diff --git a/testsuite/tests/cmm/should_run/machops/all.T b/testsuite/tests/cmm/should_run/machops/all.T
index d705f331dd8095883f4dbdf014fee699d119e4ed..a10500f7c8784451c2149c777619f1cfea276446 100644
--- a/testsuite/tests/cmm/should_run/machops/all.T
+++ b/testsuite/tests/cmm/should_run/machops/all.T
@@ -1,11 +1,12 @@
 setTestOpts(extra_files(['TestMachOp.hs']))
 
-def cmm_test(name):
-    test(name, normal, multi_compile_and_run,
+def cmm_test(name, ws):
+    test(name,
+         [unless(wordsize(ws), skip), normal],
+         multi_compile_and_run,
          ['TestMachOp', [(name+'.cmm', '')], ''])
 
-cmm_test('T20626a')
-cmm_test('T20626b')
-cmm_test('T20638')
-cmm_test('T20634')
-cmm_test('MachOps1')
+cmm_test('T20626a', ws=64)
+cmm_test('T20626b', ws=64)
+cmm_test('T20638',  ws=64)
+cmm_test('T20634',  ws=64)