diff --git a/tests/test-reg.mac b/tests/test-reg.mac
new file mode 100644
index 0000000..57e10a3
--- /dev/null
+++ b/tests/test-reg.mac
@@ -0,0 +1,52 @@
+;;;;;
+;
+; Test expressions that evaluate to registers.
+;
+; !!! THIS TEST IS NOT RUN YET BECAUSE MANY OF THE CASES FAIL !!!
+;
+; All lines not marked "error" should assemble without complaint
+; as absolute values (no relocation etc).
+;
+; Section 3.4 (page 3-8) is a bit vague about the expressions that are allowed
+; after a %, but "the digit specifying the register can be replaced by any valid,
+; absolute term that can be evaluated during the first assembly pass."
+; It specifically mentions %3+1 to be the same as %4.
+; For the rest there is no indication where exactly register labels can be used.
+
+        A = 1
+
+        l1 = %1
+        l2 = %1+1
+        l3 = %a
+        l4 = %a + 1
+        l5 = %<1+1>
+        l6 = <%1>+1     ; must be register!
+        l7 = <%a>+1     ; must be register!
+        l8 = %1 + %2
+        l8a = <%1> + <%2> ; must be register!
+        l9 = %<%1 + %2>
+
+        B = rti		; 2
+
+        l10 = %B
+        l11 = %wait	; 1
+
+        l12 = %1.
+        l13 = %7.
+        l14 = %10	; error: too large
+        l15 = %8.	; error: too large
+
+         mov #%2,%2             ; must not be a relocatable expression!
+         mov #l1,%2             ; must not be a relocatable expression!
+         mov #<%1+%2>,%3        ; must not be a relocatable expression!
+         mov #<l1+1>,%3         ; must not be a relocatable expression!
+         mov #<%l1+1>,%3        ; must not be a relocatable expression!
+
+         l20 = %l1
+         l21 = %l20
+
+         l22 = l1        ; still a register
+         l23 = l22       ; still a register
+
+        .end
+