I have written the code for a movie ticketing system, and I have only implemented it for Action Movie 1 to test its functionality. When I run the code, everything goes well until I enter the quantity. At that point, it displays weird symbols until the payment part. How should I address this? I used emu8086 to run the code.

.MODEL SMALL
.STACK 100h

.DATA
    ; for login
    username db "testing$"   ;set username
    password db "1234$"      ; set password
    welcome_msg db 10,13,"Welcome to City Cineplex Ticketing System!$"
    enterName_msg db 10,13,"Please enter your username: $"
    enterPwd_msg db 10,13,"Please enter your password: $"
    wrong_msg db 10,13,"Invalid username or password. Please try again.$"
    correct_msg db 10,13,"Login successful!$"

    categories_msg db 10,13,"Please choose a category (1-5): $"
    
    category1 db 10,13,"1. Action$"
    category2 db 10,13,"2. Comedy$"
    category3 db 10,13,"3. Drama$"
    category4 db 10,13,"4. Sci-Fi$"
    category5 db 10,13,"5. Horror$"

    movies_msg db 10,13,"Please choose a movie(1-5): $"

    action_movie1 db 10,13,10,13,"1. Avengers: Startgame        - 2hrs 30mins     RM15$"
    action_movie2 db 10,13,"2. Mission possible           - 2hrs 15mins     RM13$"
    action_movie3 db 10,13,"3. Slow & Calm 100            - 2hrs 20mins     RM14$"
    action_movie4 db 10,13,"4. John Wick: Chapter 30      - 2hrs 10mins     RM12$"
    action_movie5 db 10,13,"5. White Panther              - 2hrs 15mins     RM13$"
    
    comedy_movie1 db 10,13,"1. The Sober                  - 1hr  45mins     RM11$"
    comedy_movie2 db 10,13,"2. SuperGood                  - 1hr  55mins     RM12$"
    comedy_movie3 db 10,13,"3. Livepool                   - 2hrs 5mins      RM13$"
    comedy_movie4 db 10,13,"4. 21 Walk Street             - 1hr  50mins     RM11$"
    comedy_movie5 db 10,13,"5. Teddy                      - 1hr  45mins     RM10$"
    
    drama_movie1  db 10,13,"1. The Shawshank Redemption   - 2hrs 22mins     RM14$"
    drama_movie2  db 10,13,"2. Schindler's List           - 3hrs 15mins     RM15$"
    drama_movie3  db 10,13,"3. Forest Gump                - 2hrs 22mins     RM14$"
    drama_movie4  db 10,13,"4. The Godfather              - 2hrs 55mins     RM16$"
    drama_movie5  db 10,13,"5. The Red Mile               - 3hrs 9mins      RM15$"
    
    scifi_movie1  db 10,13,"1. Inception                  - 2hrs 28mins     RM15$"
    scifi_movie2  db 10,13,"2. Blade Runner 2049          - 2hrs 44mins     RM17$"
    scifi_movie3  db 10,13,"3. The Matrix                 - 2hrs 16mins     RM14$"
    scifi_movie4  db 10,13,"4. Interstellar               - 2hrs 49mins     RM16$"
    scifi_movie5  db 10,13,"5. Moon Wars                  - 2hrs 1min       RM13$"
    
    horror_movie1 db 10,13,"1. The Spiritual Healer       - 2hrs 2mins      RM12$"
    horror_movie2 db 10,13,"2. The Gleaming               - 2hrs 26mins     RM14$"
    horror_movie3 db 10,13,"3. Psychopath                 - 1hr  49mins     RM11$"
    horror_movie4 db 10,13,"4. The Summoning              - 1hr  52mins     RM11$"
    horror_movie5 db 10,13,"5. A Daymare on Elm Street    - 1 hr 31mins     RM10$"

    action1_prices db 15
    action2_prices db 13
    action3_prices db 14
    action4_prices db 12
    action5_prices db 13 
    
    comedy1_prices db 11
    comedy2_prices db 12
    comedy3_prices db 13
    comedy4_prices db 11
    comedy5_prices db 10          
    
    drama1_prices db 14
    drama2_prices db 15
    drama3_prices db 14
    drama4_prices db 16
    drama5_prices db 15

    scifi1_prices db 15
    scifi2_prices db 17
    scifi3_prices db 14
    scifi4_prices db 16
    scifi5_prices db 13 
    
    horror1_prices db 12
    horror2_prices db 14
    horror3_prices db 11
    horror4_prices db 11
    horror5_prices db 10
    

    prompt_msg db 10,13,"Enter your choice (1-5): $"
    invalid_msg db 10,13,"Invalid choice. Please try again.$"
    quantity_msg db 10,13,"Enter the quantity: $"
    proceed_msg db 10,13,"Proceed to payment? (Y for Yes/N for No): $"
    payment_success_msg db 10,13,"Payment successful!$"
    payment_fail_msg db 10,13,"Payment failed. Please try again.$"
    menu_msg db 10,13,"Do you want to buy another ticket? (Y/N): $"
    goodbye_msg db 10,13,"Thank you for using City Cineplex Ticketing System. Enjoy your movie!$"
    beforetax_msg db 10,13,"This is your price before tax: $"
    
    TAX_RATE equ 105
    username_buffer db 20, ?      
    password_buffer db 20, ?      
    category_selection db ?
    movie_selection db ?
    quantity db ?
    price_before_tax db ?
    payment_confirmation db ?
    price_after_tax db ?


.CODE
MAIN PROC
    MOV AX, @data
    MOV DS, AX  

    ; Display welcome message
    MOV AH, 09h
    LEA DX, welcome_msg
    INT 21h

login_prompt:
    ; Display message asking for username
    MOV AH, 09h
    LEA DX, enterName_msg
    INT 21h

    ; Read username input
    MOV AH, 0Ah
    MOV DX, OFFSET username_buffer
    INT 21h

    ; Display message asking for password
    MOV AH, 09h
    LEA DX, enterPwd_msg
    INT 21h

    ; Read password input
    MOV AH, 0Ah
    MOV DX, OFFSET password_buffer
    INT 21h

    ; Check if username and password are correct
    MOV SI, OFFSET username
    MOV DI, OFFSET username_buffer + 2
    MOV CX, 7   ; Length of username
    CALL compare_strings  ; Compare strings
    JC login_error ; If not equal, jump to error
    MOV SI, OFFSET password
    MOV DI, OFFSET password_buffer + 2
    MOV CX, 5   ; Length of password
    CALL compare_strings  ; Compare strings
    JC login_error ; If not equal, jump to error

    ; Username and password are correct, proceed to main menu
    MOV AH, 09h
    LEA DX, correct_msg
    INT 21h

    JMP MAIN_MENU

compare_strings:
    ; Compare strings
    @@compare_loop:
        LODSB  ; Load byte from SI into AL, increment SI
        MOV BL, [DI] ; Load byte from DI into BL
        CMP AL, BL ; Compare bytes
        JNE @@not_equal ; If not equal, jump to not_equal
        TEST AL, AL ; Check for end of string
        JZ @@equal ; If end of string, strings are equal
        INC DI ; Increment DI
        LOOP @@compare_loop ; Repeat loop
    @@not_equal:
        RET ; Return with carry flag set
    @@equal:
        CLC ; Clear carry flag
        RET ; Return
login_error:
    ; Display error message
    MOV AH, 09h
    LEA DX, wrong_msg
    INT 21h
    JMP login_prompt ; Loop back to login prompt

MAIN_MENU:
    ; Display categories
   MOV AH, 09h
    LEA DX, category1
    INT 21h
    LEA DX, category2
    INT 21h
    LEA DX, category3
    INT 21h
    LEA DX, category4
    INT 21h
    LEA DX, category5
    INT 21h

    ; Read category selection
    MOV AH, 09h
    LEA DX, categories_msg
    INT 21h
    MOV AH, 01h
    INT 21h
    SUB AL, '0'    ; Convert ASCII to number
    CMP AL, 1
    JB invalid_category_selection      
    CMP AL, 5
    JA invalid_category_selection
    MOV category_selection, AL



    ; Display movies for the selected category
    MOV AH, 09h
    CMP category_selection, 1
    JE display_action_movies
    CMP category_selection, 2
    JE display_comedy_movies
    CMP category_selection, 3
    JE display_drama_movies
    CMP category_selection, 4
    JE display_scifi_movies
    CMP category_selection, 5
    JE display_horror_movies
    JMP invalid_category_selection

display_action_movies:
    MOV AH, 09h
    LEA DX, action_movie1
    INT 21h
    LEA DX, action_movie2
    INT 21h
    LEA DX, action_movie3
    INT 21h
    LEA DX, action_movie4
    INT 21h
    LEA DX, action_movie5
    INT 21h
    JMP SELECT_ACTION

display_comedy_movies:
    MOV AH, 09h
    LEA DX, comedy_movie1
    INT 21h
    LEA DX, comedy_movie2
    INT 21h
    LEA DX, comedy_movie3
    INT 21h
    LEA DX, comedy_movie4
    INT 21h
    LEA DX, comedy_movie5
    INT 21h
    ;JMP SELECT_COMEDY

display_drama_movies:
    MOV AH, 09h
    LEA DX, drama_movie1
    INT 21h
    LEA DX, drama_movie2
    INT 21h
    LEA DX, drama_movie3
    INT 21h
    LEA DX, drama_movie4
    INT 21h
    LEA DX, drama_movie5
    INT 21h
    ;JMP SELECT_DRAMA

display_scifi_movies:
    MOV AH, 09h
    LEA DX, scifi_movie1
    INT 21h
    LEA DX, scifi_movie2
    INT 21h
    LEA DX, scifi_movie3
    INT 21h
    LEA DX, scifi_movie4
    INT 21h
    LEA DX, scifi_movie5
    INT 21h
    ;JMP SELECT_SCIFI

display_horror_movies:
    MOV AH, 09h
    LEA DX, horror_movie1
    INT 21h
    LEA DX, horror_movie2
    INT 21h
    LEA DX, horror_movie3
    INT 21h
    LEA DX, horror_movie4
    INT 21h
    LEA DX, horror_movie5
    INT 21h
    ;JMP SELECT_HORROR

invalid_category_selection:
    ; Display error message
    MOV AH, 09h
    LEA DX, invalid_msg
    INT 21h
    JMP MAIN_MENU ; Loop back to main menu

SELECT_ACTION:
    MOV AH,09h
    LEA DX,movies_msg
    INT 21h  
    
    MOV AH,01h
    INT 21h
    SUB AL, '0'
    CMP AL,1
    JB invalid_action_selection
    CMP AL,5
    JA invalid_action_selection
    MOV movie_selection, AL
    
    MOV AH,09h
    CMP movie_selection, 1
    JE action1
   ; CMP movie_selection, 2
    ;JE action2
   ; CMP movie_selection, 3
    ;JE action3
   ; CMP movie_selection, 4
    ;JE action4
   ; CMP movie_selection, 5
   ; JE action5
   JMP invalid_category_selection 
    
action1:
    ; Display prompt for quantity
    MOV AH, 09h
    LEA DX, quantity_msg
    INT 21h
    
    ; Read quantity input
    MOV AH, 01h
    INT 21h
    SUB AL, '0'    ; Convert ASCII to number
    MOV quantity, AL

    ; Multiply action1_prices with quantity
   
INDEC3 PROC                        ;INDEC3 IS FOR TAKING INPUT FOR MULTIPLY WITH THE GIVEN AMOUNT
    
    PUSH BX                        ;TAKE VALUES INTO STACK 
    PUSH CX
    PUSH DX

    
    
    XOR BX,BX                       ;HOLDS TOTAL
    
    XOR CX,CX                       ;SIGN
                    
    
    MOV AH,1                        ;TAKE CHARACTER IN AL
    INT 21H


    
    REPEAT4: 
                                     
    CMP AL,48                       ;IF AL<0, PRINT ERROR MESSAGE
    JL invalid_action_selection
    
    CMP AL,57                       ;IF AL>9, PRINT ERRIR MESSAGE 
    JG invalid_action_selection

    AND AX,00FH                     ;CONVERT TO DIGIT
    PUSH AX                         ;SAVE ON STACK
    
    MOV AX,10                       ;GET 10
    MUL BX                          ;AX=TOTAL * 10
    POP BX                          ;GET DIGIT BACK
    ADD BX,AX                       ;TOTAL = TOTAL X 10 +DIGIT
    
    
    MOV AH,1
    INT 21H
    
    CMP AL,0DH                      ;CARRIAGE RETURN
    JNE REPEAT4                     ;IF NO CARRIEGE RETURN THEN MOVE ON
    
    MOV AX,BX                       ;STORE IN AX
    
                             ;AND RETURN
    ; Display price before tax
    MOV AH, 09h
    LEA DX, beforetax_msg
    INT 21h
    
    ; Display the calculated price
    MOV AH, 09h
    LEA DX, price_before_tax
    INT 21h


    ; Continue with payment confirmation
    JMP PAYCONFIRMATION


invalid_action_selection:
    ; Display error message
    MOV AH, 09h
    LEA DX, invalid_msg
    INT 21h
    JMP display_action_movies ; Loop back selection of action movies




PAYCONFIRMATION:
    ; Display payment confirmation message
    MOV AH, 09h
    LEA DX, proceed_msg
    INT 21h

    ; Read payment confirmation
    MOV AH, 01h
    INT 21h
    CMP AL, 'Y'
    JNE not_proceed_payment

    ; Calculate price after tax
    MOV Ah, price_before_tax
    MOV Bh, TAX_RATE
    MUL Bh
    MOV Bh, 100
    DIV BH
    MOV price_after_tax, AL

    ; Display price after tax
    MOV AH, 09h   ; Display function
    MOV DL, '$'
    INT 21h
    MOV AH, price_after_tax


    ; Display payment success message
    MOV AH, 09h
    LEA DX, payment_success_msg
    INT 21h

    ; Prompt for another ticket purchase
    MOV AH, 09h
    LEA DX, menu_msg
    INT 21h

    ; Read menu choice
    MOV AH, 01h
    INT 21h
    CMP AL, 'Y'
    JNE exit_program

    ; Loop back to main menu
    JMP MAIN_MENU

not_proceed_payment:
    ; Display goodbye message and exit
    MOV AH, 09h
    LEA DX, goodbye_msg
    INT 21h
    JMP exit_program

exit_program:
    ; Exit program
    MOV AH, 4Ch
    INT 21h
ascii_to_num:
    XOR AL, AL     ; Clear AL to store result
    @@convert_loop:
        MOV AH, 0    ; Clear AH for DIV operation
        LODSB        ; Load character into AL, increment SI
        CMP AL, 0DH  ; Check for Enter key
        JE @@done    ; If Enter, done converting
        SUB AL, '0'  ; Convert ASCII character to numerical value
        CMP AL, 0    ; Check for valid digit (0-9)
        JB @@error   ; If not a valid digit, exit with AL = 0
        CMP AL, 9    ; Check if digit is greater than 9
        JA @@error
        ; Multiply AL by 10 and add the current digit
        MOV BL, 10
        MUL BL
        ADD AL, AH
        JMP @@convert_loop
    @@error:
        XOR AL, AL   ; Set AL = 0 to indicate error
        RET
    @@done:
        RET



END MAIN

The system flow should be the user enter the category, it will list out all the movie in the selected categories. After that, user need to choose the movie and enter the quantity. The system should show the price before tax. Then system should ask the user to proceed to payment or not. If not , jump back to the movie selection. If yes, display the parice after adding the 5% service tax.Then user need to go the payment part.