diff --git a/cpu.h b/cpu.h
index cee84c5..5b91ed4 100644
--- a/cpu.h
+++ b/cpu.h
@@ -128,6 +128,7 @@
 	status_t status;
 	uint8_t *mem;
 	bool running;
+	bool screen_dirty;
 } cpu_t;
 
 // Argument type, includes both pointer and its value