Tandy 1000 SL Technical Reference Manual page 548

BIOS Services
Function Descriptions
Get Time of Day
Get (read) the time of day in binary format.
Entry Conditions
AH
=
0
Exit Conditions
CX
DX
AL
=
high (most significant)portion of the clock count
=
low (least significant) portion of the clock count
=
0 of the clock was read or written (via AH
=
0,l) within the
current 24-hour period; otherwise, AL
=
0
Set Time of Day
Set (write) the time of day using binary format.
Entry Conditions
AH
=
1
CX
DX
=
high (most significant)portion of clock count
=
low (least significant) portion of clock count
27.