Re: A85: Usgard question

To: assembly-85@lists.ticalc.org
Subject: Re: A85: Usgard question
From: Mike Baker <mbm00@hotmail.com>
Date: Sun, 03 Aug 1997 20:08:46 -0400
References: <19970803223948.12399.qmail@hotmail.com>
Reply-To: assembly-85@lists.ticalc.org

Matt Butch wrote:
> 
> How does usgard "relocate" files
> 
> Thanks.
> Matt Butch
> mjb25@hotmail.com
> "You'll Never Walk Alone"-Melanie Jayne Chisholm aka Sporty Spice
> 
> ______________________________________________________
> Get Your Private, Free Email at http://www.hotmail.com

i'm not on the usguard team, but i feel i can answer that question.

relocation is the art of avoiding Program_addr, why?
basically doing a
	ld hl,(program_addr)
	add hl,de
wastes space.

usgard does not "relocate" them in the sense that it moves them ;
instead it stores a large table (somewhere?) in the program. that
table is a chart of all jumps that need program_addr added to them

PhatOS on the other hand does not use any tables of any sort. It
actually shifts the programs around in memory, making sure that
program_addr is always at $8E57. with this knowledge you can
use .org $8E57 at the start and use JP instead of JUMP_

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References:

A85: Usgard question

From: "Matt Butch" <mjb25@hotmail.com>