diff --git a/hwaccess.h b/hwaccess.h
index af7054b..5602c15 100644
--- a/hwaccess.h
+++ b/hwaccess.h
@@ -291,6 +291,10 @@
 
 /* Non memory mapped I/O is not supported on ARM. */
 
+#elif IS_ARC
+
+/* Non memory mapped I/O is not supported on ARC. */
+
 #else
 
 #error Unknown architecture, please check if it supports PCI port IO.