Date: Wed, 6 Dec 2006 09:00:30 -0800
From: "H. J. Lu" <hjl@lucon.org>
To: Randy Dunlap <rdunlap@xenotime.net>
Cc: gcc@gcc.gnu.org, GNU C Library <libc-alpha@sources.redhat.com>,
       linux kernel <linux-kernel@vger.kernel.org>
Subject: Re: Change x86 prefix order
Message-ID: <20061206170030.GA543@lucon.org>
References: <20061206070014.GA535@lucon.org> <20061206084317.4c0ef28d.rdunlap@xenotime.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20061206084317.4c0ef28d.rdunlap@xenotime.net>
User-Agent: Mutt/1.4.2.2i
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1089
Lines: 35

On Wed, Dec 06, 2006 at 08:43:17AM -0800, Randy Dunlap wrote:
> On Tue, 5 Dec 2006 23:00:14 -0800 H. J. Lu wrote:
> 
> > On x86, the order of prefix SEG_PREFIX, ADDR_PREFIX, DATA_PREFIX and
> > LOCKREP_PREFIX isn't fixed. Currently, gas generates
> > 
> > LOCKREP_PREFIX ADDR_PREFIX DATA_PREFIX SEG_PREFIX
> > 
> > I will check in a patch:
> > 
> > http://sourceware.org/ml/binutils/2006-12/msg00054.html
> > 
> > tomorrow and change gas to generate
> > 
> > SEG_PREFIX ADDR_PREFIX DATA_PREFIX LOCKREP_PREFIX
> 
> Hi,
> Could you provide a "why" for this in addition to the
> "what", please?

LOCKREP_PREFIX is also used as SIMD prefix. DATA_PREFIX can be used as
either SIMD prefix or data size prefix for SIMD instructions. The new
order

SEG_PREFIX ADDR_PREFIX DATA_PREFIX LOCKREP_PREFIX

will make SIMD prefixes close to SIMD opcode.


H.J.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/