Tandy 1000 SL Technical Reference Manual page 538

BIOS Services
Write TTY
Write a character in teletype fashion. (Control characters are inter-
preted in the normal manner.)
Entry Conditions
A H
=
OEH
AL
=
character to write
BL
BH
=
dispZaypage (alpha modes)
=
foreground color (graphics mode)
Get
CRT Mode
Get the current video mode.
Entry Conditions
AH
=
OFH
Exit Conditions
AL
=
current video mode. See the previous "Set CTR Mode"
(AH
=
0) for values
AH
BH
=
number of columns on screen
=
current active display page
17.