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Re: recent binutils and mips64-linux

To: Eric Christopher <echristo@redhat.com>
Subject: Re: recent binutils and mips64-linux
From: Daniel Jacobowitz <dan@debian.org>
Date: Tue, 23 Sep 2003 14:16:59 -0400
Cc: Thiemo Seufer <ica2_ts@csv.ica.uni-stuttgart.de>, Alexandre Oliva <aoliva@redhat.com>, "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>, Atsushi Nemoto <nemoto@toshiba-tops.co.jp>, linux-mips@linux-mips.org, binutils@sources.redhat.com
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On Tue, Sep 23, 2003 at 11:01:11AM -0700, Eric Christopher wrote:
> 
> > > 
> > > objcopy?
> > 
> > You mean, let gcc generate n64 code, stuff it in n32 objects, and
> > objcopy it back to n64? Well, it may work, but it looks more like
> > a test of binutils sign-extension handling than a straightforward
> > way of creating kernels to me.
> > 
> > Besides, as soon as gcc handles 64bit expansions itself we need
> > such an option anyway.
> 
> I'm still trying to figure out why you are going through such weird
> contortions at all. I understand not having an elf64 loader. That's what
> the objcopy comment was for, everything else I don't understand. Why not
> compile for the abi you want?

Compare the optimal way to load an address into a register when you
have a full 64-bit address space and when you know that addresses are
sign extended.  I'm told it saves over 100K of code.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

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