title: What does the R in RSP stand for?
body: <p>Registers are called accordingly to their bit architecture:
      16 bit: SP = Stack Pointer
      32 bit: ESP = Extended Stack Pointer
      64 bit: RSP = R? Stack Pointer</p>
  
  <p>Does anybody know what the R stands for? I found an answer on stackoverflow suggesting that R stands for register, but there is no proof for that, it's just an guess by the user.</p>