Re: Can Ctrl-C interrupt be removed from ProDOS BASIC? (fwd)

[vandry@CAM.ORG (Phillip Vandry)]

Message-Id: <9304020603.AA14859@hub.ucsb.edu>
Date: Thu, 1 Apr 93 22:04:29 -0800
From: David Rosen <ultima@mcl.mcl.ucsb.edu>
Subject: Re: Can Ctrl-C interrupt be removed from ProDOS BASIC?
Newsgroups: comp.sys.apple2
References: <C4qLI7.8MF@news.cso.uiuc.edu> <C4rMs0.MJs@CAM.ORG>

Phillip Vandry (vandry@CAM.ORG) writes:

>swh54716@uxa.cso.uiuc.edu (Scott W. Henson) writes:

>>Can the Ctrl-C interrupt be removed from ProDOS and/or Basic.System so
>>that programs that run from self-booting disks cannot be terminated during
>>the boot sequence (i.e. before they have been loaded and execution has
>>started)?  If so, how would one go about patching things to remove the
>>interrupt handler?

>The problem is that Ctrl-C is neither in ProDOS nor in BASIC.System. It's
>in ROM. No matter how you patch BASIC.System, there's always going to be a
>short amount of time after BASIC.System has told the ROM to run the program
>and before a possible ONERR GOTO executes on the first line.

There was this one game I had that was written in BASIC but was included
as part of a machine language file.  This way you would BRUN it and
there was no way to list it or stop it with control-C.  I would go get
the code out now, but I don't see how it would be possible to add it in
to the program, as it would require changing all the line pointers.  If
you know of a way to do this, e-mail me and I'll go dig out the code.

I would say that this code probably sets the start of program pointer to
the correct start of the program and then calls some ROM routine to run
the program.

--David Rosen