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How to test
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(1) Edit the following line in Makefile

    MCKDIR=$(HOME)/project/os/install

(2) make test
(3) Check if the first value, number of instructions retired,
    shows around 3 million.
(4) Check if the second value, number of cycles taken,
    shows around 3 million / instructions-per-cycle
    (1 - 1.5, depends on the processor).