All loads take the same time and comprise 30 of the

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All loads take the same time and comprise 30% of the instructions. All stores take the same time and comprise 15% of the instructions. R-format instructions comprise 25% of the mix. Branches comprise 10% of the instructions, while jumps comprise 5%. FP add and subtract take the same time and together total 5% of the instructions. FP multiply and divide take the same time and together total 10% of the instructions. Suppose we have a floating-point unit that requires 400 ps for a floating-point add and 600 ps for a floating-point multiply, not including the time to get the instruction or read and write any registers, which take the same as for an integer instruction. Use these functional unit times: ( a ) Memory units require 200 ps, ( b ) ALU and adders require 100 ps, ( c ) Register file (read or write) require 50 ps. Assume all mux’ s, PC accesses, and sign-extension have no delay. Find the time for the FP operations. 9. For the datapath and instruction mix in problem 8, ( a ) find the “critical path” time for the processor with a single clock cycle length equal to the longest instruction (i.e. worst case path ). ( b ) What would be the fastest clock frequency that the processor could operate at (use only appropriate units: Khz, MHz, GHz)? 10. For the datapath and instruction mix in problem 8, find the weighted average of the cycle times for the different instructions types.

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