This Is a Three-Part Question About Critical Path Calculation

Essay

This is a three-part question about critical path calculation. Consider a simple single- cycle implementation of MIPS ISA. The operation times for the major functional components for this machine are as follows:
- Below is a copy of the MIPS single-cycle datapath design. In this implementation the clock cycle is determined by the longest possible path in the machine. The critical paths for the different instruction types that need to be considered are: R-format, Load-word, and store-word. All instructions have the same instruction fetch and decode steps. The basic register transfer of the instructions are:
Fetch/Decode: Instruction <- IMEM[PC];
R-type: R[rd] <- R[rs] op R[rt]; PC <- PC + 4;
load: R[rt] <- DMEM[ R[rs] + signext(offset)]; PC <- PC +4; store: DMEM[ R[rs] + signext(offset)] <- R[Rt]; PC <- PC +4;
(Part A)
In the table below, indicate the components that determine the critical path for the respective instruction, in the order that the critical path occurs. If a component is used, but not part of the critical path of the instruction (ie happens in parallel with another component), it should not be in the table. The register file is used for reading and for writing; it will appear twice for some instructions. All instruction begin by reading the PC register with a latency of 2ns.