Date: Wed, 3 Jun 1998 16:38:19 -0500 (EST) From: "John S. Dyson" <dyson@FreeBSD.ORG> To: dfr@nlsystems.com (Doug Rabson) Cc: mjacob@feral.com, jb@cimlogic.com.au, jbarbee@singular.com, freebsd-alpha@FreeBSD.ORG Subject: Re: future of slpha port Message-ID: <199806032138.QAA00439@dyson.iquest.net> In-Reply-To: <Pine.BSF.3.95q.980603205351.421D-100000@herring.nlsystems.com> from Doug Rabson at "Jun 3, 98 08:56:36 pm"
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Doug Rabson said: > On Tue, 2 Jun 1998, Matthew Jacob wrote: > > > Yes, I'd like to actually finally say that it's a great shame > > that FreeBSD and NetBSD are different efforts- the NetBSD alpha > > effort is in quite good shape- and I've been somewhat reluctant > > to try and duplicate this for FreeBSD. Is there any way the > > FreeBSD port can import the extremely solid NetBSD/alpha work? > > I have drawn very heavily on NetBSD in my porting efforts so far. Much of > the code in locore.s could be used unchanged or with small modifications. > I am using a pmap ported from FreeBSD/i386 however since I don't really > understand the differences in the pmap/vm interface between NetBSD and > FreeBSD. > There are alot of minor differences. The biggest ones are the temporary kernel mappings, and the implementation of pte preloading. Some of the opts aren't very useful for TLB based machines, but some are. The biggest issue is whether or not you want to emulate a referenced bit. If you get it working without referenced bit emulation, I can provide you a few minor mods to the upper level code to make the system work correctly (under load) without them. After that, I'll likely be able to participate with you on a better implementation. (I know that the Alpha PALcode provides a page table interface, I forget if they provide a reference bit emulation.) To help, soon, I can probably look at the NetBSD/Alpha pmap code, and see how compatible they are with our pmap interface. We really do not have to support all entry points, and some that we do support aren't really needed for functionality. (I'll print out a copy for offline reference right away, and look at it.) After looking at the NetBSD Alpha/pmap code, I'll be able to be more coherent in my comments. -- John | Never try to teach a pig to sing, dyson@freebsd.org | it just makes you look stupid, jdyson@nc.com | and it irritates the pig. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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