1 files changed, 9 insertions, 7 deletions

diff --git a/lisp/emulation/cua-base.el b/lisp/emulation/cua-base.el
index f7887575521..2c7d3ddf0b1 100644
--- a/lisp/emulation/cua-base.el
+++ b/lisp/emulation/cua-base.el
@@ -653,17 +653,19 @@ Repeating prefix key when region is active works as a single prefix key."
 (defun cua--prefix-arg (arg)
   (setq cua--register  
         (and cua-enable-register-prefix
-             (integerp (this-command-keys))
-             (cond ((eq cua-enable-register-prefix 'not-ctrl-u)
-                    (not (= (aref (this-command-keys) 0) ?\C-u)))
-                   ((eq cua-enable-register-prefix 'ctrl-u-only)
-                    (= (aref (this-command-keys) 0) ?\C-u))
-                   (t t))
              (integerp arg) (>= arg 0) (< arg 10)
+             (let* ((prefix (aref (this-command-keys) 0))
+                    (ctrl-u-prefix (and (integerp prefix)
+                                        (= prefix ?\C-u)))))
+             (cond 
+              ((eq cua-enable-register-prefix 'not-ctrl-u)
+               (not ctrl-u-prefix))
+              ((eq cua-enable-register-prefix 'ctrl-u-only)
+               ctrl-u-prefix)
+              (t t))
              (+ arg ?0)))
   (if cua--register nil arg))
 
-
 ;;; Enhanced undo - restore rectangle selections
 
 (defun cua-undo (&optional arg)