[PATCH 2/3] score: Add Beacon Handler

[Chris Johns]

Gedare Bloom wrote:
> I too would appreciate a little more background for this new feature.
>
> At first blush, it looks like an implementation of a mailbox. Is the
> "beacon" name deriving from any source, or is there some other common
> name for this pattern of asynchronous notification? How does it differ
> from events?

This looks like a "single bit" version of the existing events so why not 
take a look at existing project:

  http://www.rtems.org/wiki/index.php/RTEMSSystemEvents

A "system" event based on the existing code is my preferred solution 
because we do not add any extra code to the core. It means we add 32 
"system" event bits and we need to control the allocation and use. Use 
of an unallocated bit is not supported. To map to your beacon a single 
"transient" bit can be allocated.

Sebastian, it is really good to have this sorted so many thanks. It has 
been a wart on RTEMS for a while.

Chris