2. The importance of having a good branch predictor depends on how often conditional branches are executed. Together with branch predictor accuracy, this will determine how much time is spent stalling due to mispredicted branches. In this exercise, assume that the breakdown of dynamic instructions into various instruction categories is as follows: LW R-type 40% BEQ Jum SW 25% 5% 25% 5% The accuracies of three different branch predictors are as follow: Always-Taken 45% Always-Not-Taken 55% 2-bit Predictor 85% Stall cycles due to mispredicted branches increase the CPI. What is the extra CP due to mispredicted branches with the always-taken predictor? Assume that branch outcomes are determined in the EX stage, that there are no data hazards, and that no delay slots are used. Repeat Part a for the "always-not-taken" predictor. a. b. Repeat Part a for the 2-bit predictor. With the 2-bit predictor, what speedup would be achieved if we could convert half of the branch instructions in a way that replaces a branch instruction with an ALU instruction? Assume that correctly and incorrectly predicted instructions have the same chance of being replaced. With the 2-bit predictor, what speedup would be achieved if we could convert half of the branch instructions in a way that replaced each branch instruction with two ALU instructions? Assume that correctly and incorrectly predicted instructions have the same chance of being replaced. c. d. e