Add reference equality test (only implemented for constants so far)

wip-duuqnd/user-side-compiler/high-level.lisp

@@ -36,6 +36,9 @@
   (print-unreadable-object (object stream :type t)
     (format stream "~D" (ref-value object))))
 
+(defmethod ref= ((a reference-constant) (b reference-constant))
+  (= (value a) (value b)))
+
 (defmethod dereference ((ref reference-constant))
   (produce-instruction 'inst-lda-immediate (ref-value ref)))