ps5: function epilogue

ps5/src/generator.c

@@ -148,6 +148,10 @@ static void generate_function(symbol_t* function)
   // TODO (Task 4): the function body can be sent to generate_statement()
 
   // TODO (Task 3.2): Emit the epilogue, including a label and a default return value (0)
+  LABEL(".%s.epilogue", function->name);
+  MOVQ(RBP, RSP);
+  POPQ(RBP);
+  RET;
 }
 
 // Generates code for a function call, which can either be a statement or an expression