; very small plain text file writer

; start of code =)
org 256               ; start of all .COMs

; creat blank file
xor cx,cx             ; put zero in cx
mov ah,60             ; move 60 into ah for file creation
mov dx,filename       ; puts offset for file name into dx
int 33                ; int 33 to make file
push ax               ; pushes ax for popping later

; this part takes the input
input:
mov  bx,buffer        ; put offset of buffer into bx
mov  dx,bx            ; put offset in bx into dx aswell
mov  byte [bx],80     ; put max string size +1 into [bx]
mov  ah,0Ah           ; command thingy for get text buffer
int  21h              ; int the thingy in ah

; writes to file
add dx,2              ; add 2 to dx to skip to string
mov cl,[bx+1]         ; put string size into cl
pop bx                ; pop bx to use for file handle
mov ah,64             ; call 64 to write to a file
int 33                ; int to write to file

; check to see if nothing entered on this line
push bx               ; put bx on stack for later
cmp cx,0              ; compare characters in string to zero
jne input             ; if something typed start over from input

; close file
mov ah,62             ; put 62 in ah to close file
int 33                ; int 33 to close it

; quits
int 20h               ; we're all done, so quit!

; buffers and such
filename db 'a', 0    ; file name to use, small to save space
buffer:               ; buffer for text input, open ended    

Maurício, i tried your code additions and it seems to cause the program to quit after entering just one line of text...