private void GenerateQueenMoves(MoveGeneration MoveGeneration, ulong FromSquareMask, ulong ToSquareMask)
{
ulong queens;
ulong unOrEnemyOccupiedSquares;
ulong enemyOccupiedSquares;
int attacker;
if (WhiteMove)
{
// White Move
queens = WhiteQueens & FromSquareMask;
unOrEnemyOccupiedSquares = ~OccupancyWhite;
enemyOccupiedSquares = OccupancyBlack;
attacker = Piece.WhiteQueen;
}
else
{
// Black Move
queens = BlackQueens & FromSquareMask;
unOrEnemyOccupiedSquares = ~OccupancyBlack;
enemyOccupiedSquares = OccupancyWhite;
attacker = Piece.BlackQueen;
}
int fromSquare;
while ((fromSquare = Bitwise.FindFirstSetBit(queens)) != Square.Illegal)
{
var bishopOccupancy = Board.BishopMoveMasks[fromSquare] & Occupancy;
var rookOccupancy = Board.RookMoveMasks[fromSquare] & Occupancy;
var queenDestinations = MoveGeneration switch
{
MoveGeneration.AllMoves => (Board.PrecalculatedMoves.GetBishopMovesMask(fromSquare, bishopOccupancy) | Board.PrecalculatedMoves.GetRookMovesMask(fromSquare, rookOccupancy)) & unOrEnemyOccupiedSquares & ToSquareMask,
MoveGeneration.OnlyCaptures => (Board.PrecalculatedMoves.GetBishopMovesMask(fromSquare, bishopOccupancy) | Board.PrecalculatedMoves.GetRookMovesMask(fromSquare, rookOccupancy)) & enemyOccupiedSquares & ToSquareMask,
MoveGeneration.OnlyNonCaptures => (Board.PrecalculatedMoves.GetBishopMovesMask(fromSquare, bishopOccupancy) | Board.PrecalculatedMoves.GetRookMovesMask(fromSquare, rookOccupancy)) & ~Occupancy & ToSquareMask,
_ => throw new Exception($"{MoveGeneration} move generation not supported.")
};
int toSquare;
while ((toSquare = Bitwise.FindFirstSetBit(queenDestinations)) != Square.Illegal)
{
var victim = GetPiece(toSquare);
var move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
if (victim != Piece.None)
{
Move.SetCaptureAttacker(ref move, attacker);
}
Move.SetCaptureVictim(ref move, victim);
Move.SetIsQuiet(ref move, victim == Piece.None);
Moves[MoveIndex] = move;
MoveIndex++;
Bitwise.ClearBit(ref queenDestinations, toSquare);
}
Bitwise.ClearBit(ref queens, fromSquare);
}
}
private void GenerateKnightMoves(MoveGeneration MoveGeneration, ulong FromSquareMask, ulong ToSquareMask)
{
ulong knights;
ulong unOrEnemyOccupiedSquares;
ulong enemyOccupiedSquares;
int attacker;
if (WhiteMove)
{
// White Move
knights = WhiteKnights & FromSquareMask;
unOrEnemyOccupiedSquares = ~OccupancyWhite;
enemyOccupiedSquares = OccupancyBlack;
attacker = Piece.WhiteKnight;
}
else
{
// Black Move
knights = BlackKnights & FromSquareMask;
unOrEnemyOccupiedSquares = ~OccupancyBlack;
enemyOccupiedSquares = OccupancyWhite;
attacker = Piece.BlackKnight;
}
int fromSquare;
while ((fromSquare = Bitwise.FindFirstSetBit(knights)) != Square.Illegal)
{
var knightDestinations = MoveGeneration switch
{
MoveGeneration.AllMoves => Board.KnightMoveMasks[fromSquare] & unOrEnemyOccupiedSquares & ToSquareMask,
MoveGeneration.OnlyCaptures => Board.KnightMoveMasks[fromSquare] & enemyOccupiedSquares & ToSquareMask,
MoveGeneration.OnlyNonCaptures => Board.KnightMoveMasks[fromSquare] & ~Occupancy & ToSquareMask,
_ => throw new Exception($"{MoveGeneration} move generation not supported.")
};
int toSquare;
while ((toSquare = Bitwise.FindFirstSetBit(knightDestinations)) != Square.Illegal)
{
var victim = GetPiece(toSquare);
var move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
if (victim != Piece.None)
{
Move.SetCaptureAttacker(ref move, attacker);
}
Move.SetCaptureVictim(ref move, victim);
Move.SetIsQuiet(ref move, victim == Piece.None);
Moves[MoveIndex] = move;
MoveIndex++;
Bitwise.ClearBit(ref knightDestinations, toSquare);
}
Bitwise.ClearBit(ref knights, fromSquare);
}
}
public void FindPotentiallyPinnedPieces()
{
int kingSquare;
ulong pieces;
ulong enemyBishopsQueens;
ulong enemyRooksQueens;
if (WhiteMove)
{
// White Move
kingSquare = Bitwise.FindFirstSetBit(WhiteKing);
pieces = OccupancyWhite;
enemyBishopsQueens = BlackBishops | BlackQueens;
enemyRooksQueens = BlackRooks | BlackQueens;
}
else
{
// Black Move
kingSquare = Bitwise.FindFirstSetBit(BlackKing);
pieces = OccupancyBlack;
enemyBishopsQueens = WhiteBishops | WhiteQueens;
enemyRooksQueens = WhiteRooks | WhiteQueens;
}
PotentiallyPinnedPieces = 0;
var fileAttackers = Board.FileMasks[Board.Files[kingSquare]] & enemyRooksQueens;
if (fileAttackers > 0)
{
PotentiallyPinnedPieces |= Board.FileMasks[Board.Files[kingSquare]] & pieces;
}
var rankAttackers = Board.RankMasks[Board.WhiteRanks[kingSquare]] & enemyRooksQueens;
if (rankAttackers > 0)
{
PotentiallyPinnedPieces |= Board.RankMasks[Board.WhiteRanks[kingSquare]] & pieces;
}
var upDiagonalAttackers = Board.UpDiagonalMasks[Board.UpDiagonals[kingSquare]] & enemyBishopsQueens;
if (upDiagonalAttackers > 0)
{
PotentiallyPinnedPieces |= Board.UpDiagonalMasks[Board.UpDiagonals[kingSquare]] & pieces;
}
var downDiagonalAttackers = Board.DownDiagonalMasks[Board.DownDiagonals[kingSquare]] & enemyBishopsQueens;
if (downDiagonalAttackers > 0)
{
PotentiallyPinnedPieces |= Board.DownDiagonalMasks[Board.DownDiagonals[kingSquare]] & pieces;
}
}
public static string ToString(ulong Occupancy)
{
var stringBuilder = new StringBuilder();
for (var rank = 7; rank >= 0; rank--)
{
for (var file = 0; file < 8; file++)
{
var square = Board.GetSquare(file, rank);
stringBuilder.Append(Bitwise.IsBitSet(Occupancy, square) ? " 1 " : " . ");
}
stringBuilder.AppendLine();
}
return(stringBuilder.ToString());
}
// Castling Bits
// 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0
// 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
// K|Q|k|q
// K = White Castle Kingside
// Q = White Castle Queenside
// k = Black Castle Kingside
// q = Black Castle Queenside
static Castling()
{
// Create bit shifts and masks.
_whiteKingsideShift = 3;
_whiteKingsideMask = Bitwise.CreateUIntMask(3, 3);
_whiteKingsideUnmask = Bitwise.CreateUIntUnmask(3, 3);
_whiteQueensideShift = 2;
_whiteQueensideMask = Bitwise.CreateUIntMask(2, 2);
_whiteQueensideUnmask = Bitwise.CreateUIntUnmask(2, 2);
_blackKingsideShift = 1;
_blackKingsideMask = Bitwise.CreateUIntMask(1, 1);
_blackKingsideUnmask = Bitwise.CreateUIntUnmask(1, 1);
_blackQueensideMask = Bitwise.CreateUIntMask(0, 0);
_blackQueensideUnmask = Bitwise.CreateUIntUnmask(0, 0);
}
// CachedPosition.Data Bits
// 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0
// 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
// To Horizon |Best From |Best To |BMP |Score |SP |Last Accessed
// Best From = Best Move From (one extra bit for illegal square)
// Best To = Best Move To (one extra bit for illegal square)
// BMP = Best Move Promoted Piece
// SP = Score Precision
static CachedPositionData()
{
// Create bit shifts and masks.
_toHorizonShift = 58;
_toHorizonMask = Bitwise.CreateULongMask(58, 63);
_toHorizonUnmask = Bitwise.CreateULongUnmask(58, 63);
_bestMoveFromShift = 51;
_bestMoveFromMask = Bitwise.CreateULongMask(51, 57);
_bestMoveFromUnmask = Bitwise.CreateULongUnmask(51, 57);
_bestMoveToShift = 44;
_bestMoveToMask = Bitwise.CreateULongMask(44, 50);
_bestMoveToUnmask = Bitwise.CreateULongUnmask(44, 50);
_bestMovePromotedPieceShift = 40;
_bestMovePromotedPieceMask = Bitwise.CreateULongMask(40, 43);
_bestMovePromotedPieceUnmask = Bitwise.CreateULongUnmask(40, 43);
_scoreShift = 10;
_scoreMask = Bitwise.CreateULongMask(10, 39);
_scoreUnmask = Bitwise.CreateULongUnmask(10, 39);
_scorePrecisionShift = 8;
_scorePrecisionMask = Bitwise.CreateULongMask(8, 9);
_scorePrecisionUnmask = Bitwise.CreateULongUnmask(8, 9);
_lastAccessedMask = Bitwise.CreateULongMask(0, 7);
_lastAccessedUnmask = Bitwise.CreateULongUnmask(0, 7);
}
public void FindPinnedPieces()
{
int ownKingSquare;
ulong ownPieces;
ulong enemyRankFileAttackers;
ulong enemyDiagonalAttackers;
ulong enemyPieces;
if (WhiteMove)
{
// White Move
ownKingSquare = Bitwise.FindFirstSetBit(WhiteKing);
ownPieces = OccupancyWhite;
enemyRankFileAttackers = BlackRooks | BlackQueens;
enemyDiagonalAttackers = BlackBishops | BlackQueens;
enemyPieces = OccupancyBlack;
}
else
{
// Black Move
ownKingSquare = Bitwise.FindFirstSetBit(BlackKing);
ownPieces = OccupancyBlack;
enemyRankFileAttackers = WhiteRooks | WhiteQueens;
enemyDiagonalAttackers = WhiteBishops | WhiteQueens;
enemyPieces = OccupancyWhite;
}
// Find pieces pinned to own king by enemy rank / file attackers.
PinnedPieces = 0;
int attackerSquare;
while ((attackerSquare = Bitwise.FindFirstSetBit(enemyRankFileAttackers)) != Square.Illegal)
{
var betweenSquares = Board.RankFileBetweenSquares[attackerSquare][ownKingSquare];
if (betweenSquares == 0)
{
Bitwise.ClearBit(ref enemyRankFileAttackers, attackerSquare);
continue;
}
if ((betweenSquares & enemyPieces) == 0)
{
// No enemy pieces between enemy attacker and own king.
var potentiallyPinnedPieces = betweenSquares & ownPieces;
if (Bitwise.CountSetBits(potentiallyPinnedPieces) == 1)
{
// Exactly one own piece between enemy attacker and own king.
// Piece is pinned to own king.
PinnedPieces |= potentiallyPinnedPieces;
}
}
Bitwise.ClearBit(ref enemyRankFileAttackers, attackerSquare);
}
// Find pieces pinned to own king by enemy diagonal attackers.
while ((attackerSquare = Bitwise.FindFirstSetBit(enemyDiagonalAttackers)) != Square.Illegal)
{
var betweenSquares = Board.DiagonalBetweenSquares[attackerSquare][ownKingSquare];
if (betweenSquares == 0)
{
Bitwise.ClearBit(ref enemyDiagonalAttackers, attackerSquare);
continue;
}
if ((betweenSquares & enemyPieces) == 0)
{
// No enemy pieces between enemy attacker and own king.
var potentiallyPinnedPieces = betweenSquares & ownPieces;
if (Bitwise.CountSetBits(potentiallyPinnedPieces) == 1)
{
// Exactly one own piece between enemy attacker and own king.
// Piece is pinned to own king.
PinnedPieces |= potentiallyPinnedPieces;
}
}
Bitwise.ClearBit(ref enemyDiagonalAttackers, attackerSquare);
}
}
private void GenerateKingMoves(MoveGeneration MoveGeneration, ulong FromSquareMask, ulong ToSquareMask)
{
ulong king;
ulong unOrEnemyOccupiedSquares;
ulong enemyOccupiedSquares;
int attacker;
bool castleQueenside;
ulong castleQueensideMask;
bool castleKingside;
ulong castleKingsideMask;
if (WhiteMove)
{
// White Move
king = WhiteKing & FromSquareMask;
unOrEnemyOccupiedSquares = ~OccupancyWhite;
enemyOccupiedSquares = OccupancyBlack;
attacker = Piece.WhiteKing;
castleQueenside = Engine.Castling.WhiteQueenside(Castling);
castleQueensideMask = Board.WhiteCastleQEmptySquaresMask;
castleKingside = Engine.Castling.WhiteKingside(Castling);
castleKingsideMask = Board.WhiteCastleKEmptySquaresMask;
}
else
{
// Black Move
king = BlackKing & FromSquareMask;
unOrEnemyOccupiedSquares = ~OccupancyBlack;
enemyOccupiedSquares = OccupancyWhite;
attacker = Piece.BlackKing;
castleQueenside = Engine.Castling.BlackQueenside(Castling);
castleQueensideMask = Board.BlackCastleQEmptySquaresMask;
castleKingside = Engine.Castling.BlackKingside(Castling);
castleKingsideMask = Board.BlackCastleKEmptySquaresMask;
}
ulong move;
var fromSquare = Bitwise.FindFirstSetBit(king);
if (fromSquare == Square.Illegal)
{
return;
}
var kingDestinations = MoveGeneration switch
{
MoveGeneration.AllMoves => Board.KingMoveMasks[fromSquare] & unOrEnemyOccupiedSquares & ToSquareMask,
MoveGeneration.OnlyCaptures => Board.KingMoveMasks[fromSquare] & enemyOccupiedSquares & ToSquareMask,
MoveGeneration.OnlyNonCaptures => Board.KingMoveMasks[fromSquare] & ~Occupancy & ToSquareMask,
_ => throw new Exception($"{MoveGeneration} move generation not supported.")
};
int toSquare;
while ((toSquare = Bitwise.FindFirstSetBit(kingDestinations)) != Square.Illegal)
{
var victim = GetPiece(toSquare);
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
if (victim != Piece.None)
{
Move.SetCaptureAttacker(ref move, attacker);
}
Move.SetCaptureVictim(ref move, victim);
Move.SetIsKingMove(ref move, true);
Move.SetIsQuiet(ref move, victim == Piece.None);
Moves[MoveIndex] = move;
MoveIndex++;
Bitwise.ClearBit(ref kingDestinations, toSquare);
}
if (MoveGeneration != MoveGeneration.OnlyCaptures)
{
if (castleQueenside && ((Occupancy & castleQueensideMask) == 0))
{
// Castle Queenside
if (WhiteMove)
{
// White Move
fromSquare = Square.e1;
toSquare = Square.c1;
}
else
{
// Black Move
fromSquare = Square.e8;
toSquare = Square.c8;
}
if ((Board.SquareMasks[toSquare] & ToSquareMask) > 0)
{
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
Move.SetIsCastling(ref move, true);
Move.SetIsKingMove(ref move, true);
Move.SetIsQuiet(ref move, false);
Moves[MoveIndex] = move;
MoveIndex++;
}
}
if (castleKingside && ((Occupancy & castleKingsideMask) == 0))
{
// Castle Kingside
if (WhiteMove)
{
// White Move
fromSquare = Square.e1;
toSquare = Square.g1;
}
else
{
// Black Move
fromSquare = Square.e8;
toSquare = Square.g8;
}
if ((Board.SquareMasks[toSquare] & ToSquareMask) > 0)
{
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
Move.SetIsCastling(ref move, true);
Move.SetIsKingMove(ref move, true);
Move.SetIsQuiet(ref move, false);
Moves[MoveIndex] = move;
MoveIndex++;
}
}
}
}
private void GeneratePawnMoves(MoveGeneration MoveGeneration, ulong FromSquareMask, ulong ToSquareMask)
{
ulong pawns;
ulong[] pawnMoveMasks;
ulong[] pawnDoubleMoveMasks;
ulong[] pawnAttackMasks;
ulong enemyOccupiedSquares;
var unoccupiedSquares = ~Occupancy;
int[] ranks;
int attacker;
int queen;
int rook;
int bishop;
int knight;
int enPassantVictim;
if (WhiteMove)
{
// White Move
pawns = WhitePawns & FromSquareMask;
pawnMoveMasks = Board.WhitePawnMoveMasks;
pawnDoubleMoveMasks = Board.WhitePawnDoubleMoveMasks;
pawnAttackMasks = Board.WhitePawnAttackMasks;
enemyOccupiedSquares = OccupancyBlack;
ranks = Board.WhiteRanks;
attacker = Piece.WhitePawn;
queen = Piece.WhiteQueen;
rook = Piece.WhiteRook;
bishop = Piece.WhiteBishop;
knight = Piece.WhiteKnight;
enPassantVictim = Piece.BlackPawn;
}
else
{
// Black Move
pawns = BlackPawns & FromSquareMask;
pawnMoveMasks = Board.BlackPawnMoveMasks;
pawnDoubleMoveMasks = Board.BlackPawnDoubleMoveMasks;
pawnAttackMasks = Board.BlackPawnAttackMasks;
enemyOccupiedSquares = OccupancyWhite;
ranks = Board.BlackRanks;
attacker = Piece.BlackPawn;
queen = Piece.BlackQueen;
rook = Piece.BlackRook;
bishop = Piece.BlackBishop;
knight = Piece.BlackKnight;
enPassantVictim = Piece.WhitePawn;
}
int fromSquare;
ulong move;
if ((EnPassantSquare != Square.Illegal) && ((Board.SquareMasks[EnPassantSquare] & ToSquareMask) > 0) && (MoveGeneration != MoveGeneration.OnlyNonCaptures))
{
var enPassantAttackers = Board.EnPassantAttackerMasks[EnPassantSquare] & pawns;
while ((fromSquare = Bitwise.FindFirstSetBit(enPassantAttackers)) != Square.Illegal)
{
// Capture pawn en passant.
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, EnPassantSquare);
Move.SetCaptureAttacker(ref move, attacker);
Move.SetCaptureVictim(ref move, enPassantVictim);
Move.SetIsEnPassantCapture(ref move, true);
Move.SetIsPawnMove(ref move, true);
Move.SetIsQuiet(ref move, false);
Moves[MoveIndex] = move;
MoveIndex++;
Bitwise.ClearBit(ref enPassantAttackers, fromSquare);
}
}
while ((fromSquare = Bitwise.FindFirstSetBit(pawns)) != Square.Illegal)
{
ulong pawnDestinations;
int toSquare;
int toSquareRank;
if (MoveGeneration != MoveGeneration.OnlyCaptures)
{
// Pawns may move forward one square (or two if on initial square) if forward squares are unoccupied.
pawnDestinations = pawnMoveMasks[fromSquare] & unoccupiedSquares & ToSquareMask;
while ((toSquare = Bitwise.FindFirstSetBit(pawnDestinations)) != Square.Illegal)
{
var doubleMove = Board.SquareDistances[fromSquare][toSquare] == 2;
if (doubleMove && ((Occupancy & pawnDoubleMoveMasks[fromSquare]) > 0))
{
// Double move is blocked.
Bitwise.ClearBit(ref pawnDestinations, toSquare);
continue;
}
toSquareRank = ranks[toSquare];
if (toSquareRank < 7)
{
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
Move.SetIsDoublePawnMove(ref move, doubleMove);
Move.SetIsPawnMove(ref move, true);
Move.SetIsQuiet(ref move, true);
Moves[MoveIndex] = move;
MoveIndex++;
}
else
{
// Promote pawn to queen.
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
Move.SetPromotedPiece(ref move, queen);
Move.SetIsPawnMove(ref move, true);
Move.SetIsQuiet(ref move, false);
Moves[MoveIndex] = move;
MoveIndex++;
// Promote pawn to rook.
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
Move.SetPromotedPiece(ref move, rook);
Move.SetIsPawnMove(ref move, true);
Move.SetIsQuiet(ref move, false);
Moves[MoveIndex] = move;
MoveIndex++;
// Promote pawn to bishop.
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
Move.SetPromotedPiece(ref move, bishop);
Move.SetIsPawnMove(ref move, true);
Move.SetIsQuiet(ref move, false);
Moves[MoveIndex] = move;
MoveIndex++;
// Promote pawn to knight.
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
Move.SetPromotedPiece(ref move, knight);
Move.SetIsPawnMove(ref move, true);
Move.SetIsQuiet(ref move, false);
Moves[MoveIndex] = move;
MoveIndex++;
}
Bitwise.ClearBit(ref pawnDestinations, toSquare);
}
}
if (MoveGeneration != MoveGeneration.OnlyNonCaptures)
{
// Pawns may attack diagonally forward one square if occupied by enemy.
pawnDestinations = pawnAttackMasks[fromSquare] & enemyOccupiedSquares & ToSquareMask;
while ((toSquare = Bitwise.FindFirstSetBit(pawnDestinations)) != Square.Illegal)
{
toSquareRank = ranks[toSquare];
var victim = GetPiece(toSquare);
if (toSquareRank < 7)
{
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
Move.SetCaptureAttacker(ref move, attacker);
Move.SetCaptureVictim(ref move, victim);
Move.SetIsPawnMove(ref move, true);
Move.SetIsQuiet(ref move, false);
Moves[MoveIndex] = move;
MoveIndex++;
}
else
{
// Promote pawn to queen.
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
Move.SetPromotedPiece(ref move, queen);
Move.SetCaptureAttacker(ref move, attacker);
Move.SetCaptureVictim(ref move, victim);
Move.SetIsPawnMove(ref move, true);
Move.SetIsQuiet(ref move, false);
Moves[MoveIndex] = move;
MoveIndex++;
// Promote pawn to rook.
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
Move.SetPromotedPiece(ref move, rook);
Move.SetCaptureAttacker(ref move, attacker);
Move.SetCaptureVictim(ref move, victim);
Move.SetIsPawnMove(ref move, true);
Move.SetIsQuiet(ref move, false);
Moves[MoveIndex] = move;
MoveIndex++;
// Promote pawn to bishop.
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
Move.SetPromotedPiece(ref move, bishop);
Move.SetCaptureAttacker(ref move, attacker);
Move.SetCaptureVictim(ref move, victim);
Move.SetIsPawnMove(ref move, true);
Move.SetIsQuiet(ref move, false);
Moves[MoveIndex] = move;
MoveIndex++;
// Promote pawn to knight.
move = Move.Null;
Move.SetFrom(ref move, fromSquare);
Move.SetTo(ref move, toSquare);
Move.SetPromotedPiece(ref move, knight);
Move.SetCaptureAttacker(ref move, attacker);
Move.SetCaptureVictim(ref move, victim);
Move.SetIsPawnMove(ref move, true);
Move.SetIsQuiet(ref move, false);
Moves[MoveIndex] = move;
MoveIndex++;
}
Bitwise.ClearBit(ref pawnDestinations, toSquare);
}
}
Bitwise.ClearBit(ref pawns, fromSquare);
}
}
// Move Bits
// Higher priority moves have higher ulong value.
// 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0
// 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
// B|CapV |CapA |Promo |Kil|History |!|O|K|E|2|P|C|Q|From |To
// 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
// B = Best Move
// CapV = Capture Victim
// CapA = Capture Attacker (inverted)
// Promo = Promoted Piece
// Kil = Killer Move
// ! = Played
// O = Castling
// K = King Move
// E = En Passant Capture
// 2 = Double Pawn Move
// P = Pawn Move
// C = Check
// Q = Quiet (not capture, pawn promotion, castling, or check)
// From = From (one extra bit for illegal square)
// To = To (one extra bit for illegal square)
static Move()
{
// Create bit masks and shifts.
_bestShift = 63;
_bestMask = Bitwise.CreateULongMask(63);
_bestUnmask = Bitwise.CreateULongUnmask(63);
_captureVictimShift = 59;
_captureVictimMask = Bitwise.CreateULongMask(59, 62);
_captureVictimUnmask = Bitwise.CreateULongUnmask(59, 62);
_captureAttackerShift = 55;
_captureAttackerMask = Bitwise.CreateULongMask(55, 58);
_captureAttackerUnmask = Bitwise.CreateULongUnmask(55, 58);
_promotedPieceShift = 51;
_promotedPieceMask = Bitwise.CreateULongMask(51, 54);
_promotedPieceUnmask = Bitwise.CreateULongUnmask(51, 54);
_killerShift = 49;
_killerMask = Bitwise.CreateULongMask(49, 50);
_killerUnmask = Bitwise.CreateULongUnmask(49, 50);
_historyShift = 22;
_historyMask = Bitwise.CreateULongMask(22, 48);
_historyUnmask = Bitwise.CreateULongUnmask(22, 48);
_playedShift = 21;
_playedMask = Bitwise.CreateULongMask(21);
_playedUnmask = Bitwise.CreateULongUnmask(21);
_castlingShift = 20;
_castlingMask = Bitwise.CreateULongMask(20);
_castlingUnmask = Bitwise.CreateULongUnmask(20);
_kingMoveShift = 19;
_kingMoveMask = Bitwise.CreateULongMask(19);
_kingMoveUnmask = Bitwise.CreateULongUnmask(19);
_enPassantShift = 18;
_enPassantMask = Bitwise.CreateULongMask(18);
_enPassantUnmask = Bitwise.CreateULongUnmask(18);
_doublePawnMoveShift = 17;
_doublePawnMoveMask = Bitwise.CreateULongMask(17);
_doublePawnMoveUnmask = Bitwise.CreateULongUnmask(17);
_pawnMoveShift = 16;
_pawnMoveMask = Bitwise.CreateULongMask(16);
_pawnMoveUnmask = Bitwise.CreateULongUnmask(16);
_checkShift = 15;
_checkMask = Bitwise.CreateULongMask(15);
_checkUnmask = Bitwise.CreateULongUnmask(15);
_quietShift = 14;
_quietMask = Bitwise.CreateULongMask(14);
_quietUnmask = Bitwise.CreateULongUnmask(14);
_fromShift = 7;
_fromMask = Bitwise.CreateULongMask(7, 13);
_fromUnmask = Bitwise.CreateULongUnmask(7, 13);
_toMask = Bitwise.CreateULongMask(0, 6);
_toUnmask = Bitwise.CreateULongUnmask(0, 6);
// Set null move.
Null = 0;
SetIsBest(ref Null, false);
SetCaptureVictim(ref Null, Piece.None);
SetCaptureAttacker(ref Null, Piece.None);
SetPromotedPiece(ref Null, Piece.None);
SetKiller(ref Null, 0);
SetHistory(ref Null, 0);
SetPlayed(ref Null, false);
SetIsCastling(ref Null, false);
SetIsKingMove(ref Null, false);
SetIsEnPassantCapture(ref Null, false);
SetIsDoublePawnMove(ref Null, false);
SetIsPawnMove(ref Null, false);
SetIsCheck(ref Null, false);
SetIsQuiet(ref Null, false);
SetFrom(ref Null, Square.Illegal);
SetTo(ref Null, Square.Illegal);
}
public void FindMagicMultipliers(int Piece, Delegates.WriteMessageLine WriteMessageLine = null)
{
Direction[] directions;
ulong[] unoccupiedMoveMasks;
ulong[] relevantOccupancyMasks;
ulong[] magicMultipliers;
int[] shifts;
ulong[][] moveMasks;
switch (Piece)
{
case Engine.Piece.WhiteBishop:
case Engine.Piece.BlackBishop:
directions = new[] { Direction.NorthEast, Direction.SouthEast, Direction.SouthWest, Direction.NorthWest };
unoccupiedMoveMasks = Board.BishopMoveMasks;
relevantOccupancyMasks = _bishopRelevantOccupancyMasks;
magicMultipliers = _bishopMagicMultipliers;
shifts = _bishopShifts;
moveMasks = _bishopMoveMasks;
break;
case Engine.Piece.WhiteRook:
case Engine.Piece.BlackRook:
directions = new[] { Direction.North, Direction.East, Direction.South, Direction.West };
unoccupiedMoveMasks = Board.RookMoveMasks;
relevantOccupancyMasks = _rookRelevantOccupancyMasks;
magicMultipliers = _rookMagicMultipliers;
shifts = _rookShifts;
moveMasks = _rookMoveMasks;
break;
default:
throw new ArgumentException($"{Piece} piece not supported.");
}
// Generate moves mask on each square.
var occupancyToMovesMask = new Dictionary <ulong, ulong>();
var uniqueMovesMasks = new HashSet <ulong>();
for (var square = 0; square < 64; square++)
{
occupancyToMovesMask.Clear();
uniqueMovesMasks.Clear();
var moveDestinations = unoccupiedMoveMasks[square];
var relevantMoveDestinations = moveDestinations & relevantOccupancyMasks[square];
var uniqueOccupancies = (int)Math.Pow(2, Bitwise.CountSetBits(relevantMoveDestinations));
occupancyToMovesMask.EnsureCapacity(uniqueOccupancies);
// Generate moves mask for every permutation of relevant occupancy bits.
using (var occupancyPermutations = Bitwise.GetAllPermutations(relevantMoveDestinations).GetEnumerator())
{
while (occupancyPermutations.MoveNext())
{
var occupancy = occupancyPermutations.Current;
if (!occupancyToMovesMask.ContainsKey(occupancy))
{
// Have not yet generated moves for this occupancy mask.
var movesMask = Board.CreateMoveDestinationsMask(square, occupancy, directions);
occupancyToMovesMask.Add(occupancy, movesMask);
if (!uniqueMovesMasks.Contains(movesMask))
{
uniqueMovesMasks.Add(movesMask);
}
}
}
}
// Validate enumerator found all permutations of relevant occupancy bits.
Debug.Assert(occupancyToMovesMask.Count == uniqueOccupancies);
// Determine bit shift that produces number >= unique occupancies.
// A stricter condition is number >= unique moves but this requires more computing time to find magic multipliers.
var shift = 64 - (int)Math.Ceiling(Math.Log(uniqueOccupancies, 2d));
shifts[square] = shift;
var magicMultiplier = magicMultipliers[square];
if (magicMultiplier == 0)
{
(magicMultipliers[square], moveMasks[square]) = FindMagicMultiplier(occupancyToMovesMask, shift, null);
}
else
{
(magicMultipliers[square], moveMasks[square]) = FindMagicMultiplier(occupancyToMovesMask, shift, magicMultiplier);
}
WriteMessageLine?.Invoke($"{Board.SquareLocations[square],6} {Engine.Piece.GetName(Piece),6} {shift,5} {occupancyToMovesMask.Count,18} {uniqueMovesMasks.Count,12} {magicMultipliers[square],16:X16}");
}
}