Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!microsoft!brianw
From: brianw@microsoft.UUCP (Brian WILLOUGHBY)
Newsgroups: comp.sys.apple2
Subject: Re: Inverse characters
Message-ID: <56073@microsoft.UUCP>
Date: 25 Jul 90 18:24:26 GMT
References: <6487.apple.info@pro-abilink> <1990Jul20.200816.19293@laguna.ccsf.caltech.edu> <1990Jul21.180434.23445@hoss.unl.edu> <43258@apple.Apple.COM>
Reply-To: brianw@microsoft.UUCP (Brian WILLOUGHBY)
Organization: Microsoft Corp., Redmond WA
Lines: 43

In article <43258@apple.Apple.COM> dlyons@Apple.COM (David A. Lyons) writes:
>The difference was just that some of your Apple IIe machines were
>"enhanced" and some were not.  (The enhancement is 3 parts: replacing
>the ROM, replacing the 6502 with a 65C02, and replacing the character
>generator with one that has MouseText in there.)
>-- 
>David A. Lyons, Apple Computer, Inc.      |   DAL Systems

As far as inverse characters are concerned, both the "enhanced" and
unenhanced IIe machines were capable of inverse lower case.  MouseText is
an addition which is not necessary for inverse lower case.  Referring to
your IIe reference manual will reveal a soft switch which will enable
the alternate character set (including inverse lower case and sometimes
MouseText), although the 80 column firmware will probably reset this
switch without warning.

The default text ROM soft switch setting enabled the II+ character set,
which allows (in upper case characters) 64 inverse, 64 flash, 64 normal,
32 control and 32 normal lower case.  There was not enough room for
inverse lower case, so the IIe has a second set of 256 text characters
which do not include FLASHing text.  At first, only 32 were used for
inverse lower case, but then the //c added 32 MouseText characters in the
space where inverse upper case was repeated.

An interesting side note (well, it was interesting to me):
The older Wizardry games actually stored control character codes into
text screen memory (i.e. hex codes $80 through $9F), even though these
codes were never used by the normal Apple ROM COUT routines.  I found
this out on my II+ after I got the bright idea of using codes $80-$9F
for my own inverse lower case (available at the same time as FLASHing, I
had already added normal lower case with the proper ASCII codes of
$E0-$FF).  $80-$9F is essentially a wasted area of text ROM, so I didn't
think it would hurt.  Apparently, at the time Wizardry was written, there
were lower case adaptors which used codes $80-$9F for lower case.  I
don't see why they chose to locate lower case characters at codes which
were not ASCII standard (which caused the software to convert text files
from other computers), but there is the advantage that machines without
the lower case ROM would see upper case normal characters for codes
$80-$9F.  I guess that is an important feature, since this thread started
when someone got funky numeric/special characters instead of lower case,
because their character generator ROM was not set right.

Brian Willoughby