1. Logical and Decision Operations
Chapter 2

2. Logical operations Shift left Shift right Bit-wise AND Bit-wise OR
Example: sll $t2,$so,4
Reg t2 = $so << 4
Shift right
Example: srl $t2,$so,4
Reg t2 = $so >> 4
Bit-wise AND
Example: and $t0,$t1, $t2
Reg t0 = reg t1 & reg t2
Bit-wise OR
Example: or $t0,$t1,$t2
Reg $t0 = $t1 | $t2

3. Instructions for Selection (if..else)
If (i == j) then f = g + h; else f = g – h;
bne $s3,$s4, else
add $s0,$s1,$s2
j done
else: sub $s0,$s1,$s2
done:

4. Instructions for Iteration (while)
while (save[i] == k)
i = i + 1;
Let i be in reg $s3
Let k be in reg $s5
Let $t1 have the address of Save array element
Loop: sll $t1,$s3,2
add $t1,$t1$s6
lw $t0,0($t1)
bne $t0,$s5,Exit
addi $s3,$s3,1
j Loop

5. Compiling C procedures
int leaf_example (int g, int h, int i, int j) { int f; f = (g + h) – (i + j); return f; } How do you pass the parameters? How does compiler transport the parameters?

6. Passing Parameters/arguments
Special registers for arguments: a0, a1, a2, a3 Save temp register on the stack Perform operations And return value Restore values stored on the stack Jump back to return address