how to generate CLOCKDR signal from TAP controller?

Hi,

I have an output coming out from the TAP controller called CLOCKDR. I
know how the SHIFTDR and CAPTUREDR states are generated, but I cannot
figure out how to generate the CLOCKDR signal.


As of my reading, I think its is


CLOCKDR = ~((SHIFTDR | CAPTUREDR) & ~TCK )


I read Ken Parker's book from cover to cover but I don't see mention of

how to generate CLOCKDR. He merely mentions CLOCKDR is a "derived
clock".


Any other books I can read to make sure I am doing the right thing?


thanks
huzaifa