Question

Convert the following C function to the corresponding MIPS assembly procedure:
int count(int a[], int n, int x)
{
int res = 0;
int i = 0;
int j = 0;
int loc[];
for(i = 0; i != n; i++)
if(a[i] == x) {
res = res + 1;
loc [j] = i;
j = j+1}
return res, loc;
}

Answer 1

Important Note:

I added code for printing the locations of x also the below code is for that if you don't want this code and only the converted c function, please follow the second program I submitted in this answer.

Program:

.data
n: .word 7 #n
a: .word 10, 20, 30, 4, 20, 10, 11   #array a[]
loc: .word 0:7 #array loc[]
x: .word 20
pos: .asciiz "\nPosition of x is at : "
.text
.globl main
main:
   la $s1, a # $s1 = &a
   lw $s2, n #s2 = n
   la $s3,loc #$s3 = &loc
   lw $s4,x #s4 = x
   li $t0,0 #res=0
   li $t1,0 #i=0
   li $t2,0 #j=0
   la $s6,loc
  
loop:   beq $t1,$s2,loop2
   lw $t3,0($s1) #get a[i]
   bne $t3,$s4,inc
   addi $t0,$t0,1 #increment res value
   sw $t1,0($s3) #loc[j] = i
   addi $s3,$s3,4 #increment array address value
   addi $t2,$t2,1 #increment j to find size of loc[] elements are stored
   j inc
  
inc:   addi $t1,$t1,1   #increments i
   addi $s1,$s1,4 #increments array valuesin a[]
   j loop
  
  
loop2:   beq $t4,$t2,end  
   lw $t6,0($s6)
   li $v0,4
   la $a0,pos
   syscall
   li $v0,1
   move $a0,$t6
   syscall
   addi $t4,$t4,1
   addi $s6,$s6,4
   j loop2
  
end:   li $v0,10
   syscall  
  
  
  
Output:

Exact conversion of given c-program

Program:

.data
n: .word 7 #n
a: .word 10, 20, 30, 4, 20, 10, 11   #array a[]
loc: .word 0:7 #array loc[]
x: .word 20
.text
.globl main
main:
   la $s1, a # $s1 = &a
   lw $s2, n #s2 = n
   la $s3,loc #$s3 = &loc
   lw $s4,x #s4 = x
   li $t0,0 #res=0
   li $t1,0 #i=0
   li $t2,0 #j=0
  
loop:   beq $t1,$s2,end
   lw $t3,0($s1) #get a[i]
   bne $t3,$s4,inc
   addi $t0,$t0,1 #increment res value
   sw $t1,0($s3) #loc[j] = i
   addi $s3,$s3,4 #increment array address value
   addi $t2,$t2,1 #increment j to find size of loc[] elements are stored
   j inc
  
inc:   addi $t1,$t1,1   #increments i
   addi $s1,$s1,4 #increments array valuesin a[]
   j loop

end:   li $v0,10
   syscall  
  

Output: