Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!uwvax!puff!schumann
From: schumann@puff.WISC.EDU (Christopher Schumann)
Newsgroups: comp.sys.apple
Subject: Re: screen memory question
Message-ID: <409@puff.WISC.EDU>
Date: Mon, 15-Dec-86 21:08:18 EST
Article-I.D.: puff.409
Posted: Mon Dec 15 21:08:18 1986
Date-Received: Tue, 16-Dec-86 23:31:53 EST
References: 
Organization: U of Wisconsin CS Dept
Lines: 36
Summary: Wait a minute...

In article , mw22#@ANDREW.CMU.EDU (Michael Alan Wertheim) writes:
>    There seems to be a lot of confusion regarding 40 and 80 column text.

Sure does.

< Some good stuff... >
> ...  Also note that
> you can BSAVE a screen from page 1 or page 2, but you can BLOAD the image
> only back to page 2.

In ProDOS, OK. But in 3.3 (yes it is still used), you can load both back,
sometimes the screen hole stuff gets mucked and the drive complains.

> .........................................  Likewise, there is also an
> 80-column double lo res that uses the same memory and that can easily be
> accessed from Applesoft.  This was covered in a past issue of Open Apple.  If
> anyone's interested, I'll post a short summary of how to do this.
 
From my article in _Nibble_, Feb '86: (pardon my swelling head)
10 ?chr$(4)"PR#3"
20 ?:REM Needed to initialize firmware
30 x=peek(49246):gr:rem Now in 80 x 40 mode
40 color=2:hlin0,79at20:REM it works now

>    Double hi res uses the memory from $2000 to $3fff in both main and
> auxiliary memory.  I've heard that there is a double hi res page two that
> uses the memory from $4000 to $6fff in both main and auxiliary memory.
                                 5FFF
Only trouble is, firmware switches to page 1 on almost all I/O calls.
  
> Mike Wertheim
> (Carnegie Mellon University)

Chris Schumann	schumann@puff.wisc.edu
"I before E, and
 there's five E's in aiieeeee"