X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=77a6d604523f40a841a5f73ba6a2e67e41a760f3;hp=b6a8d7465d5911a84b06f52e5e48edfec5e86965;hb=f35ddb04af2a00bd9facf5b66ec97e4ab28d4480;hpb=941d923bf81128e5420ffe3dcf0116bf7758f430 diff --git a/src/position.cpp b/src/position.cpp index b6a8d746..77a6d604 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -52,8 +52,7 @@ Key Position::zobCastle[16]; Key Position::zobMaterial[2][8][16]; Key Position::zobSideToMove; -Value Position::MgPieceSquareTable[16][64]; -Value Position::EgPieceSquareTable[16][64]; +Score Position::PieceSquareTable[16][64]; static bool RequestPending = false; @@ -213,8 +212,7 @@ void Position::from_fen(const string& fen) { st->key = compute_key(); st->pawnKey = compute_pawn_key(); st->materialKey = compute_material_key(); - st->mgValue = compute_value(); - st->egValue = compute_value(); + st->value = compute_value(); st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); } @@ -458,19 +456,11 @@ void Position::find_checkers() { /// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal -bool Position::pl_move_is_legal(Move m) const { - - // If we're in check, all pseudo-legal moves are legal, because our - // check evasion generator only generates true legal moves. - return is_check() || pl_move_is_legal(m, pinned_pieces(side_to_move())); -} - bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { assert(is_ok()); assert(move_is_ok(m)); assert(pinned == pinned_pieces(side_to_move())); - assert(!is_check()); // Castling moves are checked for legality during move generation. if (move_is_castle(m)) @@ -482,7 +472,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { assert(color_of_piece_on(from) == us); assert(piece_on(king_square(us)) == piece_of_color_and_type(us, KING)); - // En passant captures are a tricky special case. Because they are + // En passant captures are a tricky special case. Because they are // rather uncommon, we do it simply by testing whether the king is attacked // after the move is made if (move_is_ep(m)) @@ -519,6 +509,32 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { } +/// Position::pl_move_is_evasion() tests whether a pseudo-legal move is a legal evasion + +bool Position::pl_move_is_evasion(Move m, Bitboard pinned) const +{ + assert(is_check()); + + Color us = side_to_move(); + Square from = move_from(m); + Square to = move_to(m); + + // King moves and en-passant captures are verified in pl_move_is_legal() + if (type_of_piece_on(from) == KING || move_is_ep(m)) + return pl_move_is_legal(m, pinned); + + Bitboard target = checkers(); + Square checksq = pop_1st_bit(&target); + + if (target) // double check ? + return false; + + // Our move must be a blocking evasion or a capture of the checking piece + target = squares_between(checksq, king_square(us)) | checkers(); + return bit_is_set(target, to) && pl_move_is_legal(m, pinned); +} + + /// Position::move_is_check() tests whether a pseudo-legal move is a check bool Position::move_is_check(Move m) const { @@ -702,10 +718,10 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { // ones which are recalculated from scratch anyway, then switch our state // pointer to point to the new, ready to be updated, state. struct ReducedStateInfo { - Key key, pawnKey, materialKey; + Key pawnKey, materialKey; int castleRights, rule50, pliesFromNull; Square epSquare; - Value mgValue, egValue; + Value value; Value npMaterial[2]; }; @@ -742,16 +758,15 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { Piece piece = piece_on(from); PieceType pt = type_of_piece(piece); + PieceType capture = ep ? PAWN : type_of_piece_on(to); assert(color_of_piece_on(from) == us); assert(color_of_piece_on(to) == them || square_is_empty(to)); assert(!(ep || pm) || piece == piece_of_color_and_type(us, PAWN)); assert(!pm || relative_rank(us, to) == RANK_8); - st->capture = ep ? PAWN : type_of_piece_on(to); - - if (st->capture) - do_capture_move(key, st->capture, them, to, ep); + if (capture) + do_capture_move(key, capture, them, to, ep); // Update hash key key ^= zobrist[us][pt][from] ^ zobrist[us][pt][to]; @@ -801,7 +816,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; // Set en passant square, only if moved pawn can be captured - if (abs(int(to) - int(from)) == 16) + if ((to ^ from) == 16) { if (attacks_from(from + (us == WHITE ? DELTA_N : DELTA_S), us) & pieces(PAWN, them)) { @@ -812,8 +827,10 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { } // Update incremental scores - st->mgValue += pst_delta(piece, from, to); - st->egValue += pst_delta(piece, from, to); + st->value += pst_delta(piece, from, to); + + // Set capture piece + st->capture = capture; if (pm) // promotion ? { @@ -848,10 +865,8 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { st->pawnKey ^= zobrist[us][PAWN][to]; // Partially revert and update incremental scores - st->mgValue -= pst(us, PAWN, to); - st->mgValue += pst(us, promotion, to); - st->egValue -= pst(us, PAWN, to); - st->egValue += pst(us, promotion, to); + st->value -= pst(us, PAWN, to); + st->value += pst(us, promotion, to); // Update material st->npMaterial[us] += piece_value_midgame(promotion); @@ -881,9 +896,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { // Finish sideToMove = opposite_color(sideToMove); - - st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); assert(is_ok()); } @@ -919,8 +932,7 @@ void Position::do_capture_move(Bitboard& key, PieceType capture, Color them, Squ key ^= zobrist[them][capture][capsq]; // Update incremental scores - st->mgValue -= pst(them, capture, capsq); - st->egValue -= pst(them, capture, capsq); + st->value -= pst(them, capture, capsq); // If the captured piece was a pawn, update pawn hash key, // otherwise update non-pawn material. @@ -1017,10 +1029,8 @@ void Position::do_castle_move(Move m) { index[rto] = tmp; // Update incremental scores - st->mgValue += pst_delta(king, kfrom, kto); - st->egValue += pst_delta(king, kfrom, kto); - st->mgValue += pst_delta(rook, rfrom, rto); - st->egValue += pst_delta(rook, rfrom, rto); + st->value += pst_delta(king, kfrom, kto); + st->value += pst_delta(rook, rfrom, rto); // Update hash key st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto]; @@ -1046,9 +1056,7 @@ void Position::do_castle_move(Move m) { // Finish sideToMove = opposite_color(sideToMove); - - st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); assert(is_ok()); } @@ -1240,8 +1248,7 @@ void Position::do_null_move(StateInfo& backupSt) { // a backup storage not as a new state to be used. backupSt.key = st->key; backupSt.epSquare = st->epSquare; - backupSt.mgValue = st->mgValue; - backupSt.egValue = st->egValue; + backupSt.value = st->value; backupSt.previous = st->previous; backupSt.pliesFromNull = st->pliesFromNull; st->previous = &backupSt; @@ -1261,10 +1268,8 @@ void Position::do_null_move(StateInfo& backupSt) { st->epSquare = SQ_NONE; st->rule50++; st->pliesFromNull = 0; + st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue; gamePly++; - - st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; } @@ -1279,8 +1284,7 @@ void Position::undo_null_move() { StateInfo* backupSt = st->previous; st->key = backupSt->key; st->epSquare = backupSt->epSquare; - st->mgValue = backupSt->mgValue; - st->egValue = backupSt->egValue; + st->value = backupSt->value; st->previous = backupSt->previous; st->pliesFromNull = backupSt->pliesFromNull; @@ -1300,13 +1304,13 @@ void Position::undo_null_move() { int Position::see(Square to) const { assert(square_is_ok(to)); - return see(SQ_NONE, to, false); + return see(SQ_NONE, to); } int Position::see(Move m) const { assert(move_is_ok(m)); - return see(move_from(m), move_to(m), false); + return see(move_from(m), move_to(m)); } int Position::see_sign(Move m) const { @@ -1322,10 +1326,10 @@ int Position::see_sign(Move m) const { && type_of_piece_on(from) != KING) return 1; - return see(from, to, true); + return see(from, to); } -int Position::see(Square from, Square to, bool shortcut) const { +int Position::see(Square from, Square to) const { // Material values static const int seeValues[18] = { @@ -1338,7 +1342,6 @@ int Position::see(Square from, Square to, bool shortcut) const { Bitboard attackers, stmAttackers, b; - assert(!shortcut || from != SQ_NONE); assert(square_is_ok(from) || from == SQ_NONE); assert(square_is_ok(to)); @@ -1351,21 +1354,9 @@ int Position::see(Square from, Square to, bool shortcut) const { Piece capture = piece_on(to); Bitboard occ = occupied_squares(); - // If captured piece is defended by enemy pawns or knights then SEE is negative - // when captured piece value is not enough to compensate the lost of capturing one. - if (shortcut) - { - int diff = seeValues[piece] - seeValues[capture]; - - if ( diff > seeValues[PAWN] - &&(attacks_from(to, us) & pieces(PAWN, them))) - return -(diff - seeValues[PAWN] / 2); - - if ( diff > seeValues[KNIGHT] - && pieces(KNIGHT, them) - &&(pieces(KNIGHT, them) & attacks_from(to))) - return -(diff - seeValues[KNIGHT] / 2); - } + // King cannot be recaptured + if (type_of_piece(piece) == KING) + return seeValues[capture]; // Handle en passant moves if (st->epSquare == to && type_of_piece_on(from) == PAWN) @@ -1640,10 +1631,9 @@ Key Position::compute_material_key() const { /// game and the endgame. These functions are used to initialize the incremental /// scores when a new position is set up, and to verify that the scores are correctly /// updated by do_move and undo_move when the program is running in debug mode. -template -Value Position::compute_value() const { +Score Position::compute_value() const { - Value result = Value(0); + Score result = make_score(0, 0); Bitboard b; Square s; @@ -1655,12 +1645,11 @@ Value Position::compute_value() const { { s = pop_1st_bit(&b); assert(piece_on(s) == piece_of_color_and_type(c, pt)); - result += pst(c, pt, s); + result += pst(c, pt, s); } } - const Value TempoValue = (Phase == MidGame ? TempoValueMidgame : TempoValueEndgame); - result += (side_to_move() == WHITE)? TempoValue / 2 : -TempoValue / 2; + result += (side_to_move() == WHITE ? TempoValue / 2 : -TempoValue / 2); return result; } @@ -1718,8 +1707,7 @@ bool Position::is_draw() const { bool Position::is_mate() const { MoveStack moves[256]; - - return is_check() && (generate_evasions(*this, moves, pinned_pieces(sideToMove)) == moves); + return is_check() && (generate_moves(*this, moves, false) == moves); } @@ -1740,11 +1728,10 @@ bool Position::has_mate_threat(Color c) { MoveStack mlist[120]; bool result = false; - Bitboard dc = discovered_check_candidates(sideToMove); Bitboard pinned = pinned_pieces(sideToMove); // Generate pseudo-legal non-capture and capture check moves - MoveStack* last = generate_non_capture_checks(*this, mlist, dc); + MoveStack* last = generate_non_capture_checks(*this, mlist); last = generate_captures(*this, last); // Loop through the moves, and see if one of them is mate @@ -1811,16 +1798,12 @@ void Position::init_piece_square_tables() { for (Piece p = WP; p <= WK; p++) { i = (r == 0)? 0 : (genrand_int32() % (r*2) - r); - MgPieceSquareTable[p][s] = Value(MgPST[p][s] + i); - EgPieceSquareTable[p][s] = Value(EgPST[p][s] + i); + PieceSquareTable[p][s] = make_score(MgPST[p][s] + i, EgPST[p][s] + i); } for (Square s = SQ_A1; s <= SQ_H8; s++) for (Piece p = BP; p <= BK; p++) - { - MgPieceSquareTable[p][s] = -MgPieceSquareTable[p-8][flip_square(s)]; - EgPieceSquareTable[p][s] = -EgPieceSquareTable[p-8][flip_square(s)]; - } + PieceSquareTable[p][s] = -PieceSquareTable[p-8][flip_square(s)]; } @@ -1875,8 +1858,7 @@ void Position::flipped_copy(const Position& pos) { st->materialKey = compute_material_key(); // Incremental scores - st->mgValue = compute_value(); - st->egValue = compute_value(); + st->value = compute_value(); // Material st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); @@ -2003,14 +1985,8 @@ bool Position::is_ok(int* failedStep) const { // Incremental eval OK? if (failedStep) (*failedStep)++; - if (debugIncrementalEval) - { - if (st->mgValue != compute_value()) - return false; - - if (st->egValue != compute_value()) - return false; - } + if (debugIncrementalEval && st->value != compute_value()) + return false; // Non-pawn material OK? if (failedStep) (*failedStep)++;