diff --git a/include/macros.h b/include/macros.h
index bf7627f..4441dd9 100644
--- a/include/macros.h
+++ b/include/macros.h
@@ -30,3 +30,4 @@
 /* Bit manipulation */
 #define BIT_SIZE(t) (CHAR_BIT * sizeof(t))
 #define BIT(n) (1 << (n))
+#define BITS(_start, _end) ((BIT(_end) - BIT(_start)) + BIT(_end))