frame n = StInd PtrRep
(StIndex PtrRep stgSp (StInt (toInteger (n-uF_SIZE))))
+ -- HWL: these values are *wrong* in a GranSim setup; ToDo: fix
a1 = StAssign PtrRep (frame uF_RET) upd_frame_info
a3 = StAssign PtrRep (frame uF_SU) stgSu
a4 = StAssign PtrRep (frame uF_UPDATEE) bhptr