Date: Fri, 1 Oct 2010 15:22:33 +0200 From: Roman Divacky <rdivacky@FreeBSD.org> To: Jilles Tjoelker <jilles@FreeBSD.org> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: svn commit: r213326 - head/lib/libc/i386/string Message-ID: <20101001132233.GA83116@freebsd.org> In-Reply-To: <201010011310.o91DABUU007534@svn.freebsd.org> References: <201010011310.o91DABUU007534@svn.freebsd.org>
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On Fri, Oct 01, 2010 at 01:10:11PM +0000, Jilles Tjoelker wrote: > Author: jilles > Date: Fri Oct 1 13:10:11 2010 > New Revision: 213326 > URL: http://svn.freebsd.org/changeset/base/213326 > > Log: > libc: Remove the i386 assembler version of strlen(3). > > On anything modern, the C version, which processes a word at a time, is much > faster. The Intel optimization manual explicitly warns against using REP > prefixes with SCAS or CMPS, which is exactly what the assembler version > does. there's "rep cmps" in bcmp.S and memcmp.S in both amd64/i386 they both have C counterparts, no idea how fast those are (they are going char by char). does this wisdom apply to those too?
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