Assemble Sum of digits of a number

.MODEL SMALL
.STACK 100H
.DATA
    ARRAY DB '35'

.CODE
MAIN PROC
    INCLUDE 'EMU8086.INC'

    MOV AX, @DATA
    MOV DS, AX

    MOV SI, 1
    MOV CX, 2

    FOR:
        ADD DX, [SI]

        DEC SI

    LOOP FOR

    SUB DX, 48
    MOV AH,2
    INT 21H

    MOV AH, 4CH
    INT 21H


END MAIN