8086 File IO

read form a file which is already opened. Check index for full io

check the procedure below for the same


readfil proc near                        ;requires offset of buffer in si
     mov bx,word ptr [file_handle]       ;number of bytes to read in cx 
     mov dx,si                           ; on error cf is set and returns
     mov ah,3fh                          ; error code in ax
     int 21h
     jc error_readfil_12
     ret
     error_readfil_12:
     mov ax,0
     stc
     ret
endp