Date: Thu, 19 Dec 2002 16:20:42 +0100 (CET)
From: bart@etpmod.phys.tue.nl
Reply-To: bart@etpmod.phys.tue.nl
Subject: Re: Intel P6 vs P7 system call performance
To: root@chaos.analogic.com
Cc: linux-kernel@vger.kernel.org, billyrose@billyrose.net
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On 19 Dec, Richard B. Johnson wrote:
> On Thu, 19 Dec 2002 billyrose@billyrose.net wrote:

>> long_call:
>>         pushl $0xfffff000
>>         ret
>> 
> 
> Because the number pushed onto the stack is a displacement, not
> an address, i.e., -4095. To have the address act as an address,

Not true. A ret(urn) is (sort of) equivalent to 'pop %eip'. The above
code would actually jump to address 0xfffff000, but probably be slow
since it confuses the branch prediction.

Bart

-- 
Bart Hartgers - TUE Eindhoven 
http://plasimo.phys.tue.nl/bart/contact.html
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