[org 0x100]
jmp start

file_open: db 'C:\first.txt' ; File to be searched
handle_open: dw 0 ; Handle of file
file_create: db íC:\new.txt' ; File to be created
handle_create: dw 0 ; Handle of file
mov ah, 0x3f ; DOS service for reading an opened file
mov bx, [handle_open] ; get file handle (pointer)
mov cx, 8192 ; number of bytes to read
mov dx, buff ; offset address of buffer
int 0x21

mov ah, 0x3e ; DOS service to close file
mov bx, [handle_open] ; file handle
int 0x21

mov si, buff ; offset of buff
mov cx, ax ; number of bytes in buffer