[Coco] [magervalp at gmail.com: Re: 6809 assembly knowledge needed]

[John W. Linville]

Cool comment regarding 6809 on the cbm-hackers list -- I thought
y'all might enjoy...

----- Forwarded message from Per Olofsson <magervalp at gmail.com> -----

> Date: Thu, 7 Jan 2010 10:38:28 +0100
> From: Per Olofsson <magervalp at gmail.com>
> To: cbm-hackers at musoftware.de
> Subject: Re: 6809 assembly knowledge needed
> 
> On Thu, Jan 7, 2010 at 7:47 AM,  <ruud.baltissen at apg.nl> wrote:
> >> According to http://en.wikipedia.org/wiki/6809 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:
> 
>   http://www.6502.org/users/andre/o65/fileformat.html
> 
> 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!
> 
>        Message was sent through the cbm-hackers mailing list
> 

----- End forwarded message -----

-- 
John W. Linville		Someday the world will need a hero, and you
linville at tuxdriver.com			might be all we have.  Be ready.