From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,bc1361a952ec75ca X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-08-15 12:52:11 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!feed2.news.rcn.net!rcn!howland.erols.net!news-out.worldnet.att.net.MISMATCH!wn3feed!worldnet.att.net!135.173.83.71!wnfilter1!worldnet-localpost!bgtnsc06-news.ops.worldnet.att.net.POSTED!not-for-mail Message-ID: <3B7AD379.5559D329@worldnet.att.net> From: James Rogers X-Mailer: Mozilla 4.76 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Ada and pointers References: <1ope7.5943$6R6.582900@news1.cableinet.net> <9ldto7$9pg$1@nh.pace.co.uk> <3B7A9D94.F34F65E@worldnet.att.net> <9leapp$f30$1@nh.pace.co.uk> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Wed, 15 Aug 2001 19:52:10 GMT NNTP-Posting-Host: 12.86.34.206 X-Complaints-To: abuse@worldnet.att.net X-Trace: bgtnsc06-news.ops.worldnet.att.net 997905130 12.86.34.206 (Wed, 15 Aug 2001 19:52:10 GMT) NNTP-Posting-Date: Wed, 15 Aug 2001 19:52:10 GMT Organization: AT&T Worldnet Xref: archiver1.google.com comp.lang.ada:11962 Date: 2001-08-15T19:52:10+00:00 List-Id: Marin David Condic wrote: > > True enough - and I did think about that case. But when you consider it for > a minute and you realize that NNNN(segment) and NNNN(offset) are really no > different than NNNN-NNNN (some integer) - then it is still a one dimensional > array. Not unlike describing "the ones digit" and "the tens digit", etc. > > Segment/Offset was invented to enable bringing older architectures forward > into larger address spaces and to possibly conserve some space and/or bus > cycles. Its still just an integer. > >> "James Rogers" wrote in message > news:3B7A9D94.F34F65E@worldnet.att.net... > > > > On many machines memory is one big array. This is not exactly true for > > the old Intel machines that use a segmented memory model. In this case > > memory is more like an array of arrays than a simple array. > > Sometimes this is correct. Some systems do have the ability to use both linear addressing and segment-offset addressing. Some of the older systems do not have any ability to support linear addressing. This is one reason the type System.Address is implementation defined. System.Address also has comparison functions, but is not an aritmetic type. It does have addition, subtraction, and modulus operations defined in System.Storage_Elements, but that does not make System.Address a numeric type. Note that there is a type called System.Storage_Elements.Integer_Address. This type is not a System.Address, but does provide conversion functions to and from System.Address. Ada provides, through these types, conversions between linear and segmented memory models, even if those conversions are not directly supported by the hardware memory model. Jim Rogers Colorado Springs, Colorado USA