Prologue and Epilogue

Prologue — set up the frame:

push rbp          ; save caller's frame pointer
mov  rbp, rsp     ; establish new frame base
sub  rsp, 0x20    ; reserve 32 bytes for locals

Epilogue — tear it down:

leave             ; == mov rsp, rbp ; pop rbp
ret               ; pop return address into RIP

• leave collapses the frame in one instruction.
• After leave, RSP points at the return address, ready for ret.