Mods to HardwareSerial to handle 9-bit data

Hi Nick et al.,
I know this topic is fairly old, but figured it was best to ask the question here vs. starting a new thread?

I recently got involved in a project where 9-bit serial data was required, and not really knowing what to do I was pretty excited to see Nick's work here (thanks, Nick!).

So my quick question is whether or not the mods to the library are specific to AVR-based micros, or more specifically will the mod work with ARM-based micros? I just don't know enough about how libraries work (yet) to be able to answer this question myself.

Thanks in advance for any pointers, and thanks again Nick for your work here!

Cheers,
David