 Assuming a call gate has been set up already by the operating system kernel, code simply does a CALL FAR with the necessary segment selector (the offset field is ignored).The processor will perform a number of checks to make sure the entry is valid and the code was operating at sufficient privilege to use the gate.Assuming all checks pass, a new CS/EIP is loaded from the segment descriptor, and continuation information is pushed onto the stack of the new privilege level (old SS, old ESP, old CS, old EIP, in that order).