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board.cpp
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board.cpp
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/*
Copyright (C) 2015 Matthew Lai
Giraffe is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Giraffe is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "board.h"
#include <string>
#include <set>
#include <sstream>
#include <regex>
#include <tuple>
#include <iostream>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include "bit_ops.h"
#include "containers.h"
#include "magic_moves.h"
#include "util.h"
#include "zobrist.h"
namespace
{
Square StringToSquare(std::string st)
{
if ((st[0] > 'h') || (st[0] < 'a') || st[1] < '1' || st[1] > '8')
{
std::cerr << "Square is invalid - " << st << std::endl;
exit(1);
}
return (st[1] - '1') * 8 + (st[0] - 'a');
}
PieceType CharToPieceType(char c)
{
switch (c)
{
case 'K':
return WK;
case 'Q':
return WQ;
case 'B':
return WB;
case 'N':
return WN;
case 'R':
return WR;
case 'P':
return WP;
case 'k':
return BK;
case 'q':
return BQ;
case 'b':
return BB;
case 'n':
return BN;
case 'r':
return BR;
case 'p':
return BP;
default:
std::cerr << "PieceType is invalid - " << c << std::endl;
exit(1);
}
return EMPTY;
}
}
Board::Board(const std::string &fen)
{
for (uint32_t i = 0; i < BOARD_DESC_BB_SIZE; ++i)
{
m_boardDescBB[i] = 0;
}
for (uint32_t i = 0; i < BOARD_DESC_U8_SIZE; ++i)
{
m_boardDescU8[i] = 0;
}
for (Square sq = 0; sq < 64; ++sq)
{
RemovePiece(sq);
}
// the board desc is up to 64 squares + 7 rank separators + 1 NUL
char boardDesc[72];
char sideToMove;
char castlingRights[5];
char enPassantSq[3];
uint32_t halfMoves;
uint32_t fullMoves;
int sscanfRet = sscanf(fen.c_str(), "%71s %c %4s %2s %u %u",
boardDesc, &sideToMove, castlingRights, enPassantSq, &halfMoves, &fullMoves);
if (sscanfRet == 6)
{
// all fields are present
}
else if (sscanfRet == 4) // some FEN/EPD positions don't have the move counts
{
halfMoves = 0;
fullMoves = 1;
}
else
{
std::cerr << "FEN is invalid - " << fen << std::endl;
exit(1);
}
size_t boardDescLen = strlen(boardDesc);
Square currentSquareFen = 0;
for (size_t i = 0; i < boardDescLen; ++i)
{
if (currentSquareFen >= 64)
{
std::cerr << "FEN is too long - " << fen << std::endl;
exit(1);
}
// FEN goes from rank 8 to 1, so we have to reverse rank... a bit of weird logic here
Square currentSquare = (7 - (currentSquareFen / 8)) * 8 + currentSquareFen % 8;
if (boardDesc[i] == '/')
{
continue;
}
else if (boardDesc[i] >= '1' && boardDesc[i] <= '8')
{
for (size_t r = 0; r < static_cast<size_t>((boardDesc[i] - '0')); ++r)
{
RemovePiece(currentSquare);
++currentSquareFen;
++currentSquare;
}
}
else if (boardDesc[i] >= 'A' && boardDesc[i] <= 'z')
{
PlacePiece(currentSquare, CharToPieceType(boardDesc[i]));
++currentSquareFen;
}
else
{
std::cerr << "FEN is invalid (invalid character encountered) - " << fen << std::endl;
exit(1);
}
}
if (currentSquareFen != 64)
{
std::cerr << "FEN is invalid (too short) - " << fen << std::endl;
exit(1);
}
if (sideToMove != 'w' && sideToMove != 'b')
{
std::cerr << "FEN is invalid (invalid side to move) - " << fen << std::endl;
exit(1);
}
m_boardDescU8[SIDE_TO_MOVE] = sideToMove == 'w' ? WHITE : BLACK;
if (enPassantSq[0] != '-')
{
m_boardDescBB[EN_PASS_SQUARE] = Bit(StringToSquare(std::string(enPassantSq)));
}
std::string strCastlingRights(castlingRights);
m_boardDescU8[W_SHORT_CASTLE] = strCastlingRights.find('K') != std::string::npos;
m_boardDescU8[W_LONG_CASTLE] = strCastlingRights.find('Q') != std::string::npos;
m_boardDescU8[B_SHORT_CASTLE] = strCastlingRights.find('k') != std::string::npos;
m_boardDescU8[B_LONG_CASTLE] = strCastlingRights.find('q') != std::string::npos;
m_boardDescU8[HALF_MOVES_CLOCK] = halfMoves;
UpdateInCheck_();
UpdateHashFull_();
#ifdef DEBUG
CheckBoardConsistency();
#endif
}
void Board::RemovePiece(Square sq)
{
m_boardDescBB[m_boardDescU8[sq]] &= InvBit(sq);
m_boardDescU8[sq] = EMPTY;
// faster to reset both than check
m_boardDescBB[WHITE_OCCUPIED] &= InvBit(sq);
m_boardDescBB[BLACK_OCCUPIED] &= InvBit(sq);
}
void Board::PlacePiece(Square sq, PieceType pt)
{
#ifdef DEBUG
assert(pt != EMPTY);
assert(m_boardDescU8[sq] == EMPTY);
#endif
m_boardDescU8[sq] = pt;
m_boardDescBB[pt] |= Bit(sq);
if (GetColor(pt) == WHITE)
{
m_boardDescBB[WHITE_OCCUPIED] |= Bit(sq);
}
else
{
m_boardDescBB[BLACK_OCCUPIED] |= Bit(sq);
}
}
template <Board::MOVE_TYPES MT>
void Board::GenerateAllLegalMoves(MoveList &moveList)
{
MoveList pseudoLegalMoves;
GenerateAllPseudoLegalMoves_<MT>(pseudoLegalMoves);
CheckInfo ci = ComputeCheckInfo();
for (size_t i = 0; i < pseudoLegalMoves.GetSize(); ++i)
{
if (CheckLegal(ci, pseudoLegalMoves[i]))
{
moveList.PushBack(pseudoLegalMoves[i]);
}
}
}
template void Board::GenerateAllLegalMoves<Board::ALL>(MoveList &);
template void Board::GenerateAllLegalMoves<Board::VIOLENT>(MoveList &);
template void Board::GenerateAllLegalMoves<Board::QUIET>(MoveList &);
void Board::CheckBoardConsistency()
{
for (uint32_t sq = 0; sq < 64; ++sq)
{
PieceType pt = m_boardDescU8[sq];
if (pt == EMPTY)
{
for (uint32_t i = 0; i < NUM_PIECETYPES; ++i)
{
assert(!(m_boardDescBB[PIECE_TYPE_INDICES[i]] & Bit(sq)));
}
assert(!(m_boardDescBB[WHITE_OCCUPIED] & Bit(sq)));
assert(!(m_boardDescBB[BLACK_OCCUPIED] & Bit(sq)));
}
else
{
if (GetColor(pt) == WHITE)
{
assert(m_boardDescBB[WHITE_OCCUPIED] & Bit(sq));
assert(!(m_boardDescBB[BLACK_OCCUPIED] & Bit(sq)));
}
else
{
assert(m_boardDescBB[BLACK_OCCUPIED] & Bit(sq));
assert(!(m_boardDescBB[WHITE_OCCUPIED] & Bit(sq)));
}
for (uint32_t i = 0; i < NUM_PIECETYPES; ++i)
{
if (PIECE_TYPE_INDICES[i] != pt)
{
assert(!(m_boardDescBB[PIECE_TYPE_INDICES[i]] & Bit(sq)));
}
}
assert(m_boardDescBB[pt] & Bit(sq));
}
}
if (m_boardDescU8[E1] != WK || m_boardDescU8[H1] != WR)
{
assert(!m_boardDescU8[W_SHORT_CASTLE]);
}
if (m_boardDescU8[E1] != WK || m_boardDescU8[A1] != WR)
{
assert(!m_boardDescU8[W_LONG_CASTLE]);
}
if (m_boardDescU8[E8] != BK || m_boardDescU8[H8] != BR)
{
if (m_boardDescU8[B_SHORT_CASTLE])
{
std::cout << PrintBoard() << std::endl;
}
assert(!m_boardDescU8[B_SHORT_CASTLE]);
}
if (m_boardDescU8[E8] != BK || m_boardDescU8[A8] != BR)
{
assert(!m_boardDescU8[B_LONG_CASTLE]);
}
uint64_t oldHash = GetHash();
UpdateHashFull_();
if (oldHash != GetHash())
{
std::cout << GetFen() << std::endl;
}
assert(oldHash == GetHash());
}
std::string Board::GetFen(bool omitMoveNums) const
{
std::stringstream ss;
for (int y = 7; y >= 0; --y)
{
for (int x = 0; x < 8;)
{
if (m_boardDescU8[Sq(x, y)] != EMPTY)
{
ss << PieceTypeToChar(m_boardDescU8[Sq(x, y)]);
++x;
}
else
{
int numOfSpaces = 0;
while (m_boardDescU8[Sq(x, y)] == EMPTY && x < 8)
{
++numOfSpaces;
++x;
}
ss << numOfSpaces;
}
}
if (y != 0)
{
ss << "/";
}
}
ss << " ";
ss << (m_boardDescU8[SIDE_TO_MOVE] == WHITE ? 'w' : 'b');
ss << " ";
if (!m_boardDescU8[W_SHORT_CASTLE] && !m_boardDescU8[W_LONG_CASTLE] && !m_boardDescU8[B_SHORT_CASTLE] && !m_boardDescU8[B_LONG_CASTLE])
{
ss << "-";
}
else
{
ss << (m_boardDescU8[W_SHORT_CASTLE] ? "K" : "") << (m_boardDescU8[W_LONG_CASTLE] ? "Q" : "")
<< (m_boardDescU8[B_SHORT_CASTLE] ? "k" : "") << (m_boardDescU8[B_LONG_CASTLE] ? "q" : "");
}
ss << " ";
if (m_boardDescBB[EN_PASS_SQUARE])
{
ss << SquareToString(BitScanForward(m_boardDescBB[EN_PASS_SQUARE]));
}
else
{
ss << "-";
}
if (!omitMoveNums)
{
ss << " " << m_boardDescU8[HALF_MOVES_CLOCK] << " " << 1; // we don't actually keep track of full moves
}
return ss.str();
}
std::string Board::PrintBoard() const
{
std::stringstream ss;
for (int y = 7; y >= 0; --y)
{
ss << " ---------------------------------" << std::endl;
ss << " " << (y + 1) << " |";
for (int x = 0; x <= 7; ++x)
{
ss << " " << PieceTypeToChar(m_boardDescU8[Sq(x, y)]) << " |";
}
ss << std::endl;
}
ss << " ---------------------------------" << std::endl;
ss << " a b c d e f g h" << std::endl;
ss << std::endl;
ss << "Side to move: " << (m_boardDescU8[SIDE_TO_MOVE] == WHITE ? "white" : "black") << std::endl;
ss << "En passant: " << (m_boardDescBB[EN_PASS_SQUARE] ? SquareToString(BitScanForward(m_boardDescBB[EN_PASS_SQUARE])) : "-") << std::endl;
ss << "White castling rights: " << (m_boardDescU8[W_SHORT_CASTLE] ? "O-O " : "") << (m_boardDescU8[W_LONG_CASTLE] ? "O-O-O" : "") << std::endl;
ss << "Black castling rights: " << (m_boardDescU8[B_SHORT_CASTLE] ? "O-O " : "") << (m_boardDescU8[B_LONG_CASTLE] ? "O-O-O" : "") << std::endl;
ss << "Half moves since last pawn move or capture: " << m_boardDescU8[HALF_MOVES_CLOCK] << std::endl;
ss << "FEN: " << GetFen() << std::endl;
ss << "In check: " << m_boardDescU8[IN_CHECK] << std::endl;
ss << "Insufficient material: " << HasInsufficientMaterial() << std::endl;
return ss.str();
}
bool Board::ApplyMove(Move mv)
{
#define MOVE_PIECE(pt, from, to) \
m_boardDescBB[pt] ^= Bit(from) | Bit(to); \
m_boardDescU8[from] = EMPTY; \
m_boardDescU8[to] = pt;
#define REMOVE_PIECE(pt, sq) \
m_boardDescBB[pt] &= InvBit(sq); \
m_boardDescU8[sq] = EMPTY;
#define PLACE_PIECE(pt, sq) \
m_boardDescBB[pt] |= Bit(sq); \
m_boardDescU8[sq] = pt;
#define REPLACE_PIECE(pt_old, pt_new, sq) \
m_boardDescBB[pt_old] &= InvBit(sq); \
m_boardDescBB[pt_new] |= Bit(sq); \
m_boardDescU8[sq] = pt_new;
UndoListBB &ulBB = m_undoStackBB.PrePush();
UndoListU8 &ulU8 = m_undoStackU8.PrePush();
ulBB.Clear();
ulU8.Clear();
PieceType pt = GetPieceType(mv);
Square from = GetFromSquare(mv);
Square to = GetToSquare(mv);
Color color = pt & COLOR_MASK;
PieceType promoType = GetPromoType(mv);
m_hashStack.Push(m_boardDescBB[HASH]);
if (m_boardDescBB[EN_PASS_SQUARE])
{
m_boardDescBB[HASH] ^= EN_PASS_ZOBRIST[BitScanForward(m_boardDescBB[EN_PASS_SQUARE])];
}
ulBB.PushBack(std::make_pair(EN_PASS_SQUARE, m_boardDescBB[EN_PASS_SQUARE]));
uint64_t currentEp = m_boardDescBB[EN_PASS_SQUARE];
m_boardDescBB[EN_PASS_SQUARE] = 0;
ulU8.PushBack(std::make_pair(IN_CHECK, m_boardDescU8[IN_CHECK]));
if (IsCastling(mv))
{
if (GetCastlingType(mv) == MoveConstants::CASTLE_WHITE_SHORT)
{
ulU8.PushBack(std::make_pair(E1, m_boardDescU8[E1]));
ulU8.PushBack(std::make_pair(G1, m_boardDescU8[G1]));
ulU8.PushBack(std::make_pair(H1, m_boardDescU8[H1]));
ulU8.PushBack(std::make_pair(F1, m_boardDescU8[F1]));
ulBB.PushBack(std::make_pair(WK, m_boardDescBB[WK]));
ulBB.PushBack(std::make_pair(WR, m_boardDescBB[WR]));
ulBB.PushBack(std::make_pair(WHITE_OCCUPIED, m_boardDescBB[WHITE_OCCUPIED]));
if (m_boardDescU8[W_SHORT_CASTLE])
{
m_boardDescBB[HASH] ^= W_SHORT_CASTLE_ZOBRIST;
}
if (m_boardDescU8[W_LONG_CASTLE])
{
m_boardDescBB[HASH] ^= W_LONG_CASTLE_ZOBRIST;
}
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[E1][WK];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[G1][WK];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[H1][WR];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[F1][WR];
MOVE_PIECE(WK, E1, G1);
MOVE_PIECE(WR, H1, F1);
ulU8.PushBack(std::make_pair(W_SHORT_CASTLE, m_boardDescU8[W_SHORT_CASTLE]));
ulU8.PushBack(std::make_pair(W_LONG_CASTLE, m_boardDescU8[W_LONG_CASTLE]));
m_boardDescU8[W_SHORT_CASTLE] = 0;
m_boardDescU8[W_LONG_CASTLE] = 0;
m_boardDescBB[WHITE_OCCUPIED] ^= Bit(E1) | Bit(G1) | Bit(H1) | Bit(F1);
}
else if (GetCastlingType(mv) == MoveConstants::CASTLE_WHITE_LONG)
{
ulU8.PushBack(std::make_pair(E1, m_boardDescU8[E1]));
ulU8.PushBack(std::make_pair(C1, m_boardDescU8[C1]));
ulU8.PushBack(std::make_pair(A1, m_boardDescU8[A1]));
ulU8.PushBack(std::make_pair(D1, m_boardDescU8[D1]));
ulBB.PushBack(std::make_pair(WK, m_boardDescBB[WK]));
ulBB.PushBack(std::make_pair(WR, m_boardDescBB[WR]));
ulBB.PushBack(std::make_pair(WHITE_OCCUPIED, m_boardDescBB[WHITE_OCCUPIED]));
if (m_boardDescU8[W_SHORT_CASTLE])
{
m_boardDescBB[HASH] ^= W_SHORT_CASTLE_ZOBRIST;
}
if (m_boardDescU8[W_LONG_CASTLE])
{
m_boardDescBB[HASH] ^= W_LONG_CASTLE_ZOBRIST;
}
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[E1][WK];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[C1][WK];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[A1][WR];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[D1][WR];
MOVE_PIECE(WK, E1, C1);
MOVE_PIECE(WR, A1, D1);
ulU8.PushBack(std::make_pair(W_SHORT_CASTLE, m_boardDescU8[W_SHORT_CASTLE]));
ulU8.PushBack(std::make_pair(W_LONG_CASTLE, m_boardDescU8[W_LONG_CASTLE]));
m_boardDescU8[W_SHORT_CASTLE] = 0;
m_boardDescU8[W_LONG_CASTLE] = 0;
m_boardDescBB[WHITE_OCCUPIED] ^= Bit(E1) | Bit(C1) | Bit(A1) | Bit(D1);
}
else if (GetCastlingType(mv) == MoveConstants::CASTLE_BLACK_SHORT)
{
ulU8.PushBack(std::make_pair(E8, m_boardDescU8[E8]));
ulU8.PushBack(std::make_pair(G8, m_boardDescU8[G8]));
ulU8.PushBack(std::make_pair(H8, m_boardDescU8[H8]));
ulU8.PushBack(std::make_pair(F8, m_boardDescU8[F8]));
ulBB.PushBack(std::make_pair(BK, m_boardDescBB[BK]));
ulBB.PushBack(std::make_pair(BR, m_boardDescBB[BR]));
ulBB.PushBack(std::make_pair(BLACK_OCCUPIED, m_boardDescBB[BLACK_OCCUPIED]));
if (m_boardDescU8[B_SHORT_CASTLE])
{
m_boardDescBB[HASH] ^= B_SHORT_CASTLE_ZOBRIST;
}
if (m_boardDescU8[B_LONG_CASTLE])
{
m_boardDescBB[HASH] ^= B_LONG_CASTLE_ZOBRIST;
}
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[E8][BK];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[G8][BK];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[H8][BR];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[F8][BR];
MOVE_PIECE(BK, E8, G8);
MOVE_PIECE(BR, H8, F8);
ulU8.PushBack(std::make_pair(B_SHORT_CASTLE, m_boardDescU8[B_SHORT_CASTLE]));
ulU8.PushBack(std::make_pair(B_LONG_CASTLE, m_boardDescU8[B_LONG_CASTLE]));
m_boardDescU8[B_SHORT_CASTLE] = 0;
m_boardDescU8[B_LONG_CASTLE] = 0;
m_boardDescBB[BLACK_OCCUPIED] ^= Bit(E8) | Bit(G8) | Bit(H8) | Bit(F8);
}
else // (GetCastlingType(mv) == MoveConstants::CASTLE_BLACK_LONG)
{
ulU8.PushBack(std::make_pair(E8, m_boardDescU8[E8]));
ulU8.PushBack(std::make_pair(C8, m_boardDescU8[C8]));
ulU8.PushBack(std::make_pair(A8, m_boardDescU8[A8]));
ulU8.PushBack(std::make_pair(D8, m_boardDescU8[D8]));
ulBB.PushBack(std::make_pair(BK, m_boardDescBB[BK]));
ulBB.PushBack(std::make_pair(BR, m_boardDescBB[BR]));
ulBB.PushBack(std::make_pair(BLACK_OCCUPIED, m_boardDescBB[BLACK_OCCUPIED]));
if (m_boardDescU8[B_SHORT_CASTLE])
{
m_boardDescBB[HASH] ^= B_SHORT_CASTLE_ZOBRIST;
}
if (m_boardDescU8[B_LONG_CASTLE])
{
m_boardDescBB[HASH] ^= B_LONG_CASTLE_ZOBRIST;
}
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[E8][BK];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[C8][BK];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[A8][BR];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[D8][BR];
MOVE_PIECE(BK, E8, C8);
MOVE_PIECE(BR, A8, D8);
ulU8.PushBack(std::make_pair(B_SHORT_CASTLE, m_boardDescU8[B_SHORT_CASTLE]));
ulU8.PushBack(std::make_pair(B_LONG_CASTLE, m_boardDescU8[B_LONG_CASTLE]));
m_boardDescU8[B_SHORT_CASTLE] = 0;
m_boardDescU8[B_LONG_CASTLE] = 0;
m_boardDescBB[BLACK_OCCUPIED] ^= Bit(E8) | Bit(C8) | Bit(A8) | Bit(D8);
}
}
else if ((pt == WP || pt == BP) && Bit(to) == currentEp) // en passant
{
if (pt == WP)
{
ulU8.PushBack(std::make_pair(from, m_boardDescU8[from]));
ulU8.PushBack(std::make_pair(to, m_boardDescU8[to]));
ulU8.PushBack(std::make_pair(to - 8, m_boardDescU8[to - 8]));
ulBB.PushBack(std::make_pair(WP, m_boardDescBB[WP]));
ulBB.PushBack(std::make_pair(BP, m_boardDescBB[BP]));
ulBB.PushBack(std::make_pair(WHITE_OCCUPIED, m_boardDescBB[WHITE_OCCUPIED]));
ulBB.PushBack(std::make_pair(BLACK_OCCUPIED, m_boardDescBB[BLACK_OCCUPIED]));
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[from][WP];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[to][WP];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[to - 8][BP];
MOVE_PIECE(WP, from, to);
REMOVE_PIECE(BP, to - 8);
m_boardDescBB[WHITE_OCCUPIED] ^= (Bit(from) | Bit(to));
m_boardDescBB[BLACK_OCCUPIED] ^= Bit(to - 8);
}
else
{
ulU8.PushBack(std::make_pair(from, m_boardDescU8[from]));
ulU8.PushBack(std::make_pair(to, m_boardDescU8[to]));
ulU8.PushBack(std::make_pair(to + 8, m_boardDescU8[to + 8]));
ulBB.PushBack(std::make_pair(WP, m_boardDescBB[WP]));
ulBB.PushBack(std::make_pair(BP, m_boardDescBB[BP]));
ulBB.PushBack(std::make_pair(WHITE_OCCUPIED, m_boardDescBB[WHITE_OCCUPIED]));
ulBB.PushBack(std::make_pair(BLACK_OCCUPIED, m_boardDescBB[BLACK_OCCUPIED]));
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[from][BP];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[to][BP];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[to + 8][WP];
MOVE_PIECE(BP, from, to);
REMOVE_PIECE(WP, to + 8);
m_boardDescBB[BLACK_OCCUPIED] ^= (Bit(from) | Bit(to));
m_boardDescBB[WHITE_OCCUPIED] ^= Bit(to + 8);
}
}
else
{
int32_t dy = GetY(from) - GetY(to);
bool isCapture = m_boardDescU8[to] != EMPTY; // this is only for NON-EP captures
bool isPromotion = promoType != 0;
bool isPawnDoubleMove = (pt == WP || pt == BP) && (dy != 1 && dy != -1);
if (isCapture && !isPromotion)
{
ulU8.PushBack(std::make_pair(from, m_boardDescU8[from]));
ulU8.PushBack(std::make_pair(to, m_boardDescU8[to]));
ulBB.PushBack(std::make_pair(pt, m_boardDescBB[pt]));
ulBB.PushBack(std::make_pair(m_boardDescU8[to], m_boardDescBB[m_boardDescU8[to]]));
ulBB.PushBack(std::make_pair(WHITE_OCCUPIED, m_boardDescBB[WHITE_OCCUPIED]));
ulBB.PushBack(std::make_pair(BLACK_OCCUPIED, m_boardDescBB[BLACK_OCCUPIED]));
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[from][pt];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[to][pt];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[to][m_boardDescU8[to]];
REMOVE_PIECE(pt, from);
REPLACE_PIECE(m_boardDescU8[to], pt, to);
m_boardDescBB[WHITE_OCCUPIED | (color ^ COLOR_MASK)] ^= Bit(to);
m_boardDescBB[WHITE_OCCUPIED | color] ^= Bit(to) | Bit(from);
}
else if (!isPromotion && !isCapture)
{
ulU8.PushBack(std::make_pair(from, m_boardDescU8[from]));
ulU8.PushBack(std::make_pair(to, m_boardDescU8[to]));
ulBB.PushBack(std::make_pair(pt, m_boardDescBB[pt]));
ulBB.PushBack(std::make_pair(WHITE_OCCUPIED | color, m_boardDescBB[WHITE_OCCUPIED | color]));
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[from][pt];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[to][pt];
MOVE_PIECE(pt, from, to);
m_boardDescBB[WHITE_OCCUPIED | color] ^= Bit(to) | Bit(from);
}
else if (isPromotion && isCapture)
{
ulU8.PushBack(std::make_pair(from, m_boardDescU8[from]));
ulU8.PushBack(std::make_pair(to, m_boardDescU8[to]));
ulBB.PushBack(std::make_pair(pt, m_boardDescBB[pt]));
ulBB.PushBack(std::make_pair(m_boardDescU8[to], m_boardDescBB[m_boardDescU8[to]]));
ulBB.PushBack(std::make_pair(promoType, m_boardDescBB[promoType]));
ulBB.PushBack(std::make_pair(WHITE_OCCUPIED, m_boardDescBB[WHITE_OCCUPIED]));
ulBB.PushBack(std::make_pair(BLACK_OCCUPIED, m_boardDescBB[BLACK_OCCUPIED]));
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[from][pt];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[to][promoType];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[to][m_boardDescU8[to]];
REMOVE_PIECE(pt, from);
REPLACE_PIECE(m_boardDescU8[to], promoType, to);
m_boardDescBB[WHITE_OCCUPIED | (color ^ COLOR_MASK)] ^= Bit(to);
m_boardDescBB[WHITE_OCCUPIED | color] ^= Bit(to) | Bit(from);
}
else // !isCapture && isPromotion
{
ulU8.PushBack(std::make_pair(from, m_boardDescU8[from]));
ulU8.PushBack(std::make_pair(to, m_boardDescU8[to]));
ulBB.PushBack(std::make_pair(pt, m_boardDescBB[pt]));
ulBB.PushBack(std::make_pair(promoType, m_boardDescBB[promoType]));
ulBB.PushBack(std::make_pair(WHITE_OCCUPIED | color, m_boardDescBB[WHITE_OCCUPIED | color]));
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[from][pt];
m_boardDescBB[HASH] ^= PIECES_ZOBRIST[to][promoType];
REMOVE_PIECE(pt, from);
PLACE_PIECE(promoType, to);
m_boardDescBB[WHITE_OCCUPIED | color] ^= Bit(to) | Bit(from);
}
// check for pawn move (update ep)
if (isPawnDoubleMove)
{
// this was saved to undo list earlier already
m_boardDescBB[EN_PASS_SQUARE] = PAWN_MOVE_1[from][pt == WP ? 0 : 1];
m_boardDescBB[HASH] ^= EN_PASS_ZOBRIST[BitScanForward(PAWN_MOVE_1[from][pt == WP ? 0 : 1])];
}
// update castling rights
if (m_boardDescU8[W_SHORT_CASTLE] && (pt == WK || (pt == WR && from == H1) || (to == H1)))
{
ulU8.PushBack(std::make_pair(W_SHORT_CASTLE, m_boardDescU8[W_SHORT_CASTLE]));
m_boardDescU8[W_SHORT_CASTLE] = 0;
m_boardDescBB[HASH] ^= W_SHORT_CASTLE_ZOBRIST;
}
if (m_boardDescU8[W_LONG_CASTLE] && (pt == WK || (pt == WR && from == A1) || (to == A1)))
{
ulU8.PushBack(std::make_pair(W_LONG_CASTLE, m_boardDescU8[W_LONG_CASTLE]));
m_boardDescU8[W_LONG_CASTLE] = 0;
m_boardDescBB[HASH] ^= W_LONG_CASTLE_ZOBRIST;
}
if (m_boardDescU8[B_SHORT_CASTLE] && (pt == BK || (pt == BR && from == H8) || (to == H8)))
{
ulU8.PushBack(std::make_pair(B_SHORT_CASTLE, m_boardDescU8[B_SHORT_CASTLE]));
m_boardDescU8[B_SHORT_CASTLE] = 0;
m_boardDescBB[HASH] ^= B_SHORT_CASTLE_ZOBRIST;
}
if (m_boardDescU8[B_LONG_CASTLE] && (pt == BK || (pt == BR && from == A8) || (to == A8)))
{
ulU8.PushBack(std::make_pair(B_LONG_CASTLE, m_boardDescU8[B_LONG_CASTLE]));
m_boardDescU8[B_LONG_CASTLE] = 0;
m_boardDescBB[HASH] ^= B_LONG_CASTLE_ZOBRIST;
}
// update half move clock
// castling does not reset the clock
ulU8.PushBack(std::make_pair(HALF_MOVES_CLOCK, m_boardDescU8[HALF_MOVES_CLOCK]));
if (isCapture || pt == WP || pt == BP)
{
m_boardDescU8[HALF_MOVES_CLOCK] = 0;
}
else
{
if (m_boardDescU8[HALF_MOVES_CLOCK] != std::numeric_limits<uint8_t>::max())
{
++m_boardDescU8[HALF_MOVES_CLOCK];
}
}
}
#ifdef DEBUG
CheckBoardConsistency();
// verify that we don't have duplicate entries in the undo lists
std::set<uint32_t> entries;
for (size_t i = 0; i < ulBB.GetSize(); ++i)
{
if (entries.find(ulBB[i].first) != entries.end())
{
std::cout << "Duplicate undo entry in BB undo list found! - " << static_cast<int>(ulBB[i].first) << std::endl;
assert(false);
}
entries.insert(ulBB[i].first);
}
entries.clear();
for (size_t i = 0; i < ulU8.GetSize(); ++i)
{
if (entries.find(ulU8[i].first) != entries.end())
{
std::cout << "Duplicate undo entry in U8 undo list found! - " << ulU8[i].first << std::endl;
assert(false);
}
entries.insert(ulU8[i].first);
}
// verify that we have updated the hash correctly
uint64_t oldHash = GetHash();
UpdateHashFull_();
if (oldHash != GetHash())
{
std::cout << GetFen() << std::endl;
std::cout << MoveToAlg(mv) << std::endl;
}
assert(oldHash == GetHash());
#endif
UpdateInCheck_();
if (InCheck())
{
// this position is illegal, undo the move
for (size_t i = 0; i < ulBB.GetSize(); ++i)
{
m_boardDescBB[ulBB[i].first] = ulBB[i].second;
}
// this position is illegal, undo the move
for (size_t i = 0; i < ulU8.GetSize(); ++i)
{
m_boardDescU8[ulU8[i].first] = ulU8[i].second;
}
m_boardDescBB[HASH] = m_hashStack.Pop();
m_undoStackBB.Pop();
m_undoStackU8.Pop();
return false;
}
// no need to store this
m_boardDescU8[SIDE_TO_MOVE] = m_boardDescU8[SIDE_TO_MOVE] ^ COLOR_MASK;
m_boardDescBB[HASH] ^= SIDE_TO_MOVE_ZOBRIST;
UpdateInCheck_(); // this is for the new side
m_moveStack.Push(mv);
return true;
#undef MOVE_PIECE
#undef REMOVE_PIECE
}
Board::CheckInfo Board::ComputeCheckInfo()
{
CheckInfo ret;
Square kingPos = (GetSideToMove() == WHITE ? BitScanForward(m_boardDescBB[WK]) : BitScanForward(m_boardDescBB[BK]));
int32_t kingX = GetX(kingPos);
int32_t kingY = GetY(kingPos);
int32_t kingDiag0 = GetDiag0(kingPos);
int32_t kingDiag1 = GetDiag1(kingPos);
uint64_t opponentQueens = (GetSideToMove() == WHITE ? m_boardDescBB[BQ] : m_boardDescBB[WQ]);
uint64_t opponentRooks = (GetSideToMove() == WHITE ? m_boardDescBB[BR] : m_boardDescBB[WR]);
uint64_t opponentBishops = (GetSideToMove() == WHITE ? m_boardDescBB[BB] : m_boardDescBB[WB]);
while (opponentQueens)
{
Square pos = Extract(opponentQueens);
// all the cases are mutually exclusive
if (GetX(pos) == kingX)
{
ret.opponentRQOnSameX = true;
}
else if (GetY(pos) == kingY)
{
ret.opponentRQOnSameY = true;
}
else if (GetDiag0(pos) == kingDiag0)
{
ret.opponentBQOnSameDiag0 = true;
}
else if (GetDiag1(pos) == kingDiag1)
{
ret.opponentBQOnSameDiag1 = true;
}
}
while (opponentRooks)
{
Square pos = Extract(opponentRooks);
// all the cases are mutually exclusive
if (GetX(pos) == kingX)
{
ret.opponentRQOnSameX = true;
}
else if (GetY(pos) == kingY)
{
ret.opponentRQOnSameY = true;
}
}
while (opponentBishops)
{
Square pos = Extract(opponentBishops);
// all the cases are mutually exclusive
if (GetDiag0(pos) == kingDiag0)
{
ret.opponentBQOnSameDiag0 = true;
}
else if (GetDiag1(pos) == kingDiag1)
{
ret.opponentBQOnSameDiag1 = true;
}
}
return ret;
}
bool Board::CheckLegal(const CheckInfo &ci, Move mv)
{
// in this function we try to determine legality of moves quickly without doing a full check (by applying the move)
PieceType pt = GetPieceType(mv);
bool doFullCheck = false;
if (InCheck())
{
// if we are in check, do a full check because there are many potential ways to get out of check, and we are lazy
doFullCheck = true;
}
else
{
switch (pt)
{
case WK:
case BK:
// if this is a king move, we do a full check because any king move can potentially put the king in check
// this includes castling
doFullCheck = true;
break;
case WP:
case BP:
if (Bit(GetToSquare(mv)) == m_boardDescBB[EN_PASS_SQUARE])
{
// if this is EP, we do a full check... because EPs are rare, and we are lazy
doFullCheck = true;
break;
}
// fall through if this is a pawn move that's not EP
default:
{
doFullCheck = false;
// now we know we are not moving the king, this is not EP, and the king is not already in check
// in this case, the only way this move can put the king in check is if we just moved away a pinned piece
// besides EP and castling (both have been dealt with), the only square that will be vacated after a move is the from square
Square vacatedSquare = GetFromSquare(mv);
Square kingPos = BitScanForward(GetSideToMove() == WHITE ? m_boardDescBB[WK] : m_boardDescBB[BK]);
if ((ci.opponentRQOnSameX && (GetX(vacatedSquare) == GetX(kingPos))) ||
(ci.opponentRQOnSameY && (GetY(vacatedSquare) == GetY(kingPos))) ||
(ci.opponentBQOnSameDiag0 && (GetDiag0(vacatedSquare) == GetDiag0(kingPos))) ||
(ci.opponentBQOnSameDiag1 && (GetDiag1(vacatedSquare) == GetDiag1(kingPos))))
{
doFullCheck = true;
}
}
}
}
if (doFullCheck)
{
bool ret = ApplyMove(mv);
if (ret)
{
UndoMove();
return true;