anchor.diff:      (if (not predictor)
           ;; Funny stuff. If there is no desired predictor in hash table,
           ;; generate it on the fly.
  -        (setf (gethash order *lpc-predictors*)
  -              (setq predictor
  -                    (eval (list 'gen-lpc-predictor order)))))
  -    
  -    (funcall (the function predictor)
  -             subframe))
  -             
  -  (subframe-out-buf subframe))
  +        (setf predictor (eval (list 'gen-lpc-predictor order))
  +              (gethash order *lpc-predictors*) predictor))
  +
  +    (funcall (the function predictor) subframe)))
   
   (defun frame-decode (frame)
     "Decode a frame destructively modifying (and garbaging) all subframes within.
  
positive.code: 
  (defmacro gen-lpc-predictor (n)
    "Generate FIR linear predictor of order N"
    #+sbcl (declare (sb-ext:muffle-conditions sb-ext:compiler-note))
    (let ((func-name (intern (format nil "LPC-PREDICTOR-~D" n))))
      `(flet ((,func-name (subframe)
                (let ((out-buf (subframe-out-buf subframe))
                      (shift (subframe-lpc-coeff-shift subframe))
                      (coeff (subframe-lpc-predictor-coeff subframe)))
  
negative.code:                 
                  (loop for i fixnum from ,n below (length out-buf)
                     for sum fixnum = 0 do
                       ,@(loop for j fixnum below n collect
                              `(incf sum
                                     (* (aref coeff ,j)
                                        (aref out-buf (- i ,(1+ j))))))
                       (incf (aref out-buf i)
                             (the fixnum
                                  (ash sum (- shift)))))
                  out-buf)))
         #',func-name)))
  
  ;; Populate hash table with predictors of orders from 1 to 12
  ;; (These are most useful).
  (macrolet ((gen-lpc-predictors (n)
               `(progn
                  ,@(loop for order fixnum from 1 to n collect
                          `(setf (gethash ,order *lpc-predictors*)
                                 (gen-lpc-predictor ,order))))))
  
  