Заменить символы «с» на «е» - Assembler

data segment
    msg db 255, 0, 255 dup ('$'), '$'
    file_name db 'C:\output.txt',0
    error_msg db 'Error! Could not handle file $'
    msg_size db 0
    handler dw 0
data ends
 
code segment
assume cs:code, ds:data
read_from_keyboard proc
    mov ah, 0ah
    lea dx, msg
    int 21h 
    ret
read_from_keyboard endp
 
replace_5 proc
    mov si, offset msg + 2 ; move to register si offset of msg's 
    ; data (we do not need first 2 bytes)
    mov al, [si] ; move current (first) symbol from pointer si 
    ;to register al
 
met:
    cmp al, 'c' ; compare current symbol with 'c'
    jne skip ; if current symbol is not equal to 'c' then 
    ; go to skip label
    mov al, 'e'
    mov [si], al ; change current symbol to 'e'
skip:    
    inc si ; go to the next symbol
    mov al, [si] ; move current symbol from pointer si 
    ;to register al
    cmp al, '$' ; compare current symbol with '$'
    jne met ;if current symbol is not equal to '$' then 
    ;go to met label
    ret
replace_5 endp
 
print_error proc
    ;write error
    mov ah, 09h
    lea dx, error_msg
    int 21h
    ret
print_error endp
 
handle_file proc  
    ;create file
    mov ah, 3ch
    xor cx, cx     ; cx = 0
    lea dx, file_name
    int 21h
    jc error_file ;check if error occured
 
    mov handler, ax
 
    ;write to file
    mov ah, 40h
    mov bx, handler
    xor cx, cx         ; cx = 0
    mov cl, [msg_size] ; number of bytes to write
    lea dx, msg + 2
    int 21h
  
    jc error_file ;check if error occured
    
    cmp ax, cx
    jne error_file ;check if string is completely written to file
    
    ;close file
    mov ah, 3Eh
    mov bx, handler
    int 21h
 
    jc error_file ;check if error occured
    ret 
 
error_file:    
    call print_error
    ret
handle_file endp
 
start:
    mov ax, ax
    mov bx, data
    mov ds, bx
    
    ;read string from keybord
    call read_from_keyboard
    ;get msg size
    lea si, msg + 1
    mov al, [si]
    mov msg_size, al
 
    ; first 2 bytes of msg is max length and length, 
    ; we do not need this data anymore
    ; change second byte to new line symbol and
    ; don't use first byte
    mov msg + 1, 0ah; change second byte to new line symbol 
    
    call replace_5
    
    ;write result to file
    call handle_file
    
    mov ah, 4ch
    int 21h
code ends
end start