OpenBSD assembly programming

[<intangible@usa.net>]

I am interested in trying to learn assembly programming.  It would be nice if
I could learn in OpenBSD, since it is the only OS I am currently using,
although I could always format one of my computers and install another OS on
it.  The closest I've come to finding OpenBSD assembly code is when there is a
FreeBSD assembly language tutorial.  However, after I compile it with nasm and
try to link it with ld, it gives me this error:
ld: hello.o: malformed input file (not rel or archive)
Is there something wrong with the nasm port, or is it because it is FreeBSD
code, or is it just me?