Tandy 1000 Programmer's Reference Manual page 234

Appendix C
I MS-DOS Memory Map
The structure and usage of the RS232 driver RAM data area is
as follows:
HEX
Offset From
Segment 004000
Length and
Intended Use
OOH
7CH
4
words
-
Base address
of
each one of
4
possible comm cards
4 words
-
1 word timeout count for
each of
4
possible comm
cards
The structure and usage of the Keyboard driver RAM data area
is as follows:
HEX Offset From Length and
Segment 0040:0010 Intended Use
17 1 byte
-
Keyboard shift state flag
returned by function 02
6
-
CAPS LOCK on/off,
5
-
NUM LOCK ordoff,
4
-
SCROLL LOCK d o f f ,
3
-
ALT key depressed,
2
-
CTRL key depressed,
1
-
Left SHIFT key
0
-
Right SHIFT key
bits 7
-
INSERT state active,
depressed,
depressed
18
1 byte
-
Secondary shift state flag
bits INSERT key depressed,
6
-
CAPS LOCK depressed,
5
-
NUM LOCK depressed,
4
-
SCROLL LOCK NUM
LOCK depressed,
4
-
SCROLL depressed,
4
-
SCROLL LOCK
depressed,
3
-
Pause ordoff, depressed,
3
-
Pause on/off,
2,1,0
-
not used
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