EE 361 Homework

Homework 2

Due Date: 9/5 (fri.)

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 $8,$10,$3
lw $14,4($9)
sw $24,2($8)

As an example, consider the MIPS assembly language instruction add $3,$8,$2. Its machine language format in decimal notation is

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

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).
```
000000 01101 00000 00000 00000 001000
000000 00001 00010 00011 00000 100010
000010 00000 00000 00000 00000 001100
100011 00011 00100 00000 00000 000100
```
[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.
1. if (k == j) k = 0;
```
        bne    $3,$4,Skip      #  if (k != j) goto Skip
        add    $3,$0,$0        #  k = 0;
Skip:
```
2. if (k != j) k = 0;
3. 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:
```
4. if (k < j) k = 0;
5. if (k >= j) k = 0;
6. if (k <= j) k = 0;