(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)
- (ecase bit
+ (case bit
(0 (%bit-position/0 vector from-end start end))
- (1 (%bit-position/1 vector from-end start end))))
+ (1 (%bit-position/1 vector from-end start end))
+ (otherwise nil)))