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