For this add another indirecton: the DSA in the LUN table points to
a table of DSA indexed by the tag number when tagged command is in use.
For non tagged command, the LUN DSA still points to the tables describing the
xfer directly.
yet.
If is restricted to SIOP which implement the load/store instruction, and
has 10 scratch registers (basically, 825 and newer, possibly 770).
It implements a different interface between host and script, using a real
ring for command starts, and improved support for reconnect which will allow
256 tag per device. It uses interrupt on the fly to signal complete command,
which allows several commands to be serviced per interrupt and doesn't require
the script to stop to signal command completion.
bouyer