Hello everyone, I am very happy that you are reading this. It’s okay if you can’t help me, but if possible, please take a little time to assist me.

My assembly program needs to ask the following:

%define BUFFER_READ_WRITE 3000

section .bss
    buffer_str resb BUFFER_READ_WRITE          ; reserve buffer for string input
    buffer_filename resb BUFFER_READ_WRITE     ; reserve buffer for filename input
    function_choice resb 1                     ; contains one digit for function selection

section .data
    str_prompt db 'Enter string: ', 0          ; prompt for entering a string
    str_prompt_len equ $-str_prompt            ; length of the prompt

    filename_prompt db 'Enter filename: ', 0   ; prompt for entering a filename
    filename_prompt_len equ $-filename_prompt  ; length of the filename prompt

    function_menu db '1. Enter and edit file', 10, '2. Exit', 10, 0   ; function menu
    function_menu_len equ $-function_menu      ; length of the function menu

    error_open_msg db 'Failed to open file', 10, 0     ; error message for file open failure
    error_open_len equ $-error_open_msg        ; length of the open file error message

    error_write_msg db 'Failed to write to file', 10, 0   ; error message for file write failure
    error_write_len equ $-error_write_msg      ; length of the write file error message

section .text
    global _start

_start:
    loop:
        ; Print function menu
        mov rsi, function_menu
        mov rdx, function_menu_len
        call print

        ; Get function selection from user
        mov rsi, function_choice
        mov rdx, 1
        call get_input

        ; Compare and branch based on function selection
        cmp byte [function_choice], '1'
        je write_file_function

        cmp byte [function_choice], '2'
        je exit_program
        jmp loop

; Function implementations
exit_program:
    ; Exit program
    mov rax, 60
    xor rdi, rdi
    syscall

print:
    ; Print string
    mov rax, 1
    mov rdi, 1
    syscall
    ret

get_input:
    ; Get string input
    mov rax, 0
    mov rdi, 0
    syscall
    ret

write_file_function:
    ; Get filename from user
    mov rsi, filename_prompt
    mov rdx, filename_prompt_len
    call print
    mov rsi, buffer_filename
    mov rdx, BUFFER_READ_WRITE
    call get_input

    ; Get string to write to file
    mov rsi, str_prompt
    mov rdx, str_prompt_len
    call print
    mov rsi, buffer_str
    mov rdx, BUFFER_READ_WRITE
    call get_input

    ; Write string to file
    mov rsi, buffer_str
    mov rdx, BUFFER_READ_WRITE
    mov rdi, buffer_filename
    call write_file
    jmp loop

write_file:
    ; Open -> write -> close file
    ; Open file with write permission
    mov rax, 2                ; syscall number for sys_open
    mov rsi, 577              ; flags (O_WRONLY | O_CREAT | O_TRUNC)
    mov rdx, 0644             ; mode (rwxr--r--)
    syscall
    test rax, rax
    js error_open
    mov r8, rax               ; file descriptor

    ; Write to file
    mov rax, 1                ; syscall number for sys_write
    mov rdi, r8               ; file descriptor
    syscall
    test rax, rax
    js error_write

    ; Close file
    mov rax, 3                ; syscall number for sys_close
    mov rdi, r8               ; file descriptor
    syscall
    ret

error_open:
    ; Print file open error message
    mov rsi, error_open_msg
    mov rdx, error_open_len
    call print
    jmp exit_program

error_write:
    ; Print file write error message
    mov rsi, error_write_msg
    mov rdx, error_write_len
    call print
    jmp exit_program

The program above prints a menu and asks the user to press 1 to enter a filename and the content to write to it, or press 2 or any other key to exit. But there is an issue with the write_file_function (Image enter image description here) and the output (quick read, no need to see the image):

Note: The autoasm.sh script is just a file for compiling, linking, and running the binary. It does not affect the output.

oen@oen-Latitude-E7440:~/oEn_file/asm/x64-roadmap/do_tasks/file$ autoasm.sh chuong_trinh.asm 
1. Enter and edit file
2. Exit
1
Enter filename: Enter string: 

Description: If, as required, when the user presses 1, the program should print “Enter filename:” and wait for the user to input, and then proceed to “Enter string:”, but somehow it prints both prompts immediately. I don’t know how to handle this. It seems similar to an instruction drift error in Java, but I’m not sure if that’s the case. I hope you can help or provide some suggestions. Thank you for reading.

I have tried:

1. Adding a loop to separate the code segments for entering the filename and the content into the file, but it didn’t
2. I have modified it as follows, but it didn’t work:

write_file_function:
    .loop:
        ; Get filename from user
        mov rsi, filename_prompt
        mov rdx, filename_prompt_len
        call print
        mov rsi, buffer_filename
        mov rdx, BUFFER_READ_WRITE
        call get_input

        mov al, byte [buffer_filename]
        cmp al, 0
        je .loop
        jne .write_to_file

    .write_to_file:
        ; Get string to write to file
        mov rsi, str_prompt
        mov rdx, str_prompt_len
        call print
        mov rsi, buffer_str
        mov rdx, BUFFER_READ_WRITE
        call get_input

    ; Write string to file
    mov rsi, buffer_str
    mov rdx, BUFFER_READ_WRITE
    mov rdi, buffer_filename
    call write_file
    jmp loop```