The sum of a sequence of numbers in assembler. Where is the mistake?

Question

assembler

I wrote a program that was supposed to find the sum of a sequence of numbers, but it does not work correctly.
Can you tell me where is the mistake?

section .text
main:
  xor eax, eax
  xor ecx, ecx
  push 20
  call ssn
ssn:
  pop ecx
  L1:
    add eax, ecx
    loop L1
  ret

Answer 1

But the eax register contains some address

call ssn -> ложит адрес следующего оператора, куда возвращаться после выхода
ssn:
  pop ecx -> тут ты этот адрес и извлекаешь