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Re: XZ graphics specs...

To: "William J. Earl" <>
Subject: Re: XZ graphics specs...
From: Ralf Baechle <>
Date: Sat, 15 Jan 2000 12:47:26 +0100
Cc: "Soren S. Jorvang" <>, John Michael Clemens <>,
In-reply-to: <>
References: <> <> <> <> <>
On Fri, Jan 14, 2000 at 09:28:02PM -0800, William J. Earl wrote:

>  > In theory yes.  In practice all firmware that I've seen so far seems to
>  > be rather fragile and for some systems also very performance limited as
>  > it's running from uncached memory (veeeerry slooow) or at times even
>  > from 8-bit wide PROMs which is so slow that it blows every meassure for
>  > slowness.  Not to mention other problems.  So this should really be
>  > considered a better than nothing solution.
>  > 
>  > That being said, Ulf Carlsson has implemented a PROM console which is
>  > in the CVS archive.  Try it, I'm interested in reports.
>       On some platforms the PROM code is actually copied to main memory
> and executed (cached) from there.  If I remember correctly, O2 works that
> way.  Indy is probably in the slow (possibly very slow) category.

Running from a PROM would explain why the Indy firmware crashes with
enabled L2 caches - the circuitry just wasn't designed to deal with the
type of access cycles (bursts?) as used by the l2 cache controller.
No major problem in practice.


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