org 100h
.model small
.stack 100h
.data
str db 80 dup
.code
mov ax,@data
mov ds,ax
main proc
    mov si,0
    mov di,0
    mov ah,1
    int 21h
    mov str[si],al
    input:
        mov ah,1
        int 21h
        inc si
        cmp al,0dh
        je newline
        mov di,0
        jmp compare


    compare:
        cmp str[di],al
        jg swap
        cmp di,si
        je new


     swap:
        mov bl,str[di]
        mov str[di],al
        mov al,bl
        inc di
        jmp compare

     new:
        mov str[si],al
        jmp input

     newline:
        mov di,0
        mov ah,2
        mov dl,0dh
        int 21h
        mov dl,0ah
        int 21h
    output:
        mov dl,str[di]
        int 21h
        inc di
        cmp di,si
        je end
        jmp output

    end:
        mov ah,4ch
        int 21h
main endp
end main