WordPress in subdomain

Hello guys,
ive got a running website that does not use wordpress.
i want to leave the website like it is, but add a wordpress to it.
say my url is http://www.havefun.com.
i now want my wordpress to appear only upon typing http://www.havefun.com/wordpress.

if people go to http://www.havefun.com they see nothing of wordpress, my original website stays the same. only when they enter http://www.havefun.com/wordpress.

ive checked with subdirectory as well as subdomain and need help please.
is what i just described possible?

thanks for the help,
Max