From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1HUgww-0002p1-7h for qemu-devel@nongnu.org; Fri, 23 Mar 2007 06:24:46 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1HUgwt-0002ka-UD for qemu-devel@nongnu.org; Fri, 23 Mar 2007 06:24:44 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1HUgwt-0002kL-Jv for qemu-devel@nongnu.org; Fri, 23 Mar 2007 05:24:43 -0500 Received: from [213.46.243.15] (helo=amsfep18-int.chello.nl) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1HUguz-0007LE-Fr for qemu-devel@nongnu.org; Fri, 23 Mar 2007 06:22:45 -0400 Received: from [192.168.1.120] (really [80.57.119.9]) by amsfep18-int.chello.nl (InterMail vM.6.01.04.04 201-2131-118-104-20050224) with ESMTP id <20070323102243.OIXC25770.amsfep18-int.chello.nl@[192.168.1.120]> for ; Fri, 23 Mar 2007 11:22:43 +0100 Message-ID: <4603AA3A.7090101@gmail.com> Date: Fri, 23 Mar 2007 11:21:46 +0100 From: Sunil Amitkumar Janki MIME-Version: 1.0 Subject: Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0) References: <20070317143730.1befbf94@neuling> <20070318093734.71d9d77d@neuling> <45FD03F0.5000801@bandsman.co.uk> <20070322204629.5552c047@neuling> <4602E34C.3000106@gmail.com> <20070323105825.0f2da762@neuling> In-Reply-To: <20070323105825.0f2da762@neuling> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Thomas Orgis wrote: > Am Thu, 22 Mar 2007 21:13:00 +0100 > schrieb Sunil Amitkumar Janki : > > >> I have seen this error as well when building with i686/pentium3/athlon >> optimisations. As I am doing a course on x86 assembly programming >> at the moment I can tell you that it suffers from register starvation >> and the message tells you that there aren't enough registers left. >> > > Yeah, that's the message... what I wonder is this is to be expected. > Does SSE steal or add registers? > -march=pentium-mmx -m3dnow > seems to work, though. Is it just a coincidence that gcc optimizattion > uses some registers with high march (and SSE) that it didn't use with lower march? > I'm wondering if it's the code that is just lucky to compile with some > march settings and not so lucky with others or if it's a gcc bug or > whatever... > > > Thomas. > > > _______________________________________________ > Qemu-devel mailing list > Qemu-devel@nongnu.org > http://lists.nongnu.org/mailman/listinfo/qemu-devel > > The reason I build it with "-march=i486" is because Pentium optimisations are really only meant for real Intel Pentium (MMX) and not for AMD K6 (I/II/II). You would probably be better off using "-march=k6-* -m3dnow -mmx" for an Athlon. I have seen my Athlon slowing to a grind with a Pentium kernel instead of an i486 or Athlon kernel. I do not understand enough of QEMU yet, but I have checked out CVS and am reading through its source. When I understand more I hope we can fix this long-standing annoyance. Do you have a 64-bit X86 processor running 64-bit software? It doesn't seem to suffer from this same problem. I am testing on an AMD Athlon 64 X2 (AM2) now and QEMU works with "-march=opteron" and of course KVM. Sunil.