From owner-freebsd-alpha Wed Jun 23 8:17:45 1999 Delivered-To: freebsd-alpha@freebsd.org Received: from lestat.nas.nasa.gov (lestat.nas.nasa.gov [129.99.50.29]) by hub.freebsd.org (Postfix) with ESMTP id 87CB1152E3 for ; Wed, 23 Jun 1999 08:17:39 -0700 (PDT) (envelope-from thorpej@lestat.nas.nasa.gov) Received: from lestat (localhost [127.0.0.1]) by lestat.nas.nasa.gov (8.8.8/8.6.12) with ESMTP id IAA22409; Wed, 23 Jun 1999 08:17:32 -0700 (PDT) Message-Id: <199906231517.IAA22409@lestat.nas.nasa.gov> To: Bram Stolk Cc: freebsd-alpha@FreeBSD.ORG Subject: Re: Significant speedups from -mcpu=ev56 Reply-To: Jason Thorpe From: Jason Thorpe Date: Wed, 23 Jun 1999 08:17:31 -0700 Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Wed, 23 Jun 1999 11:21:23 +0200 Bram Stolk wrote: > Will code compiled with -mcpu=ev56 still run on ancient alphas? > Or will there be made use of instructions that are only available > on the ev56 machines? It will, no doubt, use BWX instructions. However, it's worth noting that programs which use BWX can expect the operating system to trap and emulate those instructions in the event they don't exist on the CPU the program is running on. This is described in an Alpha ABI document, but I don't recall exactly which one. NetBSD/alpha supports all of this, of course. -- Jason R. Thorpe To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message