[Coco] RS DOS RS232 application?

[Darren A]

On Thu, Apr 14, 2016 at 11:43 PM, Gene Heskett wrote:

> On Thursday 14 April 2016 22:42:10 Dave Philipsen wrote:
>
> > Have you compared the pshs/u puls/u instructions for moving data
> > quickly?
>
> No I haven't Dave. I did look at the cycle counts a long time ago, and
> ldq/stq were a fewer cycles less on the 6309 as it skipped the 2nd
> instruction fetch on the 6309.  And moved 4 bytes at a time, so I just
> used the 6809 equ that moved 2 bytes at a time if that is what its
> running on.
>


The problem with a LDQ  ,X++  is that it only increments X by 2 when you
actually need to increment by 4. So you probably need to do something like:

  LDQ   ,X
  LEAX  4,X

Not sure if that is still an improvement.
Don't forget the 6309 also has TFM.


- Darren