con_ftab: dw con_read
dw con_write
con_read: stc
ret
con_write: push si
push bx
push cx
test cx, cx
jz .end
mov si, dx
mov ah, 0x0E
xor bx, bx
.loop: lodsb
int 0x10
loop .loop
pop cx
.end: pop bx
pop si