Control inputs (i.e. the control input to tranif switches)
are not driven in any way by the island, so use .import records
instead of .port records to bring them into the island. Properly
handle the now potentially different bindings within the island
and outside the island. This means the draw_net_input_x function
is a little more sophisticated, and the node data more complex.
Fold the bi-directional part select into the pass switch (tran) support
so that it can be really bi-directional. This involves adding a new
tranvp device that does part select in tran islands, and reworking the
tran island resolution to handle non-identical nodes. This will be needed
for resistive tran devices anyhow.
The draw_net_input function is modified to account for nexus that is
a port of an island. Draw the ports (and the islands if necessary)
to the island and use the port output for the nexus instead of the
port input. This allows the bi-directional behavior of the port to
interpose itself in the data flow.
In this process of these changes, the draw_net_input function was
reorganized, and all the considerable amount of code for it was
moved to a file of its own. (vvp_scope.c is pretty unruly.)
Stephen Williams