The intel's link is no longer working.
I got this one:
Intel Itanum Architecture Software Developer's Manual - Volume 3: Instruction Set Reference - rev2.2 jan/2006 from intel website. Its a 10MB pdf file worth of downloading.
Well, I would say this one would be most interesting not to be able to understand asm, but to understand how to optimise asm code for this given set of processors. I guess that applications made to work both on AMD and intel have an asm equivalent code which uses only basic x86 instruction set. Well... there are some applications that already implement SSE functions which works now on both processors, but in general if an application wants portability between processors architecture more than performance, it is going to keep at just x86 functions.
Anyway, if the goal is learn basic asm, just x86 must be enough to be able to read a code. Alien commands could then be searched on these references to know what they do.
Ah!.. Almost forgot to tell this. As the post above with intel's link to ASM reference has broken, my link could break sooner or later also. Then, as a rule of thumb, get into
www.intel.com and search for 'Instruction Set Reference' if you are looking for latest or basic asm instructions both for latest SSE SSSE4 or even for normal x86 (as intel processors based on x86 all have this intstruction set implemented).