Re: x86 real mode

From	Stefan Reuther <stefan.news@arcor.de>
Newsgroups	comp.arch.embedded
Subject	Re: x86 real mode
Date	2014-10-17 18:37 +0200
Message-ID	<m1rnl7.188.1@stefan.msgid.phost.de> (permalink)
References	<m1r8pj$che$1@speranza.aioe.org> <54412845$0$2932$e4fe514c@news.xs4all.nl> <m1ra20$fr8$1@speranza.aioe.org>

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Don Y wrote:
> On 10/17/2014 7:31 AM, Arlet Ottens wrote:
>> On 10/17/2014 04:23 PM, Don Y wrote:
>>> What are the most conservative, *practical* expectations I can
>>> make living in x86 real mode:  TEXT of 64K and DATA of (disjoint)
>>> 64K?  BSS in it's own segment?  Or, shared with DATA?
>>>
>>> And, how seemlessly will the compiler let me *implicitly* move
>>> those segments around as well as between them?  (e.g., practical
>>> limitations on code/data sizes).  "PC" handled 640K so should
>>> I expect that to be the size of my playground?
>>
>> It would depend on what tools you use. I remember working with Borland
>> tools, and they'd offer a choice of several different memory models.
> 
> So, the "most conservative" would be to assume a tiny-ish model -- 64K
> TOTAL address space? (with everything residing therein)

Depends on how you want to be "most conservative".

TINY model means you can effectively ignore segment registers and work
with 16-bit flat addresses. Of course this is an assumption that doesn't
hold everywhere. Being "conservative" from this standpoint would mean
you have to assume that every object is in a different segment, i.e.
LARGE / HUGE model.


  Stefan

Thread

x86 real mode Don Y <this@is.not.me.com> - 2014-10-17 07:23 -0700
  Re: x86 real mode Arlet Ottens <usenet+5@c-scape.nl> - 2014-10-17 16:31 +0200
    Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-17 07:45 -0700
      Re: x86 real mode Arlet Ottens <usenet+5@c-scape.nl> - 2014-10-17 16:53 +0200
        Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-17 08:28 -0700
          Re: x86 real mode Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2014-10-17 18:35 +0300
          Re: x86 real mode Arlet Ottens <usenet+5@c-scape.nl> - 2014-10-17 17:36 +0200
            Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-17 13:54 -0700
              Re: x86 real mode Grant Edwards <invalid@invalid.invalid> - 2014-10-17 21:02 +0000
                Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-17 14:54 -0700
              Re: x86 real mode upsidedown@downunder.com - 2014-10-18 10:09 +0300
          Re: x86 real mode Grant Edwards <invalid@invalid.invalid> - 2014-10-17 16:11 +0000
      Re: x86 real mode Stefan Reuther <stefan.news@arcor.de> - 2014-10-17 18:37 +0200
      Re: x86 real mode Les Cargill <lcargill99@comcast.com> - 2014-10-17 12:58 -0500
  Re: x86 real mode David Brown <david.brown@hesbynett.no> - 2014-10-17 16:52 +0200
    Re: x86 real mode glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-10-17 16:45 +0000
  Re: x86 real mode Robert Wessel <robertwessel2@yahoo.com> - 2014-10-17 10:03 -0500
  Re: x86 real mode Grant Edwards <invalid@invalid.invalid> - 2014-10-17 16:07 +0000
  Re: x86 real mode upsidedown@downunder.com - 2014-10-17 19:57 +0300
  Re: x86 real mode Les Cargill <lcargill99@comcast.com> - 2014-10-17 12:57 -0500
  Re: x86 real mode Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2014-10-17 21:18 +0300
    Re: x86 real mode glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-10-17 21:48 +0000
      Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-17 15:06 -0700
        Re: x86 real mode glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-10-17 22:25 +0000
          Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-17 15:39 -0700
            Re: x86 real mode George Neuner <gneuner2@comcast.net> - 2014-10-17 22:47 -0400
              Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-17 21:10 -0700
                Re: x86 real mode upsidedown@downunder.com - 2014-10-18 11:32 +0300
            Re: x86 real mode upsidedown@downunder.com - 2014-10-18 11:10 +0300
              Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-18 08:20 -0700
                Re: x86 real mode upsidedown@downunder.com - 2014-10-18 20:34 +0300
                Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-18 12:53 -0700
          Re: x86 real mode upsidedown@downunder.com - 2014-10-18 10:30 +0300
          Re: x86 real mode David Brown <david.brown@hesbynett.no> - 2014-10-18 20:22 +0200
      Re: x86 real mode upsidedown@downunder.com - 2014-10-18 10:22 +0300
        Re: x86 real mode glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-10-18 09:06 +0000
          Re: x86 real mode Robert Wessel <robertwessel2@yahoo.com> - 2014-10-18 08:43 -0500
          Re: x86 real mode Gerd Brix <gbrix@gmx.eu> - 2014-10-18 16:39 +0200
          Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-18 17:52 -0700
            Re: x86 real mode George Neuner <gneuner2@comcast.net> - 2014-10-20 01:35 -0400
              Re: x86 real mode upsidedown@downunder.com - 2014-10-20 10:14 +0300
                Re: x86 real mode George Neuner <gneuner2@comcast.net> - 2014-10-20 14:12 -0400
              Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-20 08:15 -0700
    Re: x86 real mode Les Cargill <lcargill99@comcast.com> - 2014-10-17 18:39 -0500
      Re: x86 real mode Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2014-10-18 10:46 +0300
  Re: x86 real mode George Neuner <gneuner2@comcast.net> - 2014-10-17 15:29 -0400
    Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-17 14:32 -0700
      Re: x86 real mode Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2014-10-18 00:09 +0200
        Re: x86 real mode glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-10-17 22:31 +0000
          Re: x86 real mode upsidedown@downunder.com - 2014-10-18 12:04 +0300
            Re: x86 real mode glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-10-18 23:22 +0000
            Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-18 20:59 -0700
      Re: x86 real mode upsidedown@downunder.com - 2014-10-18 11:53 +0300
        Re: x86 real mode Don Y <this@is.not.me.com> - 2014-10-18 09:34 -0700
    Re: x86 real mode glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-10-17 22:00 +0000
      Re: x86 real mode Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2014-10-18 00:26 +0200
        Re: x86 real mode glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-10-17 22:36 +0000
      Re: x86 real mode George Neuner <gneuner2@comcast.net> - 2014-10-17 21:45 -0400
        Re: x86 real mode glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-10-18 03:26 +0000
          Re: x86 real mode Robert Wessel <robertwessel2@yahoo.com> - 2014-10-17 23:26 -0500
            Re: x86 real mode glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-10-18 05:42 +0000
          Re: x86 real mode Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2014-10-18 10:53 +0300
            Re: x86 real mode glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-10-18 09:12 +0000
        Re: x86 real mode Robert Wessel <robertwessel2@yahoo.com> - 2014-10-17 22:40 -0500
      Re: x86 real mode George Neuner <gneuner2@comcast.net> - 2014-10-17 22:07 -0400

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