diff --git a/Makefile b/Makefile
index 1ee7f98..656f765 100644
--- a/Makefile
+++ b/Makefile
@@ -1,13 +1,20 @@
+SOURCE=nesgame.S \
+	include/defines.S \
+	include/math.S \
+	include/graphics.S
+MAIN_SOURCE=nesgame.S
+
 all: nesgame.nes
-nesgame.nes : nesgame.S
-	ophis -o $@ $<
+nesgame.nes : $(SOURCE)
+	ophis -o $(MAIN_SOURCE) $<
 
 .PHONY: test
-test:
+test: nesgame.nes
 	fceux nesgame.nes
 
 .PHONY: clean
 clean:
 	rm *nes
-	rm *nes.deb
-	rm *fns
+
+tags: $(SOURCE)
+	find . -name "*S" | xargs etags -a