Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!mit-eddie!uw-beaver!tektronix!orca!tekecs!frip!andrew
From: andrew@frip.gwd.tek.com (Andrew Klossner)
Newsgroups: comp.unix.wizards
Subject: Re: Data in text segment
Message-ID: <10420@tekecs.TEK.COM>
Date: 4 Oct 88 20:11:09 GMT
References: <159@taux02.UUCP> <7124@rpp386.Dallas.TX.US>
Sender: andrew@tekecs.TEK.COM
Organization: Tektronix, Wilsonville, Oregon
Lines: 22

[]

		"... separate I/D pdp11 cannot support text-segment
		shared data."

	"most modern CPU's can support separate I&D space in some sense
	by way of protection bits, blah blah blah ..."

The point missed by the second poster is that "separate I&D space" is
usually taken to mean two separate but overlapping address spaces.
There's an instruction at text location 1000, and there's a totally
unrelated data item at data location 1000.  In this environment, you
can't put data in the (shared) text segment, because an attempt to
refer to it will refer instead to whatever is at the corresponding
address within the data segment.

If this were comp.unix.questions, I would say, "If you have never
thought about this concept, take a few moments and so so.  A light of
interesting lights will dawn."  But of course we're all wizards here ...

  -=- Andrew Klossner   (decvax!tektronix!tekecs!andrew)       [UUCP]
                        (andrew%tekecs.tek.com@relay.cs.net)   [ARPA]