diff --git a/as/CMakeLists.txt b/as/CMakeLists.txt
index f5e3989..e3ed969 100644
--- a/as/CMakeLists.txt
+++ b/as/CMakeLists.txt
@@ -13,6 +13,6 @@
 endif()
 
 
-add_executable(6502-as main.c as.h as.c map.h map.c hash.c hash.c)
+add_executable(6502-as main.c as.h as.c pp.c map.h map.c hash.c hash.c)
 
 install(TARGETS 6502-as)