call/ret

Notes

• This is Jorgensen chapter 12.6
• call
  • call function
  • Remember, function is just a label.
  • Possibly:

    push rsi
    jmp function
    

  • rip, the instruction pointer or program counter
    • It will be pointing to the next instruction at this phase of the FDE cycle
    • Which is were we want to return
  • This is just a little more subtle than you think
    • It allows arbitrary returns
    • But since we are putting the value of rip on the stack, we can also do recursion.
• ret
  • possibly
    • pop rip
• Note it is very important that we don't mess with the return address.