Re: A89: Re: Various 68K/TI89 things

To: assembly-89@lists.ticalc.org
Subject: Re: A89: Re: Various 68K/TI89 things
From: "lexlugger" <darth__vader__@hotmail.com>
Date: Thu, 14 Oct 1999 14:18:38 CEST
Reply-To: assembly-89@lists.ticalc.org





>From: "Niklas Brunlid" <e96nbr@efd.lth.se>
>Reply-To: assembly-89@lists.ticalc.org
>To: <assembly-89@lists.ticalc.org>
>Subject: A89: Re: Various 68K/TI89 things
>Date: Thu, 14 Oct 1999 00:07:23 +0200
>
>
> > Second, why doesn't the 68K like odd addresses?  Do the assemblers
> > basically handle this for you, because I don't see very much use of the
> > EVEN directive.
>
>It's just designed that way (to make it faster, IIRC - it's not exactly a 
>new
>processor). As for EVEN, if you have a section if data that consists of
>words/longwords you'd better put the EVEN directive before it to avoid 
>address
>errors.
>
The real reason is that the MC68000 processor only has 23 address lines in 
order to save money. When it accesses memory it always accessed a word at a 
time, even if you're only accessing bytes. Memory is treated as an array of 
words by the hardware.

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Re: A89: Re: Various 68K/TI89 things

From: Zoltan Kocsi <zoltan@bendor.com.au>