Tandy 1000 SL Technical Reference Manual page 527

Software
Extended Shift Status Read
Entry Conditions
AH
=
12H
Exit Conditions
AL
=
shift status (bit settings: set
=
true, reset
=
false)
Bit 7
=
INSERT active
Bit 6
Bit 5
Bit
4
Bit 3
=
ALT pressed
Bit
2
=
CTRL pressed
Bit 1
Bit 0
=
CAPS LOCK active
=
NUM LOCK active
=
SCROLL LOCK active
=
LEFT SHIFT pressed
=
RIGHT SHIFT pressed
reset
=
false)
=
SYS REQ pressed
=
CAPS LOCK active
=
NUM LOCK active
=
SCROLL LOCK active
=
RIGHT ALT active
=
RIGHT CTRL active
=
LEFT ALT active
=
LEFT CTRL active
AH
=
extended shift status (bit settings: set
=
true,
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
6.