diff --git a/change_log.txt b/change_log.txt
index 15f9ddf8..a340d40e 100644
--- a/change_log.txt
+++ b/change_log.txt
@@ -2,6 +2,8 @@
  01.09.2015
   - improvement convert template inheritance into runtime processing
   - bugfix {$smarty.block.parent} did always reference the root parent block https://github.com/smarty-php/smarty/issues/68
+  - move subtemplate code into runtime extension and optimize for size and speed
+  - move template function code into runtime extension
 
  23.08.2015
   - introduce Smarty::$resource_cache_mode and cache template object of {include} inside loop
diff --git a/libs/sysplugins/smarty_internal_compile_call.php b/libs/sysplugins/smarty_internal_compile_call.php
index 05420fa5..9b1cc585 100644
--- a/libs/sysplugins/smarty_internal_compile_call.php
+++ b/libs/sysplugins/smarty_internal_compile_call.php
@@ -76,9 +76,9 @@ class Smarty_Internal_Compile_Call extends Smarty_Internal_CompileBase
         //$compiler->suppressNocacheProcessing = true;
         // was there an assign attribute
         if (isset($_assign)) {
-            $_output = "<?php ob_start();\$_smarty_tpl->callTemplateFunction ({$_name}, \$_smarty_tpl, {$_params}, {$_nocache}); \$_smarty_tpl->assign({$_assign}, ob_get_clean());?>\n";
+            $_output = "<?php ob_start();\n\$_smarty_tpl->_Function->callTemplateFunction({$_name}, \$_smarty_tpl, {$_params}, {$_nocache});\n\$_smarty_tpl->assign({$_assign}, ob_get_clean());?>\n";
         } else {
-            $_output = "<?php \$_smarty_tpl->callTemplateFunction ({$_name}, \$_smarty_tpl, {$_params}, {$_nocache});?>\n";
+            $_output = "<?php \$_smarty_tpl->_Function->callTemplateFunction({$_name}, \$_smarty_tpl, {$_params}, {$_nocache});?>\n";
         }
         return $_output;
     }
diff --git a/libs/sysplugins/smarty_internal_runtime_function.php b/libs/sysplugins/smarty_internal_runtime_function.php
new file mode 100644
index 00000000..a1f72735
--- /dev/null
+++ b/libs/sysplugins/smarty_internal_runtime_function.php
@@ -0,0 +1,48 @@
+<?php
+
+/**
+ * Runtime Method _callTemplateFunction
+ *
+ * @package    Smarty
+ * @subpackage PluginsInternal
+ * @author     Uwe Tews
+ *
+ **/
+class Smarty_Internal_Runtime_Function
+{
+    /**
+     * Call template function
+     *
+     * @param string                           $name        template function name
+     * @param object|\Smarty_Internal_Template $_smarty_tpl template object
+     * @param array                            $params      parameter array
+     * @param bool                             $nocache     true if called nocache
+     *
+     * @throws \SmartyException
+     */
+    public function callTemplateFunction($name, Smarty_Internal_Template $_smarty_tpl, $params, $nocache)
+    {
+        if (isset($_smarty_tpl->tpl_function[$name])) {
+            if (!$_smarty_tpl->caching || ($_smarty_tpl->caching && $nocache)) {
+                $function = $_smarty_tpl->tpl_function[$name]['call_name'];
+            } else {
+                if (isset($_smarty_tpl->tpl_function[$name]['call_name_caching'])) {
+                    $function = $_smarty_tpl->tpl_function[$name]['call_name_caching'];
+                } else {
+                    $function = $_smarty_tpl->tpl_function[$name]['call_name'];
+                }
+            }
+            if (function_exists($function)) {
+                $function ($_smarty_tpl, $params);
+                return;
+            }
+            // try to load template function dynamically
+            if (Smarty_Internal_Function_Call_Handler::call($name, $_smarty_tpl, $function)) {
+                $function ($_smarty_tpl, $params);
+                return;
+            }
+        }
+        throw new SmartyException("Unable to find template function '{$name}'");
+    }
+
+}
\ No newline at end of file