Due 12/4

1.   (1 point) Do the following Mic-1 instructions perform exactly the same
     operation? Explain.

     a := a + a; if n then goto 0;
     a := lshift(a); if n then goto 0;

     Remember that shifting left by 1 bit is the same as multiplying by 2.

2.   (1 point) A cache has a 90 percent hit ratio, an access time of 10 nsec on a
     cache hit and an access time of 80 nsec on a cache miss. What is the
     effective access time?

3.   (1 point) In the associative cache of figure 4-28(b), what is the address of
     the word in the cache with the value 2131?

4.   (2 points) In which slot would the following address be in the direct-mapped
     cache described in the book? What would be the tag if it were in the cache?

               E87934 (hex)

5.   (4 points) A cache is being designed for a computer with 2**32 bytes of
     memory. The cache will have 2K slots and use a 16 byte-block. Compute
     for both an associative cache and a direct-mapped cache how many bytes
     the cache will occupy.

6.   (2 points) If the program of figure 4-16 of the book were implemented
     using a nanostore, how many bits would the control store and the
     nanostore require together. How many control store bits are in the original
     design?

7.   (2 points) Consider a machine on which 20 percent of the instructions are
     conditional jumps and another 10 percent are loop jumps. The conditional
     jumps can be predicted with 60 percent accuracy and the loop jumps can be
     predicted with 90 percent accuracy. The jump penalty is 4 cycles. There is
     no penalty for unconditional jumps or correct guesses. What is the
     efficiency of the pipeline on this machine? (Hint: you can modify the
     formula from the book 1/(1 + bPwPj), except now there are two Pw's and
     two Pj's).

8.   (4 points) A virtual memory has a page size of 1024 words, eight virtual
     pages and four physical page frames. The page table is as follows:

     Virtual Page             Page Frame
     0                   3
     1                   1
     2                   Not in main memory
     3                   Not in main memory
     4                   2
     5                   Not in main memory
     6                   0
     7                   Not in main memory

     a.    Make a list of all the VIRTUAL ADDRESSES (not the page
          number) that will cause page faults.
     b.    What are the physical addresses for 1024 and 5000?

9.   (2 points) A computer has 16 pages of virtual address space but only 4
     page frames. Initially, the memory is empty. A program references the
     virtual pages in the order:

          0,7,2,7,5,8,9,2,4

     a.   Which references cause page faults using LRU?
     b.   Which references cause page faults using FIFO?

10.  (1 point) What is your name?