Re: Apple IIGS bank latching

From	mressl@macgui.com (Marc S Ressl)
Newsgroups	comp.sys.apple2
Subject	Re: Apple IIGS bank latching
Date	2012-03-06 16:07 +0000
Organization	Mac GUI
Message-ID	<mressl-1331050069@macgui.com> (permalink)
References	<cdb399a7-a411-426d-901e-c2b997092323@k29g2000yqc.googlegroups.com> <5764e358-0a03-40dd-8e1a-845ee20f68ee@w29g2000yqw.googlegroups.com>

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Antoine Vignau wrote:
> (5) returns 02
> (6) returns 03
> (7) returns
> * 1900: 19
> * 2000.2007: 12 34 00 00 00 00 00 00
> * 2080.2087: 56 78 00 00 00 00 00 00
> * 20A0.20A7: 00 00 00 00 00 00 00 00
> * 9D00: 9D
> * 9E00: 9E
> * 9F00: 9F
> * A000: A0
> 
> Antoine
>

Hello Antoine. Now this is most interesting! :-).

Here are the findings:

* The Apple IIe memory switches are always active for bank $E0.
* If the language card and I/O is enabled, Apple IIe memory switches are
active for bank $00.
* If shadowing is enabled for all banks, memory switches are active for all
even banks ($00, $02, etc).
* ROM is always available when the language card is enabled (Sweet16 1, KEGS
0 :-) )
* The New Video "memory linearization" appears to not scramble the contents
of video memory (I'm still having a hard time understanding this, as I
believed it would).

I hope this information is useful to authors of Apple IIGS emulators :-).

With the best wishes,

Mar.c-

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Thread

Apple IIGS bank latching "Marc S. Ressl" <mressl@gmail.com> - 2012-03-05 01:00 -0800
  Re: Apple IIGS bank latching Antoine Vignau <antoine.vignau@laposte.net> - 2012-03-05 02:56 -0800
    Re: Apple IIGS bank latching "Marc S. Ressl" <mressl@gmail.com> - 2012-03-05 07:36 -0800
      Re: Apple IIGS bank latching Antoine Vignau <antoine.vignau@laposte.net> - 2012-03-05 14:15 -0800
        Re: Apple IIGS bank latching Antoine Vignau <antoine.vignau@laposte.net> - 2012-03-05 14:22 -0800
          Re: Apple IIGS bank latching "Marc S. Ressl" <mressl@gmail.com> - 2012-03-05 20:02 -0800
            Re: Apple IIGS bank latching "Marc S. Ressl" <mressl@gmail.com> - 2012-03-05 20:54 -0800
              Re: Apple IIGS bank latching Antoine Vignau <antoine.vignau@laposte.net> - 2012-03-05 22:47 -0800
            Re: Apple IIGS bank latching Antoine Vignau <antoine.vignau@laposte.net> - 2012-03-05 22:52 -0800
              Re: Apple IIGS bank latching mressl@macgui.com (Marc S Ressl) - 2012-03-06 16:07 +0000
                Re: Apple IIGS bank latching Daniel Kruszyna <dan@krue.net> - 2012-03-06 23:29 +0000
                Re: Apple IIGS bank latching mressl@macgui.com (Marc S Ressl) - 2012-03-07 02:28 +0000
                Re: Apple IIGS bank latching Antoine Vignau <antoine.vignau@laposte.net> - 2012-03-06 21:50 -0800
                Re: Apple IIGS bank latching mressl@macgui.com (Marc S Ressl) - 2012-03-07 06:43 +0000
                Re: Apple IIGS bank latching Vladimir Ivanov <vladitx@XXXyahooXXX.com> - 2012-03-07 09:44 +0200
                Re: Apple IIGS bank latching Daniel Kruszyna <dan@krue.net> - 2012-03-07 12:15 +0000
                Re: Apple IIGS bank latching mressl@macgui.com (Marc S Ressl) - 2012-03-08 02:32 +0000
              Re: Apple IIGS bank latching mressl@macgui.com (Marc S Ressl) - 2012-03-06 16:16 +0000
                Re: Apple IIGS bank latching Daniel Kruszyna <dan@krue.net> - 2012-03-06 18:46 +0000

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