(def %bit-position/0 (logandc2 #.(1- (expt 2 n-word-bits))))
(def %bit-position/1 (identity)))
(defun %bit-position (bit vector from-end start end)
(def %bit-position/0 (logandc2 #.(1- (expt 2 n-word-bits))))
(def %bit-position/1 (identity)))
(defun %bit-position (bit vector from-end start end)