From: Lucio De Re <lucio@proxima.alt.za>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] delay and aamloop
Date: Mon, 28 Jan 2002 07:50:40 +0200 [thread overview]
Message-ID: <20020128075040.I9246@cackle.proxima.alt.za> (raw)
In-Reply-To: <20020127192032.87D9B19988@mail.cse.psu.edu>; from Russ Cox on Sun, Jan 27, 2002 at 02:20:30PM -0500
On Sun, Jan 27, 2002 at 02:20:30PM -0500, Russ Cox wrote:
>
> AAM is "ascii adjust AX after multiply", which may
> well have been on the 80186. It fools with AX but
> that's about it.
>
Yes, I realised with further mucking about that the actual contents of
the delay() function has nothing to do with the problem and/or the
symptoms.
By looping 100000 times (10^5) instead of 10^4, I managed to stall the
entire loading process, where 10^3 seems to work fine for
boot/pc/9load but I haven't been able to try it on 9/pc/9pcdisk.gz,
for example.
Something is dependent on timing in the most intractable fashion. I
have to confess that I do not like the PC startup code at all, not
Plan 9's nor anyone else's. It looks like a whole lot of compromises
waiting to bite one.
And, sadly, once the hurdle is overcome things behave themselves very
nicely, so there's little reason to go back and apply a more pervasive
fix.
But I'm hoping to put some effort into a bootstrap procedure that is
more robust than we have now, even if I have to lift it from Linux or
NetBSD (or, most likely, the IBM PC/XT BIOS code from the
long-cherished Technical Reference Manual).
Thank you for confirming what I already suspected.
++L
next prev parent reply other threads:[~2002-01-28 5:50 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-27 19:20 Russ Cox
2002-01-28 5:50 ` Lucio De Re [this message]
-- strict thread matches above, loose matches on Subject: below --
2002-01-27 13:55 Lucio De Re
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