🚀 go-pugleaf

In article <372@ucdavis.UUCP> ecs160s045@ucdavis.UUCP (Mark Nagel) writes:

     [Mark correct's my misunderstanding where I thought he said that
a CoCo III would be a "farce" wherein he *actually* said]
>that Tandy would ever release one is a farce.  Apparently, the rumor mill is
>still running and some people believe that Tandy will actually produce a 
>new CoCo - maybe they will and maybe they won't.  The fact is that if they do
>now, they will be way behind the game with the Amiga and Atari ST picking up
>most of the sales.  I also don't see how you can call the 6809 instruction
>set orthogonal as compared to the 68000.  The 68000 is a superset of the
>PDP-11 which is by far more orthogonal than the 6809.  For instance, I can
>not auto-increment one of the 6809's "general registers", only the index
>regs.  The 68000 has a *very* orthogonal instruction set.

     Sure you can auto-inc and auto-dec the X and Y registers.  See
Leventhal's 6809 Assembly Language Programming at pp 3-30 to 3-34.
In fact, you can even do indirect addressing with auto-inc and auto-dec.

     On the otherhand, long relative addressing for full 32 bit addressing
isn't well done on the 68000.  The 68020 looks complete (I haven't
really studied either processor in depth, but the '020 had more and
possibly all combinations covered).



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James Omura, Barrister & Solicitor, Toronto
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