title: Instruction references undefined error in MIPS/QTSPIM
body: <p>I am triying to count all characters in an array and i had the following error:</p>
  
  <p>Instruction references undefined symbol at 0x00400014
    [0x00400014] 0x0c000000  jal 0x00000000 [main]           ; 188: jal main</p>
  
  <pre><code>.data
  
   string:    .asciiz "nice work..."
  
  
  
    .text
   .globl main
  
    lw $a0,string
    jal strlength
    li $v0, 10
    syscall
  
     # METHOD STRLENGTH
     # Receives as first parameter the direction of the first character of string.
     # Returns the length of the string.
  
     strlength: li $t0, 0  #numero de caracteres
     lb $t4,string($t0)       #recorremos la cadena
     beqz $t4, fin            #si el caracter es igual a cero vamos a fin    
     addi $t0,$t0, 1      
     j strlength
  
     move $a0,$t0               #imprimimos numero de caracteres 
     li $v0, 1
     syscall 
     jr $ra 
  </code></pre>