diff --git a/code/userprog/exception.cc b/code/userprog/exception.cc
index df7ca0e..c8c0a83 100644
--- a/code/userprog/exception.cc
+++ b/code/userprog/exception.cc
@@ -131,8 +131,8 @@ ExceptionHandler (ExceptionType which)
         #ifdef CHANGED
         case SC_Exit:
           {
-            while (1)
-                currentThread->Yield();
+            // while (1)
+            //     currentThread->Yield();
             int ret = machine->ReadRegister(4);
             printf("Exit code %d\n", ret);
             interrupt->Powerdown();
diff --git a/code/userprog/userthread.cc b/code/userprog/userthread.cc
index 014d574..da97ea0 100644
--- a/code/userprog/userthread.cc
+++ b/code/userprog/userthread.cc
@@ -68,8 +68,13 @@ void do_ThreadExit(){
     DEBUG('x', "Enter do_ThreadExit function\n");
     // TODO: what should we do with thread space?
     //       Probalely desallocate it... if no threads remain
-    currentThread->space->Threads--;
+    // currentThread->space->Threads--;
     DEBUG('x', "Decrease numbers of Threads:%d\n",currentThread->space->Threads);
+    if ( --currentThread->space->Threads == 0){
+        // No threads remains, desallocate addrspace
+        delete currentThread->space;
+        interrupt->Powerdown();
+    }
     currentThread->Finish();
 }
 #endif