gistfile1.txt

(use util.match)
(use data.sparse)

(define-macro (make-dumper . labels)
  `(lambda (memory)
     (list ,@(map (^l `(list ',l (~ memory ,l))) labels))))

(define (run program memory dumper)
  (define (DJN pc)
    (match-let1 (dest ptr) (~ program pc)
      (if (zero? (rlet1 v (~ memory ptr)
                   (set! (~ memory ptr) (modulo (- v 1) 256))))
        (+ pc 1)
        (+ pc dest))))
  (let loop ((pc 0))
    (format #t "~3d: ~s\n" pc (dumper memory))
    (if (>= pc (vector-length program))
      memory
      (loop (DJN pc)))))

;; COPY A to B
(let* ((memory (make-sparse-vector 'u8 :default 0))
       (TEMP 0)
       (A 1)
       (B 2)
       (program `#((0 ,TEMP)
                   (0 ,B)
                   (1 ,TEMP)
                   (-1 ,A)
                   (1 ,A)
                   (1 ,B)
                   (-2 ,TEMP))))
  (set! (~ memory TEMP) 0)
  (set! (~ memory A) 10)
  (set! (~ memory B) 0)
  (run program memory (make-dumper TEMP A B))
  )