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Newsgroups: comp.os.386bsd.development Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!haven.umd.edu!darwin.sura.net!europa.eng.gtefsd.com!uunet!world!hd From: hd@world.std.com (HD Associates) Subject: How do I/O instructions work from user process in 386bsd? Message-ID: <CDK5vC.Ayn@world.std.com> Organization: The World Public Access UNIX, Brookline, MA Date: Sat, 18 Sep 1993 16:30:47 GMT Lines: 20 Quick question: How does the X server do inb and outb instructions? From previous postings I've gathered that the 386 has protection rings and normal user processes aren't privileged to do arbitrary port I/O, but there is some kind of hardware data structure that you can attach to the process that will permit selective access to the I/O instructions (i.e., you set it up at context switch time) but that we don't have full support for that yet. I notice that the X server seems to do inb and outb instructions directly. How is this being accomplished? Can someone point to the code that is setting things up? I grepped around and didn't find it. Peter -- Peter Dufault Real Time Machine Control and Simulation HD Associates Voice: 508 433 6936 hd@world.std.com Fax: 508 433 5267 Looking for: Orangey-brown front leather seats or NOS covers for '73 BMW 3.0cs