Date: Fri, 5 Oct 2012 16:36:16 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Dag-Erling Sm??rgrav <des@des.no> Cc: Garrett Cooper <yanegomi@gmail.com>, Dimitry Andric <dimitry@andric.com>, Andriy Gapon <avg@freebsd.org>, freebsd-arch@freebsd.org Subject: Re: x86 boot code build Message-ID: <20121005133616.GP35915@deviant.kiev.zoral.com.ua> In-Reply-To: <86a9w1kq94.fsf@ds4.des.no> References: <506C385C.3020400@FreeBSD.org> <506DEB4C.5020508@andric.com> <86haq9hq2c.fsf@ds4.des.no> <20121005033244.GL35915@deviant.kiev.zoral.com.ua> <86y5jll7kc.fsf@ds4.des.no> <CAGH67wQqs9DJoy0LSgKi1_wMFyrHUE69Dgc2dht7q8VXDVAeQQ@mail.gmail.com> <86txu9l4z9.fsf@ds4.des.no> <20121005112313.GN35915@deviant.kiev.zoral.com.ua> <86a9w1kq94.fsf@ds4.des.no>
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--aTq0RFdLe0rSEdju Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Oct 05, 2012 at 03:22:31PM +0200, Dag-Erling Sm??rgrav wrote: > Konstantin Belousov <kostikbel@gmail.com> writes: > > So what ISA additions do you expect to get advantage of by switching > > to pentium-mmx from 486 ? As I already said, I am not aware of any. >=20 > The TSC, for one. MMX, and the ability to use MMX registers to copy > data. TSC is used regardless of the compiler flags, we use it if CPU claims that TSC is supported, even in usermode. Compiler never generates MMX copies. More, in kernel, the manual FPU context save/restore is needed around the FPU/MMX register file access. --aTq0RFdLe0rSEdju Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (FreeBSD) iEYEARECAAYFAlBu4k8ACgkQC3+MBN1Mb4i/WQCfc3ri41Dl3IEnbO7hI+29sdci 8+AAoKghSanVzrgfGt/OVQpzU1vrWyng =wd3Q -----END PGP SIGNATURE----- --aTq0RFdLe0rSEdju--
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