Thanks all for the replies, excellent information as usual (and so prompt too!)...and thanks Sailor Steve for the...uh....reading my whole post
Also, in case anyone else happens across this thread, I think I found the thread to which irish1958 was referring,
here. It concerns SH4, but the structure of the file and it's elements appear largely unchanged. When/if I get this file figured out I'd be happy to collect my knowledge into one post, if someone needs it.