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Date: Wed, 3 Mar 2004 23:30:19 -0800
From: Chris Pressey <cpressey@catseye.mine.nu>
To: chungwei Hsiung <skuma17@yahoo.com>
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Subject: Re: one simple question
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On Wed, 3 Mar 2004 18:13:43 +0000
chungwei Hsiung <skuma17@yahoo.com> wrote:

> Hello..
>   I have a simple question, but I am not sure what the answer is. If
>   anyone can possibly help me, it is really appreciated. I compile a
>   test C file. I notice there are a few lines at the beginning of the
>   assembly code. I want to know what it means, but can't figure out
>   one of them. Can anyone tell me what the following line does please?
> 
> and    $0xfffffff0,%esp
> 
> best regards
> Chungwei

Hi Chungwei,

I believe that instruction is used to align the stack pointer to a
16-byte boundary, for efficiency.

However, this is just a guess, based on some discussions I've seen.
I don't know for certain.

You may have better luck asking on hackers@freebsd.org.

-Chris