1 (setf custom:*trace-indent* 1)
2 
3 (trace expmod)
4 (expmod 15 10 10)
5 ((defun louid-expmod (base exponent m)
6    (cond ((= exponent 0) 1)
7 	 ((evenp exponent)
8 	  (rem (* (louis-expmod base (/ exponent 2) m)
9 		  (louid-expmod base (/ exponent 2) m))
10 	       m))
11 	 (t (rem (* base louid-expmod base (- exponent 1) m)) m))))