Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965249AbVINR1P (ORCPT ); Wed, 14 Sep 2005 13:27:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965255AbVINR1P (ORCPT ); Wed, 14 Sep 2005 13:27:15 -0400 Received: from smtpout.mac.com ([17.250.248.45]:48086 "EHLO smtpout.mac.com") by vger.kernel.org with ESMTP id S965249AbVINR1O (ORCPT ); Wed, 14 Sep 2005 13:27:14 -0400 In-Reply-To: <20050914132045.GS28551@csclub.uwaterloo.ca> References: <4325F3D5.9040109@spamtest.viacore.net> <20050912.144107.37064900.davem@davemloft.net> <4325FADB.4090804@spamtest.viacore.net> <20050912.151230.100651236.davem@davemloft.net> <43260A8D.1090508@spamtest.viacore.net> <20050913165228.GG28578@csclub.uwaterloo.ca> <432705A0.1070407@spamtest.viacore.net> <5A770DA0-A30F-45B1-A47A-2FD21714FA3C@mac.com> <20050914132045.GS28551@csclub.uwaterloo.ca> Mime-Version: 1.0 (Apple Message framework v734) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <7B6BBC6F-EB09-4B88-A8C8-C9DFB7348711@mac.com> Cc: Joe Bob Spamtest , linux-kernel@vger.kernel.org Content-Transfer-Encoding: 7bit From: Kyle Moffett Subject: Re: Pure 64 bootloaders Date: Wed, 14 Sep 2005 13:26:54 -0400 To: Lennart Sorensen X-Mailer: Apple Mail (2.734) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1977 Lines: 45 On Sep 14, 2005, at 09:20:45, Lennart Sorensen wrote: > On Tue, Sep 13, 2005 at 11:44:55PM -0400, Kyle Moffett wrote: > >> PowerPC was designed 64-bit from the start too! It's just that the >> architecture design group also realized that there would be a demand >> for 32-bit CPUs, and so from the _64-bit_ system, they designed a 32- >> bit system whose entire instruction set would be forward-compatible >> to 64-bit systems when they came out. That's why 32-bit PowerPC >> machine code and 64-bit PowerPC machine code are completely identical >> except that 64-bit CPUs also have a few opcodes to process 64-bit >> data and a few extra kernel-mode registers. > > Hmm, so how does that fit with needing both 32 and 64bit libraries > on a > ppc system? It seems apple forgot the 64bit part of a library > recently > in a security fix, or is that something more to do with their os than > the cpu? Well, if you want to pass 64-bit pointer values to a library, the library needs to have functions that take 64-bit values and use 64- bit operations on them, just like all the other archs :-D. It also needs 32-bit compatibility functions for the old 32-bit-only programs. On the other hand, if you don't care about compatibility with 32-bit-pointer programs, you can omit functions that deal with 32-bit pointers and require everything to use 64-bit pointers. You still need stuff like atoi that uses 32-bit values, though, and 64-bit-only does have a performance penalty. Cheers, Kyle Moffett -- There is no way to make Linux robust with unreliable memory subsystems, sorry. It would be like trying to make a human more robust with an unreliable O2 supply. Memory just has to work. -- Andi Kleen - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/