linux-kernel - Re: [PATCH] Repalce strncmp by memcmp

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Date:	Tue, 30 Nov 2010 11:34:20 +0100
From:	Bernd Petrovitsch <bernd@...rovitsch.priv.at>
To:	pavel@...linux.ru
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Repalce strncmp by memcmp

On Mon, 2010-11-29 at 05:09 +0300, Pavel Vasilyev wrote: 
> This patch replace all strncmp(a, b, c) by  memcmp(a, b, c).
> 
> I test on x86_64 (AMD Opteron 285).
> 
> #include <string.h>
> char *A = "0000";
> void test_memcmp(void) {
>         memcmp(A, "TEST", 4);
> }
> void test_strn(void) {
>         strncmp(A, "TEST", 4);
> }
[...]

You use constant parameters with user-space functions defined by the
C-standard on one architecture (and CPU?) - and even worse the width is
4 so - for the memcmp() case - it boilsdown to a comparison of unsigned
ints.
So that example is (also) completely worthless.

Bernd
-- 
Bernd Petrovitsch                  Email : bernd@...rovitsch.priv.at
                     LUGA : http://www.luga.at

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