If you are interested in performant retro PRNGs, you can find a link to mine in my profile, if I am not mistaken. The counter is based on xorshift. As of the time of release it passed all tests that could be passed with only a 2^32-1 period.

On Z80 it was only about as fast as RC4 which is also a good option in terms of performance and quality but whereas RC4 has a huge state, this one only has a 32bit state, the rest staying in ROM.