diff --git a/src/asm/main.c b/src/asm/main.c
index 84340bd7..6fe3f395 100644
--- a/src/asm/main.c
+++ b/src/asm/main.c
@@ -333,6 +333,9 @@ main(int argc, char *argv[])
 
 	DefaultOptions = CurrentOptions;
 
+	if (argc == 0)
+		PrintUsage();
+
 	tzMainfile = argv[argc - 1];
 
 	setuplex();