From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3BAA363B.5010400@mc.com> Date: Thu, 20 Sep 2001 14:32:27 -0400 From: Mark Salisbury MIME-Version: 1.0 To: Brad Boyer Cc: Tom Rini , Geert Uytterhoeven , Linux/PPC Development Subject: Re: ppc LE questions (seeking help hand info pointers) References: <20010920171002.37DCA2B54A@marcus.pants.nu> Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: Brad Boyer wrote: >>>>>question 4. assuming I was willing to deliver a clean, complete LE >>>>>enabling patch (including devices that are relevant to me), as a compile >>>>>time config option and maintain that patch, what would be the primary >>>>>obstacle to inclusion in the main line. >>>>> >>>>The objection to being an arch that attempts to support both LE and BE. >>>> >>>Note that we already have a precedent: mips and mipsel, both in arch/mips/. >>> >>And SH too, iirc. I know it can be done. But do we want to do it is the >>question. >> > > At least in the case of SH, there's a good reason. There's an external pin > that controls the native endianness of the processor, and most setups just > have it forcibly pulled high or low. I suspect the MIPS is the same reason, > since it's used in similar situations. We don't have that excuse with ppc. > Someone would have to come up with an excuse along the lines of "existing > hardware won't work unless we do this" like it would have been for SH. > (I had to work with the SH4e as used by Sega in the Dreamcast...) well, this is in the context of a multi-CPU type (x86/ppc, sparc/ppc, ppc/ppc, mips/ppc) shared memory multicomputer. when dealing w/ direct mapped, shared memory, uniformity of endian-ness makes many multicomputer problems easier to solve.(not to mention easier for the customer to program...) -- /*------------------------------------------------** ** Mark Salisbury | Mercury Computer Systems ** ** mbs@mc.com | System OS - Kernel Team ** **------------------------------------------------** ** Thanks to all who sponsored me for the ** ** Multiple Sclerosis Great Mass Getaway!! ** ** Robert, Michele and I raised $10,000 and the ** ** raised over $1,000,000 ride as a whole. The ** ** ride was great, and we didn't get rained on! ** ** Thanks again to all of you who made this ** ** possible!! ** **------------------------------------------------*/ ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/