anchor.diff:           (Vmax (loop for entry across fr maximize (the fixnum (second entry))))
            (x-growth (ash Hmax 3))
            (y-growth (ash Vmax 3))
  -	 (*ws* (2d-sint16-array
  -		'(0  0  0  0  0  0  0  0)
  -		'(0  0  0  0  0  0  0  0)
  -		'(0  0  0  0  0  0  0  0)
  -		'(0  0  0  0  0  0  0  0)
  -		'(0  0  0  0  0  0  0  0)
  -		'(0  0  0  0  0  0  0  0)
  -		'(0  0  0  0  0  0  0  0)
  -		'(0  0  0  0  0  0  0  0))) ; Temporary workspace for IDCT
            (freqs (make-array ncomp :initial-contents
                               (loop for i fixnum from 0 below ncomp ; collecting sampling frequencies
                                     for cid fixnum = (first (aref (scan-cdesc scan) i))
  
positive.code:   (qdest (make-array 4) :type (simple-array t (*)))
    (zz (make-array 64 :element-type 'sint16) :type sint16-array)
    (ncomp 0 :type fixnum)
    (adobe-app14-transform nil))
  
  ;;; Reads an JPEG marker from the stream
  
negative.code:                   (zerop (s16ref block dptr 6))
                    (zerop (s16ref block dptr 7))) do
            (setf dcval (ash (the fixnum (dequantize dptr 0 block q-table)) 1))
            (setf (s16ref ws dptr 0) dcval)
            (setf (s16ref ws dptr 1) dcval)
            (setf (s16ref ws dptr 2) dcval)
            (setf (s16ref ws dptr 3) dcval)
            (setf (s16ref ws dptr 4) dcval)
            (setf (s16ref ws dptr 5) dcval)
            (setf (s16ref ws dptr 6) dcval)
            (setf (s16ref ws dptr 7) dcval)
            else do
            (setf z2 (dequantize dptr 2 block q-table))
            (setf z3 (dequantize dptr 6 block q-table))
  