Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!xanth!nic.MR.NET!shamash!rosevax!ems!pwcs!stag!daemon
From: to_stdnet@stag.UUCP
Newsgroups: comp.sys.atari.st
Subject: Re: bios function 0x7f
Message-ID: <680@stag.UUCP>
Date: 19 Dec 88 21:12:10 GMT
Sender: daemon@stag.UUCP
Lines: 61

From: dynasoft!john@stag.UUCP (John Stanley)

[dlm@druhi.ATT.COM (Dan Moore) writes...]

> in article <12076@hall.cray.com>, rosenkra@hall.cray.com (Bill Rosenkranz) says:
>> after disassembling a code i found on some bbs which doubles the effective
>> on-screen travel of the mouse form, i found it ixecutes bios function 0x7F
> 
> 	There isn't a bios function 0x7f.  But it is a useful bios call
> if you intended to patch the bios handler on the ST.  When the ST bios
> or xbios handler receives an illegal function number it returns an error
> code and a pointer to the bios/xbios function pointer table.  I believe
> it returns the pointer in A0.

  All correct up to this point...

>  You need this pointer if you are going to
> have your own code handle the bios/xbios traps. 

  Wrong!

  There are better methods for doing this...  Using this method the way
many people have been using it makes it impossible to use many other
useful resident programs.  Bypassing the bios vector chain just to install
your own program is not necessary at-all(!) and definately isn't friendly
to other programs that use the bios vector...

> This is a trick Dave Small and I used in the MOUSE program in STart
> #2 or #3.  MOUSE kept the mouse out of the menu bar unless you pressed
> the right button.

  I've seen the code for this program.  While interesting, it isn't
useable with Flash or any other program that uses the right mouse button
for it's own purposes.  Someone else took it and modified it to allow
using the right button for other purposes, but it was still incompatable
with many resident programs because it used a very bad installation method
(bypasses the bios vector chain which means that -any- bios vector-using
programs loaded before it was are no longer called after this program gets
its hooks into the system).

  If anyone wants a copy of my own version of this program which works
with everything including the mouse modifier prorams, feel free to drop me
a note (PLEASE read the mail warning at the end of this msg first.).  If
there's enough interest my program, I'll post it to the comp.binaries
atari.st newsgroup.

  Please don't get me wrong Dan... I have the highest regards for 99% of
the software that you and Dave Small have written.  I just don't want
these TSR hostile methods to get out any further.  There's already too
much incompatable software out there...  And from what I've seen, none of
the incompatabilities are necessary.

> 				Dan Moore

--
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---
John Stanley (dynasoft!john@stag.UUCP)
Software Consultant / Dynasoft Systems