diff --git a/basis/cpu/architecture/architecture-tests.factor b/basis/cpu/architecture/architecture-tests.factor
index e62c93d5d1..1a9ef57754 100644
--- a/basis/cpu/architecture/architecture-tests.factor
+++ b/basis/cpu/architecture/architecture-tests.factor
@@ -1,19 +1,19 @@
-USING: compiler.cfg.instructions compiler.cfg.stack-frame kernel namespaces
-system tools.test ;
-IN: cpu.architecture
+USING: accessors compiler.cfg.instructions compiler.cfg.stack-frame
+cpu.architecture cpu.x86 kernel layouts math namespaces system tools.test ;
+IN: cpu.architecture.tests
+
+: expected-gc-root-offset ( slot-number spill-area-base -- offset )
+    [ spill-slot boa ] [ stack-frame new swap >>spill-area-base ] bi*
+    stack-frame [
+        gc-root-offset reserved-stack-space cell / -
+    ] with-variable ;
 
 cpu x86.64? [
     ! The offset is 1, not 0 because the return address occupies the
     ! first position in the stack frame.
-    { 1 } [
-        T{ stack-frame { spill-area-base 0 } } stack-frame [
-            T{ spill-slot { n 0 } } gc-root-offset
-        ] with-variable
-    ] unit-test
+    { 1 } [ 0 0 expected-gc-root-offset ] unit-test
 
-    { 10 } [
-        T{ stack-frame { spill-area-base 64 } } stack-frame [
-            T{ spill-slot { n 8 } } gc-root-offset
-        ] with-variable
-    ] unit-test
+    { 10 } [ 8 64 expected-gc-root-offset ] unit-test
+
+    { 20 } [ 24 128 expected-gc-root-offset ] unit-test
 ] when