Fleshing out executive function.

diff --git a/mars.scm b/mars.scm
index 57e3e13..c77e2d3 100644 (file)
--- a/mars.scm
+++ b/mars.scm
@@ -2,6 +2,10 @@
 ;;; An implementation of the Memory Array Redcode Simulator (MARS)
 ;;;
 
+(import (chicken io)
+        (chicken string)
+        matchable)
+
 ;;; Constants
 ;;
 
@@ -40,24 +44,38 @@
 ;;; Main loop
 ;;
 
-(define (list-rot l)
-  (if (> (length l) 1)
-      (append (cdr l) (list (car l)))
-      l))
-
-(define (run playerA playerB step)
+(define (run players step)
   (cond
-   ((> step max-steps) 'tie)
-   ((null? (player-ptrs playerA) playerB))
-   ((null? (player-ptrs playerB) playerA))
+   ((> step max-steps) players) ;Tie between remaining players
+   ((null? players) '())        ;Somehow we have no players remaining
    (else
-    (let ((ptrs (player-ptrs playerA)))
-      (player-set-ptrs! (append (cdr ptrs)
-                                (execute-instr (car ptrs)))))
-    (run playerB player A (+ step 1)))))
+    (let ((player (car players))
+          (other-players (cdr players)))
+      (if (null? ptrs)
+          (run other-players (+ step 1))  ;Player is out
+          (let* ((ptrs (player-ptrs player))
+                 (new-ptrs (execute-instr (car ptrs))))
+            (player-set-ptrs! (append (cdr ptrs) new-ptrs))
+            (run (append other-players (list player)) (+ step 1))))))))
 
 (define (execute-instr ptr)
   (let ((instr (vector-ref core ptr)))
-    (match instr
-      ())))
+    (case (instr-opcode instr)
+      ((DAT))
+      ((MOV))
+      ((ADD))
+      ((SUB))
+      ((MUL))
+      ((DIV))
+      ((MOD))
+      ((JMP))
+      ((JMN))
+      ((DJN))
+      ((SEQ CMP))
+      ((SNE))
+      ((SLT))
+      ((SPL))
+      ((NOP))
+      (else
+       (error "Unrecognised opcode" (instr-opcode instr))))))