Re: A86: GET_KEY vs ports

To: assembly-86@lists.ticalc.org
Subject: Re: A86: GET_KEY vs ports
From: David Phillips <electrum@tfs.net>
Date: Sun, 27 Sep 1998 20:50:20 -0500
Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
Reply-To: assembly-86@lists.ticalc.org

Actually, this is not entirely true.  It is not using getkey that causes
the bug.  It is the rom's interrupt routine that causes the bug.  For
example, Sqrxz reads the ports directly and it still has the bug.  The way
to disable the bug is to 1) write your own int handler, or 2) disable
interrupts entirely.

On a side note, does disabling interrupts have any bad effects on the calc?
 I am using this in a game now, and I can find nothing wrong with it,
though it has been said not to do this.  (Yes, I know you have to enable
before exiting, and you can't use the rom getkey routines, etc...)

At 08:51 PM 9/27/98 CDT, you wrote:
>
>Reading the ports directly is better.  While it may be harder (at least 
>to me) using GET_KEY you have the "down left bug" which is basically a 
>bug that "pauses" your calc when you hold down and left at the same 
>time.  But most gaems now use the ports directly so its not as common.
>
>Matt
>
>
>>
>>
>>Is it better to read keypad input using GET_KEY or by reading the ports
>>directly?
>>
>>Thanx,
>>Dave VanEe
>>
>>
>
>
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David Phillips
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