HW2.sols.09 - Computer Architecture Homework 2 Due:...

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Computer Architecture Homework 2 Due: Wednesday, September 23, 2009 SOLUTIONS 1. Frequency Instruction type MIPS examples Average CPI gcc spice Avg arithmetic add, sub, addi 1.0 clock cycles 55% 55% 53% data transfer lw, sw, lui 1.5 clock cycles 31% 40% 35.5% conditional branch beq, bne 1.6 clock cycles 11% 7% 9% jump j, jr, jal 1.2 clock cycles 3% 2% 2.5% Effective CPI = (1*.53) + (1.5 * .355) + (1.6 * .09) + (1.2 * .025) = 1.2365 1.24 2. a) Using the above data, with gcc if N instructions are executed: .31N are data transfer (L/S) instructions .55 of L/S instructions are loads, so .55 * (.31N) = 0.1705N are loads This part of the problem assumes that 50% of the loads occur in the load-add pattern that will be replaced (in the new machine) by a single addm instruction, and this .5 * (0.1705N) = 0.08525N instructions will be eliminated T old = N * CPI * CCT T new = N’ * CPI * (1.1*CCT) = (N - .08525N) * CPI * (1.1*CCT) = (1 - .08525) * 1.1 * N * CPI * CCT = (.91475) * 1.1 * T
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This note was uploaded on 12/20/2009 for the course ECE 466 taught by Professor Staff during the Fall '09 term at Clarkson University .

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HW2.sols.09 - Computer Architecture Homework 2 Due:...

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