(defun rotl (x width bits)
  "Compute bitwise left rotation of x by 'bits' bits, represented on 'width' bits"
  (logior (logand (ash x (mod bits width))
                  (1- (ash 1 width)))
          (logand (ash x (- (- width (mod bits width))))
                  (1- (ash 1 width)))))

(defun rotr (x width bits)
  "Compute bitwise right rotation of x by 'bits' bits, represented on 'width' bits"
  (logior (logand (ash x (- (mod bits width)))
                  (1- (ash 1 width)))
          (logand (ash x (- width (mod bits width)))
                  (1- (ash 1 width)))))