
0xf4 - fastgetblock	(machdep.c)
0xf5 - fastsendblock	(machdep.c)
0xf6 - ???
0xf7 - client_type query (clientdep.c)
0xf8 - jsr		(comm-lpt.c)
0xf9 - ???
0xfd - print		(comm-lpt.c)
0xfe - error		(comm-lpt.c)
	0 - none
	4 - file not found
	xx - error code
0xff - followed by:	(comm-lpt.c)
	1 - poke
	2 - peek
