1. Fibonacci with Loop int fib1(int i) { int f1 = 1; int f2 = 1; int f3;
while (i >= 3) {
f3 = f1+f2;
f1 = f2;
f2 = f3;
i--; }
return f2;

2. Fibonacci with loop fib: li $t0, 1 li $v0, 1 li $t1, 3
L1: blt $a0, $t1, fibExit
add $t2, $t0, $v0
move $t0, $v0
move $v0, $t2
addi $a0, $a0, -1
j L1
fibExit:
jr $ra

3. Fibonacci with Recursion
int fib(int i) {
if (i < 3) return 1;
int j = fib(i-1);
int k = fib(i-2);
return j+k; }

4. Fibonacci with recursion
addi $sp, $sp, -16
sw $s0, 12($sp)
sw $s1, 8($sp)
sw $a0, 4($sp)
sw $ra, 0($sp)
li $s0, 0
li $s1, 1
li $t1, 3
L1: blt $a0, $t1, fibExit
addi $a0, $a0, -1
jal fib first recursive call
move $s0, $v0
jal fib second recursive call
move $s1, $v0

5. Fibonacci with recursion
fibExit:
add $v0, $s0,$s1
lw $s0, 12($sp)
lw $s1, 8($sp)
lw $a0, 4($sp)
lw $ra, 0($sp)
addi $sp, $sp, 16
jr $ra

6. Main program .text .align 2 .globl main main: li $v0, 4 la $a0, PR
syscall
li $v0, 5
move $a0, $v0
jal fib
li $v0, 1
la $a0, LF
li $v0,10

7. Main program .data .align 4 PR: .asciiz "Enter a positive integer "
LF: .asciiz "\n"

8. Execute spim gendreaus-computer:fall10 tom$ spim
SPIM Version 6.3a of January 14, 2001
Copyright by James R. Larus
All Rights Reserved.
See the file README for a full copyright notice.
Loaded: ./trap.handler
(spim) read "Fib1.s"
(spim) run
Enter a positive integer 8 21
(spim) read "Fib2.s"
(spim) exit