Date: Sat, 28 Jun 2008 12:09:13 +1000 (EST) From: Bruce Evans <brde@optusnet.com.au> To: Marius Strobl <marius@alchemy.franken.de> Cc: cvs-src@freebsd.org, Christoph Mallon <christoph.mallon@gmx.de>, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/sparc64/include in_cksum.h Message-ID: <20080628120700.S89039@delplex.bde.org> In-Reply-To: <20080627222404.GJ1215@alchemy.franken.de> References: <200806252105.m5PL5AUp064418@repoman.freebsd.org> <48654667.1040401@gmx.de> <20080627222404.GJ1215@alchemy.franken.de>
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On Sat, 28 Jun 2008, Marius Strobl wrote: > On Fri, Jun 27, 2008 at 09:58:31PM +0200, Christoph Mallon wrote: >> >> This approach seems wrong to me and I think it works only by chance. The > > I wasn't aware that the clobber list allows to explicitly specify > the condition codes, thanks for the hint. Though it unfortunately > took me longer than two days to verify it's effect on the generated > code; sparc64 could still have been one of the archs where "cc" has > no effect. I think it still only works by chance. > Besides I don't think using "__volatile" for this is > that wrong, given that the sparc64 code generated by using "cc" > and "__volatile" is nearly identical and given that at least i386 > relies on "__volatile" telling GCC that the inline assembler uses > the condition codes since quite some time. So the condition codes > are probably part of what GCC treats as "important side-effects". No, the comments in the i386 version are rotted bits left over from old failing attempts to fix this problem. Bruce
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