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From: james@reality1.uucp (james)
Newsgroups: comp.sys.intel
Subject: Re: POPF still broken in 286?
Message-ID: <83@reality1.uucp>
Date: Fri, 21-Nov-86 09:33:04 EST
Article-I.D.: reality1.83
Posted: Fri Nov 21 09:33:04 1986
Date-Received: Wed, 26-Nov-86 20:45:16 EST
References: <2646@gitpyr.gatech.EDU> <405@intsc.UUCP>
Reply-To: james@reality1.UUCP (james)
Organization: F.B.N. Software, Austin TX
Lines: 25

IN article <405@intsc.UUCP>, tomk@intsc.UUCP (Tom Kohrs) wrote:
> The problem with the POPF instruction (it would always enable interrupts)
> was only in the B-step parts (identifiable by markings of (c) Intel'82 or
> (c) Intel '83).  The C-step and E-step have this problem fixed.  Almost all
> of the B-step parts that were shipped went to IBM.

Well, what's the most current rev. level for the 80286, ie, how recent
should mine be to avoid all known bugs?  Chip bugs are normally top secret,
but I assume the the current chip rev. level isn't sensitive.

> How much gets found and fixed before the parts ship in volume has
> more to do with marketing considerations than the technical correctness of
> the chip.  Long term testing is done by trying to put the chip through every
> conceivable sequence of events (both hardware and software) and by following
> up on problem reports from the field. You would be amazed at what some people 
> will try to do to a chip.

Well, gee, I can't think of any bugs in the MC68020 (not XC68020) offhand,
although the argument might be that they haven't been found yet, or that
Motorola has had better luck hiding them than Intel has had.  Of course,
the 68000 did have the bug with the status register in which you could read
the priviledge level directly from user mode (although this was later
documented as a feature :-).
-- 
James R. Van Artsdalen    ...!ut-ngp!utastro!osi3b2!james    "Live Free or Die"