RE: A86: Capture key-press

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RE: A86: Capture key-press

The reason why I'm questioning about this, is that my exams are getting close. As a little preparation, I thought of writing a small little TSR to snap up thos clear-mem keystrokes, so to fool the clear-calc crew. Is that possible to do?, or does anyone have any other ideas of how to solve this, please share them. A totaly fool-proof fake reset program would be a REAL nice thing to have.

As for J. Mårdell's answer below, I have to (probably stupid) questions:
1) What is IM 2?
2) What is a 257 byte vector table

-Martin

-----Original Message-----
From:	Jimmy Mårdell [SMTP:yarin@acc.umu.se]
Sent:	Wednesday, November 19, 1997 11:22 PM
To:	assembly-86@lists.ticalc.org
Subject:	Re: A86: Capture key-press

At 13:31 1997-11-19 +0100, you wrote:
>I just wondered if something like this would be possible to do:
>Write an interrupt that would monitor keypresses during normal calc
operation, and run a >specific code if a certain key is pressed. As far as
I have understood, interrupts aren't >easy to do, but if somebody have any
experience, please let me know.

As you say, runlength interrupt handlers are easy, but TSR programs
(interrupts still
running after you quit the program that 'hooked' it) are, as far as we
know, kind
of hard. Or at least, they will be unstable.

If you want to use IM 2, you'll have to store a 257 byte vector table +
interrupt handler
somewhere in the RAM which doesn't change. That would be at the end of
_asm_exec_ram
or something. This wouldn't be too hard if we knew how to allocate memory
at the end
of the _asm_exec_ram as the TI financial program does.

I still suspect that TI might have added some support for creating
interrupt handlers
without using IM 2 (since there is a call in the interrupt handler at 38h
to a location
in the RAM which could be changed).

--
Real name: Jimmy Mårdell                 
IRC......: Yarin                         
Email....: mailto:yarin@acc.umu.se      <-- NEW E-MAIL ADDRESS!!!!
Homepage.: http://www.algonet.se/~mja/
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