INT 0x21 - 0x06 - Direct console output

Request/Call:

reg	value	descr
AH	0x06
DL		Character to output (except FFh)

reg	descr
AL	character output (despite the official docs which state nothing is returned) (at least DOS 3.3-5.0)

does NOT check ^C/^Break
writes to standard output, which is always the screen under DOS 1.x, but may be redirected under DOS 2+