Maximum frequency attained till date-
Multiplexers - 178.348 Mhz
Register File - 598.498 Mhz
Data Memory- 274.72 Mhz
Datapath- 112.215 Mhz
Top Module- 119.97 Mhz
Fetching and Executing instruction each take single clock cycle.
Fetching cycles had AluOp as XXXX and result too as XXXX
The next cycle is the result of the fetched instruction and Reg-write or memory write is procesed at the fall of the clock cycle.
Register R0 always contains zero although it can be changed and overwritten by any instruction. However it isn't suggested. MIPS procesors have R0 set as zero. The Mux with input from Register and sign extend also has an input zero incase R0 is overwritten and one needs to use. Hence its select line in of 2 bits.