title: Decrementing register with 0 in PIC assembly
body: <p>If the W register contains 0 and I try to subtract some value from it, what would the value in the register become? Would it set the zero flag inside <code>STATUS</code> register and how can I use it to check if we are going to go to negative numbers?</p>
  
  <p>For example, in this code</p>
  
  <pre><code>MOVLW b'00000000' ; W has value 0
  SUBLW b'00000001' ; trying to decrement
  </code></pre>
  
  <p>I'm trying to decrement W register, what are the consequences of it?</p>