anchor.diff:                  (setf (aref buffer pv) ; RED
                         (the uint8 (limit (plus yy (aref *cr-r-tab* cr)))))))))
   
  +(defun ycck-cmyk-convert (image)
  +  (let* ((buffer (descriptor-buffer image))
  +         (nw (mul (descriptor-width image) 4)))
  +    (declare #.*optimize*
  +	     (type (simple-array uint8 (*)) buffer)
  +             (type fixnum nw))
  +    (loop for y fixnum from 0 below (descriptor-height image)
  +       for yp fixnum from 0 by nw do
  +	 (loop for x fixnum from 0 below (descriptor-width image)
  +	    for py fixnum from yp by 4
  +	    for pu fixnum = (1+ py)
  +	    for pv fixnum = (plus py 2)
  +	    for yy fixnum = (aref buffer py)
  +	    for cb fixnum = (aref buffer pu)
  +	    for cr fixnum = (aref buffer pv) do
  +	      (setf (aref buffer pv)	; BLUE
  +		    (the uint8 (limit (minus +max-sample+ (plus yy (aref *cb-b-tab* cb))))))
  +	      (setf (aref buffer pu)	; GREEN
  +		    (the uint8 (limit (minus +max-sample+
  +					     (plus yy (ash (plus
  +							    (aref *cb-g-tab* cb)
  +							    (aref *cr-g-tab* cr))
  +							   (- shift)))))))
  +	      (setf (aref buffer py)	; RED
  +		    (the uint8 (limit (minus +max-sample+ (plus yy (aref *cr-r-tab* cr))))))))))
  +
   (defun allocate-buffer (height width ncomp)
     (make-array (* height width ncomp) 
   	      :element-type 'uint8
  
positive.code:   (iV (make-array 4) :type (simple-array t (*)))
    (qdest (make-array 4) :type (simple-array t (*)))
    (zz (make-array 64 :element-type 'sint16) :type sint16-array)
    (ncomp 0 :type fixnum))
  
  ;;; Reads an JPEG marker from the stream
  (defun read-marker (s)
  
negative.code:          (marker (interpret-markers image 0 stream)))
      (cond ((= +M_SOF0+ marker)
             (decode-frame image stream buffer)
             (when colorspace-conversion
  	     (cond ((and (= (descriptor-ncomp image) 3) (eql (descriptor-adobe-app14-transform image) :ycbcr-rgb))
  		    (inverse-colorspace-convert image))
  		   ((eql (descriptor-adobe-app14-transform image) :ycck-cmyk)
  		    (ycck-cmyk-convert image))
  		   ((= (descriptor-ncomp image) 3)
  		    (inverse-colorspace-convert image))))
             (values (descriptor-buffer image)
                     (descriptor-height image)
                     (descriptor-width image)
  