A Reversible MIPS multi-cycle control FSM design

Design of sequential circuits involves memory elements and combinational gates. The specification of these circuits is usually done by using the finite state machines. A microprocessor can be visualized as a large finite state machine. Thus it is a known fact that FSM design plays major role in specifying the sequential circuits. A reversible design of the infamous MIPS multi-cycle FSM is introduced in this paper. Three FSMs namely original, reverse and reversible FSM of the MIPS control circuit is designed, synthesized and simulated. Synthesis and simulation results are provided for the three implementations. The overhead for designing the reversible FSM are log₂(N)_rceil conflict pins and one direction pin along with extra logic for inserting them.