Re: A86: interrupts

To: <assembly-86@lists.ticalc.org>
Subject: Re: A86: interrupts
From: "Matt2000" <matt2000@gte.net>
Date: Fri, 1 May 1998 21:53:42 -0400
Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
Reply-To: assembly-86@lists.ticalc.org


>im 2 goes straight into our assembly code.  Even if you use pop hl and
>skip part of the interrupt, there is still about 50 bytes of code being
>needlessly run every time the interrupt is called.  It adds up...
>
>
>Just use the instruction <im 2>, and your back to normal, with the
>interrupt restored, even!


Oh ok, well use IM 1 to restore the normal mode right? And IM 2 to use the
routine.. I found this on the list posted earlier

---
im 2 - jump to (i*$100+v) where v is a value gotten of the bus (in ti
calcs its random)  would crash the calc about 999 times outta 1000

No.  You can install a table of jumps that will account for every possible
alue that can be put on the bus.  There's a mail about it a few months ago
on he list.
--

So I assume that explains why you need 256 byte table right? Why did someone
mention you would need 257 bytes? And would the table just be a bunch of
jumps to the interrupt service routine? If so, dont you need three bytes per
call? What if it jumped in the table and right in the middle of the opcode
but before the next opcode, wouldnt that crash the calculator?

-Matt
http://www.dogtech.com/cybop/ti86/

Follow-Ups:

Re: A86: interrupts

From: Dux Gregis <assets@eden.rutgers.edu>