/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008 Marco Costalba
+ Copyright (C) 2008-2009 Marco Costalba
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 <fstream>
#include <iostream>
+#include "bitcount.h"
#include "mersenne.h"
#include "movegen.h"
#include "movepick.h"
#include "position.h"
#include "psqtab.h"
#include "san.h"
+#include "tt.h"
#include "ucioption.h"
+using std::string;
+
////
//// Variables
////
-extern SearchStack EmptySearchStack;
-
int Position::castleRightsMask[64];
Key Position::zobrist[2][8][64];
copy(pos);
}
-Position::Position(const std::string& fen) {
+Position::Position(const string& fen) {
from_fen(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 std::string& fen) {
+void Position::from_fen(const string& fen) {
- static const std::string pieceLetters = "KQRBNPkqrbnp";
+ static const string pieceLetters = "KQRBNPkqrbnp";
static const Piece pieces[] = { WK, WQ, WR, WB, WN, WP, BK, BQ, BR, BB, BN, BP };
clear();
continue;
}
size_t idx = pieceLetters.find(fen[i]);
- if (idx == std::string::npos)
+ if (idx == string::npos)
{
std::cout << "Error in FEN at character " << i << std::endl;
return;
i++;
// En passant square
- if ( i < fen.length() - 2
+ if ( i <= fen.length() - 2
&& (fen[i] >= 'a' && fen[i] <= 'h')
&& (fen[i+1] == '3' || fen[i+1] == '6'))
st->epSquare = square_from_string(fen.substr(i, 2));
st->materialKey = compute_material_key();
st->mgValue = compute_value<MidGame>();
st->egValue = compute_value<EndGame>();
- npMaterial[WHITE] = compute_non_pawn_material(WHITE);
- npMaterial[BLACK] = compute_non_pawn_material(BLACK);
+ st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
+ st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
}
/// Position::to_fen() converts the position object to a FEN string. This is
/// probably only useful for debugging.
-const std::string Position::to_fen() const {
+const string Position::to_fen() const {
- static const std::string pieceLetters = " PNBRQK pnbrqk";
- std::string fen;
+ static const string pieceLetters = " PNBRQK pnbrqk";
+ string fen;
int skip;
for (Rank rank = RANK_8; rank >= RANK_1; rank--)
void Position::print(Move m) const {
- static const std::string pieceLetters = " PNBRQK PNBRQK .";
+ static const string pieceLetters = " PNBRQK PNBRQK .";
// Check for reentrancy, as example when called from inside
// MovePicker that is used also here in move_to_san()
std::cout << std::endl;
if (m != MOVE_NONE)
{
- std::string col = (color_of_piece_on(move_from(m)) == BLACK ? ".." : "");
+ string col = (color_of_piece_on(move_from(m)) == BLACK ? ".." : "");
std::cout << "Move is: " << col << move_to_san(*this, m) << std::endl;
}
for (Rank rank = RANK_8; rank >= RANK_1; rank--)
/// Position::copy() creates a copy of the input position.
-void Position::copy(const Position &pos) {
+void Position::copy(const Position& pos) {
memcpy(this, &pos, sizeof(Position));
+ saveState(); // detach and copy state info
}
}
/// Position::attacks_to() computes a bitboard containing all pieces which
-/// attacks a given square. There are two versions of this function: One
-/// which finds attackers of both colors, and one which only finds the
-/// attackers for one side.
+/// attacks a given square.
Bitboard Position::attacks_to(Square s) const {
bool Position::pl_move_is_legal(Move m) const {
- return pl_move_is_legal(m, pinned_pieces(side_to_move()));
+ // If we're in check, all pseudo-legal moves are legal, because our
+ // check evasion generator only generates true legal moves.
+ return is_check() || pl_move_is_legal(m, pinned_pieces(side_to_move()));
}
bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
assert(is_ok());
assert(move_is_ok(m));
assert(pinned == pinned_pieces(side_to_move()));
-
- // If we're in check, all pseudo-legal moves are legal, because our
- // check evasion generator only generates true legal moves.
- if (is_check())
- return true;
+ assert(!is_check());
// Castling moves are checked for legality during move generation.
if (move_is_castle(m))
&& (direction_between_squares(from, ksq) != direction_between_squares(to, ksq)))
return true;
- if (move_promotion(m)) // Promotion with check?
+ if (move_is_promotion(m)) // Promotion with check?
{
Bitboard b = occupied_squares();
clear_bit(&b, from);
- switch (move_promotion(m))
+ switch (move_promotion_piece(m))
{
case KNIGHT:
return bit_is_set(piece_attacks<KNIGHT>(to), ksq);
case BISHOP:
return (dcCandidates && bit_is_set(dcCandidates, from))
- || ( direction_between_squares(ksq, to) != DIR_NONE
- && bit_is_set(piece_attacks<BISHOP>(ksq), to));
+ || (direction_is_diagonal(ksq, to) && bit_is_set(piece_attacks<BISHOP>(ksq), to));
case ROOK:
return (dcCandidates && bit_is_set(dcCandidates, from))
- || ( direction_between_squares(ksq, to) != DIR_NONE
- && bit_is_set(piece_attacks<ROOK>(ksq), to));
+ || (direction_is_straight(ksq, to) && bit_is_set(piece_attacks<ROOK>(ksq), to));
case QUEEN:
// Discovered checks are impossible!
assert(!bit_is_set(dcCandidates, from));
- return ( direction_between_squares(ksq, to) != DIR_NONE
- && bit_is_set(piece_attacks<QUEEN>(ksq), to));
+ return ( (direction_is_straight(ksq, to) && bit_is_set(piece_attacks<ROOK>(ksq), to))
+ || (direction_is_diagonal(ksq, to) && bit_is_set(piece_attacks<BISHOP>(ksq), to)));
case KING:
// Discovered check?
}
-/// Position::move_is_capture() tests whether a move from the current
-/// position is a capture. Move must not be MOVE_NONE.
-
-bool Position::move_is_capture(Move m) const {
-
- assert(m != MOVE_NONE);
-
- return ( !square_is_empty(move_to(m))
- && (color_of_piece_on(move_to(m)) != color_of_piece_on(move_from(m)))
- )
- || move_is_ep(m);
-}
-
-
/// Position::update_checkers() udpates chekers info given the move. It is called
/// in do_move() and is faster then find_checkers().
const bool Rook = (Piece == QUEEN || Piece == ROOK);
const bool Slider = Bishop || Rook;
+ // Direct checks
if ( ( (Bishop && bit_is_set(BishopPseudoAttacks[ksq], to))
|| (Rook && bit_is_set(RookPseudoAttacks[ksq], to)))
&& bit_is_set(piece_attacks<Piece>(ksq), to)) // slow, try to early skip
&& bit_is_set(piece_attacks<Piece>(ksq), to))
set_bit(pCheckersBB, to);
+ // Discovery checks
if (Piece != QUEEN && bit_is_set(dcCandidates, from))
{
if (Piece != ROOK)
int castleRights, rule50;
Square epSquare;
Value mgValue, egValue;
+ Value npMaterial[2];
};
memcpy(&newSt, st, sizeof(ReducedStateInfo));
// case of non-reversible moves is taken care of later.
st->rule50++;
+ // Update side to move
+ st->key ^= zobSideToMove;
+
if (move_is_castle(m))
do_castle_move(m);
- else if (move_promotion(m))
- do_promotion_move(m);
- else if (move_is_ep(m))
- do_ep_move(m);
else
{
Color us = side_to_move();
Color them = opposite_color(us);
Square from = move_from(m);
Square to = move_to(m);
+ bool ep = move_is_ep(m);
+ bool pm = move_is_promotion(m);
- assert(color_of_piece_on(from) == us);
- assert(color_of_piece_on(to) == them || piece_on(to) == EMPTY);
+ Piece piece = piece_on(from);
+ PieceType pt = type_of_piece(piece);
- PieceType piece = type_of_piece_on(from);
+ assert(color_of_piece_on(from) == us);
+ assert(color_of_piece_on(to) == them || square_is_empty(to));
+ assert(!(ep || pm) || piece == piece_of_color_and_type(us, PAWN));
+ assert(!pm || relative_rank(us, to) == RANK_8);
- st->capture = type_of_piece_on(to);
+ st->capture = ep ? PAWN : type_of_piece_on(to);
if (st->capture)
- do_capture_move(m, st->capture, them, to);
-
- // Move the piece
- clear_bit(&(byColorBB[us]), from);
- clear_bit(&(byTypeBB[piece]), from);
- clear_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares
- set_bit(&(byColorBB[us]), to);
- set_bit(&(byTypeBB[piece]), to);
- set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
- board[to] = board[from];
- board[from] = EMPTY;
+ do_capture_move(st->capture, them, to, ep);
// Update hash key
- st->key ^= zobrist[us][piece][from] ^ zobrist[us][piece][to];
-
- // Update incremental scores
- st->mgValue -= pst<MidGame>(us, piece, from);
- st->mgValue += pst<MidGame>(us, piece, to);
- st->egValue -= pst<EndGame>(us, piece, from);
- st->egValue += pst<EndGame>(us, piece, to);
-
- // If the moving piece was a king, update the king square
- if (piece == KING)
- kingSquare[us] = to;
+ st->key ^= zobrist[us][pt][from] ^ zobrist[us][pt][to];
// Reset en passant square
if (st->epSquare != SQ_NONE)
st->epSquare = SQ_NONE;
}
+ // Update castle rights, try to shortcut a common case
+ if ((castleRightsMask[from] & castleRightsMask[to]) != ALL_CASTLES)
+ {
+ st->key ^= zobCastle[st->castleRights];
+ st->castleRights &= castleRightsMask[from];
+ st->castleRights &= castleRightsMask[to];
+ st->key ^= zobCastle[st->castleRights];
+ }
+
+ // Prefetch TT access as soon as we know key is updated
+ TT.prefetch(st->key);
+
+ // Move the piece
+ Bitboard move_bb = make_move_bb(from, to);
+ do_move_bb(&(byColorBB[us]), move_bb);
+ do_move_bb(&(byTypeBB[pt]), move_bb);
+ do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares
+
+ board[to] = board[from];
+ board[from] = EMPTY;
+
// If the moving piece was a pawn do some special extra work
- if (piece == PAWN)
+ if (pt == PAWN)
{
// Reset rule 50 draw counter
st->rule50 = 0;
}
}
+ // Update incremental scores
+ st->mgValue += pst_delta<MidGame>(piece, from, to);
+ st->egValue += pst_delta<EndGame>(piece, from, to);
+
+ // If the moving piece was a king, update the king square
+ if (pt == KING)
+ kingSquare[us] = to;
+
// Update piece lists
- pieceList[us][piece][index[from]] = to;
+ pieceList[us][pt][index[from]] = to;
index[to] = index[from];
- // Update castle rights
- st->key ^= zobCastle[st->castleRights];
- st->castleRights &= castleRightsMask[from];
- st->castleRights &= castleRightsMask[to];
- st->key ^= zobCastle[st->castleRights];
+ if (pm)
+ {
+ 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);
+
+ // Partially revert hash keys update
+ st->key ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to];
+ st->pawnKey ^= zobrist[us][PAWN][to];
+
+ // Update material key
+ st->materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]];
+ st->materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1];
+
+ // Update piece counts
+ pieceCount[us][PAWN]--;
+ pieceCount[us][promotion]++;
+
+ // Update piece lists
+ pieceList[us][PAWN][index[from]] = pieceList[us][PAWN][pieceCount[us][PAWN]];
+ index[pieceList[us][PAWN][index[from]]] = index[from];
+ pieceList[us][promotion][pieceCount[us][promotion] - 1] = to;
+ index[to] = pieceCount[us][promotion] - 1;
+
+ // Partially revert and update incremental scores
+ st->mgValue -= pst<MidGame>(us, PAWN, to);
+ st->mgValue += pst<MidGame>(us, promotion, to);
+ st->egValue -= pst<EndGame>(us, PAWN, to);
+ st->egValue += pst<EndGame>(us, promotion, to);
+
+ // Update material
+ st->npMaterial[us] += piece_value_midgame(promotion);
+ }
// Update checkers bitboard, piece must be already moved
- st->checkersBB = EmptyBoardBB;
- Square ksq = king_square(them);
- switch (piece)
+ if (ep || pm)
+ st->checkersBB = attacks_to(king_square(them), us);
+ else
{
- case PAWN: update_checkers<PAWN>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
- case KNIGHT: update_checkers<KNIGHT>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
- case BISHOP: update_checkers<BISHOP>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
- case ROOK: update_checkers<ROOK>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
- case QUEEN: update_checkers<QUEEN>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
- case KING: update_checkers<KING>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
- default: assert(false); break;
+ st->checkersBB = EmptyBoardBB; // FIXME EP ?
+ Square ksq = king_square(them);
+ switch (pt)
+ {
+ case PAWN: update_checkers<PAWN>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
+ case KNIGHT: update_checkers<KNIGHT>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
+ case BISHOP: update_checkers<BISHOP>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
+ case ROOK: update_checkers<ROOK>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
+ case QUEEN: update_checkers<QUEEN>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
+ case KING: update_checkers<KING>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
+ default: assert(false); break;
+ }
}
}
// Finish
- st->key ^= zobSideToMove;
sideToMove = opposite_color(sideToMove);
gamePly++;
/// 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(Move m, PieceType capture, Color them, Square to) {
+void Position::do_capture_move(PieceType capture, Color them, Square to, bool ep) {
assert(capture != KING);
+ Square capsq = to;
+
+ if (ep)
+ {
+ 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(from) == piece_of_color_and_type(us, PAWN));
+ assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN));
+
+ board[capsq] = EMPTY;
+ }
+
// Remove captured piece
- clear_bit(&(byColorBB[them]), to);
- clear_bit(&(byTypeBB[capture]), to);
+ clear_bit(&(byColorBB[them]), capsq);
+ clear_bit(&(byTypeBB[capture]), capsq);
+ clear_bit(&(byTypeBB[0]), capsq); // HACK: byTypeBB[0] == occupied squares
// Update hash key
- st->key ^= zobrist[them][capture][to];
+ st->key ^= zobrist[them][capture][capsq];
// If the captured piece was a pawn, update pawn hash key
if (capture == PAWN)
- st->pawnKey ^= zobrist[them][PAWN][to];
+ st->pawnKey ^= zobrist[them][PAWN][capsq];
// Update incremental scores
- st->mgValue -= pst<MidGame>(them, capture, to);
- st->egValue -= pst<EndGame>(them, capture, to);
-
- assert(!move_promotion(m) || capture != PAWN);
+ st->mgValue -= pst<MidGame>(them, capture, capsq);
+ st->egValue -= pst<EndGame>(them, capture, capsq);
// Update material
if (capture != PAWN)
- npMaterial[them] -= piece_value_midgame(capture);
+ st->npMaterial[them] -= piece_value_midgame(capture);
// Update material hash key
st->materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]];
pieceCount[them][capture]--;
// Update piece list
- pieceList[them][capture][index[to]] = pieceList[them][capture][pieceCount[them][capture]];
- index[pieceList[them][capture][index[to]]] = index[to];
+ pieceList[them][capture][index[capsq]] = pieceList[them][capture][pieceCount[them][capture]];
+ index[pieceList[them][capture][index[capsq]]] = index[capsq];
// Reset rule 50 counter
st->rule50 = 0;
rto = relative_square(us, SQ_D1);
}
- // Remove pieces from source squares
- clear_bit(&(byColorBB[us]), kfrom);
- clear_bit(&(byTypeBB[KING]), kfrom);
- clear_bit(&(byTypeBB[0]), kfrom); // HACK: byTypeBB[0] == occupied squares
- clear_bit(&(byColorBB[us]), rfrom);
- clear_bit(&(byTypeBB[ROOK]), rfrom);
- clear_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares
-
- // Put pieces on destination squares
- set_bit(&(byColorBB[us]), kto);
- set_bit(&(byTypeBB[KING]), kto);
- set_bit(&(byTypeBB[0]), kto); // HACK: byTypeBB[0] == occupied squares
- set_bit(&(byColorBB[us]), rto);
- set_bit(&(byTypeBB[ROOK]), rto);
- set_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares
+ // Move the pieces
+ Bitboard kmove_bb = make_move_bb(kfrom, kto);
+ do_move_bb(&(byColorBB[us]), kmove_bb);
+ do_move_bb(&(byTypeBB[KING]), kmove_bb);
+ do_move_bb(&(byTypeBB[0]), kmove_bb); // HACK: byTypeBB[0] == occupied squares
+
+ Bitboard rmove_bb = make_move_bb(rfrom, rto);
+ do_move_bb(&(byColorBB[us]), rmove_bb);
+ do_move_bb(&(byTypeBB[ROOK]), rmove_bb);
+ do_move_bb(&(byTypeBB[0]), rmove_bb); // HACK: byTypeBB[0] == occupied squares
// 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[kto] = piece_of_color_and_type(us, KING);
- board[rto] = piece_of_color_and_type(us, ROOK);
+ board[kto] = king;
+ board[rto] = rook;
// Update king square
kingSquare[us] = kto;
index[rto] = tmp;
// Update incremental scores
- st->mgValue -= pst<MidGame>(us, KING, kfrom);
- st->mgValue += pst<MidGame>(us, KING, kto);
- st->egValue -= pst<EndGame>(us, KING, kfrom);
- st->egValue += pst<EndGame>(us, KING, kto);
- st->mgValue -= pst<MidGame>(us, ROOK, rfrom);
- st->mgValue += pst<MidGame>(us, ROOK, rto);
- st->egValue -= pst<EndGame>(us, ROOK, rfrom);
- st->egValue += pst<EndGame>(us, ROOK, rto);
+ st->mgValue += pst_delta<MidGame>(king, kfrom, kto);
+ st->egValue += pst_delta<EndGame>(king, kfrom, kto);
+ st->mgValue += pst_delta<MidGame>(rook, rfrom, rto);
+ st->egValue += pst_delta<EndGame>(rook, rfrom, rto);
// Update hash key
st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto];
}
-/// Position::do_promotion_move() is a private method used to make a promotion
-/// move. It is called from the main Position::do_move function.
-
-void Position::do_promotion_move(Move m) {
-
- Color us, them;
- Square from, to;
- PieceType promotion;
-
- assert(is_ok());
- assert(move_is_ok(m));
- assert(move_promotion(m));
-
- us = side_to_move();
- them = opposite_color(us);
- from = move_from(m);
- to = move_to(m);
-
- assert(relative_rank(us, to) == RANK_8);
- assert(piece_on(from) == piece_of_color_and_type(us, PAWN));
- assert(color_of_piece_on(to) == them || square_is_empty(to));
-
- st->capture = type_of_piece_on(to);
-
- if (st->capture)
- do_capture_move(m, st->capture, them, to);
-
- // Remove pawn
- clear_bit(&(byColorBB[us]), from);
- clear_bit(&(byTypeBB[PAWN]), from);
- clear_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares
- board[from] = EMPTY;
-
- // Insert promoted piece
- promotion = move_promotion(m);
- assert(promotion >= KNIGHT && promotion <= QUEEN);
- set_bit(&(byColorBB[us]), to);
- set_bit(&(byTypeBB[promotion]), to);
- set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
- board[to] = piece_of_color_and_type(us, promotion);
-
- // Update hash key
- st->key ^= zobrist[us][PAWN][from] ^ zobrist[us][promotion][to];
-
- // Update pawn hash key
- st->pawnKey ^= zobrist[us][PAWN][from];
-
- // 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
- pieceList[us][PAWN][index[from]] = pieceList[us][PAWN][pieceCount[us][PAWN]];
- index[pieceList[us][PAWN][index[from]]] = index[from];
- pieceList[us][promotion][pieceCount[us][promotion] - 1] = to;
- index[to] = pieceCount[us][promotion] - 1;
-
- // Update incremental scores
- st->mgValue -= pst<MidGame>(us, PAWN, from);
- st->mgValue += pst<MidGame>(us, promotion, to);
- st->egValue -= pst<EndGame>(us, PAWN, from);
- st->egValue += pst<EndGame>(us, promotion, to);
-
- // Update material
- npMaterial[us] += piece_value_midgame(promotion);
-
- // Clear the en passant square
- if (st->epSquare != SQ_NONE)
- {
- st->key ^= zobEp[st->epSquare];
- st->epSquare = SQ_NONE;
- }
-
- // Update castle rights
- st->key ^= zobCastle[st->castleRights];
- st->castleRights &= castleRightsMask[to];
- st->key ^= zobCastle[st->castleRights];
-
- // Reset rule 50 counter
- st->rule50 = 0;
-
- // Update checkers BB
- st->checkersBB = attacks_to(king_square(them), us);
-}
-
-
-/// Position::do_ep_move() is a private method used to make an en passant
-/// capture. It is called from the main Position::do_move function.
-
-void Position::do_ep_move(Move m) {
-
- Color us, them;
- Square from, to, capsq;
-
- assert(is_ok());
- assert(move_is_ok(m));
- assert(move_is_ep(m));
-
- us = side_to_move();
- them = opposite_color(us);
- from = move_from(m);
- to = move_to(m);
- capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
-
- assert(to == st->epSquare);
- assert(relative_rank(us, to) == RANK_6);
- assert(piece_on(to) == EMPTY);
- assert(piece_on(from) == piece_of_color_and_type(us, PAWN));
- assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN));
-
- // Remove captured piece
- clear_bit(&(byColorBB[them]), capsq);
- clear_bit(&(byTypeBB[PAWN]), capsq);
- clear_bit(&(byTypeBB[0]), capsq); // HACK: byTypeBB[0] == occupied squares
- board[capsq] = EMPTY;
-
- // Remove moving piece from source square
- clear_bit(&(byColorBB[us]), from);
- clear_bit(&(byTypeBB[PAWN]), from);
- clear_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares
-
- // Put moving piece on destination square
- set_bit(&(byColorBB[us]), to);
- set_bit(&(byTypeBB[PAWN]), to);
- set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
- board[to] = board[from];
- board[from] = EMPTY;
-
- // Update material hash key
- st->materialKey ^= zobMaterial[them][PAWN][pieceCount[them][PAWN]];
-
- // Update piece count
- pieceCount[them][PAWN]--;
-
- // Update piece list
- pieceList[us][PAWN][index[from]] = to;
- index[to] = index[from];
- pieceList[them][PAWN][index[capsq]] = pieceList[them][PAWN][pieceCount[them][PAWN]];
- index[pieceList[them][PAWN][index[capsq]]] = index[capsq];
-
- // Update hash key
- st->key ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
- st->key ^= zobrist[them][PAWN][capsq];
- st->key ^= zobEp[st->epSquare];
-
- // Update pawn hash key
- st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
- st->pawnKey ^= zobrist[them][PAWN][capsq];
-
- // Update incremental scores
- st->mgValue -= pst<MidGame>(them, PAWN, capsq);
- st->mgValue -= pst<MidGame>(us, PAWN, from);
- st->mgValue += pst<MidGame>(us, PAWN, to);
- st->egValue -= pst<EndGame>(them, PAWN, capsq);
- st->egValue -= pst<EndGame>(us, PAWN, from);
- st->egValue += pst<EndGame>(us, PAWN, to);
-
- // Reset en passant square
- st->epSquare = SQ_NONE;
-
- // Reset rule 50 counter
- st->rule50 = 0;
-
- // Update checkers BB
- st->checkersBB = attacks_to(king_square(them), us);
-}
-
-
/// Position::undo_move() unmakes a move. When it returns, the position should
/// be restored to exactly the same state as before the move was made.
if (move_is_castle(m))
undo_castle_move(m);
- else if (move_promotion(m))
- undo_promotion_move(m);
- else if (move_is_ep(m))
- undo_ep_move(m);
else
{
- Color us, them;
- Square from, to;
- PieceType piece;
+ Color us = side_to_move();
+ Color them = opposite_color(us);
+ Square from = move_from(m);
+ Square to = move_to(m);
+ bool ep = move_is_ep(m);
+ bool pm = move_is_promotion(m);
- us = side_to_move();
- them = opposite_color(us);
- from = move_from(m);
- to = move_to(m);
+ PieceType piece = type_of_piece_on(to);
- assert(piece_on(from) == EMPTY);
+ assert(square_is_empty(from));
assert(color_of_piece_on(to) == us);
+ assert(!pm || relative_rank(us, to) == RANK_8);
+ assert(!ep || to == st->previous->epSquare);
+ assert(!ep || relative_rank(us, to) == RANK_6);
+ assert(!ep || piece_on(to) == piece_of_color_and_type(us, PAWN));
+
+ if (pm)
+ {
+ PieceType promotion = move_promotion_piece(m);
+
+ assert(piece_on(to) == piece_of_color_and_type(us, promotion));
+ assert(promotion >= KNIGHT && promotion <= QUEEN);
+
+ // Replace promoted piece with a pawn
+ clear_bit(&(byTypeBB[promotion]), to);
+ set_bit(&(byTypeBB[PAWN]), to);
+
+ // Update piece list replacing promotion piece with a pawn
+ pieceList[us][promotion][index[to]] = pieceList[us][promotion][pieceCount[us][promotion] - 1];
+ index[pieceList[us][promotion][index[to]]] = index[to];
+ pieceList[us][PAWN][pieceCount[us][PAWN]] = to;
+ index[to] = pieceCount[us][PAWN];
+
+ // Update piece counts
+ pieceCount[us][promotion]--;
+ pieceCount[us][PAWN]++;
+
+ piece = PAWN;
+ }
// Put the piece back at the source square
- piece = type_of_piece_on(to);
- set_bit(&(byColorBB[us]), from);
- set_bit(&(byTypeBB[piece]), from);
- set_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares
+ Bitboard move_bb = make_move_bb(to, from);
+ do_move_bb(&(byColorBB[us]), move_bb);
+ do_move_bb(&(byTypeBB[piece]), move_bb);
+ do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares
board[from] = piece_of_color_and_type(us, piece);
-
- // Clear the destination square
- clear_bit(&(byColorBB[us]), to);
- clear_bit(&(byTypeBB[piece]), to);
- clear_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
+ board[to] = EMPTY;
// If the moving piece was a king, update the king square
if (piece == KING)
if (st->capture)
{
- assert(st->capture != KING);
+ Square capsq = to;
+
+ if (ep)
+ capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
- // Replace the captured piece
- set_bit(&(byColorBB[them]), to);
- set_bit(&(byTypeBB[st->capture]), to);
- set_bit(&(byTypeBB[0]), to);
- board[to] = piece_of_color_and_type(them, st->capture);
+ assert(st->capture != KING);
+ assert(!ep || square_is_empty(capsq));
- // Update material
- if (st->capture != PAWN)
- npMaterial[them] += piece_value_midgame(st->capture);
+ // Restore the captured piece
+ set_bit(&(byColorBB[them]), capsq);
+ set_bit(&(byTypeBB[st->capture]), capsq);
+ set_bit(&(byTypeBB[0]), capsq);
+ board[capsq] = piece_of_color_and_type(them, st->capture);
// Update piece list
- pieceList[them][st->capture][pieceCount[them][st->capture]] = to;
- index[to] = pieceCount[them][st->capture];
+ pieceList[them][st->capture][pieceCount[them][st->capture]] = capsq;
+ index[capsq] = pieceCount[them][st->capture];
// Update piece count
pieceCount[them][st->capture]++;
- } else
- board[to] = EMPTY;
+ }
}
// Finally point our state pointer back to the previous state
assert(piece_on(kto) == piece_of_color_and_type(us, KING));
assert(piece_on(rto) == piece_of_color_and_type(us, ROOK));
- // Remove pieces from destination squares
- clear_bit(&(byColorBB[us]), kto);
- clear_bit(&(byTypeBB[KING]), kto);
- clear_bit(&(byTypeBB[0]), kto); // HACK: byTypeBB[0] == occupied squares
- clear_bit(&(byColorBB[us]), rto);
- clear_bit(&(byTypeBB[ROOK]), rto);
- clear_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares
-
- // Put pieces on source squares
- set_bit(&(byColorBB[us]), kfrom);
- set_bit(&(byTypeBB[KING]), kfrom);
- set_bit(&(byTypeBB[0]), kfrom); // HACK: byTypeBB[0] == occupied squares
- set_bit(&(byColorBB[us]), rfrom);
- set_bit(&(byTypeBB[ROOK]), rfrom);
- set_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares
+ // Put the pieces back at the source square
+ Bitboard kmove_bb = make_move_bb(kto, kfrom);
+ do_move_bb(&(byColorBB[us]), kmove_bb);
+ do_move_bb(&(byTypeBB[KING]), kmove_bb);
+ do_move_bb(&(byTypeBB[0]), kmove_bb); // HACK: byTypeBB[0] == occupied squares
+
+ Bitboard rmove_bb = make_move_bb(rto, rfrom);
+ do_move_bb(&(byColorBB[us]), rmove_bb);
+ do_move_bb(&(byTypeBB[ROOK]), rmove_bb);
+ do_move_bb(&(byTypeBB[0]), rmove_bb); // HACK: byTypeBB[0] == occupied squares
// Update board
board[rto] = board[kto] = EMPTY;
}
-/// Position::undo_promotion_move() is a private method used to unmake a
-/// promotion move. It is called from the main Position::do_move
-/// function.
-
-void Position::undo_promotion_move(Move m) {
-
- Color us, them;
- Square from, to;
- PieceType promotion;
-
- assert(move_is_ok(m));
- assert(move_promotion(m));
-
- // When we have arrived here, some work has already been done by
- // Position::undo_move. In particular, the side to move has been switched,
- // so the code below is correct.
- us = side_to_move();
- them = opposite_color(us);
- from = move_from(m);
- to = move_to(m);
-
- assert(relative_rank(us, to) == RANK_8);
- assert(piece_on(from) == EMPTY);
-
- // Remove promoted piece
- promotion = move_promotion(m);
- assert(piece_on(to)==piece_of_color_and_type(us, promotion));
- assert(promotion >= KNIGHT && promotion <= QUEEN);
- clear_bit(&(byColorBB[us]), to);
- clear_bit(&(byTypeBB[promotion]), to);
- clear_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
-
- // Insert pawn at source square
- set_bit(&(byColorBB[us]), from);
- set_bit(&(byTypeBB[PAWN]), from);
- set_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares
- board[from] = piece_of_color_and_type(us, PAWN);
-
- // Update material
- npMaterial[us] -= piece_value_midgame(promotion);
-
- // Update piece list
- pieceList[us][PAWN][pieceCount[us][PAWN]] = from;
- index[from] = pieceCount[us][PAWN];
- pieceList[us][promotion][index[to]] =
- pieceList[us][promotion][pieceCount[us][promotion] - 1];
- index[pieceList[us][promotion][index[to]]] = index[to];
-
- // Update piece counts
- pieceCount[us][promotion]--;
- pieceCount[us][PAWN]++;
-
- if (st->capture)
- {
- assert(st->capture != KING);
-
- // Insert captured piece:
- set_bit(&(byColorBB[them]), to);
- set_bit(&(byTypeBB[st->capture]), to);
- set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
- board[to] = piece_of_color_and_type(them, st->capture);
-
- // Update material. Because the move is a promotion move, we know
- // that the captured piece cannot be a pawn.
- assert(st->capture != PAWN);
- npMaterial[them] += piece_value_midgame(st->capture);
-
- // Update piece list
- pieceList[them][st->capture][pieceCount[them][st->capture]] = to;
- index[to] = pieceCount[them][st->capture];
-
- // Update piece count
- pieceCount[them][st->capture]++;
- } else
- board[to] = EMPTY;
-}
-
-
-/// Position::undo_ep_move() is a private method used to unmake an en passant
-/// capture. It is called from the main Position::undo_move function.
-
-void Position::undo_ep_move(Move m) {
-
- assert(move_is_ok(m));
- assert(move_is_ep(m));
-
- // When we have arrived here, some work has already been done by
- // Position::undo_move. In particular, the side to move has been switched,
- // so the code below is correct.
- Color us = side_to_move();
- Color them = opposite_color(us);
- Square from = move_from(m);
- Square to = move_to(m);
- Square capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
-
- assert(to == st->previous->epSquare);
- assert(relative_rank(us, to) == RANK_6);
- assert(piece_on(to) == piece_of_color_and_type(us, PAWN));
- assert(piece_on(from) == EMPTY);
- assert(piece_on(capsq) == EMPTY);
-
- // Replace captured piece
- set_bit(&(byColorBB[them]), capsq);
- set_bit(&(byTypeBB[PAWN]), capsq);
- set_bit(&(byTypeBB[0]), capsq);
- board[capsq] = piece_of_color_and_type(them, PAWN);
-
- // Remove moving piece from destination square
- clear_bit(&(byColorBB[us]), to);
- clear_bit(&(byTypeBB[PAWN]), to);
- clear_bit(&(byTypeBB[0]), to);
- board[to] = EMPTY;
-
- // Replace moving piece at source square
- set_bit(&(byColorBB[us]), from);
- set_bit(&(byTypeBB[PAWN]), from);
- set_bit(&(byTypeBB[0]), from);
- board[from] = piece_of_color_and_type(us, PAWN);
-
- // Update piece list:
- pieceList[us][PAWN][index[to]] = from;
- index[from] = index[to];
- pieceList[them][PAWN][pieceCount[them][PAWN]] = capsq;
- index[capsq] = pieceCount[them][PAWN];
-
- // Update piece count:
- pieceCount[them][PAWN]++;
-}
-
-
/// Position::do_null_move makes() a "null move": It switches the side to move
/// and updates the hash key without executing any move on the board.
assert(!is_check());
// Back up the information necessary to undo the null move to the supplied
- // StateInfo object. In the case of a null move, the only thing we need to
- // remember is the last move made and the en passant square.
+ // StateInfo object.
// Note that differently from normal case here backupSt is actually used as
// a backup storage not as a new state to be used.
- backupSt.lastMove = st->lastMove;
backupSt.epSquare = st->epSquare;
+ backupSt.key = st->key;
+ backupSt.mgValue = st->mgValue;
+ backupSt.egValue = st->egValue;
backupSt.previous = st->previous;
st->previous = &backupSt;
history[gamePly] = st->key;
// Update the necessary information
- sideToMove = opposite_color(sideToMove);
if (st->epSquare != SQ_NONE)
st->key ^= zobEp[st->epSquare];
+ st->key ^= zobSideToMove;
+ TT.prefetch(st->key);
+ sideToMove = opposite_color(sideToMove);
st->epSquare = SQ_NONE;
st->rule50++;
gamePly++;
- st->key ^= zobSideToMove;
st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
assert(!is_check());
// Restore information from the our backup StateInfo object
- st->lastMove = st->previous->lastMove;
st->epSquare = st->previous->epSquare;
+ st->key = st->previous->key;
+ st->mgValue = st->previous->mgValue;
+ st->egValue = st->previous->egValue;
st->previous = st->previous->previous;
- if (st->epSquare != SQ_NONE)
- st->key ^= zobEp[st->epSquare];
-
// Update the necessary information
sideToMove = opposite_color(sideToMove);
st->rule50--;
gamePly--;
- st->key ^= zobSideToMove;
-
- st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
- st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
assert(is_ok());
}
return see(move_from(m), move_to(m));
}
+int Position::see_sign(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;
+
+ return see(from, to);
+}
+
int Position::see(Square from, Square to) const {
// Material values
0, 0
};
- Bitboard attackers, occ, b;
+ Bitboard attackers, stmAttackers, occ, b;
assert(square_is_ok(from) || from == SQ_NONE);
assert(square_is_ok(to));
Square capQq = (side_to_move() == WHITE)? (to - DELTA_N) : (to - DELTA_S);
capture = piece_on(capQq);
-
assert(type_of_piece_on(capQq) == PAWN);
// Remove the captured pawn
}
// If the opponent has no attackers we are finished
- if ((attackers & pieces_of_color(them)) == EmptyBoardBB)
+ stmAttackers = attackers & pieces_of_color(them);
+ if (!stmAttackers)
return seeValues[capture];
attackers &= occ; // Remove the moving piece
// 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; !(attackers & pieces_of_color_and_type(c, pt)); pt++)
+ for (pt = PAWN; !(stmAttackers & pieces_of_type(pt)); pt++)
assert(pt < KING);
// Remove the attacker we just found from the 'attackers' bitboard,
// and scan for new X-ray attacks behind the attacker.
- b = attackers & pieces_of_color_and_type(c, pt);
- occ ^= (b & -b);
+ b = stmAttackers & pieces_of_type(pt);
+ occ ^= (b & (~b + 1));
attackers |= (rook_attacks_bb(to, occ) & rooks_and_queens())
| (bishop_attacks_bb(to, occ) & bishops_and_queens());
// before beginning the next iteration
lastCapturingPieceValue = seeValues[pt];
c = opposite_color(c);
+ stmAttackers = attackers & pieces_of_color(c);
// Stop after a king capture
- if (pt == KING && (attackers & pieces_of_color(c)))
+ if (pt == KING && stmAttackers)
{
assert(n < 32);
- swapList[n++] = 100;
+ swapList[n++] = QueenValueMidgame*10;
break;
}
- } while (attackers & pieces_of_color(c));
+ } 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
}
-/// Position::setStartState() copies the content of the argument
+/// 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::setStartState(const StateInfo& s) {
+void Position::saveState() {
- startState = s;
+ startState = *st;
st = &startState;
+ st->previous = NULL; // as a safe guard
}
}
-/// Position::is_mate() returns true or false depending on whether the
-/// side to move is checkmated. Note that this function is currently very
-/// slow, and shouldn't be used frequently inside the search.
-
-bool Position::is_mate() const {
-
- if (is_check())
- {
- MovePicker mp = MovePicker(*this, false, MOVE_NONE, EmptySearchStack, Depth(0));
- return mp.get_next_move() == MOVE_NONE;
- }
- return false;
-}
-
-
/// 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.
}
+/// Position::is_mate() returns true or false depending on whether the
+/// side to move is checkmated.
+
+bool Position::is_mate() const {
+
+ MoveStack moves[256];
+
+ return is_check() && !generate_evasions(*this, moves, pinned_pieces(sideToMove));
+}
+
+
/// Position::has_mate_threat() tests whether a given color has a mate in one
-/// from the current position. This function is quite slow, but it doesn't
-/// matter, because it is currently only called from PV nodes, which are rare.
+/// from the current position.
bool Position::has_mate_threat(Color c) {
StateInfo st1, st2;
Color stm = side_to_move();
- // The following lines are useless and silly, but prevents gcc from
- // emitting a stupid warning stating that u1.lastMove and u1.epSquare might
- // be used uninitialized.
- st1.lastMove = st->lastMove;
- st1.epSquare = st->epSquare;
-
if (is_check())
return false;
MoveStack mlist[120];
int count;
bool result = false;
+ Bitboard dc = discovered_check_candidates(sideToMove);
+ Bitboard pinned = pinned_pieces(sideToMove);
- // Generate legal moves
- count = generate_legal_moves(*this, mlist);
+ // Generate pseudo-legal non-capture and capture check moves
+ count = generate_non_capture_checks(*this, mlist, dc);
+ count += generate_captures(*this, mlist + count);
// Loop through the moves, and see if one of them is mate
for (int i = 0; i < count; i++)
{
- do_move(mlist[i].move, st2);
+ Move move = mlist[i].move;
+
+ if (!pl_move_is_legal(move, pinned))
+ continue;
+
+ do_move(move, st2);
if (is_mate())
result = true;
- undo_move(mlist[i].move);
+ undo_move(move);
}
// Undo null move, if necessary
/// the white and black sides reversed. This is only useful for debugging,
/// especially for finding evaluation symmetry bugs.
-void Position::flipped_copy(const Position &pos) {
+void Position::flipped_copy(const Position& pos) {
assert(pos.is_ok());
st->egValue = compute_value<EndGame>();
// Material
- npMaterial[WHITE] = compute_non_pawn_material(WHITE);
- npMaterial[BLACK] = compute_non_pawn_material(BLACK);
+ st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
+ st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
assert(is_ok());
}
if (failedStep) (*failedStep)++;
if (debugNonPawnMaterial)
{
- if (npMaterial[WHITE] != compute_non_pawn_material(WHITE))
+ if (st->npMaterial[WHITE] != compute_non_pawn_material(WHITE))
return false;
- if (npMaterial[BLACK] != compute_non_pawn_material(BLACK))
+ if (st->npMaterial[BLACK] != compute_non_pawn_material(BLACK))
return false;
}
projects / stockfish / blobdiff