Date: Thu, 15 Aug 2013 22:30:49 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Dimitry Andric <dim@FreeBSD.org> Cc: "freebsd-current@freebsd.org CURRENT" <freebsd-current@FreeBSD.org>, Dmitry Morozovsky <marck@rinet.ru>, Peter Wemm <peter@wemm.org> Subject: Re: building i386 world on amd64 host: failed @svn Message-ID: <20130815193049.GU4972@kib.kiev.ua> In-Reply-To: <D559C583-B0A9-4731-B454-3521635AEC79@FreeBSD.org> 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>
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--MHqfkqUQ5gNQyfXO Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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> wrot= e: > > 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. >=20 > Ah yes, you are totally right, with -v it gives: >=20 > COLLECT_GCC_OPTIONS=3D'-O2' '-S' '-v' '-mtune=3Dgeneric' '-march=3Di586' >=20 > 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). --MHqfkqUQ5gNQyfXO Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (FreeBSD) iQIcBAEBAgAGBQJSDSxoAAoJEJDCuSvBvK1BpBwP/1BXFf2cYQeggvK5WRW68aWS iofa4yRFqZG2XqgR0WsCMb2Ii306Ry+9BWRMtKDN1CqfDoajwA3QQJjZqNImEJ1D aJ35bf8AHlGVWvqyToLxfSSo/jOEIxlXm4JgPyA56FRAzA07TsxBJ+NxOjPtQ7TH e1c9BNOenKV+DdeuIFgsgFHGrEdlKhAQ4Wxz0WBQxhXar9Gz9Im60q28X1QnNRug CT9oTu8YEIV3lUbUvYvClO47uJyE97IwCZMz6vd2YTmy9al5Ul3+w87HIetGnxct oqywZt1FfDqebwewdqWxj9jXnkGssEFeZ2oCVJjpiccLH/h4Nf3oyOsu46vkgnmC BTBIr/7eZtxQtdXwlNnJQUNj/ptj87yzomXyZxKGejU+01ReoRHG1kYnJCY69/nP m6k8DSUA8hUELdGmQRYrCeBKUZ+Wi6HMyrqRCGEZFDj7wrV36MyUxMJL5JYr2oLL 5BcWv/Sl72KS0hNEZYbzKPzo2mpC4EbM2gCKROhpeMPGpPNT7rNzP59iaqR1qkgm qNDCFhByz90oeuG0j9UvwkUoimFjcKXPFMJROX7MTloOdxkEI1f29wrohWa4+WHI 5DFt8cD7uwBMc9ochNSbOYEyA3bGg1Mh932HokTl7syT1TI0k+Fnm8DXOAKZmDvx xqlmezsuw4Z91LO1vwUa =bQrv -----END PGP SIGNATURE----- --MHqfkqUQ5gNQyfXO--
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