[A83] Re: interrupt with shutdown

To: assembly-83@lists.ticalc.org
Subject: [A83] Re: interrupt with shutdown
From: "David Phillips" <david@acz.org>
Date: Sun, 9 Dec 2001 19:41:49 -0700
References: <F224v5iJarnJ3kEPF3c00001e12@hotmail.com> <004f01c18107$4322e8c0$d905040a@tijl>
Reply-To: assembly-83@lists.ticalc.org


I'm not sure if you are correct.  An IM 2 handler doesn't need to enable
them when it returns, and "reti" does not enable them.  I was looking
through the source to the new VTI z80 core, and it appears to support your
theory.  However, I don't see how it can work.  I don't know if it has been
tested with IM 2, so it might not.  The MAME z80 core also disables
interrupts.  But I know for a fact that the code works.  It might be a
special feature of TI hardware.

> The Z80 disables interrupts at the moment it accepts one. If you enable
> interrupts again during the execution of your interrupt routine then it
> might happen an interrupt occures, which causes a whole lot of trouble.

References:

[A83] Re: interrupt with shutdown

From: "SUCKER from the old days" <sucker_pvn@hotmail.com>

[A83] Re: interrupt with shutdown

From: "Tijl Coosemans" <tijl@ulyssis.org>