Re: LF: lots of stuff, mem expander
[Prev][Next][Index][Thread]
Re: LF: lots of stuff, mem expander
Andrew Von Dollen wrote:
> Yes, as you read it is possible to directly access the TI-92's Link
> Port.
> Bryan Turner was the one who figured this out. There are documents in
> the
> works on how to do this. This discovery makes a 92 expander fully
> possible,
> both with Mel Tsai's existing design and a few different designs that
> are
> slowly surfacing. The expander driver for the TI-92 and the existing
> exapander design is being developed.
I've explained the technique to David Ellsworth for the next version
of the ports.txt file. If anyone needs the information sooner, just
mail me directly.
> >Thus, i tried to put between these lines :
> >lsl #8,D3
> >lsl #8,D3
> >lsr #8,D3
> >lsr #8,D3
> >but this doesn' t work: the D3 reg is empty after this...
>
> hmm, this will shift d3 right 8*4=32 times, zeroing it out completely
> as
> you found.
Actually, I don't know why that DIDN'T work. The first two are left,
and the second two are right shifts. It ought to work that way.
(although it's highly inefficient)
> If you want to clear the upper word of d3, you could
>
> swap d3 ;swaps the two word sized halves of d3
>
> clr.w d3
> swap d3 ;swap them back, the upper word is now
> clear
>
> or
>
> and $FFFF,d3
The smallest method would simply be:ext.l d3
This would sign extend D3 from a word to a long - and assuming it's less
than $8000, it would clear the upper two bytes.
> Well, I don't quite understand what you are asking, so cannot help
> much,
> but if you can clarify what exactly you are trying to do, I will be
> happy
> to help.
I agree, what exactly are you trying to do - that way we can help you
out more efficiently.
--Bryan
bcturner@eos.ncsu.edu
References: