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Re: What is the maximum physical RAM for a 32bit MIPS core?

To: Pete Popov <ppopov@pacbell.net>
Subject: Re: What is the maximum physical RAM for a 32bit MIPS core?
From: "Steven J. Hill" <sjhill@cotw.com>
Date: Tue, 05 Feb 2002 15:24:03 -0600
Cc: Hartvig Ekner <hartvige@mips.com>, linux-mips <linux-mips@oss.sgi.com>
References: <200202051747.SAA21696@copsun18.mips.com> <3C6044A7.13FEB2E2@cotw.com> <1012943709.10659.106.camel@zeus>
Reply-to: sjhill@cotw.com
Sender: owner-linux-mips@oss.sgi.com
Pete Popov wrote:
> 
> I'm not sure if it's a "little" though.  Ralf has already done the work
> for 64bit memory support on 32bit kernels, but that only works currently
> on 64bit CPUs.  I started hacking on the 64bit memory patch to get it to
> work on 32bit processors, but had to put that aside for a few weeks. I
> hope to get back to it soon.
> 
Sure, the "little" is a relative term. As far as your patch is concerned,
you are essentially trying to use a true 32-bit processor (my definition
being that it is not a 64-bit processor running in 32-bit mode), to address
address more than 4GB of physical memory. I don't see how that is possible
with just the MMU and TLB unless you are using chip selects and customm
logic.

-Steve

-- 
 Steven J. Hill - Embedded SW Engineer

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