Date: Wed, 22 Aug 2012 13:50:04 -0600 From: Warner Losh <imp@bsdimp.com> To: Adrian Chadd <adrian@freebsd.org> Cc: freebsd-hackers@freebsd.org, freebsd-net@freebsd.org, Mitya <mitya@cabletv.dp.ua>, John Baldwin <jhb@freebsd.org>, Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl> Subject: Re: Replace bcopy() to update ether_addr Message-ID: <3952D2BB-2181-430C-86BC-F9F90706C7A0@bsdimp.com> In-Reply-To: <CAJ-Vmo=1cbJn3pkSvoCq7y-kEGig-h1Vxo6M5V0=b9=MkfuMRA@mail.gmail.com> References: <50324DB4.6080905@cabletv.dp.ua> <420BA06C-C776-47DB-B3BB-F1414C115F99@bsdimp.com> <CAJ-VmokQLD6YgyrsOyez=3cLm4Q8jZOnJ9vo4Wq3sjRu%2BG-E7A@mail.gmail.com> <201208220802.14588.jhb@freebsd.org> <CAJ-Vmo=1cbJn3pkSvoCq7y-kEGig-h1Vxo6M5V0=b9=MkfuMRA@mail.gmail.com>
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On Aug 22, 2012, at 12:54 PM, Adrian Chadd wrote: > On 22 August 2012 05:02, John Baldwin <jhb@freebsd.org> wrote: >> On Tuesday, August 21, 2012 12:34:42 pm Adrian Chadd wrote: >>> Hi, >>> >>> What about just creating an ETHER_ADDR_COPY(dst, src) and putting that >>> in a relevant include file, then hide the ugliness there? >>> >>> The same benefits will likely appear when copying wifi MAC addresses >>> to/from headers. >>> >>> Thanks, I'm glad someone noticed this. >> >> I doubt we even _need_ the ugliness. We should just use *dst = *src >> unless there is a compelling reason not to. > > Because it's not very clear? :-) I'd much prefer my array-of-things > copies to be explicit. But it isn't an array of things. It is a structure.a > Also, the optimisation and compiler silliness may not be THAT obvious > on intel (except when you're luigi and using netmap) but I can't help > but wonder whether the same does hold for MIPS/ARM. Getting it wrong > there will lead to some very very poor performing code. Which is why we need to check that output to make sure it isn't too horrible. Warnerhome | help
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