From owner-freebsd-alpha Tue Dec 14 14: 5:22 1999 Delivered-To: freebsd-alpha@freebsd.org Received: from uni4nn.gn.iaf.nl (osmium.gn.iaf.nl [193.67.144.12]) by hub.freebsd.org (Postfix) with ESMTP id 6B5BC15409 for ; Tue, 14 Dec 1999 14:05:15 -0800 (PST) (envelope-from wilko@yedi.iaf.nl) Received: from yedi.iaf.nl (uucp@localhost) by uni4nn.gn.iaf.nl (8.9.2/8.9.2) with UUCP id WAA21790; Tue, 14 Dec 1999 22:09:58 +0100 (MET) Received: (from wilko@localhost) by yedi.iaf.nl (8.9.3/8.9.3) id WAA36193; Tue, 14 Dec 1999 22:47:35 +0100 (CET) (envelope-from wilko) Date: Tue, 14 Dec 1999 22:47:29 +0100 From: Wilko Bulte To: Jason Thorpe Cc: FreeBSD-alpha mailing list Subject: Re: use of -mcpu=21164a Message-ID: <19991214224728.A36085@yedi.iaf.nl> References: <199912142109.NAA29906@lestat.nas.nasa.gov> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <199912142109.NAA29906@lestat.nas.nasa.gov>; from thorpej@nas.nasa.gov on Tue, Dec 14, 1999 at 01:09:39PM -0800 X-OS: FreeBSD yedi.iaf.nl 3.3-STABLE FreeBSD 3.3-STABLE X-PGP: finger wilko@freebsd.org Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Tue, Dec 14, 1999 at 01:09:39PM -0800, Jason Thorpe wrote: > On Tue, 14 Dec 1999 21:39:15 +0100 > Wilko Bulte wrote: > > > Will adding -mcpu=21164a to CFLAGS in /etc/make.conf > > result in code not running on EV4/21064 CPUs? > > The Alpha Architecture specifies that user programs can expect the kernel > to emulate BWX, so it should work, albeit a bit more slowly in the event > that BWX is actually used. OK. > Also, your assembler has to do the right thing; gas will treat the BWX > instructions are macros and open-code the equivalent in EV4 instructions > unless it is explicitly in EV56 (or greater) mode. So, in case of -mcpu=21164a gas will generate BWX and if -mcpu=21164a is omitted it will open-code in EV4 instructions? > If your compiler is targeted correctly, the assembler will behave properly. > If not, you'll have to pass additional flags. Time to explain where I'm coming from: what if I generate 'netboot' on a Miata with mcpu=m21164a and want to use the generated netboot on a Sandpiper (EV4)? There is no kernel (yet) to emulate BWX so I lose, right? Thanks, -- Wilko Bulte Arnhem, The Netherlands - The FreeBSD Project WWW : http://www.tcja.nl http://www.freebsd.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message