On 2020-07-10 02:19, Paul Koning wrote:
The VAX architecture seems to have been an explicit design effort. For the
Alpha this was even more obvious, where a monstrously large book (certainly 500
pages, maybe double that) was written and reviewed in depth before anything was
cast into silicon. Not so for the PDP11, as you pointed out.
It definitely was an explicit effort. I seem to remember seeing/reading
somewhere at some point that this was because of what had happened on
the PDP-11. So a lesson learned kind of thing.
I used to have an Alpha Architecture manual, but I lost it somewhere
along the way. :-(
I do have the VARM on paper, though. If I remember right, it's even the
later version which also covers the extensions that happened. (And of
course, this document is available online anyway...)
My suspicion is that the PDP-11 architecture handbook was an after the fact
effort. The date (1983) supports that notion. Also, it's a handbook, a fat
paperback like the processor and peripheral handbooks. I don't know of any
internal analog, like DEC Std 032 for VAX.
Yeah, I would expect that it would an after the fact thing. But it would
still be interesting to see any effort made by DEC to put it all in one
book. As mentioned, the list (maybe in different revisions) do exist in
multiple other handbooks and manuals. But then it's just an appendix
without much further analysis.
I think I also saw/read somewhere that different new PDP-11
implementations basically tried to look at what had previously been
done, and tried to just match that, as there was no official definition
of a PDP-11. But then they always did some deviation or other for the
sake of efficiency, cost or just clean up.
The document number is EB-23657-18. They seem to be around for sale, I see
some in the $20-25 range which is not bad. I'm hesitant to let mine out of my
sights though I might at some point.
No worries. I always have some curiosity for all kind of documentation,
but this is not very critical for any understanding, or work.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: b...@softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
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