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Re: Latest sources from CVS.

To: "Maciej W. Rozycki" <>
Subject: Re: Latest sources from CVS.
From: Thiemo Seufer <>
Date: Fri, 6 Dec 2002 19:41:33 +0100
Cc: Carsten Langgaard <>, Ralf Baechle <>, "Kevin D. Kissell" <>,
In-reply-to: <>
Original-recipient: rfc822;
References: <> <>
User-agent: Mutt/1.4i
Maciej W. Rozycki wrote:
> On Fri, 6 Dec 2002, Thiemo Seufer wrote:
> > Maybe I wasn't clear about it, I meant kernels with 32 bit address
> > space but 64 bit register width, allowing for userland N32 ABI.
> > 
> > E.g. the old DECstations with R4k CPU and limited memory would fit
> > in this scheme. :-)
>  I'm only going to support n64 on the DECstation.  You are welcomed to do
> n32 stuff yourself if you want to. 

What does N64 on the DECstation better than N32 could do? N32 has
more compact code, better cache usage and less memory consumption.

> > >  Remember we are writing of the kernel -- we don't know what userland is
> > > going to bring us
> > 
> > I don't understand this. The kernel _defines_ what the userland is allowed
> > to do.
>  I haven't considered you may mean crippling the available user address
> space.

IIRC is the maximum of RAM 448 MB on some machines. Actually utilizing
an user address space larger than 2 GB would mean a RAM/Swap ratio of
about 1:4, IOW, it likely gets unusable slow.

Is there any point besides of hack value to use N64 on these machines?


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