diff --git a/project/arch.mk b/project/arch.mk
index 750987b..8aab40d 100644
--- a/project/arch.mk
+++ b/project/arch.mk
@@ -6,8 +6,8 @@ else ifeq ($(ARCH),w64)
 endif
 
 # process
-src/process/%.lo: $(PROJECT_DIR)/src/process/$(ARCH)/%.s $(ALL_HEADERS) host.tag tree.tag
+src/process/%.lo: $(SOURCE_DIR)/src/process/$(ARCH)/%.s $(ALL_HEADERS) host.tag tree.tag
 		$(CC) -c -o $@ $<
 
-src/process/%.o: $(PROJECT_DIR)/src/process/$(ARCH)/%.s $(ALL_HEADERS) host.tag tree.tag
+src/process/%.o: $(SOURCE_DIR)/src/process/$(ARCH)/%.s $(ALL_HEADERS) host.tag tree.tag
 		$(CC) -c -o $@ $<