NASM 2.05 based x86 Instruction Reference[ch157]
A.5.136 LEAVE: Destroy Stack Frame LEAVE ; C9 [186] LEAVE destroys a stack frame of the form created by the ENTER instruction (see section A.5.65). It is functionally equivalent to MOV ESP,EBP followed by POP EBP (or MOV SP,BP followed by POP BP in 16- bit mode).