Yo Guys, i want a data added in a text file by ady be create and also some previous data in the text file. The tutorial that i found are just replace the front word/data.

伙计们，我想要一个由阿迪在文本文件中添加的数据，并在文本文件中创建一些以前的数据。我找到的教程只是替换了前面的单词/数据。

i want to add a new data in the text file that the new data is after the previous data. After the program , the new data must at the last line of the text file and the previous data are still there.

我想在文本文件中添加一个新数据，即新数据在以前的数据之后。程序完成后，新数据必须位于文本文件的最后一行，以前的数据仍在那里。

My idea is to use int 21h,42h to hold the buffer when reading the file and int 21h ,40h to write the data in text file. But i still not idea how to do. Is it use those both function ? If yes then how to do it ?

我的想法是在读取文件时使用INT 21h，42h来保存缓冲区，使用INT 21h，40h来将数据写入文本文件。但我还是不知道该怎么做。它使用的是这两种功能吗？如果是，那么怎么做呢？

Example :

示例：

Before (test.txt):

在(est.txt)之前：

Banana$

香蕉$

After Program (if i want add "Banana" in):

节目后(如果我想在中添加“Banana”)：

BananaBanana$

香蕉香蕉$

Thanks and hope u guys have a great day !

谢谢你们，祝你们有愉快的一天！

So, I had a little bit fun today with this assignment. ;) I applied few file services int 21h:

所以，我今天的任务很有趣。；)我在21小时内应用了很少的文件服务：

5bh - Create file for reading or writing

3dh - Open file

42h - Move file pointer to calculate file size

40h - Write to file and screen

3eh - Close file

5BH-创建用于读取或写入的文件3DH-打开文件42H-移动文件指针以计算文件大小40H-写入文件和屏幕3EH-关闭文件

.286
.model small
.stack 0ffh

.data
    file_name           db 'file.txt',0 ; The name of the file

    inputSize           db 11           ; buffered input, ah = 0ah, int 21h, size 10 characters + enter
    inputChars          db 0            ; how many characters user inputed
    inputBuffer         db 11 dup(0)    ; space for characters  

    buffer              db 30 dup(0)    ; read from file and write data here
                                        
    buffer_size         dw 30           ; append up to 30 bytes
    memory_left         dw 30           ; do we have more space for data?
    file_handle         dw 0
    file_size           dw 0                
    array_4_value       db 5 dup('x')       
    
    file_status_msg     db "File status: ",'$'
    before              db "Data inside file: ",13,10,'$'
    file_error          db "<< Something is wrong with the file (ax = 2,3,4 or 5).",13,10,13,10,'$'
    file_exists         db "<< File already exists (ax = 80) >>",13,10,13,10,'$'
    file_success        db "<< File successfuly created >>",13,10,13,10,'$'
    file_open_error     db "<< Error opening the file (ax = 2,3,4,5,12) >>",13,10,13,10,'$'
    hdd_error_msg       db "Not enough memory. Sorry, can't append new data.",13,10,13,10,"Press any key to quit.",'$'
    free_mem            db "Free memory : ",'$' 
    bytes               db " byte(s) left.",13,10,13,10,'$' 
    line_30             db "------------------------------",13,10,'$'       
    data_added          db 13,10,"Data added successfuly. ",13,10,13,10,'$' 
    
    append_msg          db "Add text to file (max 10 characters): ",'$' 
    
    new_line            db 13,10,'$'    
    
.code
main:
    mov ax,@data
    mov ds,ax
    
;;---------------------------------------
;; Create the file for reading/writing

    mov ah,09h                  ; Print message "File status: " 
    lea dx, file_status_msg
    int 21h 

create_file:    
    mov ah, 5bh
    lea dx, file_name           ; file name asciiz  
    mov cx,0                    ; normal attributes                 
    int 21h
    jc create_error         ; error ?

    mov ah,09h                  ; Print message "<< File successfuly created >>"    
    lea dx, file_success
    int 21h 

;;---------------------------------------
;; Open the file for reading/writing
    
open_file:  
    mov ah, 3dh
    lea dx, file_name           ; file name asciiz  
    mov al,2                    ; read/write permission
    int 21h
    jc open_error               ; error ?
    
;;---------------------------------------
;; Save the file handle

handle:
    mov [file_handle], ax
    
;;---------------------------------------
;; Calculate file size

calculate_file_size:    
    mov ah,42h                  ; move file pointer
    mov bx, [file_handle]       ; file handle
    mov al,2                    ; move file pointer starting from end of the file   
    mov cx,0                    ; cx:dx = new pointer location, beginning of the file
    mov dx,0
    int 21h
    
;;---------------------------------------
;; Save file size   

    mov [file_size], ax         ; number of characters in file

;;---------------------------------------
;; Reset file pointer to start of the file

reset_and_read: 
    mov ah,42h                  ; move file pointer
    mov bx, [file_handle]       ; file handle
    mov al,0                    ; file pointer was at the end of the file now should be at the beginning    
    mov cx,0                    ; cx:dx = new pointer location, beginning of the file
    mov dx,0
    int 21h

;;---------------------------------------
;; Print file content

    mov ah,09h                  ; Print message "Data inside file before modification: "    
    lea dx, before
    int 21h
    
    mov ah,09h                  ; Print message "------"    
    lea dx, line_30
    int 21h 
    
read_service_3fh:
    mov ah,3fh                  ; read file or device
    mov cx, [buffer_size]       ; how many bytes to read
    mov bx, [file_handle]       ; file handle
    lea dx,buffer               ; where to read
    int 21h             

print_to_screen_service_40h:
    mov ah,40h                  ; write file or device
    mov cx, [buffer_size]       ; how many bytes to write
    mov bx, 1                   ; write to screen
    lea dx,buffer               ; what to write
    int 21h                     

    mov ah,09h                  ; move to new line
    lea dx, new_line
    int 21h
    
    mov ah,09h                  ; Print message "------"    
    lea dx, line_30
    int 21h 
    
    mov ah,09h                  ; move to new line
    lea dx, new_line
    int 21h     
;;---------------------------------------
;; Print how many more bytes we can add

    mov ah,09h                  ; Print message "Free memory : "    
    lea dx, free_mem
    int 21h

    mov ax,[file_size]
    mov bx,[buffer_size]
    sub bx,ax
    mov [memory_left],bx    
    mov ax,bx
    push ax
;;---------------------------------------------
;; This is probably worst part in the code :D
;; Just calculate how long is value and print digits    

    mov cl, 5           ; max value is 65535 so we need 5 characters                    
    mov ch, 0           
    mov bl, 10          
    mov di,offset array_4_value + 4
    
    bin_2_ascii:
        div bl
        cmp al, 0
        jz b2a_show 
        
        mov [di],ah
        dec di              
                
        mov ah, 0   
        dec cl
        jnz bin_2_ascii

    b2a_show:
        mov [di],ah
        
    mov si, offset array_4_value
    mov cx, 5
    
    b2a_print:      
        mov dl,[si]
        cmp dl,'x'
        jz skip
        mov ah,2
        add dl,30h
        int 21h

        skip:
            inc si
            dec cx
            jnz b2a_print
            
    mov ah,09h                  ; Print message " byte(s)"  
    lea dx, bytes
    int 21h 

    pop ax
    
    cmp ax,0
    jz mem_error

;;---------------------------------------
;; Add new data to file

    mov ah,09h                  ; Print message "Add text to file (max 10 characters): "    
    lea dx, append_msg
    int 21h

    mov ah,0ah                  ; user input
    lea dx, inputSize
    int 21h

disk_space: 
    mov ax,[file_size]
    add al,[inputChars]
    cmp ax,30
    jg mem_error

append_to_file_service_40h:
    mov ah,40h                  ; write file or device
    xor cx,cx
    mov cl, [inputChars]        ; how many bytes to write
    mov bx, [file_handle]       ; write to file
    lea dx,inputBuffer              ; what to write
    int 21h                     

    mov ah,09h                  ; move to new line
    lea dx, new_line
    int 21h 

    mov ah,09h                  ; Print message "Data dded."    
    lea dx, data_added
    int 21h     

    mov di, offset array_4_value
    mov cx, 5
    mov al, 'x'
    
    array_clear:        
        mov [di], al
        inc di
        loop array_clear

    jmp calculate_file_size

jmp_hlt:
hlt
jmp jmp_hlt 

mem_error:
    mov ah,09h                  ; move to new line
    lea dx, hdd_error_msg
    int 21h 
    
    mov ah,8
    int 21h
    jmp closeApp
    
        mov ah,40h                  ; reading file or device
        mov bx,1
        mov al,0                    ; move file pointer starting from begining of the file
        mov cx,[file_size]                  ; cx:dx, where to move pointer
        mov dx,0                    ; file_size, number of characters in file
        int 21h                     
    
    
create_error: 
    cmp ax,80
    jz file_already_exists

    mov ah,09h                      ; Print message "<< Something is wrong with the file (ax = 2,3,4 or 5)>>"   
    lea dx, file_error
    int 21h     
    jmp file_msg_done
    
    file_already_exists:
        mov ah,09h                  ; Print message "<< File already exists (ax = 80) >>"   
        lea dx, file_exists
        int 21h     
        
    file_msg_done:
  
    jmp open_file 

open_error: 
    mov ah,09h                  ; Print message "<< Error opening the file (ax = 2,3,4,5,12) >>"    
    lea dx, file_open_error
    int 21h     

closeApp:  
    mov ah, 3eh
    mov bx,[file_handle]
    int 21h

    mov ax, 4C00h                   ; exit
    int 21h

end main