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Date: Tue, 23 Sep 2008 07:56:11 -0700
From: Sam Leffler <sam@freebsd.org>
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To: "David E. O'Brien" <obrien@freebsd.org>
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Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org
Subject: Re: cvs commit: src/sys/conf files src/sys/fs/tmpfs tmpfs.h     
 tmpfs_subr.c tmpfs_vnops.c src/sys/i386/i386 bios.c src/sys/ia64/ia64
 efi.c sal.c src/sys/libkern memcmp.c         src/sys/mips/mips support.S
 src/sys/sys libkern.h
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David E. O'Brien wrote:
> obrien      2008-09-23 14:45:10 UTC
>
>   FreeBSD src repository
>
>   Modified files:
>     sys/conf             files 
>     sys/fs/tmpfs         tmpfs.h tmpfs_subr.c tmpfs_vnops.c 
>     sys/i386/i386        bios.c 
>     sys/ia64/ia64        efi.c sal.c 
>     sys/mips/mips        support.S 
>     sys/sys              libkern.h 
>   Added files:
>     sys/libkern          memcmp.c 
>   Log:
>   SVN rev 183299 on 2008-09-23 14:45:10Z by obrien
>   
>   The kernel implemented 'memcmp' is an alias for 'bcmp'.  However, memcmp
>   and bcmp are not the same thing.  'man bcmp' states that the return is
>   "non-zero" if the two byte strings are not identical.  Where as,
>   'man memcmp' states that the return is the "difference between the
>   first two differing bytes (treated as unsigned char values" if the
>   two byte strings are not identical.
>   
>   So provide a proper memcmp(9), but it is a C implementation not a tuned
>   assembly implementation.  Therefore bcmp(9) should be preferred over memcmp(9).
>   
>  
Given the performance difference this change should have been reviewed 
before dumping it into the tree.  I do not agree with this; did you post 
it somewhere?

    Sam