diff --git a/common_arm64.h b/common_arm64.h
index 2ab34686e..d80b9e434 100644
--- a/common_arm64.h
+++ b/common_arm64.h
@@ -63,7 +63,8 @@ static __inline int WhereAmI(void){
                  :"=r" (ret)
                  :: "memory"
                );
-  if (ret > MAX_CPU_NUMBER) ret = MAX_CPU_NUMBER;
+  ret +=1;
+  if ((int)ret <0) ret = 0;
   return (int)ret;
 }