EE 361 Homework

Homework 2

Due Date: Sept 8 (wed.)

Assignment:

Problem A [4 pts] Find the machine code for the following MIPS assembly language instructions in decimal notation (the back of the textbook book has the machine instruction format).
- sub $7,$2,$5
- sw $20,16($7)
- sw $24,24($2)
As an example, consider the MIPS assembly language instruction add $3,$8,$2. Its machine language format in decimal notation is

0
8
2
3
0
32
Problem B [1 pt]: Write a MIPS assembly language implementation of the following C language instruction
A[2*i] = A[2*k+j];

where the array A starts at address Astart, and variables i, j, and k are, respectively, registers $3, $4, and $5. You may use registers $6, $7, and $8 for temporary values if needed.
[1 pt]Textbook problem 2.10.
[2 pt]Textbook problem 2.13.

[2 pt]Problem A. What are the MIPS assembly language instructions for the following words (see back cover of textbook for instruction format and op codes).

Instruction 1:  100011 00011 00100 00000 00000 000100

Instruction 2:  000000 01101 00000 00000 00000 001000

Instruction 3:  000000 00001 00010 00011 00000 100010

Instruction 4:  000010 00000 00000 00000 00000 00110

[2 pts]Problem C (You should be able do this problem after lecture 
on wed 9/3).  Convert each of the following lines of  C language code 
to MIPS assembly language.  Note that two of the six  lines are done as examples, 
so you only need to do the other four (each counts half a point).  The variables
 "k" and "j" are stored in registers $3 and $4, respectively.   You may 
use register $2 for temporary storage.

if (k == j) k = 0;

        bne    $3,$4,Skip      #  if (k != j) goto Skip
        add    $3,$0,$0        #  k = 0;
Skip:

if (k != j) k = 0;

if (k > j) k = 0;

        #  if (k <= j) goto Skip
        slt   $2,$4,$3      # if (k > j) then $2 = 1
                            # Otherwise, "k <= j" and $2 = 0
        beq   $2,$0,Skip    # if (k <= j) goto Skip
        add   $3,$0,$0
Skip:

if (k < j) k = 0;
if (k >= j) k = 0;
if (k <= j) k = 0;