These are books that I have that have some circuitry descriptions pertaining to microprocessors:
Principles of CMOS VLSI Design, Weste and Eshraghian, Addision Wesley ,1985
Hardware and Software Concepts in VLSI, Rabbat, Van Nostrand, 1983
Advanced Microprocessors, Gupta and Toong, IEEE Press, 1983.
Also, IEEE Transactions on Solid State Circuits as well as the Proceedings from the IEEE Solid State Circuits Conference have lots of information pertaining to the circuit design of microprocessors.
TTFN