diff --git a/src/c/stacks.d b/src/c/stacks.d
index 01c214598..07b6c51e6 100644
--- a/src/c/stacks.d
+++ b/src/c/stacks.d
@@ -874,6 +874,31 @@ ecl_stack_push(cl_object self, cl_object elt)
   return self;
 }
 
+cl_object
+ecl_stack_pop(cl_object self)
+{
+  cl_index fillp = self->vector.fillp;
+  cl_object elt = ECL_NIL;
+  if (ecl_unlikely(fillp == 0)) {
+    ecl_internal_error("ecl_stack_pop: stack underflow");
+  }
+  elt = self->vector.self.t[fillp-1];
+  self->vector.self.t[fillp-1] = ECL_NIL;
+  self->vector.fillp--;
+  return elt;
+}
+
+cl_object
+ecl_stack_dup(cl_object self)
+{
+  cl_index fillp = self->vector.fillp;
+  if (ecl_unlikely(fillp == 0)) {
+    ecl_internal_error("ecl_stack_dup: empty stack");
+  }
+  ecl_stack_push(self, self->vector.self.t[fillp-1]);
+  return self;
+}
+
 cl_object
 ecl_stack_del(cl_object self, cl_object elt)
 {
@@ -899,3 +924,15 @@ ecl_stack_popu(cl_object self)
   self->vector.self.t[self->vector.fillp] = ECL_NIL;
   return result;
 }
+
+void
+ecl_stack_grow(cl_object self, cl_index n)
+{
+  self->vector.fillp += n;
+}
+
+void
+ecl_stack_drop(cl_object self, cl_index n)
+{
+  self->vector.fillp -= n;
+}