From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank Kotler Subject: Re: Segment override and lldt instruction Date: Sun, 10 Jun 2007 21:14:00 -0400 Message-ID: <466CA1D8.9090600@verizon.net> References: Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-reply-to: Sender: linux-assembly-owner@vger.kernel.org List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: A D Cc: hvjunk@gmail.com, linux-assembly@vger.kernel.org A D wrote: >>> Frank Kotler wrote: >>> In "Linux assembly", there is no reason you'd *want* to use a segment >>> override, or alter a segment register. >> >> >> Hendrik Visage wrote: >> Not while your program and/or data space fits in 4GB of memory space ;) > > > So please correct my understanding if i'm wrong: it is not possible > or necessary to override segment register in protected mode but one can do > the same thing in real mode. right? Right. (In Windows, you might want to do [fs:somevalue] - Windows uses fs for "thread local storage"(???) - a descriptor that does *not* have a base of 0, and limit is... 64k-1(???)... I think) > So if answer is yes, and if more > than 4GB > of memory space is needed for a program how will segmentation register go > beyond 4gig without override? Dunno. I'll leave that one to Hendrik. :) Best, Frank