strm2oas ignores def net routing wire extensions

[stefanottili]

strm2oas ignores net routing wire extensions when converting def to gds/oas

+ ROUTED M2 ( 1670 830 ) ( * * 300 ) ( 4950 * 300 ) ( * 2000 300 ) ;

The-OpenROAD-Project/OpenROAD#555
As the OR issue states, this was used for older technologies, e.g. 90nm.
Not urgent, since OpenRoad doesn't route with wire extensions.
But it displays them correctly.

test_wire_extension.tgz

[klayoutmatthias]

Hi @stefanottili,

thanks for the nicely prepared test case, as usual! :)

I see that my understanding is wrong. My understanding was the extensions would only apply the first and last point of the full path formed by the routing points, not to each piece individually. But after studying the examples in the spec it becomes clear that each individual segment is meant.

I just think the duplicate first point is a corner case.

How should this net look like?

+ ROUTED M2 ( 1670 830 ) ( * * 0 ) ( 4950 * ) ( * 2000 0 ) ;

The first point gets two competing definitions of extensions: the first coordinate pair specifies half width implicitly and the second one zero extension.

So something like this?

Matthias

[stefanottili]

Sorry, my bad for mudding the water with ambiguity.
I think the 0 length path segment was a leftover from "this is where a via would be".
Since one cannot determine the direction of a 0 length path segment, I would always ignore them.