Re: A86: Interrupts vs. SQRT and ANS

To: <assembly-86@lists.ticalc.org>
Subject: Re: A86: Interrupts vs. SQRT and ANS
From: "Ahmed El-Helw" <ahmed@ticalc.org>
Date: Sat, 27 Feb 1999 17:40:20 -0500
Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
Delivered-To: assembly-86@lists.ticalc.org
Reply-To: assembly-86@lists.ticalc.org


thanks, that helps a lot :)
well, I mainly doing 68k now, but sometimes, i get the nostalgia and look at
z80 again :)

Ahmed El-Helw <ahmed@ticalc.org>
   Program Ideas and Upcoming Programs
   the ticalc.org project - http://www.ticalc.org/
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----- Original Message -----
From: <ComAsYuAre@aol.com>
To: <assembly-86@lists.ticalc.org>
Sent: Saturday, February 27, 1999 5:28 PM
Subject: Re: A86: Interrupts vs. SQRT and ANS


>
>In a message dated 2/27/99 4:45:41 PM Eastern Standard Time,
ahmed@ticalc.org
>writes:
>
>> Would someone tell me the major difference.. I thought they were the
>>  same thing, but I heard from Kirk that you can't change variables from
an
>>  interrupt but you can from a SQRT.. and also, what are the calls for
>>  modifying "ans?" thanks!
>
>the interrupt runs at 200hz and starts at $38.  you can install your own im
1
>interrupt addon (limited to 200 bytes), or your own im 2 routine, which is
>probably the better choice.  from an interrupt, you don't really have
direct
>access to any specific thing in the way you do in a sqrt.  however, i'm
pretty
>sure that you can modifty variables and write to the screen and just about
>anything else you want from an interrupt.  unless di is executed, an
interrupt
>is constantly running.
>
>a sqrt is a program which is executed when a specific event is called.
>probably the most common is the sqrt key program, which runs every time
>_getkey is called. from that, you can very easily modify all keypresses
>handled by the system.  other sqrt key programs (that i can think of off
the
>top of my head) are: sqrt form, sqrt graph, sqrt exec, sqrt parse, and
maybe a
>couple others.
>
>a sqrt program is optimized for handling specific calculator events,
whereas
>an interrupt is run 200 times a second, regardless of what else is going
on.
>
>hope this clears things up.
>
>
>btw, didn't you quit z80 programming?
>

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