;; ------------------------------------------------------------------
;; The CPU

(define run
  (lambda ()
    (begin
      (execute (decode (get-mem (get&inc-pc))))
      (run))))

(define step 
  (lambda ()
    (local ((define num (get-mem (get&inc-pc))))
      (begin
	(printf "~n~s~n" (disassemble num))
	(execute (decode num))
	(print-regs)))))

(define decode
  (lambda (num)
    (cons (sign num)
      (cons (build-vector DIGITS (lambda (i) (extract num i 1)))
	null))))

(define execute
  (lambda (sign&digits)
    (local ((define sign (car sign&digits))
	    (define digits (cadr sign&digits)))
      ((vector-ref ImmediateInstructions (vector-ref digits 0)) sign digits))))

(define dispatch-to
  (lambda (InstructionTable index)
    (lambda (sign digits)
      ((vector-ref InstructionTable (vector-ref digits index)) sign digits))))