why displays the sum of numbers incorrectly-CodePudding

I have numbers like 5000 and 5001, and I need to add them.I added but the result of the output : .what did me do wrong emu8086

s3       DW  5000
s4       DW 5001
s5       DW 0
mov ax, s3
        add ax, s4
        mov bx, 10
        div bx
        add dx, '0'
        mov s5 3, dx
        mov dx, 0
        mov bx, 10
        div bx
        add dx, '0'
        mov s5 2, dx
        mov dx, 0
        mov bx, 10
        div bx
        add ax, '00'
        mov s5, ax
        mov s5 1, dx
        mov s5 4, '$'
        LEA DX, s5
        mov ah, 9
        INT 21h

CodePudding user response：

s3  DW 5000
s4  DW 5001
s5  DB '00000$'   ; Reserve space for 5 digits, $-terminated.

   mov ax, [s3]   ; AX=5000.
   add ax, [s4]   ; AX is now 5000 5001=10001, five decimal digits to display.
   MOV DX, 0      ; Do not relay on undefined register contents.
   mov bx, 10
   div bx         ; AX=1000, DX=1.
   add dx, '0'    ; DX=0x0031
 ; mov [s5 3], dx ; Wrong, the last (fifth) digit of the sum should go from DL to [s5 4].
   MOV [s5 4],DL
   mov dx, 0
 ; mov bx, 10     ; This is redundand, BX=10 unchanged.
   div bx         ; AX=100, DX=0.
   add dx, '0'
 ; mov [s5 2], dx ; Wrong, the fourth digit of the sum should go from DL to [s5 3].
   MOV [s5 3],DL
   mov dx, 0
 ; mov bx, 10     ; This is redundand, BX=10 unchanged.
   div bx         ; AX=10, DX=0.
 ; add ax, '00'
 ; mov [s5], ax   ; Wrong, the third digit of the sum should go from DL to [s5 2].
   ADD DL, '0'
   MOV [s5 2],DL
   MOV DX, 0
   DIV BX          ; AX=1, DX=0.
   ADD DL, '0'
 ; mov [s5 1], dx  ; Wrong, the second digit of the sum should go from DL to [s5 1].
   MOV [s5 1], DL
   ADD AL,'0'      ; The first digit of the sum should go from AL to [s5 0].
   MOV [s5 0], AL
 ; mov [s5 4], '$' ; Wrong, this would overwrite the fifth digit of the sum.
   LEA DX, [s5]
   mov ah, 9       ; Display the sum at s5.
   INT 21h
   MOV AH,4Ch      ; Don't forget return to DOS.
   INT 21h

CodePudding user response：

It's because you read the indicator character which will remove and ignore the next input digit by the user from the input stream.