;int f ( int x )
;{
        segment .text
f:
        push    rfp
        mov     rfp, rsp  ; create stack frame
        reserve L, P      ; generates sub rsp, M
                          ; L: number of desired local variables
                          ; P: maximum number of parameters in called functions

    ;return 0;
        xor     retd, retd  ; return value in retq (rax)
        leave               ; undo initial push-mov-sub
        ret 
;}
