From: Denis Vlasenko <vda@ilport.com.ua>
To: Chris Wedgwood <cw@f00f.org>
Subject: Re: [PATCH 2 of 3] memcpy32 for x86_64
Date: Fri, 13 Jan 2006 12:24:36 +0200
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Cc: "Bryan O'Sullivan" <bos@pathscale.com>, akpm@osdl.org,
       linux-kernel@vger.kernel.org, hch@infradead.org, ak@suse.de,
       rdreier@cisco.com
References: <b4863171295fdb6e8206.1136922838@serpentine.internal.keyresearch.com> <1137081882.28011.1.camel@serpentine.pathscale.com> <20060113095625.GA3707@taniwha.stupidest.org>
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On Friday 13 January 2006 11:56, Chris Wedgwood wrote:
> On Thu, Jan 12, 2006 at 08:04:41AM -0800, Bryan O'Sullivan wrote:
> 
> > This is true for 64-bit writes over Hypertransport
> 
> is this something that will always be or just something current
> hardware does?

Yes, why risking that things will go wrong?
Also you'll get shorter code. Instead of

> + ????.globl memcpy32
> +memcpy32:
> +?????movl %edx,%ecx
> +?????shrl $1,%ecx
> +?????andl $1,%edx
> +?????rep movsq
> +?????movl %edx,%ecx
> +?????rep movsd
> +?????ret

you need just

	.globl memcpy32
memcpy32:
	movl %edx,%ecx
	rep movsd
	ret

With properly written inlined asms code will be
reduced to just "rep movsd".
--
vda
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