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From: Dan Malek <dan@mvista.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: linuxppc-embedded@lists.linuxppc.org
Subject: Re: 4xx - a question and a patch
Date: Wed, 05 Sep 2001 00:18:30 -0400	[thread overview]
Message-ID: <3B95A796.248A0E99@mvista.com> (raw)
In-Reply-To: 20010905110451.A599@zax


David Gibson wrote:

> The 405gp manual implies that an mtspr to the PIT writes both the
> decrementing value and the reload register.  Is this a hardware /
> documentation bug?

Well, the point is that it writes the reload register.  When it
gets to zero, it reloads with this register, which is wrong.

> .....  Could the PIT be used this way if auto-reload was
> disabled?

No, because the PIT doesn't count down past zero.  If they would
have allowed this, we could have disabled the auto-reload and
treated it just like the decrementer.

The best I could come up with is just allow the PIT run with a
proper and fixed reload value.  It isn't a decrementer and we
can't treat it like one.


> Sure, but it's still useful to be able to run binaries copied from
> "normal" PPC machines.

Just remember that you can't be mixing float emulation and in-line
floating point software.


	-- Dan

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

  reply	other threads:[~2001-09-05  4:18 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-08-30  7:52 4xx - a question and a patch David Gibson
2001-08-30  8:54 ` HHL 2.0 Journeyman and SuSE Linux Steven Scholz
2001-08-30 16:21   ` Tom Rini
2001-08-31  7:48     ` Steven Scholz
2001-09-04 19:50 ` 4xx - a question and a patch Dan Malek
2001-09-05  1:04   ` David Gibson
2001-09-05  4:18     ` Dan Malek [this message]
2001-09-05  4:41       ` David Gibson
2001-09-05 15:34         ` Dan Malek
2001-09-06  1:06           ` David Gibson

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