diff --git a/wip-duuqnd/user-side-compiler/asm-function.lisp b/wip-duuqnd/user-side-compiler/asm-function.lisp
index 90e8e23..f1aa905 100644
--- a/wip-duuqnd/user-side-compiler/asm-function.lisp
+++ b/wip-duuqnd/user-side-compiler/asm-function.lisp
@@ -27,6 +27,7 @@
         asm-function
         (progn
           (cerror "Create dummy function with placeholder address."
-                  "Tried to transform token into non-existent function ~A."
-                  (name token))
+                  'missing-function-error
+                  :format-control "~A"
+                  :format-arguments (list (name token)))
           (add-asm-function (name token) #xC0FE)))))
diff --git a/wip-duuqnd/user-side-compiler/error-handling.lisp b/wip-duuqnd/user-side-compiler/error-handling.lisp
index 4bfc669..ed4e95c 100644
--- a/wip-duuqnd/user-side-compiler/error-handling.lisp
+++ b/wip-duuqnd/user-side-compiler/error-handling.lisp
@@ -38,6 +38,9 @@
 (define-condition tokenizer-error (usc-error)
   ((%context-string :initform "Tokenizing error:")))
 
+(define-condition missing-function-error (usc-error)
+  ((%context-string :initform "Non-existent function (TODO nicer error for this):")))
+
 (define-condition parser-error (usc-error)
   ((%context-string :initform "Syntax error:")))