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From: John Baldwin <jhb@freebsd.org>
To: Adrian Chadd <adrian@freebsd.org>
Date: Wed, 22 Aug 2012 15:21:06 -0400
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	(bigwig.baldwin.cx); Wed, 22 Aug 2012 16:06:30 -0400 (EDT)
Cc: freebsd-hackers@freebsd.org, freebsd-net@freebsd.org,
	Mitya <mitya@cabletv.dp.ua>, Warner Losh <imp@bsdimp.com>,
	Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
Subject: Re: Replace bcopy() to update ether_addr
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On Wednesday, August 22, 2012 2:54:07 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.

Eh?  'struct foo *src, *dst; *dst = *src' is pretty bog-standard C.  That 
isn't really all that obtuse.

> 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.

Don't you think there's a really good chance the compiler knows how to copy a 
structure appropriately for each architecture already?

-- 
John Baldwin