anchor.diff:  
   (defun bit-difference (&rest rest)
     "Subtraction for bit-vectors.  Return result DIFFERENCE forced to absolute ceiling value."
  -  (let* ((intlist (loop for i in rest collect (bits->int i)))
  +  (let* ((intlist (loop for i in rest collect (int<- i)))
            (difference (apply #'- intlist)))
  -    (int->bits (abs (ceiling difference)))))
  +    (bits<- (abs (ceiling difference)))))
   
   (defmacro bit- (&rest rest)
     "Shorthand for BIT-DIFFERENCE function."
  
positive.code: 
  (defun bit-product (&rest rest)
    "Multiplication for bit-vectors.  Return result PRODUCT forced to absolute ceiling value."
    (let* ((intlist (loop for i in rest collect (bits->int i)))
           (prod (apply #'* intlist)))
      (int->bits (abs (ceiling prod)))))
  
  (defmacro bit* (&rest rest)
    "Shorthand for BIT-PRODUCT function."
  
negative.code: 
  (defun bit-quotient (&rest rest)
    "Division for bit-vectors.  Return results QUOTIENT and REMAINDER forced to absolute ceiling values."
    (let* ((intlist (loop for i in rest collect (int<- i))))
      (multiple-value-bind (quotient remainder)
          (floor (apply #'/ intlist))
        (values (bits<- (abs (ceiling quotient))) (bits<- (abs (ceiling remainder)))))))
  
  (defmacro bit/ (&rest rest)
    "Shorthand for BIT-QUOTIENT function."
  