Newsgroups: comp.arch
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: more Observability
Message-ID: <1989Aug24.221628.11330@utzoo.uucp>
Organization: U of Toronto Zoology
References: <5945@pt.cs.cmu.edu> <21547@cup.portal.com>
Date: Thu, 24 Aug 89 22:16:28 GMT

In article <21547@cup.portal.com> mmm@cup.portal.com (Mark Robert Thorson) writes:
>(DATIP is DEC parlance for data-in-pause, which is same as an RMW operation.
>...
>It turned out that the hardware engineering group had not implemented DATIP
>cycles, figuring that read and write are enough.

Major mistake, and not just because of R-M-W instructions.  Even some
operations you would think would be straight writes were done with RMW
on some Unibus CPUs.  (I can remember being very surprised to discover
that a byte clear, I think it was, on an 11/45 was doing RMW on its
destination.)
-- 
V7 /bin/mail source: 554 lines.|     Henry Spencer at U of Toronto Zoology
1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu