(sap> control-stack-end x)
(zerop (logand (sap-int x) #b11)))))
-#!+x86
(sb!alien:define-alien-routine component-ptr-from-pc (system-area-pointer)
(pc system-area-pointer))
-#!+x86
(defun component-from-component-ptr (component-ptr)
(declare (type system-area-pointer component-ptr))
(make-lisp-obj (logior (sap-int component-ptr)