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Message-ID:	<19980713111822.15232@cerebro.laendle>
Date:	Mon, 13 Jul 1998 11:18:22 +0200
From:	Marc Lehmann <pcg AT goof DOT com>
To:	somasekh AT ecn DOT purdue DOT edu, beastium <beastium-list AT Desk DOT nl>
Subject:	Re: please benchmark / MMX #2
Mail-Followup-To:	somasekh AT ecn DOT purdue DOT edu, beastium <beastium-list AT Desk DOT nl>
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In-Reply-To:	<13733.51867.888722.918209@ppp-x8-34.>; from Dinesh Somasekhar on Fri, Jul 10, 1998 at 03:08:05AM -0500
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Status:	RO
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On Fri, Jul 10, 1998 at 03:08:05AM -0500, Dinesh Somasekhar wrote:
> 
>   Marc, can you tell the list what exactly does the mmx patch do ?  Does
>   it just use the mmx registers as temp space (at least thats how it looks)
>   or does it use mmx compute instructions. 

Look at the patch ;-> currently it uses mmx add/subtract and shift
instructionns on SImodes. these are the only ones mmx has. it also
uses shift instructions for DImode registers.

There surely is room for some other instructions to be used, but egcs is, at
the moment, unable to use the parallelity available for the mmx instructions
(and I doubt this will ever be the case since the loops must they are quite
specific, the places where we can take advantage of these are quite rare.
Most algorithms must be re-written to be asble to take advantage of mmx, and
I doubt a compiler will go that far in the next years)

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      ---==---(_)__  __ ____  __       Marc Lehmann       +--
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      -=====/_/_//_/\_,_/ /_/\_\                          --+
    The choice of a GNU generation                        |
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