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Mail Archives: pgcc/1999/10/24/15:09:39

Message-ID: <38134004.54280D6@lycosmail.com>
Date: Sun, 24 Oct 1999 13:21:08 -0400
From: Adam Schrotenboer <ajschrotenboer AT lycosmail DOT com>
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To: pgcc AT delorie DOT com
Subject: Re: using cmov* not that great
References: <3 DOT 0 DOT 32 DOT 19990926231125 DOT 00c757a0 AT pop DOT xs4all DOT nl> <380A4183 DOT B3794352 AT lycosmail DOT com> <19991018215203 DOT B612 AT cerebro DOT laendle>
Reply-To: pgcc AT delorie DOT com

Hadn't thought of that. Thanks for the info.

Marc Lehmann wrote:

> On Sun, Oct 17, 1999 at 05:37:08PM -0400, Adam Schrotenboer <ajschrotenboer AT lycosmail DOT com> wrote:
> > I can not thing of any (intel x86 at least) cpu that can use such.
>
> Sure it can. One can reorder code that it suits static prediction.
>
> > Itanium (stupid name, Merced was better) however I do believe will be
>
> even better, it can just execute the if branch speculatively and then use
> the equivalent of cmov/cadd. calculating two much in many cases hurts less
> than a single jump.
>
> --
>       -----==-                                             |
>       ----==-- _                                           |
>       ---==---(_)__  __ ____  __       Marc Lehmann      +--
>       --==---/ / _ \/ // /\ \/ /       pcg AT opengroup DOT org |e|
>       -=====/_/_//_/\_,_/ /_/\_\       XX11-RIPE         --+
>     The choice of a GNU generation                       |
>                                                          |

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