diff --git a/src/userprog/process.c b/src/userprog/process.c
index 48c067c..6d6fef7 100644
--- a/src/userprog/process.c
+++ b/src/userprog/process.c
@@ -60,16 +60,9 @@ process_execute (const char *file_name)
   return tid;
 }
 
-static void *
-push_to_stack (void **esp, void *data, size_t data_size)
-{
-  *esp -= data_size;
-  memcpy (*esp, data, data_size);
-  return *esp;
-}
-
 static void process_init_stack (void *file_name_, char *saveptr, void **esp,
                                 char *file_name);
+static void *push_to_stack (void **esp, void *data, size_t data_size);
 
 /* A thread function that loads a user process and starts it
    running. */
@@ -205,6 +198,17 @@ process_init_stack (void *file_name_, char *saveptr, void **esp,
     *(char *) *esp = 0;
  }
 
+/* Helper function that pushes the first 'data_size' bytes stored in the
+   address '*data' into the stack given a pointer to the stack pointer
+   '**esp'. */
+static void *
+push_to_stack (void **esp, void *data, size_t data_size)
+{
+  *esp -= data_size;
+  memcpy (*esp, data, data_size);
+  return *esp;
+}
+
 /* Waits for thread TID to die and returns its exit status. 
  * If it was terminated by the kernel (i.e. killed due to an exception), 
  * returns -1.