PaulS:
Why don't you look at the code generated when you perform the multiplication the usual way? Why are you trying to do this in assembler?
It's much faster to do in assembly.. 
Where can I find the reference for In-line Assembly in GCC? Only resource I can find is:
http://www.nongnu.org/avr-libc/user-manual/inline_asm.html
Which is not sufficient... 