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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 11:14:09 -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 05:10:51PM +0200, Maciej W. Rozycki wrote:
> On Thu, 5 Sep 2002, Daniel Jacobowitz wrote:
> > No - the point is that all data types have the same size in N32.  It
> > was created explicitly as a transitional sop for people who didn't want
> > to fix their code, but wanted a performance increase from their 64-bit
> > hardware.
>  Well, what's the performance increase of n32 over o32?  The increased
> number of argument registers?  I doubt it's noticeable in most cases.

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.

Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

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