From owner-freebsd-hackers@FreeBSD.ORG Sun Dec 30 18:55:15 2007 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A6D9216A418 for ; Sun, 30 Dec 2007 18:55:15 +0000 (UTC) (envelope-from mwm-keyword-freebsdhackers2.e313df@mired.org) Received: from mired.org (bhuda.mired.org [66.92.153.74]) by mx1.freebsd.org (Postfix) with SMTP id 0BC1613C468 for ; Sun, 30 Dec 2007 18:55:14 +0000 (UTC) (envelope-from mwm-keyword-freebsdhackers2.e313df@mired.org) Received: (qmail 60261 invoked by uid 1001); 30 Dec 2007 18:55:07 -0000 Received: from bhuda.mired.org (localhost.localdomain [127.0.0.1]) by bhuda.mired.org (tmda-ofmipd) with ESMTP; Sun, 30 Dec 2007 13:55:07 -0500 Date: Sun, 30 Dec 2007 13:55:06 -0500 To: freebsd-hackers@freebsd.org Message-ID: <20071230135506.47beac58@bhuda.mired.org> In-Reply-To: <20071230093432.GF31522@cicely12.cicely.de> References: <20071229.122221.-432830441.imp@bsdimp.com> <20071229193034.GA73845@freebie.xs4all.nl> <86prwp161k.fsf@ds4.des.no> <20071230093432.GF31522@cicely12.cicely.de> Organization: Meyer Consulting X-Mailer: Claws Mail 2.9.1 (GTK+ 2.10.12; amd64-portbld-freebsd6.2) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Delivery-Agent: TMDA/1.1.11 (Ladyburn) From: Mike Meyer Cc: ticso@cicely.de Subject: Re: Architectures with strict alignment? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Dec 2007 18:55:15 -0000 On Sun, 30 Dec 2007 10:34:33 +0100 Bernd Walter = wrote: > On Sat, Dec 29, 2007 at 11:37:27PM +0100, Dag-Erling Sm=C3=B8rgrav wrote: > > Wilko Bulte writes: > > > In the past the alpha port had it too. > >=20 > > No, it was optional and defaulted to off. >=20 > It was never optional, since no alpha CPU can do missaligned access > Alphas can fix missaligned access by software trap handlers in the same > way as most other strong alignment architectures can and we did this > for userland, but not in kernel. > Nevertheless it is horribly slow to do this, but was required since > there was so many crappy software that days - fortunately this has > changed over time, although I still see aligment traps on new software > as well. > Sadly said we never implemented missaligment traps for x86 so [...] Ok, I'm a bit confused. Since you're talking about moving code from the x86 to the alpha, I'm assuming you're talking about C code. Isn't it the *compilers* job to enforce alignment issues, unless the programmer specifically asks for byte-specific control of the layout of a set of variables? Or are these the issue, and the problem is that people do that and then don't use the appropriate APIs to pull data from them, thus causing you headaches? Thanks, http://www.mired.org/consulting.html Independent Network/Unix/Perforce consultant, email for more information.