideToMove;
assert(pos_is_ok());
}
assert(is_ok(m));
- sideToMove = flip(sideToMove);
+ sideToMove = ~sideToMove;
- if (is_castle(m))
+ if (type_of(m) == CASTLE)
{
do_castle_move<false>(m);
return;
}
- Color us = side_to_move();
- Color them = flip(us);
- Square from = move_from(m);
- Square to = move_to(m);
+ Color us = sideToMove;
+ Color them = ~us;
+ Square from = from_sq(m);
+ Square to = to_sq(m);
Piece piece = piece_on(to);
PieceType pt = type_of(piece);
PieceType capture = st->capturedType;
- assert(square_is_empty(from));
+ assert(is_empty(from));
assert(color_of(piece) == us);
assert(capture != KING);
- if (is_promotion(m))
+ if (type_of(m) == PROMOTION)
{
- PieceType promotion = promotion_piece_type(m);
+ PieceType promotion = promotion_type(m);
assert(promotion == pt);
assert(relative_rank(us, to) == RANK_8);
assert(promotion >= KNIGHT && promotion <= QUEEN);
// Replace the promoted piece with the pawn
- clear_bit(&byTypeBB[promotion], to);
- set_bit(&byTypeBB[PAWN], to);
+ byTypeBB[promotion] ^= to;
+ byTypeBB[PAWN] |= to;
board[to] = make_piece(us, PAWN);
// Update piece lists, move the last promoted piece at index[to] position
}
// Put the piece back at the source square
- Bitboard move_bb = make_move_bb(to, from);
- do_move_bb(&byColorBB[us], move_bb);
- do_move_bb(&byTypeBB[pt], move_bb);
- do_move_bb(&occupied, move_bb);
+ Bitboard from_to_bb = SquareBB[from] ^ SquareBB[to];
+ byTypeBB[ALL_PIECES] ^= from_to_bb;
+ byTypeBB[pt] ^= from_to_bb;
+ byColorBB[us] ^= from_to_bb;
board[from] = board[to];
- board[to] = PIECE_NONE;
+ board[to] = NO_PIECE;
// Update piece lists, index[to] is not updated and becomes stale. This
// works as long as index[] is accessed just by known occupied squares.
{
Square capsq = to;
- if (is_enpassant(m))
+ if (type_of(m) == ENPASSANT)
{
capsq -= pawn_push(us);
assert(pt == PAWN);
assert(to == st->previous->epSquare);
assert(relative_rank(us, to) == RANK_6);
- assert(piece_on(capsq) == PIECE_NONE);
+ assert(piece_on(capsq) == NO_PIECE);
}
// Restore the captured piece
- set_bit(&byColorBB[them], capsq);
- set_bit(&byTypeBB[capture], capsq);
- set_bit(&occupied, capsq);
+ byTypeBB[ALL_PIECES] |= capsq;
+ byTypeBB[capture] |= capsq;
+ byColorBB[them] |= capsq;
board[capsq] = make_piece(them, capture);
void Position::do_castle_move(Move m) {
assert(is_ok(m));
- assert(is_castle(m));
+ assert(type_of(m) == CASTLE);
Square kto, kfrom, rfrom, rto, kAfter, rAfter;
- Color us = side_to_move();
- Square kBefore = move_from(m);
- Square rBefore = move_to(m);
+ Color us = sideToMove;
+ Square kBefore = from_sq(m);
+ Square rBefore = to_sq(m);
// Find after-castle squares for king and rook
if (rBefore > kBefore) // O-O
assert(piece_on(kfrom) == make_piece(us, KING));
assert(piece_on(rfrom) == make_piece(us, ROOK));
- // Remove pieces from source squares
- clear_bit(&byColorBB[us], kfrom);
- clear_bit(&byTypeBB[KING], kfrom);
- clear_bit(&occupied, kfrom);
- clear_bit(&byColorBB[us], rfrom);
- clear_bit(&byTypeBB[ROOK], rfrom);
- clear_bit(&occupied, rfrom);
-
- // Put pieces on destination squares
- set_bit(&byColorBB[us], kto);
- set_bit(&byTypeBB[KING], kto);
- set_bit(&occupied, kto);
- set_bit(&byColorBB[us], rto);
- set_bit(&byTypeBB[ROOK], rto);
- set_bit(&occupied, rto);
+ // Move the pieces, with some care; in chess960 could be kto == rfrom
+ Bitboard k_from_to_bb = SquareBB[kfrom] ^ SquareBB[kto];
+ Bitboard r_from_to_bb = SquareBB[rfrom] ^ SquareBB[rto];
+ byTypeBB[KING] ^= k_from_to_bb;
+ byTypeBB[ROOK] ^= r_from_to_bb;
+ byTypeBB[ALL_PIECES] ^= k_from_to_bb ^ r_from_to_bb;
+ byColorBB[us] ^= k_from_to_bb ^ r_from_to_bb;
// Update board
Piece king = make_piece(us, KING);
Piece rook = make_piece(us, ROOK);
- board[kfrom] = board[rfrom] = PIECE_NONE;
+ board[kfrom] = board[rfrom] = NO_PIECE;
board[kto] = king;
board[rto] = rook;
if (Do)
{
// Reset capture field
- st->capturedType = PIECE_TYPE_NONE;
+ st->capturedType = NO_PIECE_TYPE;
// Update incremental scores
- st->value += pst_delta(king, kfrom, kto);
- st->value += pst_delta(rook, rfrom, rto);
+ st->psqScore += psq_delta(king, kfrom, kto);
+ st->psqScore += psq_delta(rook, rfrom, rto);
// Update hash key
- st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto];
- st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto];
+ st->key ^= Zobrist::psq[us][KING][kfrom] ^ Zobrist::psq[us][KING][kto];
+ st->key ^= Zobrist::psq[us][ROOK][rfrom] ^ Zobrist::psq[us][ROOK][rto];
// Clear en passant square
if (st->epSquare != SQ_NONE)
{
- st->key ^= zobEp[st->epSquare];
+ st->key ^= Zobrist::enpassant[file_of(st->epSquare)];
st->epSquare = SQ_NONE;
}
// Update castling rights
- st->key ^= zobCastle[st->castleRights];
- st->castleRights &= castleRightsMask[kfrom];
- st->key ^= zobCastle[st->castleRights];
-
- // Reset rule 50 counter
- st->rule50 = 0;
+ st->key ^= Zobrist::castle[st->castleRights & castleRightsMask[kfrom]];
+ st->castleRights &= ~castleRightsMask[kfrom];
// Update checkers BB
- st->checkersBB = attackers_to(king_square(flip(us))) & pieces(us);
+ st->checkersBB = attackers_to(king_square(~us)) & pieces(us);
- // Finish
- sideToMove = flip(sideToMove);
- st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
+ sideToMove = ~sideToMove;
}
else
// Undo: point our state pointer back to the previous state
template<bool Do>
void Position::do_null_move(StateInfo& backupSt) {
- assert(!in_check());
+ assert(!checkers());
// Back up the information necessary to undo the null move to the supplied
// StateInfo object. Note that differently from normal case here backupSt
dst->key = src->key;
dst->epSquare = src->epSquare;
- dst->value = src->value;
+ dst->psqScore = src->psqScore;
dst->rule50 = src->rule50;
dst->pliesFromNull = src->pliesFromNull;
- sideToMove = flip(sideToMove);
+ sideToMove = ~sideToMove;
if (Do)
{
if (st->epSquare != SQ_NONE)
- st->key ^= zobEp[st->epSquare];
+ st->key ^= Zobrist::enpassant[file_of(st->epSquare)];
- st->key ^= zobSideToMove;
+ st->key ^= Zobrist::side;
prefetch((char*)TT.first_entry(st->key));
st->epSquare = SQ_NONE;
st->rule50++;
st->pliesFromNull = 0;
- st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue;
}
assert(pos_is_ok());
assert(is_ok(m));
- Square from = move_from(m);
- Square to = move_to(m);
-
// Early return if SEE cannot be negative because captured piece value
// is not less then capturing one. Note that king moves always return
// here because king midgame value is set to 0.
- if (PieceValueMidgame[piece_on(to)] >= PieceValueMidgame[piece_on(from)])
+ if (PieceValue[MG][piece_on(to_sq(m))] >= PieceValue[MG][piece_moved(m)])
return 1;
return see(m);
int Position::see(Move m) const {
Square from, to;
- Bitboard occ, attackers, stmAttackers, b;
+ Bitboard occupied, attackers, stmAttackers;
int swapList[32], slIndex = 1;
- PieceType capturedType, pt;
+ PieceType captured;
Color stm;
assert(is_ok(m));
- // As castle moves are implemented as capturing the rook, they have
- // SEE == RookValueMidgame most of the times (unless the rook is under
- // attack).
- if (is_castle(m))
- return 0;
-
- from = move_from(m);
- to = move_to(m);
- capturedType = type_of(piece_on(to));
- occ = occupied_squares();
+ from = from_sq(m);
+ to = to_sq(m);
+ captured = type_of(piece_on(to));
+ occupied = pieces() ^ from;
// Handle en passant moves
- if (is_enpassant(m))
+ if (type_of(m) == ENPASSANT)
{
- Square capQq = to - pawn_push(side_to_move());
+ Square capQq = to - pawn_push(sideToMove);
- assert(capturedType == PIECE_TYPE_NONE);
+ assert(!captured);
assert(type_of(piece_on(capQq)) == PAWN);
// Remove the captured pawn
- clear_bit(&occ, capQq);
- capturedType = PAWN;
+ occupied ^= capQq;
+ captured = PAWN;
}
+ else if (type_of(m) == CASTLE)
+ // Castle moves are implemented as king capturing the rook so cannot be
+ // handled correctly. Simply return 0 that is always the correct value
+ // unless the rook is ends up under attack.
+ return 0;
// 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 = attackers_to(to, occ);
+ attackers = attackers_to(to, occupied);
// If the opponent has no attackers we are finished
- stm = flip(color_of(piece_on(from)));
+ stm = ~color_of(piece_on(from));
stmAttackers = attackers & pieces(stm);
if (!stmAttackers)
- return PieceValueMidgame[capturedType];
+ return PieceValue[MG][captured];
// The destination square is defended, which makes things rather more
// difficult to compute. We proceed by building up a "swap list" containing
// destination square, where the sides alternately capture, and always
// capture with the least valuable piece. After each capture, we look for
// new X-ray attacks from behind the capturing piece.
- swapList[0] = PieceValueMidgame[capturedType];
- capturedType = type_of(piece_on(from));
+ swapList[0] = PieceValue[MG][captured];
+ captured = type_of(piece_on(from));
do {
- // Locate the least valuable attacker for the side to move. The loop
- // below looks like it is potentially infinite, but it isn't. We know
- // that the side to move still has at least one attacker left.
- for (pt = PAWN; !(stmAttackers & pieces(pt)); pt++)
- assert(pt < KING);
-
- // Remove the attacker we just found from the 'occupied' bitboard,
- // 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))
- | (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN));
-
- attackers &= occ; // Cut out pieces we've already done
+ assert(slIndex < 32);
// Add the new entry to the swap list
- assert(slIndex < 32);
- swapList[slIndex] = -swapList[slIndex - 1] + PieceValueMidgame[capturedType];
+ swapList[slIndex] = -swapList[slIndex - 1] + PieceValue[MG][captured];
slIndex++;
- // Remember the value of the capturing piece, and change the side to
- // move before beginning the next iteration.
- capturedType = pt;
- stm = flip(stm);
+ // Locate and remove from 'occupied' the next least valuable attacker
+ captured = next_attacker<PAWN>(byTypeBB, to, stmAttackers, occupied, attackers);
+
+ attackers &= occupied; // Remove the just found attacker
+ stm = ~stm;
stmAttackers = attackers & pieces(stm);
- // Stop before processing a king capture
- if (capturedType == KING && stmAttackers)
+ if (captured == KING)
{
- assert(slIndex < 32);
- swapList[slIndex++] = QueenValueMidgame*10;
+ // Stop before processing a king capture
+ if (stmAttackers)
+ swapList[slIndex++] = QueenValueMg * 16;
+
break;
}
+
} while (stmAttackers);
// Having built the swap list, we negamax through it to find the best
void Position::clear() {
+ memset(this, 0, sizeof(Position));
+ startState.epSquare = SQ_NONE;
st = &startState;
- memset(st, 0, sizeof(StateInfo));
- st->epSquare = SQ_NONE;
-
- memset(byColorBB, 0, sizeof(Bitboard) * 2);
- memset(byTypeBB, 0, sizeof(Bitboard) * 8);
- memset(pieceCount, 0, sizeof(int) * 2 * 8);
- memset(index, 0, sizeof(int) * 64);
for (int i = 0; i < 8; i++)
for (int j = 0; j < 16; j++)
pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
-
- for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
- {
- board[sq] = PIECE_NONE;
- castleRightsMask[sq] = ALL_CASTLES;
- }
- sideToMove = WHITE;
- nodes = 0;
- occupied = 0;
}
index[s] = pieceCount[c][pt]++;
pieceList[c][pt][index[s]] = s;
- set_bit(&byTypeBB[pt], s);
- set_bit(&byColorBB[c], s);
- set_bit(&occupied, s);
+ byTypeBB[ALL_PIECES] |= s;
+ byTypeBB[pt] |= s;
+ byColorBB[c] |= s;
}
Key Position::compute_key() const {
- Key result = zobCastle[st->castleRights];
+ Key k = Zobrist::castle[st->castleRights];
- for (Square s = SQ_A1; s <= SQ_H8; s++)
- if (!square_is_empty(s))
- result ^= zobrist[color_of(piece_on(s))][type_of(piece_on(s))][s];
+ for (Bitboard b = pieces(); b; )
+ {
+ Square s = pop_lsb(&b);
+ k ^= Zobrist::psq[color_of(piece_on(s))][type_of(piece_on(s))][s];
+ }
if (ep_square() != SQ_NONE)
- result ^= zobEp[ep_square()];
+ k ^= Zobrist::enpassant[file_of(ep_square())];
- if (side_to_move() == BLACK)
- result ^= zobSideToMove;
+ if (sideToMove == BLACK)
+ k ^= Zobrist::side;
- return result;
+ return k;
}
Key Position::compute_pawn_key() const {
- Bitboard b;
- Key result = 0;
+ Key k = 0;
- for (Color c = WHITE; c <= BLACK; c++)
+ for (Bitboard b = pieces(PAWN); b; )
{
- b = pieces(PAWN, c);
- while (b)
- result ^= zobrist[c][PAWN][pop_1st_bit(&b)];
+ Square s = pop_lsb(&b);
+ k ^= Zobrist::psq[color_of(piece_on(s))][PAWN][s];
}
- return result;
+
+ return k;
}
Key Position::compute_material_key() const {
- Key result = 0;
+ Key k = 0;
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= QUEEN; pt++)
- for (int i = 0; i < piece_count(c, pt); i++)
- result ^= zobrist[c][pt][i];
+ for (int cnt = 0; cnt < piece_count(c, pt); cnt++)
+ k ^= Zobrist::psq[c][pt][cnt];
- return result;
+ return k;
}
-/// Position::compute_value() compute the incremental scores for the middle
+/// Position::compute_psq_score() computes the incremental scores for the middle
/// 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.
-Score Position::compute_value() const {
+Score Position::compute_psq_score() const {
- Bitboard b;
- Score result = SCORE_ZERO;
+ Score score = SCORE_ZERO;
- for (Color c = WHITE; c <= BLACK; c++)
- for (PieceType pt = PAWN; pt <= KING; pt++)
- {
- b = pieces(pt, c);
- while (b)
- result += pst(make_piece(c, pt), pop_1st_bit(&b));
- }
+ for (Bitboard b = pieces(); b; )
+ {
+ Square s = pop_lsb(&b);
+ score += pieceSquareTable[piece_on(s)][s];
+ }
- result += (side_to_move() == WHITE ? TempoValue / 2 : -TempoValue / 2);
- return result;
+ return score;
}
Value Position::compute_non_pawn_material(Color c) const {
- Value result = VALUE_ZERO;
+ Value value = VALUE_ZERO;
for (PieceType pt = KNIGHT; pt <= QUEEN; pt++)
- result += piece_count(c, pt) * PieceValueMidgame[pt];
+ value += piece_count(c, pt) * PieceValue[MG][pt];
- return result;
+ return value;
}
/// Position::is_draw() tests whether the position is drawn by material,
/// repetition, or the 50 moves rule. It does not detect stalemates, this
/// must be done by the search.
-template<bool SkipRepetition>
+template<bool CheckRepetition, bool CheckThreeFold>
bool Position::is_draw() const {
- // Draw by material?
if ( !pieces(PAWN)
- && (non_pawn_material(WHITE) + non_pawn_material(BLACK) <= BishopValueMidgame))
+ && (non_pawn_material(WHITE) + non_pawn_material(BLACK) <= BishopValueMg))
return true;
- // Draw by the 50 moves rule?
- if (st->rule50 > 99 && !is_mate())
+ if (st->rule50 > 99 && (!checkers() || MoveList<LEGAL>(*this).size()))
return true;
- // Draw by repetition?
- if (!SkipRepetition)
+ if (CheckRepetition)
{
- int i = 4, e = std::min(st->rule50, st->pliesFromNull);
+ int i = 4, e = std::min(st->rule50, st->pliesFromNull), cnt;
if (i <= e)
{
StateInfo* stp = st->previous->previous;
- do {
+ for (cnt = 0; i <= e; i += 2)
+ {
stp = stp->previous->previous;
- if (stp->key == st->key)
+ if (stp->key == st->key && (!CheckThreeFold || ++cnt >= 2))
return true;
-
- i +=2;
-
- } while (i <= e);
+ }
}
}
}
// Explicit template instantiations
-template bool Position::is_draw<false>() const;
-template bool Position::is_draw<true>() const;
-
-
-/// Position::is_mate() returns true or false depending on whether the
-/// side to move is checkmated.
+template bool Position::is_draw<true, true>() const;
+template bool Position::is_draw<true, false>() const;
+template bool Position::is_draw<false,false>() const;
-bool Position::is_mate() const {
- return in_check() && !MoveList<MV_LEGAL>(*this).size();
-}
-
-
-/// Position::init() is a static member function which initializes at startup
-/// the various arrays used to compute hash keys and the piece square tables.
-/// The latter is a two-step operation: First, the white halves of the tables
-/// are copied from PSQT[] tables. Second, the black halves of the tables are
-/// initialized by flipping and changing the sign of the white scores.
-
-void Position::init() {
-
- RKISS rk;
-
- for (Color c = WHITE; c <= BLACK; c++)
- for (PieceType pt = PAWN; pt <= KING; pt++)
- for (Square s = SQ_A1; s <= SQ_H8; s++)
- zobrist[c][pt][s] = rk.rand<Key>();
-
- for (Square s = SQ_A1; s <= SQ_H8; s++)
- zobEp[s] = rk.rand<Key>();
-
- for (int i = 0; i < 16; i++)
- zobCastle[i] = rk.rand<Key>();
-
- zobSideToMove = rk.rand<Key>();
- zobExclusion = rk.rand<Key>();
-
- for (Piece p = WP; p <= WK; p++)
- {
- Score ps = make_score(PieceValueMidgame[p], PieceValueEndgame[p]);
-
- for (Square s = SQ_A1; s <= SQ_H8; s++)
- {
- pieceSquareTable[p][s] = ps + PSQT[p][s];
- pieceSquareTable[p+8][flip(s)] = -pieceSquareTable[p][s];
- }
- }
-}
-
-
-/// Position::flip_me() flips position with the white and black sides reversed. This
+/// Position::flip() flips position with the white and black sides reversed. This
/// is only useful for debugging especially for finding evaluation symmetry bugs.
-void Position::flip_me() {
+void Position::flip() {
- // Make a copy of current position before to start changing
- const Position pos(*this, threadID);
+ const Position pos(*this);
clear();
- threadID = pos.thread();
- // Board
- for (Square s = SQ_A1; s <= SQ_H8; s++)
- if (!pos.square_is_empty(s))
- put_piece(Piece(pos.piece_on(s) ^ 8), flip(s));
+ sideToMove = ~pos.side_to_move();
+ thisThread = pos.this_thread();
+ nodes = pos.nodes_searched();
+ chess960 = pos.is_chess960();
+ startPosPly = pos.startpos_ply_counter();
- // Side to move
- sideToMove = flip(pos.side_to_move());
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ if (!pos.is_empty(s))
+ put_piece(Piece(pos.piece_on(s) ^ 8), ~s);
- // Castling rights
if (pos.can_castle(WHITE_OO))
- set_castle_right(king_square(BLACK), flip(pos.castle_rook_square(WHITE_OO)));
+ set_castle_right(BLACK, ~pos.castle_rook_square(WHITE, KING_SIDE));
if (pos.can_castle(WHITE_OOO))
- set_castle_right(king_square(BLACK), flip(pos.castle_rook_square(WHITE_OOO)));
+ set_castle_right(BLACK, ~pos.castle_rook_square(WHITE, QUEEN_SIDE));
if (pos.can_castle(BLACK_OO))
- set_castle_right(king_square(WHITE), flip(pos.castle_rook_square(BLACK_OO)));
+ set_castle_right(WHITE, ~pos.castle_rook_square(BLACK, KING_SIDE));
if (pos.can_castle(BLACK_OOO))
- set_castle_right(king_square(WHITE), flip(pos.castle_rook_square(BLACK_OOO)));
+ set_castle_right(WHITE, ~pos.castle_rook_square(BLACK, QUEEN_SIDE));
- // En passant square
if (pos.st->epSquare != SQ_NONE)
- st->epSquare = flip(pos.st->epSquare);
+ st->epSquare = ~pos.st->epSquare;
- // Checkers
- st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(flip(sideToMove));
+ st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove);
- // Hash keys
st->key = compute_key();
st->pawnKey = compute_pawn_key();
st->materialKey = compute_material_key();
-
- // Incremental scores
- st->value = compute_value();
-
- // Material
+ st->psqScore = compute_psq_score();
st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
bool Position::pos_is_ok(int* failedStep) const {
+ int dummy, *step = failedStep ? failedStep : &dummy;
+
// What features of the position should be verified?
- const bool debugAll = false;
-
- const bool debugBitboards = debugAll || false;
- const bool debugKingCount = debugAll || false;
- const bool debugKingCapture = debugAll || false;
- const bool debugCheckerCount = debugAll || false;
- const bool debugKey = debugAll || false;
- const bool debugMaterialKey = debugAll || false;
- const bool debugPawnKey = debugAll || false;
- const bool debugIncrementalEval = debugAll || false;
- const bool debugNonPawnMaterial = debugAll || false;
- const bool debugPieceCounts = debugAll || false;
- const bool debugPieceList = debugAll || false;
- const bool debugCastleSquares = debugAll || false;
-
- if (failedStep) *failedStep = 1;
-
- // Side to move OK?
- if (side_to_move() != WHITE && side_to_move() != BLACK)
+ const bool all = false;
+
+ const bool debugBitboards = all || false;
+ const bool debugKingCount = all || false;
+ const bool debugKingCapture = all || false;
+ const bool debugCheckerCount = all || false;
+ const bool debugKey = all || false;
+ const bool debugMaterialKey = all || false;
+ const bool debugPawnKey = all || false;
+ const bool debugIncrementalEval = all || false;
+ const bool debugNonPawnMaterial = all || false;
+ const bool debugPieceCounts = all || false;
+ const bool debugPieceList = all || false;
+ const bool debugCastleSquares = all || false;
+
+ *step = 1;
+
+ if (sideToMove != WHITE && sideToMove != BLACK)
return false;
- // Are the king squares in the position correct?
- if (failedStep) (*failedStep)++;
- if (piece_on(king_square(WHITE)) != WK)
+ if ((*step)++, piece_on(king_square(WHITE)) != W_KING)
return false;
- if (failedStep) (*failedStep)++;
- if (piece_on(king_square(BLACK)) != BK)
+ if ((*step)++, piece_on(king_square(BLACK)) != B_KING)
return false;
- // Do both sides have exactly one king?
- if (failedStep) (*failedStep)++;
- if (debugKingCount)
+ if ((*step)++, debugKingCount)
{
- int kingCount[2] = {0, 0};
+ int kingCount[COLOR_NB] = {};
+
for (Square s = SQ_A1; s <= SQ_H8; s++)
if (type_of(piece_on(s)) == KING)
kingCount[color_of(piece_on(s))]++;
return false;
}
- // Can the side to move capture the opponent's king?
- if (failedStep) (*failedStep)++;
- if (debugKingCapture)
- {
- Color us = side_to_move();
- Color them = flip(us);
- Square ksq = king_square(them);
- if (attackers_to(ksq) & pieces(us))
+ if ((*step)++, debugKingCapture)
+ if (attackers_to(king_square(~sideToMove)) & pieces(sideToMove))
return false;
- }
- // Is there more than 2 checkers?
- if (failedStep) (*failedStep)++;
- if (debugCheckerCount && count_1s<CNT32>(st->checkersBB) > 2)
+ if ((*step)++, debugCheckerCount && popcount<Full>(st->checkersBB) > 2)
return false;
- // Bitboards OK?
- if (failedStep) (*failedStep)++;
- if (debugBitboards)
+ if ((*step)++, debugBitboards)
{
// The intersection of the white and black pieces must be empty
- if (!(pieces(WHITE) & pieces(BLACK)))
+ if (pieces(WHITE) & pieces(BLACK))
return false;
// The union of the white and black pieces must be equal to all
// occupied squares
- if ((pieces(WHITE) | pieces(BLACK)) != occupied_squares())
+ if ((pieces(WHITE) | pieces(BLACK)) != pieces())
return false;
// Separate piece type bitboards must have empty intersections
return false;
}
- // En passant square OK?
- if (failedStep) (*failedStep)++;
- if (ep_square() != SQ_NONE)
- {
- // The en passant square must be on rank 6, from the point of view of the
- // side to move.
- if (relative_rank(side_to_move(), ep_square()) != RANK_6)
- return false;
- }
+ if ((*step)++, ep_square() != SQ_NONE && relative_rank(sideToMove, ep_square()) != RANK_6)
+ return false;
- // Hash key OK?
- if (failedStep) (*failedStep)++;
- if (debugKey && st->key != compute_key())
+ if ((*step)++, debugKey && st->key != compute_key())
return false;
- // Pawn hash key OK?
- if (failedStep) (*failedStep)++;
- if (debugPawnKey && st->pawnKey != compute_pawn_key())
+ if ((*step)++, debugPawnKey && st->pawnKey != compute_pawn_key())
return false;
- // Material hash key OK?
- if (failedStep) (*failedStep)++;
- if (debugMaterialKey && st->materialKey != compute_material_key())
+ if ((*step)++, debugMaterialKey && st->materialKey != compute_material_key())
return false;
- // Incremental eval OK?
- if (failedStep) (*failedStep)++;
- if (debugIncrementalEval && st->value != compute_value())
+ if ((*step)++, debugIncrementalEval && st->psqScore != compute_psq_score())
return false;
- // Non-pawn material OK?
- if (failedStep) (*failedStep)++;
- if (debugNonPawnMaterial)
+ if ((*step)++, debugNonPawnMaterial)
{
- if (st->npMaterial[WHITE] != compute_non_pawn_material(WHITE))
- return false;
-
- if (st->npMaterial[BLACK] != compute_non_pawn_material(BLACK))
+ if ( st->npMaterial[WHITE] != compute_non_pawn_material(WHITE)
+ || st->npMaterial[BLACK] != compute_non_pawn_material(BLACK))
return false;
}
- // Piece counts OK?
- if (failedStep) (*failedStep)++;
- if (debugPieceCounts)
+ if ((*step)++, debugPieceCounts)
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= KING; pt++)
- if (pieceCount[c][pt] != count_1s<CNT32>(pieces(pt, c)))
+ if (pieceCount[c][pt] != popcount<Full>(pieces(c, pt)))
return false;
- if (failedStep) (*failedStep)++;
- if (debugPieceList)
+ if ((*step)++, debugPieceList)
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= KING; pt++)
for (int i = 0; i < pieceCount[c][pt]; i++)
return false;
}
- if (failedStep) (*failedStep)++;
- if (debugCastleSquares)
- for (CastleRight f = WHITE_OO; f <= BLACK_OOO; f = CastleRight(f << 1))
- {
- if (!can_castle(f))
- continue;
+ if ((*step)++, debugCastleSquares)
+ for (Color c = WHITE; c <= BLACK; c++)
+ for (CastlingSide s = KING_SIDE; s <= QUEEN_SIDE; s = CastlingSide(s + 1))
+ {
+ CastleRight cr = make_castle_right(c, s);
- Piece rook = (f & (WHITE_OO | WHITE_OOO) ? WR : BR);
+ if (!can_castle(cr))
+ continue;
- if ( castleRightsMask[castleRookSquare[f]] != (ALL_CASTLES ^ f)
- || piece_on(castleRookSquare[f]) != rook)
- return false;
- }
+ if ((castleRightsMask[king_square(c)] & cr) != cr)
+ return false;
+
+ if ( piece_on(castleRookSquare[c][s]) != make_piece(c, ROOK)
+ || castleRightsMask[castleRookSquare[c][s]] != cr)
+ return false;
+ }
- if (failedStep) *failedStep = 0;
+ *step = 0;
return true;
}
projects / stockfish / blobdiff