109 年 - 109國立臺灣大學_碩士班招生考試_電機工程研究所丙組:計算機結構與作業系統(A)#105855　

3. (5 points) The following is the critical section solution by Leslie Lamport in 1974.
The parenthesized numbers on the left are the line numbers. Please answer which of the following statements is/are correct! 

11. (5 points) One critical factor in powering a server farm is cooling.   If heat is not removed from the computer efficiently, the fans will blow hot air back onto the computer, not cold air.   We will look at how different design decisions affect the necessary cooling, and thus the price, of a system.   Please use the components and devices in the following for your power calculations. Please answer which of the following statements is/are correct.

15. (5 points) Assume that we have the following machine instruction program.
Also assume that our processor has the following microarchitecture that the arithmetic-logical units (ALUs) can do all arithmetic ops in the above program and that the Rcservation Station (RS) can simultaneously dispatch at most one operation to each functional unit per cycle (one op to each ALU plus one memory op to the LD/ST). 

 Suppose all of the instructions from the program in the above are present in the RS, with no renaming having been done.Please answer which of the following statements is/are correct ?Hint: An instruction with latency +2 requires two ＜stall＞ cycles to be inserted into the code sequence. Think of it this way: A one-cycle instruction has latency 1 + 0, meaning zero extra wait states. So, latency 1 + 1 implies one stall cycle; latency 1 + N has N extra stall cycles.)

17. (5 points) Consider the following code.

Assume that the processor runs at 700 MHz and has a maximum vector length of 128. The load/store unit has a start-up overhead of 16 cycles; the multiply/division unit, 8 cycles; and the add/subtract unit, 6 cycles. Pleasc answer which of the following statements is/are correct.