;;;
;;; An implementation of the Memory Array Redcode Simulator (MARS)
;;;

;;; Constants
;;

(define core-size 8000)
(define max-steps 10000)


;;; Memory setup
;;

(define core (make-vector core-size '()))


;;; Instructions
;;

(define (make-instr opcode modifier addrA modeA addrB modeB))


;;; Players
;;

(define (make-player name . ptrs)
  (cons name ptrs))

(define (player-ptrs player)
  (cdr player))

(define (player-name player)
  (car player))

(define (player-set-ptrs! player ptrs)
  (set-cdr! player ptrs))


;;; Main loop
;;

(define (list-rot l)
  (if (> (length l) 1)
      (append (cdr l) (list (car l)))
      l))

(define (run playerA playerB step)
  (cond
   ((> step max-steps) 'tie)
   ((null? (player-ptrs playerA) playerB))
   ((null? (player-ptrs playerB) playerA))
   (else
    (let ((ptrs (player-ptrs playerA)))
      (player-set-ptrs! (append (cdr ptrs)
                                (execute-instr (car ptrs)))))
    (run playerB player A (+ step 1)))))

(define (execute-instr ptr)
  (let ((instr (vector-ref core ptr)))
    (match instr
      ())))