anchor.diff:    "The DECODE procedure, as described in CCITT rec."
     (let ((i 1)
           (code (funcall nextbit s)))
  +    (declare #.*optimize*
  +             (type (simple-array uint8 (*)) huffval)
  +             (type (simple-array fixnum (*)) maxcode mincode valptr)
  +             (type fixnum i code))
       (loop while (> code (aref maxcode i)) do
             (incf i)
             (setf code (plus (ash code 1) (funcall nextbit s))))
  
positive.code: (defun izigzag8 (inbuf zzbuf)
    (declare #.*optimize*
             (type uint8-array inbuf)
  	   (type uint8-2d-array zzbuf))
    "Performs inverse zigzag block arrangement"
    (loop for zrow across +zigzag-index+
          for row across zzbuf do
          (loop for pos fixnum across zrow
                for x fixnum from 0 do
                (setf (aref row x) (aref inbuf pos))))
  
negative.code:              (type uint8-array buffer)
               (type fixnum x y H V ncomp xbase ybase nwidth nx dend nxbase nybase offset)
               (dynamic-extent ncomp xbase ybase nxbase nybase))
      (loop for row of-type sint16-array across block
            for y fixnum from ybase below (descriptor-height image) by V
            for ypos fixnum from nybase by nw do
            (loop for val fixnum across row
  