Add Syscall: Exit, PutChar, GetCar, PutString, GetString

code/threads/system.cc

@@ -33,7 +33,12 @@ SynchDisk *synchDisk;
 
 #ifdef USER_PROGRAM		// requires either FILESYS or FILESYS_STUB
 Machine *machine;		// user program memory and registers
-#endif
+
+#ifdef CHANGED // Define our consoledriver Object
+ConsoleDriver *consoledriver;
+#endif // CHANGED
+
+#endif // USER_PROGRAM
 
 #ifdef NETWORK
 PostOffice *postOffice;
@@ -230,6 +235,12 @@ Cleanup ()
 	delete machine;
 	machine = NULL;
     }
+#ifdef CHANGED
+    if (consoledriver) {
+        delete consoledriver;
+        consoledriver = NULL;
+    }
+#endif
 #endif
 
 #ifdef FILESYS_NEEDED