Date: Wed, 17 Jan 2001 18:44:04 +0100 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Robert Drehmel <robert@gizmo.quizbot.org> Cc: John Baldwin <jhb@FreeBSD.ORG>, Garrett Wollman <wollman@khavrinen.lcs.mit.edu>, current@FreeBSD.ORG, Peter Jeremy <peter.jeremy@alcatel.com.au> Subject: Re: Atomic breakage? Message-ID: <53512.979753444@critter> In-Reply-To: Your message of "Wed, 17 Jan 2001 18:36:16 %2B0100." <3A65D810.6304785A@gizmo.quizbot.org>
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In message <3A65D810.6304785A@gizmo.quizbot.org>, Robert Drehmel writes: >In <XFMail.010117084010.jhb@FreeBSD.org>, John Baldwin wrote: >> Early Pentiums (<= P90) don't support CX8 or so I've heard, which make this >> slightly more complicated, as for a pentium we would have to use a function >> pointer that we setup during probe. Also, during a SMP boot we would have to >> panic if CX8 wasn't enabled on all CPU's. > >P75 (stepping 5): <FPU,VME,DE,PSE,TSC,MSR,MCE,CX8> > >cmpxchg8 was actually introduced with the Pentium processors, >as Mr. Wollman already wrote. Either way, it's precense should be determined by looking at the CPUID feature bit. It's the only reliable way. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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