/** Remove pseudo-legal EP square if it is not legal, ie would leave king in check. */
public static void fixupEPSquare(Position pos)
{
int epSquare = pos.getEpSquare();
if (epSquare >= 0) {
MoveGen MG = new MoveGen();
MoveGen.MoveList moves = MG.pseudoLegalMoves(pos);
MoveGen.RemoveIllegal(pos, moves);
bool epValid = false;
for (int mi = 0; mi < moves.size; mi++) {
Move m = moves.m[mi];
if (m.to == epSquare) {
if (pos.getPiece(m.from) == (pos.whiteMove ? Piece.WPAWN : Piece.BPAWN)) {
epValid = true;
break;
}
}
}
if (!epValid) {
pos.setEpSquare(-1);
}
}
}
private static bool isCapture(Position pos, Move move)
{
if (pos.getPiece(move.to) == Piece.EMPTY) {
int p = pos.getPiece(move.from);
if ((p == (pos.whiteMove ? Piece.WPAWN : Piece.BPAWN)) && (move.to == pos.getEpSquare())) {
return true;
} else {
return false;
}
} else {
return true;
}
}
/** Return a FEN string corresponding to a chess Position object. */
public static string toFEN(Position pos)
{
string ret = "";
// Piece placement
for (int r = 7; r >=0; r--) {
int numEmpty = 0;
for (int c = 0; c < 8; c++) {
int p = pos.getPiece(Position.getSquare(c, r));
if (p == Piece.EMPTY) {
numEmpty++;
} else {
if (numEmpty > 0) {
ret+=numEmpty.ToString();
numEmpty = 0;
}
switch (p) {
case Piece.WKING: ret+=('K'); break;
case Piece.WQUEEN: ret+=('Q'); break;
case Piece.WROOK: ret+=('R'); break;
case Piece.WBISHOP: ret+=('B'); break;
case Piece.WKNIGHT: ret+=('N'); break;
case Piece.WPAWN: ret+=('P'); break;
case Piece.BKING: ret+=('k'); break;
case Piece.BQUEEN: ret+=('q'); break;
case Piece.BROOK: ret+=('r'); break;
case Piece.BBISHOP: ret+=('b'); break;
case Piece.BKNIGHT: ret+=('n'); break;
case Piece.BPAWN: ret+=('p'); break;
default: throw new RuntimeException();
}
}
}
if (numEmpty > 0) {
ret += numEmpty.ToString();
}
if (r > 0) {
ret += ('/');
}
}
ret += (pos.whiteMove ? " w " : " b ");
// Castling rights
bool anyCastle = false;
if (pos.h1Castle()) {
ret += ('K');
anyCastle = true;
}
if (pos.a1Castle()) {
ret += ('Q');
anyCastle = true;
}
if (pos.h8Castle()) {
ret += ('k');
anyCastle = true;
}
if (pos.a8Castle()) {
ret += ('q');
anyCastle = true;
}
if (!anyCastle) {
ret += ('-');
}
// En passant target square
{
ret += (' ');
if (pos.getEpSquare() >= 0) {
int x = Position.getX(pos.getEpSquare());
int y = Position.getY(pos.getEpSquare());
ret += ((char)(x + 'a'));
ret += ((char)(y + '1'));
} else {
ret += ('-');
}
}
// Move counters
ret += " " + pos.halfMoveClock;
ret += " " + pos.fullMoveCounter;
return ret;
}
/**
* Generate and return a list of pseudo-legal moves.
* Pseudo-legal means that the moves doesn't necessarily defend from check threats.
*/
public MoveList pseudoLegalMoves(Position pos)
{
MoveList moveList = getMoveListObj();
ulong occupied = pos.whiteBB | pos.blackBB;
if (pos.whiteMove) {
int sq = 0;
ulong m = 0;
// Queen moves
ulong squares = pos.pieceTypeBB[Piece.WQUEEN];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = (BitBoard.rookAttacks(sq, occupied) | BitBoard.bishopAttacks(sq, occupied)) & ~pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Rook moves
squares = pos.pieceTypeBB[Piece.WROOK];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.rookAttacks(sq, occupied) & ~pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Bishop moves
squares = pos.pieceTypeBB[Piece.WBISHOP];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.bishopAttacks(sq, occupied) & ~pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// King moves
{
sq = pos.getKingSq(true);
m = BitBoard.kingAttacks[sq] & ~pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
int k0 = 4;
if (sq == k0) {
ulong OO_SQ = 0x60L;
ulong OOO_SQ = 0xEL;
if (((pos.getCastleMask() & (1 << Position.H1_CASTLE)) != 0) &&
((OO_SQ & (pos.whiteBB | pos.blackBB)) == 0) &&
(pos.getPiece(k0 + 3) == Piece.WROOK) &&
!sqAttacked(pos, k0) &&
!sqAttacked(pos, k0 + 1)) {
setMove(moveList, k0, k0 + 2, Piece.EMPTY);
}
if (((pos.getCastleMask() & (1 << Position.A1_CASTLE)) != 0) &&
((OOO_SQ & (pos.whiteBB | pos.blackBB)) == 0) &&
(pos.getPiece(k0 - 4) == Piece.WROOK) &&
!sqAttacked(pos, k0) &&
!sqAttacked(pos, k0 - 1)) {
setMove(moveList, k0, k0 - 2, Piece.EMPTY);
}
}
}
// Knight moves
ulong knights = pos.pieceTypeBB[Piece.WKNIGHT];
while (knights != 0) {
sq = BitBoard.numberOfTrailingZeros(knights);
m = BitBoard.knightAttacks[sq] & ~pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
knights &= knights-1;
}
// Pawn moves
ulong pawns = pos.pieceTypeBB[Piece.WPAWN];
m = (pawns << 8) & ~occupied;
if (addPawnMovesByMask(moveList, pos, m, -8, true)) return moveList;
m = ((m & BitBoard.maskRow3) << 8) & ~occupied;
addPawnDoubleMovesByMask(moveList, pos, m, -16);
int epSquare = pos.getEpSquare();
ulong epMask = (epSquare >= 0) ? (1UL << epSquare) : 0L;
m = (pawns << 7) & BitBoard.maskAToGFiles & (pos.blackBB | epMask);
if (addPawnMovesByMask(moveList, pos, m, -7, true)) return moveList;
m = (pawns << 9) & BitBoard.maskBToHFiles & (pos.blackBB | epMask);
if (addPawnMovesByMask(moveList, pos, m, -9, true)) return moveList;
} else {
int sq = 0;
ulong m = 0;
// Queen moves
ulong squares = pos.pieceTypeBB[Piece.BQUEEN];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = (BitBoard.rookAttacks(sq, occupied) | BitBoard.bishopAttacks(sq, occupied)) & ~pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Rook moves
squares = pos.pieceTypeBB[Piece.BROOK];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.rookAttacks(sq, occupied) & ~pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Bishop moves
squares = pos.pieceTypeBB[Piece.BBISHOP];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.bishopAttacks(sq, occupied) & ~pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// King moves
{
sq = pos.getKingSq(false);
m = BitBoard.kingAttacks[sq] & ~pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
int k0 = 60;
if (sq == k0) {
ulong OO_SQ = 0x6000000000000000L;
ulong OOO_SQ = 0xE00000000000000L;
if (((pos.getCastleMask() & (1 << Position.H8_CASTLE)) != 0) &&
((OO_SQ & (pos.whiteBB | pos.blackBB)) == 0) &&
(pos.getPiece(k0 + 3) == Piece.BROOK) &&
!sqAttacked(pos, k0) &&
!sqAttacked(pos, k0 + 1)) {
setMove(moveList, k0, k0 + 2, Piece.EMPTY);
}
if (((pos.getCastleMask() & (1 << Position.A8_CASTLE)) != 0) &&
((OOO_SQ & (pos.whiteBB | pos.blackBB)) == 0) &&
(pos.getPiece(k0 - 4) == Piece.BROOK) &&
!sqAttacked(pos, k0) &&
!sqAttacked(pos, k0 - 1)) {
setMove(moveList, k0, k0 - 2, Piece.EMPTY);
}
}
}
// Knight moves
ulong knights = pos.pieceTypeBB[Piece.BKNIGHT];
while (knights != 0) {
sq = BitBoard.numberOfTrailingZeros(knights);
m = BitBoard.knightAttacks[sq] & ~pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
knights &= knights-1;
}
// Pawn moves
ulong pawns = pos.pieceTypeBB[Piece.BPAWN];
m = (pawns >> 8) & ~occupied;
if (addPawnMovesByMask(moveList, pos, m, 8, true)) return moveList;
m = ((m & BitBoard.maskRow6) >> 8) & ~occupied;
addPawnDoubleMovesByMask(moveList, pos, m, 16);
int epSquare = pos.getEpSquare();
ulong epMask = (epSquare >= 0) ? (1UL << epSquare) : 0L;
m = (pawns >> 9) & BitBoard.maskAToGFiles & (pos.whiteBB | epMask);
if (addPawnMovesByMask(moveList, pos, m, 9, true)) return moveList;
m = (pawns >> 7) & BitBoard.maskBToHFiles & (pos.whiteBB | epMask);
if (addPawnMovesByMask(moveList, pos, m, 7, true)) return moveList;
}
return moveList;
}
/** Generate captures, checks, and possibly some other moves that are too hard to filter out. */
public MoveList pseudoLegalCapturesAndChecks(Position pos)
{
MoveList moveList = getMoveListObj();
ulong occupied = pos.whiteBB | pos.blackBB;
if (pos.whiteMove) {
int sq = 0;
ulong m = 0;
int bKingSq = pos.getKingSq(false);
ulong discovered = 0; // Squares that could generate discovered checks
ulong kRookAtk = BitBoard.rookAttacks(bKingSq, occupied);
if ((BitBoard.rookAttacks(bKingSq, occupied & ~kRookAtk) &
(pos.pieceTypeBB[Piece.WQUEEN] | pos.pieceTypeBB[Piece.WROOK])) != 0)
discovered |= kRookAtk;
ulong kBishAtk = BitBoard.bishopAttacks(bKingSq, occupied);
if ((BitBoard.bishopAttacks(bKingSq, occupied & ~kBishAtk) &
(pos.pieceTypeBB[Piece.WQUEEN] | pos.pieceTypeBB[Piece.WBISHOP])) != 0)
discovered |= kBishAtk;
// Queen moves
ulong squares = pos.pieceTypeBB[Piece.WQUEEN];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = (BitBoard.rookAttacks(sq, occupied) | BitBoard.bishopAttacks(sq, occupied));
if ((discovered & (1UL<<sq)) == 0) m &= (pos.blackBB | kRookAtk | kBishAtk);
m &= ~pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Rook moves
squares = pos.pieceTypeBB[Piece.WROOK];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.rookAttacks(sq, occupied);
if ((discovered & (1UL<<sq)) == 0) m &= (pos.blackBB | kRookAtk);
m &= ~pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Bishop moves
squares = pos.pieceTypeBB[Piece.WBISHOP];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.bishopAttacks(sq, occupied);
if ((discovered & (1UL<<sq)) == 0) m &= (pos.blackBB | kBishAtk);
m &= ~pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// King moves
{
sq = pos.getKingSq(true);
m = BitBoard.kingAttacks[sq];
m &= ((discovered & (1UL<<sq)) == 0) ? pos.blackBB : ~pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
int k0 = 4;
if (sq == k0) {
ulong OO_SQ = 0x60L;
ulong OOO_SQ = 0xEL;
if (((pos.getCastleMask() & (1 << Position.H1_CASTLE)) != 0) &&
((OO_SQ & (pos.whiteBB | pos.blackBB)) == 0) &&
(pos.getPiece(k0 + 3) == Piece.WROOK) &&
!sqAttacked(pos, k0) &&
!sqAttacked(pos, k0 + 1)) {
setMove(moveList, k0, k0 + 2, Piece.EMPTY);
}
if (((pos.getCastleMask() & (1 << Position.A1_CASTLE)) != 0) &&
((OOO_SQ & (pos.whiteBB | pos.blackBB)) == 0) &&
(pos.getPiece(k0 - 4) == Piece.WROOK) &&
!sqAttacked(pos, k0) &&
!sqAttacked(pos, k0 - 1)) {
setMove(moveList, k0, k0 - 2, Piece.EMPTY);
}
}
}
// Knight moves
ulong knights = pos.pieceTypeBB[Piece.WKNIGHT];
ulong kKnightAtk = BitBoard.knightAttacks[bKingSq];
while (knights != 0) {
sq = BitBoard.numberOfTrailingZeros(knights);
m = BitBoard.knightAttacks[sq] & ~pos.whiteBB;
if ((discovered & (1UL<<sq)) == 0) m &= (pos.blackBB | kKnightAtk);
m &= ~pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
knights &= knights-1;
}
// Pawn moves
// Captures
ulong pawns = pos.pieceTypeBB[Piece.WPAWN];
int epSquare = pos.getEpSquare();
ulong epMask = (epSquare >= 0) ? (1UL << epSquare) : 0L;
m = (pawns << 7) & BitBoard.maskAToGFiles & (pos.blackBB | epMask);
if (addPawnMovesByMask(moveList, pos, m, -7, false)) return moveList;
m = (pawns << 9) & BitBoard.maskBToHFiles & (pos.blackBB | epMask);
if (addPawnMovesByMask(moveList, pos, m, -9, false)) return moveList;
// Discovered checks and promotions
ulong pawnAll = discovered | BitBoard.maskRow7;
m = ((pawns & pawnAll) << 8) & ~(pos.whiteBB | pos.blackBB);
if (addPawnMovesByMask(moveList, pos, m, -8, false)) return moveList;
m = ((m & BitBoard.maskRow3) << 8) & ~(pos.whiteBB | pos.blackBB);
addPawnDoubleMovesByMask(moveList, pos, m, -16);
// Normal checks
m = ((pawns & ~pawnAll) << 8) & ~(pos.whiteBB | pos.blackBB);
if (addPawnMovesByMask(moveList, pos, m & BitBoard.bPawnAttacks[bKingSq], -8, false)) return moveList;
m = ((m & BitBoard.maskRow3) << 8) & ~(pos.whiteBB | pos.blackBB);
addPawnDoubleMovesByMask(moveList, pos, m & BitBoard.bPawnAttacks[bKingSq], -16);
} else {
int sq = 0;
ulong m = 0;
int wKingSq = pos.getKingSq(true);
ulong discovered = 0; // Squares that could generate discovered checks
ulong kRookAtk = BitBoard.rookAttacks(wKingSq, occupied);
if ((BitBoard.rookAttacks(wKingSq, occupied & ~kRookAtk) &
(pos.pieceTypeBB[Piece.BQUEEN] | pos.pieceTypeBB[Piece.BROOK])) != 0)
discovered |= kRookAtk;
ulong kBishAtk = BitBoard.bishopAttacks(wKingSq, occupied);
if ((BitBoard.bishopAttacks(wKingSq, occupied & ~kBishAtk) &
(pos.pieceTypeBB[Piece.BQUEEN] | pos.pieceTypeBB[Piece.BBISHOP])) != 0)
discovered |= kBishAtk;
// Queen moves
ulong squares = pos.pieceTypeBB[Piece.BQUEEN];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = (BitBoard.rookAttacks(sq, occupied) | BitBoard.bishopAttacks(sq, occupied));
if ((discovered & (1UL<<sq)) == 0) m &= pos.whiteBB | kRookAtk | kBishAtk;
m &= ~pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Rook moves
squares = pos.pieceTypeBB[Piece.BROOK];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.rookAttacks(sq, occupied);
if ((discovered & (1UL<<sq)) == 0) m &= pos.whiteBB | kRookAtk;
m &= ~pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Bishop moves
squares = pos.pieceTypeBB[Piece.BBISHOP];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.bishopAttacks(sq, occupied);
if ((discovered & (1UL<<sq)) == 0) m &= pos.whiteBB | kBishAtk;
m &= ~pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// King moves
{
sq = pos.getKingSq(false);
m = BitBoard.kingAttacks[sq];
m &= ((discovered & (1UL<<sq)) == 0) ? pos.whiteBB : ~pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
int k0 = 60;
if (sq == k0) {
ulong OO_SQ = 0x6000000000000000L;
ulong OOO_SQ = 0xE00000000000000L;
if (((pos.getCastleMask() & (1 << Position.H8_CASTLE)) != 0) &&
((OO_SQ & (pos.whiteBB | pos.blackBB)) == 0) &&
(pos.getPiece(k0 + 3) == Piece.BROOK) &&
!sqAttacked(pos, k0) &&
!sqAttacked(pos, k0 + 1)) {
setMove(moveList, k0, k0 + 2, Piece.EMPTY);
}
if (((pos.getCastleMask() & (1 << Position.A8_CASTLE)) != 0) &&
((OOO_SQ & (pos.whiteBB | pos.blackBB)) == 0) &&
(pos.getPiece(k0 - 4) == Piece.BROOK) &&
!sqAttacked(pos, k0) &&
!sqAttacked(pos, k0 - 1)) {
setMove(moveList, k0, k0 - 2, Piece.EMPTY);
}
}
}
// Knight moves
ulong knights = pos.pieceTypeBB[Piece.BKNIGHT];
ulong kKnightAtk = BitBoard.knightAttacks[wKingSq];
while (knights != 0) {
sq = BitBoard.numberOfTrailingZeros(knights);
m = BitBoard.knightAttacks[sq] & ~pos.blackBB;
if ((discovered & (1UL<<sq)) == 0) m &= pos.whiteBB | kKnightAtk;
m &= ~pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
knights &= knights-1;
}
// Pawn moves
// Captures
ulong pawns = pos.pieceTypeBB[Piece.BPAWN];
int epSquare = pos.getEpSquare();
ulong epMask = (epSquare >= 0) ? (1UL << epSquare) : 0L;
m = (pawns >> 9) & BitBoard.maskAToGFiles & (pos.whiteBB | epMask);
if (addPawnMovesByMask(moveList, pos, m, 9, false)) return moveList;
m = (pawns >> 7) & BitBoard.maskBToHFiles & (pos.whiteBB | epMask);
if (addPawnMovesByMask(moveList, pos, m, 7, false)) return moveList;
// Discovered checks and promotions
ulong pawnAll = discovered | BitBoard.maskRow2;
m = ((pawns & pawnAll) >> 8) & ~(pos.whiteBB | pos.blackBB);
if (addPawnMovesByMask(moveList, pos, m, 8, false)) return moveList;
m = ((m & BitBoard.maskRow6) >> 8) & ~(pos.whiteBB | pos.blackBB);
addPawnDoubleMovesByMask(moveList, pos, m, 16);
// Normal checks
m = ((pawns & ~pawnAll) >> 8) & ~(pos.whiteBB | pos.blackBB);
if (addPawnMovesByMask(moveList, pos, m & BitBoard.wPawnAttacks[wKingSq], 8, false)) return moveList;
m = ((m & BitBoard.maskRow6) >> 8) & ~(pos.whiteBB | pos.blackBB);
addPawnDoubleMovesByMask(moveList, pos, m & BitBoard.wPawnAttacks[wKingSq], 16);
}
return moveList;
}
public MoveList pseudoLegalCaptures(Position pos)
{
MoveList moveList = getMoveListObj();
ulong occupied = pos.whiteBB | pos.blackBB;
if (pos.whiteMove) {
int sq = 0;
ulong m = 0;
// Queen moves
ulong squares = pos.pieceTypeBB[Piece.WQUEEN];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = (BitBoard.rookAttacks(sq, occupied) | BitBoard.bishopAttacks(sq, occupied)) & pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Rook moves
squares = pos.pieceTypeBB[Piece.WROOK];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.rookAttacks(sq, occupied) & pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Bishop moves
squares = pos.pieceTypeBB[Piece.WBISHOP];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.bishopAttacks(sq, occupied) & pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Knight moves
ulong knights = pos.pieceTypeBB[Piece.WKNIGHT];
while (knights != 0) {
sq = BitBoard.numberOfTrailingZeros(knights);
m = BitBoard.knightAttacks[sq] & pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
knights &= knights-1;
}
// King moves
sq = pos.getKingSq(true);
m = BitBoard.kingAttacks[sq] & pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
// Pawn moves
ulong pawns = pos.pieceTypeBB[Piece.WPAWN];
m = (pawns << 8) & ~(pos.whiteBB | pos.blackBB);
m &= BitBoard.maskRow8;
if (addPawnMovesByMask(moveList, pos, m, -8, false)) return moveList;
int epSquare = pos.getEpSquare();
ulong epMask = (epSquare >= 0) ? (1UL << epSquare) : 0L;
m = (pawns << 7) & BitBoard.maskAToGFiles & (pos.blackBB | epMask);
if (addPawnMovesByMask(moveList, pos, m, -7, false)) return moveList;
m = (pawns << 9) & BitBoard.maskBToHFiles & (pos.blackBB | epMask);
if (addPawnMovesByMask(moveList, pos, m, -9, false)) return moveList;
} else {
int sq = 0;
ulong m = 0;
// Queen moves
ulong squares = pos.pieceTypeBB[Piece.BQUEEN];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = (BitBoard.rookAttacks(sq, occupied) | BitBoard.bishopAttacks(sq, occupied)) & pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Rook moves
squares = pos.pieceTypeBB[Piece.BROOK];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.rookAttacks(sq, occupied) & pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Bishop moves
squares = pos.pieceTypeBB[Piece.BBISHOP];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.bishopAttacks(sq, occupied) & pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Knight moves
ulong knights = pos.pieceTypeBB[Piece.BKNIGHT];
while (knights != 0) {
sq = BitBoard.numberOfTrailingZeros(knights);
m = BitBoard.knightAttacks[sq] & pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
knights &= knights-1;
}
// King moves
sq = pos.getKingSq(false);
m = BitBoard.kingAttacks[sq] & pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
// Pawn moves
ulong pawns = pos.pieceTypeBB[Piece.BPAWN];
m = (pawns >> 8) & ~(pos.whiteBB | pos.blackBB);
m &= BitBoard.maskRow1;
if (addPawnMovesByMask(moveList, pos, m, 8, false)) return moveList;
int epSquare = pos.getEpSquare();
ulong epMask = (epSquare >= 0) ? (1UL << epSquare) : 0L;
m = (pawns >> 9) & BitBoard.maskAToGFiles & (pos.whiteBB | epMask);
if (addPawnMovesByMask(moveList, pos, m, 9, false)) return moveList;
m = (pawns >> 7) & BitBoard.maskBToHFiles & (pos.whiteBB | epMask);
if (addPawnMovesByMask(moveList, pos, m, 7, false)) return moveList;
}
return moveList;
}
/**
* Generate and return a list of pseudo-legal check evasion moves.
* Pseudo-legal means that the moves doesn't necessarily defend from check threats.
*/
public MoveList checkEvasions(Position pos)
{
MoveList moveList = getMoveListObj();
ulong occupied = pos.whiteBB | pos.blackBB;
if (pos.whiteMove) {
int sq = 0;
ulong m = 0;
ulong kingThreats = pos.pieceTypeBB[Piece.BKNIGHT] & BitBoard.knightAttacks[pos.wKingSq];
ulong rookPieces = pos.pieceTypeBB[Piece.BROOK] | pos.pieceTypeBB[Piece.BQUEEN];
if (rookPieces != 0)
kingThreats |= rookPieces & BitBoard.rookAttacks(pos.wKingSq, occupied);
ulong bishPieces = pos.pieceTypeBB[Piece.BBISHOP] | pos.pieceTypeBB[Piece.BQUEEN];
if (bishPieces != 0)
kingThreats |= bishPieces & BitBoard.bishopAttacks(pos.wKingSq, occupied);
kingThreats |= pos.pieceTypeBB[Piece.BPAWN] & BitBoard.wPawnAttacks[pos.wKingSq];
ulong validTargets = 0;
if ((kingThreats != 0) && ((kingThreats & (kingThreats-1)) == 0)) { // Exactly one attacking piece
int threatSq = BitBoard.numberOfTrailingZeros(kingThreats);
validTargets = kingThreats | BitBoard.squaresBetween[pos.wKingSq][threatSq];
}
validTargets |= pos.pieceTypeBB[Piece.BKING];
// Queen moves
ulong squares = pos.pieceTypeBB[Piece.WQUEEN];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = (BitBoard.rookAttacks(sq, occupied) | BitBoard.bishopAttacks(sq, occupied)) &
~pos.whiteBB & validTargets;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Rook moves
squares = pos.pieceTypeBB[Piece.WROOK];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.rookAttacks(sq, occupied) & ~pos.whiteBB & validTargets;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Bishop moves
squares = pos.pieceTypeBB[Piece.WBISHOP];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.bishopAttacks(sq, occupied) & ~pos.whiteBB & validTargets;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// King moves
{
sq = pos.getKingSq(true);
m = BitBoard.kingAttacks[sq] & ~pos.whiteBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
}
// Knight moves
ulong knights = pos.pieceTypeBB[Piece.WKNIGHT];
while (knights != 0) {
sq = BitBoard.numberOfTrailingZeros(knights);
m = BitBoard.knightAttacks[sq] & ~pos.whiteBB & validTargets;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
knights &= knights-1;
}
// Pawn moves
ulong pawns = pos.pieceTypeBB[Piece.WPAWN];
m = (pawns << 8) & ~occupied;
if (addPawnMovesByMask(moveList, pos, m & validTargets, -8, true)) return moveList;
m = ((m & BitBoard.maskRow3) << 8) & ~occupied;
addPawnDoubleMovesByMask(moveList, pos, m & validTargets, -16);
int epSquare = pos.getEpSquare();
ulong epMask = (epSquare >= 0) ? (1UL << epSquare) : 0L;
m = (pawns << 7) & BitBoard.maskAToGFiles & ((pos.blackBB & validTargets) | epMask);
if (addPawnMovesByMask(moveList, pos, m, -7, true)) return moveList;
m = (pawns << 9) & BitBoard.maskBToHFiles & ((pos.blackBB & validTargets) | epMask);
if (addPawnMovesByMask(moveList, pos, m, -9, true)) return moveList;
} else {
int sq = 0;
ulong m = 0;
ulong kingThreats = pos.pieceTypeBB[Piece.WKNIGHT] & BitBoard.knightAttacks[pos.bKingSq];
ulong rookPieces = pos.pieceTypeBB[Piece.WROOK] | pos.pieceTypeBB[Piece.WQUEEN];
if (rookPieces != 0)
kingThreats |= rookPieces & BitBoard.rookAttacks(pos.bKingSq, occupied);
ulong bishPieces = pos.pieceTypeBB[Piece.WBISHOP] | pos.pieceTypeBB[Piece.WQUEEN];
if (bishPieces != 0)
kingThreats |= bishPieces & BitBoard.bishopAttacks(pos.bKingSq, occupied);
kingThreats |= pos.pieceTypeBB[Piece.WPAWN] & BitBoard.bPawnAttacks[pos.bKingSq];
ulong validTargets = 0;
if ((kingThreats != 0) && ((kingThreats & (kingThreats-1)) == 0)) { // Exactly one attacking piece
int threatSq = BitBoard.numberOfTrailingZeros(kingThreats);
validTargets = kingThreats | BitBoard.squaresBetween[pos.bKingSq][threatSq];
}
validTargets |= pos.pieceTypeBB[Piece.WKING];
// Queen moves
ulong squares = pos.pieceTypeBB[Piece.BQUEEN];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = (BitBoard.rookAttacks(sq, occupied) | BitBoard.bishopAttacks(sq, occupied)) &
~pos.blackBB & validTargets;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Rook moves
squares = pos.pieceTypeBB[Piece.BROOK];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.rookAttacks(sq, occupied) & ~pos.blackBB & validTargets;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// Bishop moves
squares = pos.pieceTypeBB[Piece.BBISHOP];
while (squares != 0) {
sq = BitBoard.numberOfTrailingZeros(squares);
m = BitBoard.bishopAttacks(sq, occupied) & ~pos.blackBB & validTargets;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
squares &= squares-1;
}
// King moves
{
sq = pos.getKingSq(false);
m = BitBoard.kingAttacks[sq] & ~pos.blackBB;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
}
// Knight moves
ulong knights = pos.pieceTypeBB[Piece.BKNIGHT];
while (knights != 0) {
sq = BitBoard.numberOfTrailingZeros(knights);
m = BitBoard.knightAttacks[sq] & ~pos.blackBB & validTargets;
if (addMovesByMask(moveList, pos, sq, m)) return moveList;
knights &= knights-1;
}
// Pawn moves
ulong pawns = pos.pieceTypeBB[Piece.BPAWN];
m = (pawns >> 8) & ~occupied;
if (addPawnMovesByMask(moveList, pos, m & validTargets, 8, true)) return moveList;
m = ((m & BitBoard.maskRow6) >> 8) & ~occupied;
addPawnDoubleMovesByMask(moveList, pos, m & validTargets, 16);
int epSquare = pos.getEpSquare();
ulong epMask = (epSquare >= 0) ? (1UL << epSquare) : 0L;
m = (pawns >> 9) & BitBoard.maskAToGFiles & ((pos.whiteBB & validTargets) | epMask);
if (addPawnMovesByMask(moveList, pos, m, 9, true)) return moveList;
m = (pawns >> 7) & BitBoard.maskBToHFiles & ((pos.whiteBB & validTargets) | epMask);
if (addPawnMovesByMask(moveList, pos, m, 7, true)) return moveList;
}
return moveList;
}