add the digits of a number in assambler

At school they gave me an exercise that goes like this: Write a program in assembly language to define three standard arrays Block 1 Block 2 Block 3 and where each array has 8 bytes of size data when block 3 will end with the results. The first digit must be taken from block 1 and decomposed into hundreds, tens and unit, part must also be taken from block 2 and decomposed into one hundred, ten and one unit of the sum whose digits are the largest will be placed in block 3 I wrote a code that does not work for me and I can not find a solution to the program:

    GODEL EQU 8
DSEG SEGMENT
    BLOCK1  DB 10H,20H,30H,40H,50H,60H,70H,80H
    BLOCK2  DB 20H,30H,40H,50H,60H,70H,80H,90H
    BLOCK3  DB  GODEL DUP(?)
    TOTAL1 DB ?
    TOTAL2 DB ?
     DSEG  ENDS 
    SSEG   SEGMENT STACK                
           DB 100H DUP(?)   
    SSEG   ENDS 
    CSEG   SEGMENT            
           ASSUME CS:CSEG,DS:DSEG,SS:SSEG 
    BEGIN:           MOV AX,DSEG                        
                     MOV DS,AX                        
                     MOV CX,GODEL
                     MOV BL,10
                     MOV SI,0H
                     MOV TOTAL1,0H
                     MOV TOTAL2,0H
    INCBLOCK1:  MOV  AL,BLOCK1[SI]
                MOV  TOTAL1,0H
                MOV  TOTAL2,0H
    SUMBLOCK1BLOCK1:        
                MOV AH,0H
                DIV BL
                ADD TOTAL1,AH
                SUB AL,0H
                JNZ SUMBLOCK1
            MOV  AL,BLOCK2[SI]
    SUMBLOCK2:  
                MOV AH,0H
                DIV BL
                ADD TOTAL2,AH
                SUB AL,0H
                JNZ SUMBLOCK2
                JB TOTAL1,TOTAL2
                JMP TOTBLOCK3
                MOV BLOCK3[SI],TOTAL2
                JMP SOF
    TOTBLOCK3:  MOV BLOCK3[SI],TOTAL1
    SOF:        INC SI
                LOOP INCBLOCK1


    CSEG  ENDS                
    END  BEGIN