Here;'s a simple procedure to compare two string in 8086 assembly language. some one can use these procedures and macros in my library to make a good tutorial 

strcmp proc near                    ;requires the offset of first and second 
    push bx cx dx si di
    loop_strcmp_loop1:              ;string in si and di 
        mov al,byte ptr cs:[si]     ;if s1s2 then al=2
        inc si
        cmp al,bl
        jg loop_strcmp_great
        cmp al,bl
        jl loop_strcmp_less
        cmp al,'$'
        je loop_strcmp_quit
        cmp bl,'$'
        je loop_strcmp_quit
        jmp loop_strcmp_loop1
        loop_strcmp_quit:
        mov al,1
        pop di si dx cx bx
        ret
    loop_strcmp_great:
        mov al,2
        pop di si dx cx bx
        ret
    loop_strcmp_less:
        mov al,0
        pop di si dx cx bx
        ret
endp