diff -r fd1eb081de40 -r 2e5846019b4f src/chess/bishop.c
--- a/src/chess/bishop.c	Mon Mar 31 11:41:08 2014 +0200
+++ b/src/chess/bishop.c	Mon Mar 31 14:00:58 2014 +0200
@@ -42,13 +42,13 @@
     uint8_t y = move->fromrow;
     uint8_t x = move->fromfile;
     
-    do {
+    while (x != move->tofile-dx && y != move->torow-dy) {
         x += dx;
         y += dy;
         if (board[y][x]) {
             return 1;
         }
-    } while (x != move->tofile && y != move->torow);
+    }
     
     return 0;
 }