anchor.diff:  (defun apply-mask-to-index (index mask)
     (declare (type index index)
              (type (unsigned-byte 64) mask))
  -  (assert (< index 32))
  +  (assert (< index 64))
     (logcount (ldb (byte index 0) mask)))
   
   
  
positive.code: 
  (defun alter-mask (index mask)
    (declare (type index index)
             (type (unsigned-byte 32) mask))
    (assert (< index 32))
    (dpb 1 (byte 1 index) mask))
  
  
  
negative.code:     :type (unsigned-byte 64)
      :initarg :mask
      :reader read-mask))
    (:documentation "Lookuptable that can hold up to 64 elements, under 64 indexes (from 0 to 63)."))
  
  
  (defmethod print-object ((object fixed-lookuptable) stream)
  