Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!mcsun!cernvax!chx400!ugun2b!ugsc2a!fisher
From: fisher@sc2a.unige.ch
Newsgroups: comp.binaries.ibm.pc.d
Subject: Re: ALED ... does *not* mask the 8-th bit!
Message-ID: <1991Jun18.104523.484@sc2a.unige.ch>
Date: 18 Jun 91 08:45:23 GMT
References: <3245@krafla.rhi.hi.is> <4089@sixhub.UUCP> <3258@krafla.rhi.hi.is>
Organization: University of Geneva, Switzerland
Lines: 34

In article <3258@krafla.rhi.hi.is>, einari@rhi.hi.is (Einar Indridason) writes:
> I don't know how that ALED reads the keyboard, but it seem to me to be
> something like this:
> 	int	16h
> 	cmp	al,7fh
> 	ja	error		; Nobody uses the 8th bit, so why should I???
> 	....
> This is clearly the Wrong way of reading the keyboard.

This is not correct.  Using the swiss-french keyboard, I can enter without
problem chars such as ('e), (`a), (,c) or (`e).  This means that the 8-th
bit is *not* masked.  On the other hand, keys such as ("u) or ("a) return
an error message "Macro not defined", the ("o) gets me an ascii table (this
I find really funny) and (~n) displays the time in the top right corner...

Even the non-US AltGr key works on some keys (@), (#), etc.  The AltGr key
is often confused by US software with a regular Alt...

I suspect the main problem with ALED is the macro feature.  I also suspect
that this behavior is due to a bug with the NULL character.  Any normal key
returns a character between 32 and 254.  Control keys and special keys like
Tab return characters between 1 and 31.  Shift keys return nothing, only an
internal shift-state table is updated.  All others return a NULL character
followed by a unique code.  It seems that the input routine of ALED sometimes
confuses "normal" characters with an "extended" code.  Another bug would be
to mask the 8-th bit when checking for control characters, but this seems
unlikely.  BTW: the display of an ASCII table or of a clock are both mapped
to Alt-keys, which makes the first therory more likely.

Thus: ALED does *not* mask the 8-th bit!  It *has* a serious bug involving
extended codes and possibly the Alt-key, making the program useless for
non-english users.

Markus G. Fischer                              fisher@sc2a.unige.ch