Question

how do program fibbonocci sequence in MIPS:
.data
msg: .asciiz "enter a number"

.text
main:
top:
la $a0,msg
li $v0 , 4 #printing the prompt
syscall
li $v0, 5 #read integer. from user
syscall

add $a0,$v0,$zero
jal fib

add $a0,$v0,$zero
li $v0,1
syscall

li $v0, 10
syscall

fib:
#a0=y
#if (y==0) return 0;
#if (y==1) return 1;
# else: return fib(y-1)+fib(y-2)