.section    .data
prime_number_str:
.asciz  "%d "

.section    .text

.global     _start
_start:
pushl   $20
call .first_prime_numbers
addl $4, %esp
pushl $0
call exit


.first_prime_numbers:       #argument first n numbers
movl 4(%esp), %ecx  #get the first argument
do_test:
pushl %ecx      #push function arguments
call .prime
addl $4, %esp       #restore the stack

#if not prime jump to the next number
cmpl $0, %eax
je no_not_prime

#print the number
pushl %eax          #save eax
pushl %ecx          #first argument
pushl $prime_number_str     #text to print
call printf
addl $4, %esp
popl %eax           #restore eax

no_not_prime:
loop do_test
ret


.prime:             #argument: number to check
movl 4(%esp), %eax  #get the first argument

#divide the argument by 2
xorl %edx, %edx
movl $2, %ecx
pushl %eax      #save the value of eax
divl %ecx
movl %eax, %ecx     #init the counter register
popl %eax       #restore the value of eax

movl $1, %ebx       #assume the argument is prime
test_prime:
# if ecx == 1 then return exit the function
cmpl $1, %ecx
jle return_value

pushl %eax      #save the old value of eax

#divide the value by the value of counter
xorl %edx, %edx
divl %ecx

#if the reminder is 0 then the number is not prime
cmpl $0, %edx
popl %eax       #restore the value of eax
je not_prime


subl $1, %ecx       #decrease counter
jmp test_prime      #try next division

not_prime:
movl $0, %ebx
return_value:
movl %ebx, %eax
ret

gdb youprogram