Article View: comp.sys.ibm.pc
Article #8556Re: SEGMENT:OFFSET Madness
From: Jeff Pipkins
Date: Fri, 12 Jan 1990 17:27
Date: Fri, 12 Jan 1990 17:27
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What you are saying is true, for the 8086. I suppose a better connotation would be base:displacement. But any way you slice it, the terminology is the least of the things they *SCREWED*UP*, imho. With the advent of protected mode on the '286 and V86 mode on the '386, the value in the segment register really is a segment number, but a segment is no longer (necessarily) 64k bytes. It is a segment selector. This also presents real problems (no pun intended). On the 8086, before there was an 80286, it was perfectly legitimate to normalize the address so that the segment was between 0 and F. Programs that use this technique will not run under '286 protected mode or V86 mode on the '386. This is the main reason that the term "DOS INcompatibility bos" was coined. [My employer my not share my opinions. Insert your favorite disclaimer here.]
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!tut.cis.ohio-state.edu!cs.utexas.edu!sun-barr!newstop!sun!imagen!qmsseq!pipkins From: pipkins@qmsseq.imagen.com (Jeff Pipkins) Newsgroups: comp.sys.ibm.pc Subject: Re: SEGMENT:OFFSET Madness Message-ID: <84@qmsseq.imagen.com> Date: 12 Jan 90 17:27:26 GMT References: <25821@cup.portal.com> Reply-To: pipkins@qmsseq.UUCP (Jeff Pipkins) Organization: QMS Inc., Mobile, Alabama Lines: 16