在汇编中读取文件，程序可以正常工作，但仍会输出错误信息

Question

我正在尝试读取文本文件并在程序集中打印内容。读取文件并打印出内容。但是，“读取文件”将打印在文件内容之后的下一行。我想知道为什么在代码工作正常的情况下打印错误。

    .model tiny

    .data


  filename db "file.txt", 0
  bufferSize = 512
  filehandle dw ?
  buffer db ' $'
  message1 db 'Cannot open file $'
  message2 db 'Cannot read file $'
  message3 db 'Cannot close file $'


    .code
    org 100h

    start:

 call open
 call read
 call close
 call Exit

open:
  mov ah,3DH
  mov al,0
  mov dx, offset filename
  int 21h
  jc openErr
  mov filehandle, ax
  ret

 read:
mov ah, 3Fh
mov bx, filehandle
mov cx,bufferSize
mov dx, offset buffer
int 21h
cmp ax,0
    jc readErr

    ;changes are here

;displays content of file
    call clear
mov ah, 9
mov dx, offset buffer
    int 21h
    ret

;changes stop here
  close:
 mov ah, 3Eh
 mov bx, filehandle
 int 21h
 jc closeErr
 ret

  Exit: 
 mov ax, 4C00h
 int 21h

openErr:
      call newline
      lea  DX,message1     ;set up pointer to error message
      mov  AH,9          ;display string function
      int  21H           ;DOS call
      stc               ;set error flag
      ret

readErr:
      call newline
      lea  DX,message2     ;set up pointer to error message
      mov  AH,9          ;display string function
      int  21H           ;DOS call
      stc               ;set error flag
      ret

closeErr:
      call newline
      lea  DX,message3     ;set up pointer to error message
      mov  AH,9          ;display string function
      int  21H           ;DOS call
      stc               ;set error flag
      ret


newline:  ;prints a newline                           
            mov ah, 2                    
            mov dl, 0DH
            int 21h            
            mov dl, 0AH                 
            int 21h         
            ret

           clear: ;clears the screen

        mov ax,003h
        int 10h
        ret 



      end start