CS2200 Summer 2005 Practice Test 1

Preassessment

1P. Write a function that will swap two integer pointers.

   So if the code looked like this:
   
   int i = 42;
   int j = 99;
   int *ip = &i;
   int *jp = &j
   /* Call your function here */
   
   __________________________________________________
   
   printf("i=%d j=%d *ip=%d *jp=%d|n", i, j, *ip, *jp);
   
   Would print:
   
   i=42 j=99 *ip=99 *jp=42 
   
   ________ void swapIntPointers(                                   )
   {
   
   
   
   
   
   
   
   }

Processor Design

2P. Compare and contrast RISC versus CISC processor architectures.



Addressing Modes

3P. Explain what is meant by "addressing modes." Give examples that 
    illustrate the different modes that you are aware of using MIPS, 
    LC-3 or LC2200 assembler


    
Basic Assembly Language Constructs
    
4P. Assume that you have the address of a block of 10 numbers in $s0 
    and the address of a second block of 10 numbers in $s1. Write 
    LC- 2200 assembly code which will add the corresponding numbers 
    from each block and store the result in the block whose address 
    is in $s0.



    
Calling Conventions    
    
5P. Here is the code for fibbonacci

    int fib(int n)
    {
        if(n == 0 or n ==1)
            return 1;
        else
        {
            int t1, t2;
            t1 = fib(n-1);
            t2 = fib(n-2);
            return t1+t2;
        }
    }    
    
    Write fibonacci in assembly language. Note: You must use
    augmentative or head recursion NOT tail recursion!
    
    Note: It might be a good idea to actually run the code
    to make sure you are doing it correctly.
    
    
    
   
Endianess   
    
6P. Write a program in C that will determine if a processor is Big 
    Endian or Little Endian. Run your program on acme, lennon amd 
    turku. Explain what is happening and why.
    
    
    
    
7P. Examine the LC-2200-8 datapath diagram for Project 1.  

    We would like to implement a push and a pop instruction on the 
    LC-2200-8.
    
        PUSH    R
        POP     R
        
    PUSH will automatically decrement the stack pointer ($sp) and 
    then store the contents of R into the memory location pointed to 
    by the stack pointer.
    
    POP will store the contents of the memory location pointed to
    by the stack pointer ($sp) into R and will then increment the 
    stack pointer.
    
    Can these instructions be implemented on the existing LC-2200-8
    datapath? If no, what changes would you make?
    
    In either case, existing datapath if it will work and modified
    datapath is that is necessary:
    
    Show the finite state machines steps required to implement
    this instruction. Assume that an opcode is available.
    
    
    
    
Performance
    
8P. Explain how CPI and speedup are affected by pipelining a 
    processor. Give examples using sample numbers to show how
    calculations are performed.