→ da0910cc:帥哥讀很快哦 07/06 09:25
assume that the breakdown of dynamic instructions into various instruction
categories is as follows:
R-type 50%, beq 15%, jump 10%, lw 15%, sw 10%
branch predictor accuracies: always-taken 40%, always not-taken 60%, 2-bit 80%
(1) with the 2-bit prdictor, what speed-up 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
1 + 3*(1-0.8)*0.15
--------------------------------
1 + 3*(1-0.8)*0.15*0.5
請問這題為什麼要加1?
(2)同上，把黃字改成two ALU
1 + 3*(1-0.8))*0.15
--------------------------------
1 + (1 + 3*(1-0.8))*0.15*0.5
請問為什麼還要再加1?
謝謝
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