Make position bitboard management more idiomatic
This commit is contained in:
parent
2b16b5ec61
commit
77ff697df7
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@ -14,7 +14,6 @@
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import std/strutils
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import std/strformat
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import std/bitops
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import nimfishpkg/bitboards
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@ -49,9 +48,9 @@ type
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# The side to move
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sideToMove: PieceColor
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# Positional bitboards for all pieces
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pieces: tuple[white, black: tuple[king, queens, rooks, bishops, knights, pawns: Bitboard]]
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# Pinned pieces for each side
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pins: tuple[white, black: Bitboard]
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pieces: array[2, array[6, Bitboard]]
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# Pinned pieces for the current side to move
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pins: Bitboard
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# Pieces checking the current side to move
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checkers: Bitboard
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@ -135,6 +134,7 @@ func shortCastleRook*(color: PieceColor): Square {.inline.} = (if color == White
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proc inCheck*(self: ChessBoard): bool
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proc fromChar*(c: char): Piece
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proc newChessboard: ChessBoard =
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@ -142,50 +142,25 @@ proc newChessboard: ChessBoard =
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new(result)
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for i in 0..63:
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result.grid[i] = nullPiece()
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result.position = Position(enPassantSquare: nullSquare(), sideToMove: White)
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result.position = Position(enPassantSquare: nullSquare(), sideToMove: White, pieces: [
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[Bitboard(0), Bitboard(0), Bitboard(0), Bitboard(0), Bitboard(0), Bitboard(0)],
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[Bitboard(0), Bitboard(0), Bitboard(0), Bitboard(0), Bitboard(0), Bitboard(0)]])
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# Indexing operations
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func `[]`(self: array[64, Piece], square: Square): Piece {.inline.} = self[square.int8]
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func `[]=`(self: var array[64, Piece], square: Square, piece: Piece) {.inline.} = self[square.int8] = piece
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func `[]`(self: array[2, array[6, Bitboard]], color: PieceColor): ptr array[6, Bitboard] {.inline.} = addr self[color.int]
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func `[]`(self: array[6, Bitboard], kind: PieceKind): Bitboard {.inline.} = self[kind.int]
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func `[]=`(self: var array[6, Bitboard], kind: PieceKind, bitboard: Bitboard) {.inline.} = self[kind.int] = bitboard
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func getBitboard*(self: ChessBoard, kind: PieceKind, color: PieceColor): Bitboard =
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## Returns the positional bitboard for the given piece kind and color
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case color:
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of White:
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case kind:
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of Pawn:
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return self.position.pieces.white.pawns
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of Knight:
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return self.position.pieces.white.knights
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of Bishop:
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return self.position.pieces.white.bishops
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of Rook:
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return self.position.pieces.white.rooks
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of Queen:
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return self.position.pieces.white.queens
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of King:
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return self.position.pieces.white.king
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else:
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discard
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of Black:
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case kind:
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of Pawn:
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return self.position.pieces.black.pawns
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of Knight:
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return self.position.pieces.black.knights
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of Bishop:
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return self.position.pieces.black.bishops
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of Rook:
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return self.position.pieces.black.rooks
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of Queen:
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return self.position.pieces.black.queens
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of King:
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return self.position.pieces.black.king
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else:
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discard
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else:
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discard
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return self.position.pieces[color.int][kind.int]
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func getBitboard*(self: ChessBoard, piece: Piece): Bitboard =
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@ -221,52 +196,11 @@ proc newChessboardFromFEN*(fen: string): ChessBoard =
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case c.toLowerAscii():
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# Piece
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of 'r', 'n', 'b', 'q', 'k', 'p':
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let
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square: Square = makeSquare(row, column)
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bitIndex = square.int8
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# We know for a fact these values are in our
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# enumeration, so all is good
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{.warning[HoleEnumConv]:off.}
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piece = Piece(kind: PieceKind(c.toLowerAscii()), color: if c.isUpperAscii(): White else: Black)
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case piece.color:
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of Black:
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case piece.kind:
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of Pawn:
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result.position.pieces.black.pawns.uint64.uint64.setBit(bitIndex)
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of Bishop:
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result.position.pieces.black.bishops.uint64.setBit(bitIndex)
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of Knight:
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result.position.pieces.black.knights.uint64.setBit(bitIndex)
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of Rook:
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result.position.pieces.black.rooks.uint64.setBit(bitIndex)
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of Queen:
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result.position.pieces.black.queens.uint64.setBit(bitIndex)
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of King:
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if result.position.pieces.black.king != 0:
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raise newException(ValueError, "invalid position: exactly one king of each color must be present")
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result.position.pieces.black.king.uint64.setBit(bitIndex)
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else:
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discard
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of White:
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case piece.kind:
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of Pawn:
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result.position.pieces.white.pawns.uint64.setBit(bitIndex)
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of Bishop:
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result.position.pieces.white.bishops.uint64.setBit(bitIndex)
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of Knight:
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result.position.pieces.white.knights.uint64.setBit(bitIndex)
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of Rook:
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result.position.pieces.white.rooks.uint64.setBit(bitIndex)
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of Queen:
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result.position.pieces.white.queens.uint64.setBit(bitIndex)
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of King:
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if result.position.pieces.white.king != 0:
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raise newException(ValueError, "invalid position: exactly one king of each color must be present")
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result.position.pieces.white.king.uint64.setBit(bitIndex)
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else:
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discard
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else:
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discard
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let square: Square = makeSquare(row, column)
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piece = c.fromChar()
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var b = result.position.pieces[piece.color][piece.kind]
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b.setBit(square)
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result.position.pieces[piece.color][piece.kind] = b
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result.grid[square] = piece
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inc(column)
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of '/':
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@ -340,9 +274,6 @@ proc newChessboardFromFEN*(fen: string): ChessBoard =
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else:
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raise newException(ValueError, "invalid FEN: too many fields in FEN string")
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inc(index)
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if result.position.pieces.white.king == 0 or result.position.pieces.black.king == 0:
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# Both kings must be on the board
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raise newException(ValueError, "invalid position: exactly one king of each color must be present")
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proc newDefaultChessboard*: ChessBoard {.inline.} =
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@ -355,41 +286,8 @@ proc countPieces*(self: ChessBoard, kind: PieceKind, color: PieceColor): int =
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## Returns the number of pieces with
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## the given color and type in the
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## current position
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case color:
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of White:
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case kind:
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of Pawn:
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return self.position.pieces.white.pawns.uint64.countSetBits()
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of Bishop:
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return self.position.pieces.white.bishops.uint64.countSetBits()
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of Knight:
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return self.position.pieces.white.knights.uint64.countSetBits()
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of Rook:
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return self.position.pieces.white.rooks.uint64.countSetBits()
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of Queen:
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return self.position.pieces.white.queens.uint64.countSetBits()
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of King:
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return self.position.pieces.white.king.uint64.countSetBits()
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else:
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raise newException(ValueError, "invalid piece type")
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of Black:
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case kind:
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of Pawn:
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return self.position.pieces.black.pawns.uint64.countSetBits()
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of Bishop:
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return self.position.pieces.black.bishops.uint64.countSetBits()
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of Knight:
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return self.position.pieces.black.knights.uint64.countSetBits()
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of Rook:
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return self.position.pieces.black.rooks.uint64.countSetBits()
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of Queen:
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return self.position.pieces.black.queens.uint64.countSetBits()
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of King:
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return self.position.pieces.black.king.uint64.countSetBits()
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else:
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raise newException(ValueError, "invalid piece type")
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of None:
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raise newException(ValueError, "invalid piece color")
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return self.position.pieces[color][kind].countSetBits()
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func countPieces*(self: ChessBoard, piece: Piece): int {.inline.} =
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@ -474,16 +372,9 @@ func getFlags*(move: Move): seq[MoveFlag] =
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proc getOccupancyFor(self: ChessBoard, color: PieceColor): Bitboard =
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## Get the occupancy bitboard for every piece of the given color
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case color:
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of White:
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let b = self.position.pieces.white
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return b.pawns or b.knights or b.bishops or b.rooks or b.queens or b.king
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of Black:
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let b = self.position.pieces.black
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return b.pawns or b.knights or b.bishops or b.rooks or b.queens or b.king
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else:
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# huh?
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discard
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result = Bitboard(0)
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for b in self.position.pieces[color][]:
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result = result or b
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proc getOccupancy(self: ChessBoard): Bitboard =
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@ -738,81 +629,17 @@ proc removePieceFromBitboard(self: ChessBoard, square: Square) =
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## Removes a piece at the given square in the chessboard from
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## its respective bitboard
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let piece = self.grid[square]
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case piece.color:
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of White:
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case piece.kind:
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of Pawn:
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self.position.pieces.white.pawns.uint64.clearBit(square.int8)
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of Bishop:
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self.position.pieces.white.bishops.uint64.clearBit(square.int8)
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of Knight:
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self.position.pieces.white.knights.uint64.clearBit(square.int8)
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of Rook:
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self.position.pieces.white.rooks.uint64.clearBit(square.int8)
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of Queen:
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self.position.pieces.white.queens.uint64.clearBit(square.int8)
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of King:
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self.position.pieces.white.king.uint64.clearBit(square.int8)
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of Empty:
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doAssert false, &"cannot remove empty white piece from {square}"
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of Black:
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case piece.kind:
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of Pawn:
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self.position.pieces.black.pawns.uint64.clearBit(square.int8)
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of Bishop:
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self.position.pieces.black.bishops.uint64.clearBit(square.int8)
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of Knight:
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self.position.pieces.black.knights.uint64.clearBit(square.int8)
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of Rook:
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self.position.pieces.black.rooks.uint64.clearBit(square.int8)
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of Queen:
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self.position.pieces.black.queens.uint64.clearBit(square.int8)
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of King:
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self.position.pieces.black.king.uint64.clearBit(square.int8)
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of Empty:
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doAssert false, &"cannot remove empty black piece from {square}"
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else:
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doAssert false, &"cannot remove empty piece from colorless square {square}"
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var b = self.position.pieces[piece.color][piece.kind]
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b.clearBit(square)
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self.position.pieces[piece.color][piece.kind] = b
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proc addPieceToBitboard(self: ChessBoard, square: Square, piece: Piece) =
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## Adds the given piece at the given square in the chessboard to
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## its respective bitboard
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case piece.color:
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of White:
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case piece.kind:
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of Pawn:
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self.position.pieces.white.pawns.uint64.setBit(square.int8)
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of Bishop:
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self.position.pieces.white.bishops.uint64.setBit(square.int8)
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of Knight:
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self.position.pieces.white.knights.uint64.setBit(square.int8)
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of Rook:
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self.position.pieces.white.rooks.uint64.setBit(square.int8)
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of Queen:
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self.position.pieces.white.queens.uint64.setBit(square.int8)
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of King:
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self.position.pieces.white.king.uint64.setBit(square.int8)
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else:
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discard
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of Black:
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case piece.kind:
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of Pawn:
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self.position.pieces.black.pawns.uint64.setBit(square.int8)
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of Bishop:
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self.position.pieces.black.bishops.uint64.setBit(square.int8)
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of Knight:
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self.position.pieces.black.knights.uint64.setBit(square.int8)
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of Rook:
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self.position.pieces.black.rooks.uint64.setBit(square.int8)
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of Queen:
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self.position.pieces.black.queens.uint64.setBit(square.int8)
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of King:
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self.position.pieces.black.king.uint64.setBit(square.int8)
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else:
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discard
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else:
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discard
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var b = self.position.pieces[piece.color][piece.kind]
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b.setBit(square)
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self.position.pieces[piece.color][piece.kind] = b
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proc removePiece(self: ChessBoard, square: Square) =
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@ -924,29 +751,29 @@ proc update*(self: ChessBoard) =
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## in the chessboard
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for i in 0..63:
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self.grid[i] = nullPiece()
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for sq in self.position.pieces.white.pawns:
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for sq in self.position.pieces[White][Pawn]:
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self.grid[sq] = Piece(color: White, kind: Pawn)
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for sq in self.position.pieces.black.pawns:
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for sq in self.position.pieces[Black][Pawn]:
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self.grid[sq] = Piece(color: Black, kind: Pawn)
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for sq in self.position.pieces.white.bishops:
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for sq in self.position.pieces[White][Bishop]:
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self.grid[sq] = Piece(color: White, kind: Bishop)
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for sq in self.position.pieces.black.bishops:
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for sq in self.position.pieces[Black][Bishop]:
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self.grid[sq] = Piece(color: Black, kind: Bishop)
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for sq in self.position.pieces.white.knights:
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for sq in self.position.pieces[White][Knight]:
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self.grid[sq] = Piece(color: White, kind: Knight)
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for sq in self.position.pieces.black.knights:
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for sq in self.position.pieces[Black][Knight]:
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self.grid[sq] = Piece(color: Black, kind: Knight)
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for sq in self.position.pieces.white.rooks:
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for sq in self.position.pieces[White][Rook]:
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self.grid[sq] = Piece(color: White, kind: Rook)
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for sq in self.position.pieces.black.rooks:
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for sq in self.position.pieces[Black][Rook]:
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self.grid[sq] = Piece(color: Black, kind: Rook)
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for sq in self.position.pieces.white.queens:
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for sq in self.position.pieces[White][Queen]:
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self.grid[sq] = Piece(color: White, kind: Queen)
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for sq in self.position.pieces.black.queens:
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for sq in self.position.pieces[Black][Queen]:
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self.grid[sq] = Piece(color: Black, kind: Queen)
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for sq in self.position.pieces.white.king:
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for sq in self.position.pieces[White][King]:
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self.grid[sq] = Piece(color: White, kind: King)
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for sq in self.position.pieces.black.king:
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for sq in self.position.pieces[Black][King]:
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self.grid[sq] = Piece(color: Black, kind: King)
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@ -973,9 +800,47 @@ proc makeMove*(self: ChessBoard, move: Move): Move {.discardable.} =
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proc toChar*(piece: Piece): char =
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case piece.kind:
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of Bishop:
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result = 'b'
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of King:
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result = 'k'
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of Knight:
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result = 'n'
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of Pawn:
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result = 'p'
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of Queen:
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result = 'q'
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of Rook:
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result = 'r'
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else:
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discard
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if piece.color == White:
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return char(piece.kind).toUpperAscii()
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return char(piece.kind)
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result = result.toUpperAscii()
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proc fromChar*(c: char): Piece =
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var
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kind: PieceKind
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color = Black
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case c.toLowerAscii():
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of 'b':
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kind = Bishop
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of 'k':
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kind = King
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of 'n':
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kind = Knight
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of 'p':
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kind = Pawn
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of 'q':
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kind = Queen
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of 'r':
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kind = Rook
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else:
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discard
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if c.isUpperAscii():
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color = White
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result = Piece(kind: kind, color: color)
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proc `$`*(self: ChessBoard): string =
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@ -45,6 +45,13 @@ func `==`*(a, b: Bitboard): bool {.inline.} = a.uint64 == b.uint64
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func `==`*(a: Bitboard, b: SomeInteger): bool {.inline.} = a.uint64 == b.uint64
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func `!=`*(a, b: Bitboard): bool {.inline.} = a.uint64 != b.uint64
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func `!=`*(a: Bitboard, b: SomeInteger): bool {.inline.} = a.uint64 != b.uint64
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func countSetBits*(a: Bitboard): int = a.uint64.countSetBits()
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func countLeadingZeroBits*(a: Bitboard): int = a.uint64.countLeadingZeroBits()
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func countTrailingZeroBits*(a: Bitboard): int = a.uint64.countTrailingZeroBits()
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func clearBit*(a: var Bitboard, bit: SomeInteger) = a.uint64.clearBit(bit)
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func setBit*(a: var Bitboard, bit: SomeInteger) = a.uint64.setBit(bit)
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func clearBit*(a: var Bitboard, bit: Square) = a.uint64.clearBit(bit.int)
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func setBit*(a: var Bitboard, bit: Square) = a.uint64.setBit(bit.int)
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func getFileMask*(file: int): Bitboard = Bitboard(0x101010101010101'u64) shl file.uint64
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@ -9,25 +9,26 @@ type
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PieceColor* = enum
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## A piece color enumeration
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None = 0'i8
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White
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Black
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White = 0'i8
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Black = 1
|
||||
None
|
||||
|
||||
PieceKind* = enum
|
||||
## A chess piece enumeration
|
||||
Empty = 0'i8, # No piece
|
||||
Bishop = 'b',
|
||||
King = 'k'
|
||||
Knight = 'n',
|
||||
Pawn = 'p',
|
||||
Queen = 'q',
|
||||
Rook = 'r',
|
||||
Bishop = 0'i8
|
||||
King = 1
|
||||
Knight = 2
|
||||
Pawn = 3
|
||||
Queen = 4
|
||||
Rook = 5
|
||||
Empty = 6 # No piece
|
||||
|
||||
|
||||
Piece* = object
|
||||
## A chess piece
|
||||
color*: PieceColor
|
||||
kind*: PieceKind
|
||||
|
||||
|
||||
|
||||
func nullPiece*: Piece {.inline.} = Piece(kind: Empty, color: None)
|
||||
func nullSquare*: Square {.inline.} = Square(-1'i8)
|
||||
|
|
|
|||
|
|
@ -421,6 +421,8 @@ proc commandLoop*: int =
|
|||
echo &"Castling rights for {($board.getSideToMove()).toLowerAscii()}:\n - King side: {(if canCastle.king: \"yes\" else: \"no\")}\n - Queen side: {(if canCastle.queen: \"yes\" else: \"no\")}"
|
||||
of "check":
|
||||
echo &"{board.getSideToMove()} king in check: {(if board.inCheck(): \"yes\" else: \"no\")}"
|
||||
of "quit":
|
||||
return 0
|
||||
else:
|
||||
echo &"Unknown command '{cmd[0]}'. Type 'help' for more information."
|
||||
except IOError:
|
||||
|
|
|
|||
Loading…
Reference in New Issue