I have taken a quick look, and haven't done anything with it yet. I wonder if the docs are enough to, say, write your own assembler? (Which may have been one of your goals, as the assembler tool looks like it's windows-only with no source code, at least that I've seen.)
Looking at the datasheet, just to get an idea of this PIOC thing, apparently it can control only up to 2 GPIOs. And they have implemented a full, yet minimal RISC core for that, as opposed to the RPi PIO, which is much simpler.