t selector
              THEN #GP(selector); FI;
    IF stack segment not present
         THEN #SS(StackSegmentSelector); FI;
    IF the return instruction pointer is not within the return code segment limit
         THEN #GP(0); FI;
    CPL ← ReturnCodeSegmentSelector(RPL);
    IF OperandSize = 32
         THEN
              EIP ← Pop();
              CS ← Pop(); (* 32-bit pop, high-order 16 bits discarded; segment descriptor loaded *)
              CS(RPL) ← CPL;
              IF instruction has 