Ah, sorry then. At least it parses the CUE files fine. Playing audio CD is shouldn't be a "big" task at all, basically you sent bits from the faked CD drive to the sound card.

https://cvsweb.openbsd.org/cgi-bin/cvsweb/~checkout~/src/usr...

Implementing the whole fake unit reading the media would be the most difficult task by far.

I haven't looked into it but what might be complicated is implementing the support for audio cd in the vhdl of the sound card component...