Different Registration and Login Messages

I want to have a different messages for registration and Login pages ABOVE THE FORM, but it seems like they are the same page?

I tried this and It doesn’t work, Obviously.

<?php if site_url(‘wp-login.php?action=register’) : ?>
<div id=”RegisterMessage”>This one time registration on our site will allow you to register for seminars </div>
<?php endif; ?>

Any Help is greatly appreciated!