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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.unix-wizards
Subject: re: VAX Compatibility Mode
Message-ID: <5089@utzoo.UUCP>
Date: Fri, 22-Feb-85 12:43:17 EST
Article-I.D.: utzoo.5089
Posted: Fri Feb 22 12:43:17 1985
Date-Received: Fri, 22-Feb-85 12:43:17 EST
References: <598@decwrl.UUCP>
Organization: U of Toronto Zoology
Lines: 16

> A minute or so with the documentation - in my case, the 1981 edition of
> the VAX Architecture Handbook - reveals Table 17-3 - "Compatibility Mode
> Reserved Instructions" - which lists those PDP-11 instructions that fault
> to native mode (i.e., are not implemented by the hardware).  MARK is right
> in the middle of the list.
> 
> Given the usual high quality of Henry's writing, I was rather surprised to
> see him "shooting from the hit" on something so easy to check.

It's easy to check only if you happen to have a VAX, or at least VAX
documentation, handy.  Fortunately, I don't.  (If you think you detect
some anti-VAX bias... you're right.)  My friend claimed that the absence
of MARK was undocumented; he was probably right at the time.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry