Date:	Sun, 18 Feb 2001 18:40:04 +0100
From:	Marc Lehmann <pcg AT goof DOT com>
To:	pgcc AT delorie DOT com
Subject:	Re: Probably pgcc-2.95.2.1 does not optimized propertly?
Message-ID:	<20010218184004.B2821@cerebro.laendle>
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On Sun, Feb 18, 2001 at 07:00:21PM +0000, Nick Kurshev <nickols_k AT mail DOT ru> wrote:
> But code which is produced in last case probably will be executed much faster of first (and it is smaller). 

please benchmark. "probably" is always wrong, especially when quoting out
of the amd optimization manual. The way to go, usually, is to implement
the exact opposite of what is in the manual. I am quite fed-up with AMD
since I invested quite some time in implementing some of their suggestions
(for AMD-K6) only to find out code gets slower. Especially their mmx unit
is the biggets joke ever heard :(

>  Avoid long instruction length Use x86 instructions that are
>  less than eight bytes in length. An x86 instruction that is longer
> 
> Clear registers using MOV reg, 0 instead of XOR reg, reg

is mov 0, reg longer than seven bytes?

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