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Re: 64-bit and N32 kernel interfaces

To: "Maciej W. Rozycki" <>
Subject: Re: 64-bit and N32 kernel interfaces
From: Daniel Jacobowitz <>
Date: Thu, 5 Sep 2002 12:19:33 -0400
Cc: Hartvig Ekner <>, "Kevin D. Kissell" <>, Tor Arntsen <>, Carsten Langgaard <>, Ralf Baechle <>,
In-reply-to: <>
Original-recipient: rfc822;
References: <> <>
User-agent: Mutt/1.5.1i
On Thu, Sep 05, 2002 at 06:16:49PM +0200, Maciej W. Rozycki wrote:
> On Thu, 5 Sep 2002, Daniel Jacobowitz wrote:
> > N32 supports saving and restoring 64-bit registers, which O32 doesn't -
> > according to some comments in GCC, O32 is in fact incompatible with
> > using 64-bit operations.
>  But that old software wouldn't benefit as it didn't perform 64-bit
> operations unless manually coded in software using narrower data types. 
> There is no 64-bit C data type for o32 and long long is quite a recent
> invention -- it didn't exist in the 80s or even early 90s. 

Right.  You don't recompile and get a magic bullet speed improvement
(well, you do, but not a drastic one I think); but you don't recompile
and get a magic bullet binary incompatibility either.  Then you add
64-bit pieces by hand as necessary.

That's my understanding anyway.

Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

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