model tiny
    .code
    org 100h
start:
    mov ax, 1
    mov bx, 5
    cmp bx, 9
    jge @@6
    cmp bx, 0
    jl @@7
    je @@2
    jmp @@1
;
greErr  db, 'A number in BX is too long', 24h
lesErr  db, 'A number in BX is less that zero', 24h
@@1:
    mul bx
    dec bx
    cmp bx, 1
    jge @@1
@@2:
    mov bx, 10
    xor cx, cx
@@3:
    xor dx, dx
    div bx
    push dx
    inc cx
    test ax, ax
    jnz @@3
@@4:
    pop dx
    cmp dl, 9
    jbe @@5
    add dl, 7
@@5:
    add dl, 30h
    mov ah, 2
    int 21h
    loop @@4
    ret
@@6:
    mov ah, 09h
    lea dx, greErr
    int 21h
    ret
@@7:
    mov ah, 09h
    lea dx, lesErr
    int 21h
    ret
end start