From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Grundler Subject: Re: [parisc-linux] [RFC] using 64bit wide registers with 32bit kernel Date: Sun, 14 May 2006 00:27:17 -0600 Message-ID: <20060514062717.GA25973@colo.lackof.org> References: <7d01f9f00605131543p1458c0c9l55863d71f1a039d8@mail.gmail.com> <200605132335.k4DNZmAY002050@hiauly1.hia.nrc.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: parisc-linux@lists.parisc-linux.org, Thibaut VARENE To: John David Anglin Return-Path: In-Reply-To: <200605132335.k4DNZmAY002050@hiauly1.hia.nrc.ca> List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: parisc-linux-bounces@lists.parisc-linux.org On Sat, May 13, 2006 at 07:35:48PM -0400, John David Anglin wrote: > > Are you trying to say that userspace code shouldn't be using the full > > registers width when running a 32bit (narrow) kernel? > > I don't believe that it's impossible to support the full register width > with a 32bit (narrow) kernel. However, hpux to my knowledge doesn't > support 64-bit registers when using a narrow kernel. I believe later 10.20 updates/patches to support PA2.0 processors did in fact support saving/restoring 64-bits. But it's been a _long_ time since I've look at that. > I think this > reflects the historical development of hpux. The first PA 2.0 kernels > were narrow and based on the 32-bit PA 1.1 implementation. Correct. Mostly in the form of 10.20 patches. > Wide kernels were introduced with HP-UX 11. Trivia: 10.30 was a T600/customer specific release that provided 64-bit support before 11.00 was ready. ... > Personally, I think the wide register support is most important > when running a 64-bit kernel and that's the place it would be > easiest to implement. I can see that there are situations where > it would be nice to use 64-bit registers on a narrow kernel but > this would change the size of register files, the context passed > to signal handlers, etc. Oh..good point. I'm really not willing to tolerate an ABI event for this kind of perf optimization. I'd much rather start advocating use of 64-bit kernels in order to enable use of MAX insns. Until HP 24-bit color gfx PCI cards work on pa2.0, I don't see a good reason to implement this. Maybe 8-bit color with a private color map is sufficient... thanks, grant grant _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux