voroskoi/pistike - Change WSRRWTTVBE2K6NKPS54CXMY3QYK5YTDRGEH3YJ53VQ2XW5UM5O2QC

Checkmate, stalemate detection

Created by voroskoi on January 20, 2023

WSRRWTTVBE2K6NKPS54CXMY3QYK5YTDRGEH3YJ53VQ2XW5UM5O2QC

Dependencies

In channels

main

Change contents

Insertion in src/eval.zig at line 3 [3.33]

[3.79]

pub const CHECKMATE_SCORE = -49000;
pub const STALEMATE_SCORE = 0;

Replacement in src/Chess.zig at line 9 [5.7502]

B:BD[4.1988] → [4.1988:2029]

    pub fn enemy(self: @This()) Colors {

[4.1988]

[4.2029]

    pub inline fn enemy(self: @This()) Colors {

Replacement in src/Board.zig at line 194 [6.16071]

B:BD[6.20370] → [2.0:36]

    best_move: BitMove = undefined,

[6.20370]

[2.36]

    best_move: BitMove = @bitCast(BitMove, @as(BitMoveType, 0)),

Replacement in src/Board.zig at line 279 [6.16071]

B:BD[2.207] → [2.207:271]

        _ = self.negamax(ALPHA, BETA, depth) catch unreachable;

[2.207]

[7.982]

        const score = self.negamax(ALPHA, BETA, depth) catch unreachable;

Replacement in src/Board.zig at line 281 [6.16071]

B:BD[7.983] → [2.272:542]

        return std.fmt.bufPrint(&buf, "bestmove {s}{s}{s}\n", .{
            @tagName(self.best_move.source),
            @tagName(self.best_move.target),
            if (self.best_move.prom != .none) @tagName(self.best_move.prom) else "",
        }) catch unreachable;

[7.983]

[2.542]

        std.debug.print("info score cp {d} depth {d}\n", .{ score, depth });
        if (@bitCast(BitMoveType, self.best_move) != 0) {
            return std.fmt.bufPrint(&buf, "bestmove {s}{s}{s}\n", .{
                @tagName(self.best_move.source),
                @tagName(self.best_move.target),
                if (self.best_move.prom != .none) @tagName(self.best_move.prom) else "",
            }) catch unreachable;
        } else return "";

Replacement in src/Board.zig at line 301 [6.16071]

B:BD[2.792] → [2.792:837]

        var best_sofar: BitMove = undefined;

[2.792]

[2.837]

        const king = switch (self.side) {
            .white => @intCast(SquareType, @ctz(@bitCast(BoardType, self.bitboards[@enumToInt(Chess.PE.K)]))),
            .black => @intCast(SquareType, @ctz(@bitCast(BoardType, self.bitboards[@enumToInt(Chess.PE.k)]))),
        };
        var in_check = self.isSquareAttacked(king, self.side.enemy());
        var legal_moves: usize = 0;

Insertion in src/Board.zig at line 310 [6.16071]

[2.838]

        var best_sofar: BitMove = @bitCast(BitMove, @as(BitMoveType, 0));

Insertion in src/Board.zig at line 325 [6.16071]
[2.1210]
[2.1210]
```
            legal_moves += 1;
```

Insertion in src/Board.zig at line 348 [6.16071]

[2.1782]

            }
        }
        // Detect check- and stalemate
        if (legal_moves == 0) {
            if (in_check) {
                // Adding ply helps the engine finding fastest mates.
                return eval.CHECKMATE_SCORE + @intCast(isize, self.ply);
            } else {
                return eval.STALEMATE_SCORE;