Date: Wed, 08 Dec 1999 18:31:07 -0700 From: Brett Glass <brett@lariat.org> To: Alfred Perlstein <bright@wintelcom.net> Cc: Roelof Osinga <roelof@nisser.com>, Jonathon McKitrick <jcm@dogma.freebsd-uk.eu.org>, Kris Kennaway <kris@hub.freebsd.org>, freebsd-chat <chat@FreeBSD.ORG> Subject: Re: Yahoo hacked last night Message-ID: <4.2.0.58.19991208182954.048a3460@localhost> In-Reply-To: <Pine.BSF.4.21.9912081716440.4557-100000@fw.wintelcom.net> References: <4.2.0.58.19991208172738.0495eef0@localhost>
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At 06:19 PM 12/8/1999 , Alfred Perlstein wrote: >> So, Intel had no incentive to make the instructions which manipulated > > segments fast. To this day, Pentiums support them only for downward > > compatibility and to allow the implementation of VMs. The segmentation > > instructions are microcoded rather than hardwired, and can cause > > expensive pipeline stalls or (worse) flushes if you use them. > >So they really can only be done in page sized chunks... :) No, you just have to be willing to take a hit of about 60 cycles per function call, worst case. The thing is, with clock speeds ready to hit 1 MHz, this is getting to be a trivial amount of overhead. --Brett Glass To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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