anchor.diff:                   (bitbv (newbit bv)))))
   
   (defun make-prbs (n &optional (iv 2))
  +  "return a lazy list of n-bit bitvectors"
     (let ((taps '(0 1))
           (init (num->bits iv n)))
       (labels ((rec (v)
  
positive.code:              b)))))
        
  (defun num-gen (n)
    (let ((v (make-prbs n)))
      (labels ((rec (&optional (c 1))
                    (when (> c 0)
  
negative.code:                 :take)
    (:export :make-prbs
             :num-gen
             :bvlist-gen
             :bit-gen
             :byte-gen))
  
  (in-package :prbs)
  
  