diff --git a/a8/a8.h b/a8/a8.h
index 0b60508..2c28608 100644
--- a/a8/a8.h
+++ b/a8/a8.h
@@ -33,5 +33,6 @@ namespace std
 
 #define NEW_NET
 #define A8_SAFE_DELETE(p) { if(p){delete(p);  (p)=nullptr;} }
+#define A8_DEFINE_RANGE_BIT(type, begin, end) ((((type)1) << (end + 1)) - 1) & (~((((type)1) << (begin + 0)) - 1))
 
 #endif