Data commit

Task/Subleq/Racket/subleq.rkt

@@ -0,0 +1,28 @@
+#lang racket
+
+(define (subleq v)
+  (define (mem n)
+    (vector-ref v n))
+  (define (mem-set! n x)
+    (vector-set! v n x))
+  (let loop ([ip 0])
+    (when (>= ip 0)
+      (define m0 (mem ip))
+      (define m1 (mem (add1 ip)))
+      (cond
+        [(< m0 0) (mem-set! m1 (read-byte))
+                  (loop (+ ip 3))]
+        [(< m1 0) (write-byte (mem m0))
+                  (loop (+ ip 3))]
+        [else (define v (- (mem m1) (mem m0)))
+              (mem-set! m1 v)
+              (if (<= v 0)
+                 (loop (mem (+ ip 2)))
+                 (loop (+ ip 3)))]))))
+
+(define Hello (vector 15 17 -1 17 -1 -1 16 1 -1 16 3 -1 15 15 0 0 -1
+                    ; H    e    l    l    o    ,  <sp> w    o    r    l    d    !   \n
+                      72   101  108  108  111  44  32  119  111  114  108  100  33  10
+                      0))
+
+(subleq Hello)