working knightCalc

src/move.zig

@@ -81,8 +81,28 @@ pub fn knightMove(g: *types.game, arr: *std.ArrayList(types.move)) void {
 }
 
 fn knightCalc(index: u8) u64 {
-    _ = index;
+    var moves: u64 = 0;
-    return @as(u64,1)<<32;
+    const offsets = [_]i8{ 17, -17, 15, -15, 10, -10, 6, -6 };
+    var cnt: u8 = undefined;
+    for (offsets) |off| {
+        if (off > 0) {
+            cnt = index + @abs(off);
+        } else if (index > @abs(off)) { //Icky bad that zig makes me do
+            cnt = index - @abs(off);
+        }
+        const fromFile: i32 = index % 8;
+        const toFile: i32 = cnt % 8;
+        const fromRank: i32 = index / 8;
+        const toRank: i32 = cnt / 8;
+
+        const fileDiff = @abs(fromFile - toFile);
+        const rankDiff = @abs(fromRank - toRank);
+        if (!((fileDiff == 1 and rankDiff == 2) or
+            (fileDiff == 2 and rankDiff == 1)) or cnt > 63)
+            continue;
+        moves = moves | @as(u64, 1) << @truncate(cnt);
+    }
+    return moves;
 }
 
 fn bitboardToMoves(start: u8, moves: u64, arr: *std.ArrayList(types.move)) void {