anchor.diff:  (defpackage :galois
     (:use :common-lisp)
     (:export :gf
  +           :gf16
  +           :gf64
              :gf256
  -           :gf16
  +           :gf1024
  +           :gf4096
              :n
              :p
              :g+
  
positive.code:         (+ (* mult car) (bv->num cdr (/ mult 2))))))
  
  (defun normpoly (l p)
    (if (>= (length p) l)
        p
        (cons 0 (normpoly (1- l) p))))
  
  (defun polyprod (p q)
    "build the structure of the product of two arbitrary-length polynomials"
    (append
     (loop for p0 in p
        collecting p0 into pp
  
negative.code:          as r = (g* gf px base)
           finally (return r))))
  
  
  (defmethod gdiv ((gf gf) dividend divisor)
    (let* ((numsym (1- (length divisor)))
  