diff --git a/miscellaneous.h b/miscellaneous.h
index a3d5df7b4d..4aaba9439a 100644
--- a/miscellaneous.h
+++ b/miscellaneous.h
@@ -121,9 +121,9 @@ typedef struct
 #define BIT128_GET(a, bit)   ((a).data[(bit) >> 5] &   (1 << ((bit) & 31)))
 #define BIT128_CLEAR_ALL(a)  memset(&(a), 0, sizeof(a));
 
-#define BIT64_SET(a, bit)   ((a) |= (1ULL << (bit)))
-#define BIT64_CLEAR(a, bit) ((a) &= (1ULL << (bit)))
-#define BIT64_GET(a, bit)   (((a) & (1ULL << (bit))) != 0)
+#define BIT64_SET(a, bit)   ((a) |=  (1ULL << ((bit) & 63)))
+#define BIT64_CLEAR(a, bit) ((a) &= ~(1ULL << ((bit) & 63)))
+#define BIT64_GET(a, bit)   (((a) &  (1ULL << ((bit) & 63))))
 #define BIT64_CLEAR_ALL(a)  ((a) = 0)
 
 #define BIT_SET(a, bit)   ((a)[(bit) >> 3] |=  (1 << ((bit) & 7)))