RANK1(c) || \
FILEA(c) || \
FILEH(c))
-#define CORNER_DISTANCE(c) (MAX(MIN((ULONG)abs(RANK(c) - 7), RANK(c)),\
- MIN((ULONG)abs(FILE(c) - 7), FILE(c))))
+#define CORNER_DISTANCE(c) (MAX(MIN((ULONG)(RANK(c) - 7), RANK(c)),\
+ MIN((ULONG)(FILE(c) - 7), FILE(c))))
#define IN_CORNER(c) (((c) == A8) || \
((c) == A1) || \
((c) == H8) || \