LEAVE -- High Level Procedure Exit

LEAVE -- High Level Procedure Exit Opcode Instruction Clocks Description C9 LEAVE 4 Set SP to BP, then pop BP C9 LEAVE 4 Set ESP to EBP, then pop EBP Operation IF StackAddrSize = 16 THEN SP = BP; ELSE (* StackAddrSize = 32 *) ESP = EBP; FI; IF OperandSize = 16 THEN BP = Pop(); ELSE (* OperandSize = 32 *) EBP = Pop(); FI; Description LEAVE reverses the actions of the ENTER instruction. By copying the frame pointer to the stack pointer, LEAVE releases the stack space used by a procedure for its local variables. The old frame pointer is popped into BP or EBP, restoring the caller's frame. A subsequent RET instruction removes any arguments pushed onto the stack of the exiting procedure. Flags Affected None Protected Mode Exceptions #SS(0) if BP does not point to a location within the limits of the current stack segment Real Address Mode Exceptions Interrupt 13 if any part of the operand would lie outside of the effective address space from 0 to 0FFFFH Virtual 8086 Mode Exceptions Same exceptions as in Real Address Mode