So I have a task to write the algorithm for eratosthenes' sieve. The code works fine apart from the fact that it just won't print the newline when i need it. It just ignores the syscall for printing. I tried googling but couldn't find anything similar to my problem.

The problematic syscall is in lines 119-121

Here is my code:

.data				#Data Segment
isprime:
	.space  400			#Array size 100*sizeof(int)
 
nl:
	.asciiz "\n" 		#New line
	
	.text				#Text Segment
	.globl main
main:
	subu $sp, $sp, 32	#Stack frame is 32 bytes long   
	sw $ra, 20($sp) 	#Save return address to the stack
	sw $fp, 16($sp) 	#Save the old frame pointer to the stack 
	addiu $fp, $sp, 28 	#Set up frame pointer
	la $a0, isprime 	#Load pointer to isprime and prepare argument of initialize function 
	sw $a0, 12($sp) 	#Save pointer to isprime to the stack
	
	jal initialize		#Call initialize function 

	lw $a0, 12($sp)		#Prepare argument of find_primes function 
	jal find_primes		#Call find_primes function
	
	lw $a0, 12($sp)		#Prepare argument of print function
	jal print			#Call print function
	
	#Return code
	lw $ra, 20($sp)		#Restore return address		
	lw $fp, 16($sp)		#Restore old frame pointer 
	addiu $sp, $sp, 32	#Pop stack
	jr $ra				#Return to caller

initialize:				#Function initialize 
	subu $sp, $sp, 32	#Stack frame is 32 bytes long
	sw $ra, 20($sp)		#Save return address
	sw $fp, 16($sp)		#Save old frame pointer
	addiu $fp, $sp, 28	#Set up new frame pointer
	
	li $t0, 2			#Initialize i=2
	li $t1, 100			#Initialize N
	li $s1, 1			#Store value 1 to a register 

	sw $zero, 0($a0)	#isprime[0] = 0
	addi $a0, 4			
	sw $zero, 0($a0)	#isprime[1] = 0
	addi $a0, 4
	
init_loop:				#loop for(i=2; i<=N; i++)
	sw $s1, 0($a0)		#isprime[i] = 1
	addi $a0, 4
	addi $t0, 1
	bne $t0, $t1, init_loop 
	
	#Return code
	lw $ra, 20($sp)		#Restore return address	
	lw $fp, 16($sp)		#Restore old frame pointer 
	addiu $sp, $sp, 32	#Pop stack
	jr $ra				#Return to caller

	la $a0, nl
	li $v0, 4			#Prepare for system call print_string
	la $a0, nl
	syscall
	
find_primes:			#Function find_primes 
	subu $sp, $sp, 32	#Stack frame is 32 bytes long
	sw $ra, 20($sp)		#Save return address
	sw $fp, 16($sp)		#Save old frame pointer
	addiu $fp, $fp, 28	#Set up new frame pointer
	
	la $a1, isprime 	#Save pointer to isprime to a register other than $a0
	
	li $t0, 2			#Initialize i=2 
	li $s1, 1			#Store value 1 to a register 
	li $t1, 100			#Initialize N
	
	addi $a1, 8			#Start from isprime[2]
	
outer_loop:				#loop for(i=2; i<N; i++) 
	lw  $t5, 0($a1)
	bne $t5, $s1, cont	#if(isprime[i])
	add $t2, $t0, $t0	#Initialize j
	
inner_loop:				#loop for(j=i+i; j<=N; j+=i)
	mul $t3, $t0, 4		#align address of the next element of isprime
	add $a1, $a1, $t3
	sw $zero, 0($a1)	#isprime[j] = 0
	add $t2, $t2 ,$t0
	ble	$t2, $t1, inner_loop
	
cont:
	addi $t0, 1
	mul $t4, $t0, 4
	add $a1, $a0, $t4
	bne $t0, $t1, outer_loop
	
	#Return code
	lw $ra, 20($sp)		#Restore return address	
	lw $fp, 16($sp)		#Restore old frame pointer 
	addiu $sp, $sp, 32	#Pop stack
	jr $ra				#Return to caller
	
print:					#Function print
	subu $sp, $sp, 32	#Stack frame is 32 bytes long
	sw $ra, 20($sp)		#Save return address
	sw $fp, 16($sp)		#Save old frame pointer
	addiu $fp, $fp, 28	#Set up new frame pointer	
	la $a1, isprime		#Save pointer to isprime to a register other than $a0
	li $t0, 0			#Initialize i=0	
	li $t1, 100			#Initialize N
	li $s1, 1			#Store value 1 to a register
	
print_primes_loop:		#loop  for(i=0; i<=N; i++)
	lw  $t5, 0($a1)	
	bne $t5, $s1, cont_print	#if(isprime[i])
	move $a0, $t0
	li $v0, 1			#Prepare for system call print_int 
	syscall
	
	li $v0, 4			#Prepare for system call print_string
	la $a0, nl
	syscall
	
cont_print:
	addi $a1, 4
	addi $t0, 1
	ble	$t0, $t1, print_primes_loop
 
	
	#Return code
	lw $ra, 20($sp)		#Restore return address	
	lw $fp, 16($sp)		#Restore old frame pointer 
	addiu $sp, $sp, 32	#Pop stack
	jr $ra				#Return to caller

There is also something that weirds me out. I tried randomly pasting the same syscall in other parts of the program and it only worked when i placed it in line 40. I have no idea what it could be.

If you want me to clarify someting just ask, thanks in advance!

Well I found what was wrong with my code.

Find_primes function is executed more times than it should and it overwrites nl.

You can fix that by correcting the number of repeats in find_primes, or just change space for isprime to 404 (or 408 sometimes).

This question has already been answered. Start a new discussion instead.