Re: Apple IIGS Won't Enter Control Panel

[dempson@actrix.gen.nz (David Empson)]

Moll <molly@spam.spam.spam.dosius.spam.net> wrote:

> David Empson wrote:
> > Any program which leaves interrupts disabled will prevent access to the
> > classic Desk Accessory menu, as well as causing other problems with the
> > IIgs, such as stopping the system tick count and killing AppleTalk
> > connections.
> 
> I wonder why some running programs, if you hit OA-Ctrl-ESC, would crash
> into the monitor.

Possibly an issue with lack of space on the stack.  If the program is
running in emulation mode, and the stack pointer is near the bottom of
the stack ($0100), then an interrupt may result in the stack pointer
wrapping around to near $01FF.  A crash is a likely result, as the
interrupt handler may access the wrong area when looking back up the
stack, and some data higher up the stack will have been overwritten.

Crashing on _exit_ from the desk accessory menu seems more likely in
these conditions.

-- 
David Empson
dempson@actrix.gen.nz