title: Negative numbers are stored as 2's complement in memory, how does the CPU know if it's negative or positive?
body: <p>-1 can be represented in 4 bit binary as (2's complement) 1111 </p>
  
  <p>15 is also represented as 1111.</p>
  
  <p>So, how does CPU differentiate between 15 and -1 when it gets values from memory?  </p>