Specify register machines

Specify register machines that implement each of the following procedures. For each machine, write a controller instruction sequence and draw a diagram showing the data paths.

a. Recursive exponentiation:

(define (expt b n)
  (if (= n 0)
      1
      (* b (expt b (- n 1)))))

b. Iterative exponentiation:

(define (expt b n)
  (define (expt-iter counter product)
    (if (= counter 0)
        product
        (expt-iter (- counter 1) (* b product))))
  (expt-iter n 1))

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