INT 29 - DOS Fast Character I/O (Undocumented 2.x+)
AL = character to write returns nothing ??? - used by DOS device drivers to output data to the screen if bit 4 of the device attribute word is set - similar to INT 21,2 and INT 21,9 but much faster - simply calls the BIOS INT 10,E in DOS versions 2.x and 3.x - advances the cursor after character output