anchor.diff:  (defun zeroize-page (addr)
     (dotimes (i 512)
       (setf (sys.int::memref-unsigned-byte-64 addr i) 0)))
  +
  +(defun page-aligned-p (value)
  +  (zerop (logand value #xFFF)))
   
   (defun allocate-page (&optional mandatory)
     (let ((frame (allocate-physical-pages 1 :mandatory-p mandatory)))
  
positive.code:     (thread-pager-argument-1 (current-thread))))
  
  (defun allocate-memory-range (base length flags)
    (assert (zerop (logand (logior base length) #xFFF)) () "Range not page aligned.")
    (pager-rpc 'allocate-memory-range-in-pager base length flags))
  
  (defun allocate-memory-range-in-pager (base length flags)
  
negative.code: 
  (defun map-physical-memory (base size name)
    ;; Page alignment required.
    (assert (page-aligned-p base))
    (assert (page-aligned-p size))
    (with-mutex (*vm-lock*)
      (dotimes (i (truncate size #x1000))
        (let ((pte (get-pte-for-address (+ +physical-map-base+ base (* i #x1000)))))
  