如何使用汇编语言创建一个带有.txt文件的文件夹？

Question

我正在尝试创建一个文件夹，然后在里面创建一个.txt文件。它会创建文件夹和.txt文件，但它位于文件夹之外。程序也没有正确终止，因为输入输入后Dos框崩溃了。

这是我的代码：

.model small
.stack 100h

.data
        buff db 30                                              ; allow 30 characters on string
        total db 0
        char db 30 dup (0)                                  ; array, 30 duplicates of 0 (0,0...)
        x db "Input a string: $"
        y db 10, 13, "SUCCESS!$"
        z db 10, 13,  "FAILED!$"

        a  db  "File.txt", 0
        b dw  ?
        d db "Hello world!$"

.code

main    proc near
        mov ax, @data          
        mov ds, ax      

        call prompt
        call input
        call cfolder
        call ctext

        int 20h
main    endp

prompt  proc near
        mov dx, offset x                    ; print x
        mov ah, 9                           ; accept string
        int 21h
        ret
prompt  endp

input   proc near
        mov dx, offset buff                 
        mov ah, 0ah                         ; buffered input
        int 21h
        ret
input endp

cfolder proc near
        mov bh, 0                               ; keyboard input
        mov bl, total                           
        add bx, offset char
        mov byte ptr [bx], 0
        mov dx, offset char             ; char = filepath
        mov ah, 39h                         ; make directory
        int 21h  
        jnc succ
        jc fail
        ret
cfolder endp

ctext   proc near

        mov ah,3ch
        mov cx,0
        mov dx, offset a
        int 21h
        jc fail                    

        mov b, ax

        mov ah,40h
        mov bx, b
        mov dx, offset d
        mov cx, 12                 ; no. of characters
        int 21h
        jc fail
        ret
ctext   endp

succ    proc near
        mov dx, offset y                    ; displays SUCCESS!
        mov ah,9
        int 21h   
        ret   
succ    endp

fail    proc near
        mov dx, offset z                    ; displays FAILED!
        mov ah,9
        int 21h  
        ret  
fail    endp

end main

你能帮我找到错误并用正确的错误代替吗？