From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Fri, 15 Nov 2002 01:55:02 +0000 Subject: Re: [Linux-ia64] One little, two little, three little endian... Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Hi Gavin, >>>>> On Thu, 14 Nov 2002 16:52:13 -0800, "Gavin Scott" said: Gavin> Hello list, I want a big endian version of Linux for IPF. Gavin> Just how crazy am I? Very! ;-) Seriously though: running big-endian processes is the easy part, the hard part is developing (& maintaining) big-endian versions of all libraries. Not only is it a lot of work, but it would also fragment the ia64 linux market, so I'd consider it a Bad Thing (TM). Gavin> Of course both MPE/iX and HP-UX are big-endian environments, Gavin> and many of the people I talk to would be very interested in Gavin> having an endian-compatible Linux that would run on big Gavin> (i.e. IA-64) HP servers. For this group, x86 compatibility Gavin> is probably a non-issue. It would be a lot easier to add an hp-ux compatibility layer on top of ia64 linux. The layer would emulate the (big-endian) hp-ux system calls and then you would install the big-endian hp-ux libraries on top of that (e.g., in the /emul/ia64-hpux/ tree). Of course, I'm ignoring legal issues here as copying the hp-ux libraries would presumably require some sort of license. But legal issues aside, this is doable and has been done many times before (e.g., alpha linux can run (some) Tru64 binaries, sparc linux can run sunos/solaris(?) binaries, etc.). Gavin> I'm interested in any comments that come to mind. I'm most Gavin> interested in just how complex the task would be from a Gavin> technical point of view, either to make the system buildable Gavin> either way, or possibly supporting a per-process endian bit Gavin> (which would be cool, but probably a lot more work). Actually, adding a per-process endian bit would be easy. In fact, even without, a little-endian program can turn on the big-endian bit as long as it's prepared to deal with the consequences. The hard part is really the libraries. --david