more related to a programming tool than programming directly, but--

I carefully observing the syntax of:
diff3 [options] mine older yours
with the only option being --merge.. however, instead of the man page's predicted behavior of:
<<<<<<< mine
lines from mine
=======
lines from yours
>>>>>>> yours
I get:
<<<<<<< older
lines from older
=======
lines from yours
>>>>>>> yours

this is with Mandrake 8.1 and diff3 - GNU diffutils version 2.7

Do I have a mutant strain? Is this a known bug? Is this not a bug at all, but a proper behavior and I'm a moron who can't read a man page? I couldn't find anything about this on a google search or a search of this board.

Thanks for any help or direction you can give..