Date   : Mon, 28 Sep 2009 20:53:09 +0100
From   : info@... (Sprow)
Subject: Couple of Tube operation queries

In article <0A96BC63A71E4750968BE92BF54A0FCF@...>,
   Michael Firth <mfirth@...> wrote:
> The Tube "T" bit (sort of a soft reset):
> 1) Is it used by the actual software implementation? - the BeebEm code for 
> emulating this bit looks very broken, so I think that if it was used by 
> the Tube host code implemented by Acorn then it wouldn't work properly.
> 2) Is this bit a set / reset flag (as implied by page 13 of the App Note), 
> or is it self-clearing (as implied by page 12 of the App note)?

For the ARM coprocessor, the T bit clears all the fifos & corresponding
status except P V M J I and Q. I made it a set/reset flag, but I'm not aware
of any software using it,
Sprow.