Re: 6809 assembly knowledge needed

From: Per Olofsson <>
Date: Thu, 7 Jan 2010 10:38:28 +0100
Message-ID: <>
On Thu, Jan 7, 2010 at 7:47 AM,  <> wrote:
>> According to this ....
> Many thanks for the conformation! But AFAIK this is the only reentrant
> related code for accessing a table. And a meager one IMHO; it is
> equivalent to LDA Label / LDA [Label] ie. you can only address one
> value. And I wonder if the indirect instruction is of any use: if
> "Label" is part of this reentrant code, what value should the compiler
> calculate? I think I'll take Jack's advice to consult the FLEX group.

Position independent code is a huge boon for drivers & libraries, and
on operating systems where everything doesn't load at a fixed address
also whole applications. For example this:

would be mostly redundant on 6809, and would have saved André, Daniel,
and Uz a lot of work (and together with drivecode was one of the
things that tripped me up with SMOS). Just take a look at OS-9,
there's a reason we never got anything as advanced as that for the
6502 or Z80 (well, until the late 90s :).

On C= 8-bits its use is a little more limited, but would still be
handy e.g. for decrunchers and drivecode.

Anders Carlsson wrote:
> Of course I could get me a cheapish Dragon 32 or similar if I really wanted the 6809 covered.

Don't forget the Vectrex!

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Received on 2010-01-07 10:00:04

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