Date: Thu, 15 Aug 2013 15:38:40 -0400 From: Jung-uk Kim <jkim@FreeBSD.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: freebsd-current@FreeBSD.org, Dimitry Andric <dim@FreeBSD.org>, Dmitry Morozovsky <marck@rinet.ru>, Peter Wemm <peter@wemm.org> Subject: Re: building i386 world on amd64 host: failed @svn Message-ID: <520D2E40.2090704@FreeBSD.org> In-Reply-To: <20130815193049.GU4972@kib.kiev.ua> References: <alpine.BSF.2.00.1307281713160.55051@woozle.rinet.ru> <17A40261-A0DA-4070-990F-0D0777A5BE44@FreeBSD.org> <20130815183640.GR4972@kib.kiev.ua> <D559C583-B0A9-4731-B454-3521635AEC79@FreeBSD.org> <20130815193049.GU4972@kib.kiev.ua>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 2013-08-15 15:30:49 -0400, Konstantin Belousov wrote: > On Thu, Aug 15, 2013 at 09:12:52PM +0200, Dimitry Andric wrote: >> On Aug 15, 2013, at 20:36, Konstantin Belousov >> <kostikbel@gmail.com> wrote: >>> Does the linux box defaults to pentium or higher for -march ? >>> 64 bit atomics cannot be implemented in usermode on i386 on >>> processors which do not have cmpxchg8b instruction. >> >> Ah yes, you are totally right, with -v it gives: >> >> COLLECT_GCC_OPTIONS='-O2' '-S' '-v' '-mtune=generic' >> '-march=i586' >> >> So we should really disable atomics for i486 and lower? Though I >> have understood that there also some pentiums without >> cmpxchg8b... > > I do not think that there was any Pentium-branded CPU which did > not implemented cmpxchg8b. Some late 486 did provided cpuid, but I > am almost certain that they did not have cmpxchg8b (cannot check > anyway). It is actually little complicated. http://www.geoffchappell.com/studies/windows/km/cpu/cx8.htm Jung-uk Kim -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (FreeBSD) iQEcBAEBAgAGBQJSDS5AAAoJECXpabHZMqHOGkMIAKEXxd9G0cTwjnMuQFt6D0VP ba2ZLJa2wXWzYVeelXnRxYtt2BRU8xUzc7YUC86E7pW1AdN1geR0EOt1ggTAVpX4 t1W9k2PsBCfURW+6560m3ze0xfyH66SwLuadyeyQJ0G11XWbAigTRx56j2BLZRth ghmcOqQS4tfjyDd3uKnU4JTGzRo2irmKlzsoHWuAJJ5R2qoUsr/3cxnRUU2lSBXv UHx6Ml6VM1OQgEzZkLuLD30JLAYJoCK1n7IKXdUx1cRAs1ZO8uZuMBddp8sLaymB zdn0bSjBB+vutm4/lhQA38BVZlls1O287rhwb51/3RS3Db1zTDXKw1BYf2Q5YNE= =wwyz -----END PGP SIGNATURE-----
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