Messages in this thread | | | Date | Fri, 14 Mar 2008 08:09:40 +0000 | From | "Jan Beulich" <> | Subject | Re: [RFC] x86: bitops asm constraint fixes |
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>>> "H. Peter Anvin" <hpa@zytor.com> 14.03.08 08:51 >>> >Jan Beulich wrote: >> >> I'd really like understand, though, what the policy of (not) having a >> "memory" clobber in these operations is - currently, this appears to >> be totally inconsistent. Also, many comments of the non-atomic >> functions say those may also be re-ordered - this contradicts the use >> of "asm volatile" in there, which again I'd like to understand. >> > >In general, proper "m" constraints are better than "memory" clobbers, >since they give gcc more information. Note that the "m" constraint >doesn't actually have to be *manifest* in the assembly string.
... which is the case with the patch applied.
So am I taking this as 'yes, a proper re-write of these routines is worthwhile'? But - you didn't comment on the other issues raised, so before getting to that I'll have to wait to see what's the reason (if any) for the other anomalies.
Jan
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