LOC
OBJECT
0018
??
0080
0040
0020
0010
0008
0019
77
001
A
7777
001C
????
00
IE
(16
7777
)'"
LINE
SOURCE
(BIOS
FOR
THE
I
BM
PERSONAL
COMPUTER
XT)
11/08/82
106
KB_FLAG
-
1
DB
SECOND
BYTE
OF KEYBOARD
STATUS
107
108
INS
SHIFT
EQU
80H
I
NSERT
KEY I S
DEPRESSED
109
CAPS
SHIFT
EQU
40H
CAPS LOCK KEY I S DEPRE SSED
110
NUM
SHIFT
EQU
20H
NUM
LOCK KEY
I S
DEPRESSED
111
SCROLL
SH
I
FT
EQU
10H
SCROLL
LOCK
KEY
I S
DEPRESSED
112
HOLD_STATE
EQU
08H
SUSPEND KEY HAS
BEEN
TOGGLED
113
114
ALT
INPUT
DB
7
STORAGE FOR
ALTERNATE
KEYPAD
ENTRY
115
BUFFER
HEAD
D¥f
7
PO I
NTER
TO HEAD OF KEYBOARD
BUFFER
116
BUFFER-TA
I L
OW
7
PO I
NTER
TO
TA
I L OF KEYBOARD
BUFFER
117
KB_BUFFER
OW
i6
DUP(?)
ROOM
FOR
15
ENTRIES
KB_BUFFER_END
LABEL
WORD
;------
HEAD =
TAIL
INDICATES
THAT
THE
BUFFER
IS
EMPTY
.
----------------------------------------
SEEK_STATUS
DB
DR
I VE
RECALl
BRAT
ION
STATUS
BIT
3-0
=
DRIVE
3-0
NEEDS
RECAL
BEFORE
NEXT
SEEK
IF
BIT
IS
= 0
DISKETTE
DATA
AREA S
DB
STATUS
BYTES
FROM NEC
T I
ME
OUT COUNTER FOR
DR
I VE TURN OFF
2 SECS
OF
COUNTS FOR MOTOR TURN OFF
RETURN CODE
STATUS
BYTE
ATT
ACHMENT
FA
I
LED
TO RESPOND
SEEK OPERAT I
ON
FA
I
LED
NEC CONTROLLER HA S F A I
LED
BAD
CRC
ON
0 I
SKETTE
READ
ATTEMPT
TO
DMA
ACROSS
64K
BOUNDARY
DMA
OVERRUN
ON
OPERAT I
ON
REQUESTED SECTOR NOT FOUND
WR
I
TE
ATTEMPTED
ON
WR
I
TE
PROT 0 I
SK
ADDRESS MARK NOT FOUND
BAD
COMMAND
PASSED
TO 0 I
SKETTE
I/O
I
NTERRUPT
OCCURRENCE
FLAG
MOTOR
STATUS
BIT
3-0
=
DRIVE
3-0
IS
CURRENTLY
RUNNING
BIT
7 = CURRENT
OPERATION
I S A
WR
I
TE.
REQU I RES
DELA
Y
SCAN CODE FOR NUMBER LOCK
SCROLL
LOCK KEY
AL
TERNATE
SH
I
FT
KEY
SCAN CODE
SCAN CODE FOR CONTROL KEY
SCAN CODE FOR
SH
I
FT
LOCK
SCAN CODE FOR
LEFT
SH
I
FT
SCAN CODE FOR
RIGHT
SH
I
FT
SCAN CODE FOR I
NSERT
KEY
SCAN CODE FOR
DELETE
KEY
7
37
7
80H
40H
20H
10H
09H
08H
04H
03H
02H
01H
7
DUP(?)
080H
7
69
70
56
29
58
42
54
82
83
DB
EQU
EQU
DB
EQU
EQU
EQU
EQU
EQU
EQU
EQU
EQU
EQU
MOTOR COUNT
MOTOR=WA I T
DISKETTE
STATUS
DB
T I
ME
OUT-
EQU
BAD
SEEK
EQU
BAD-NEC
EQU
BAD-CRC
EQU
DMA
-BOUNDARY
EQU
BAD-DMA
EQU
RECORD NOT
FND
EQU
WR
I
TE
PROTECT
EQU
BAD ADDR MARK EQU
BAD=CMD
- EQU
INT
FLAG
MOTOR_STATUS
NUM
KEY
SCROLL
KEY
AL
T
KEY
CTL
-KEY
CAPS
KEY
LEFT-KEY
RIGHT
KEY
INS
KEY
DEL=KEY
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
0045
0046
0038
0010
003A
002A
0036
0052
0053
0041
77
0080
'
0040
0020
0010
0009
0008
0004
0003
0002
0001
0042
(7
77
j'
0040
??
0025
0080
003F
??
003E
??
003E
162
163
•
----------------------------------------
164
V
IDEO
0 I
SPLA
Y OATA AREA
165
•
----------------------------------------
166
CRT
MODE
DB 7 CURRENT CRT
MODE
167
CRT-COLS
OW
7 NUMBER OF COLUMNS
ON
SC~EEN
168
CRT-LEN
OW
7
LENGTH
OF REGEN I N
BYTES
169
CRT-START
OW
7
STARTING
ADDRESS
IN
REGEN
BUFFER
170
CURSOR_POSN
OW
8 DUP
(?)
CURSOR FOR EACH OF UP TO 8 PAGES
SYSTEM
DATA
AREA
FIXED
DISK
DATA
AREAS
CURRENT CURSOR MODE
SETT
I
NG
CURRENT PAGE
BE
I
NG
0 I
SPLA
YEO
BASE
ADDRESS FOR ACT I VE 0 I
SPLAY
CARD
CURRENT
SETT
I
NG
OF
THE
3X8
REG I STER
CURRENT
PALETTE
SETT
I
NG
COLOR CARD
LOW
WORD
OF T I
MER
COUNT
•
HIGH
WORD
OF
T I
MER
COUNT
; T I
MER
HAS
ROLLED
OVER
SINCE
LAST
READ
4
DUP(?)
OW
DB
OW
DB
DB
PR I
NTER
AND
RS232
T I
ME-OUT
VAR I
ABLES
OW
OW
TIMER
DATA
AREA
·
----------------------------------------
TIMER
LOW
OW
7
TIMER-HIGH
OW
7
T I
MER-OFL
DB 7
; COUNTS SEC EQU
18
;
COUNTS-M
I N EQU
1092
;
COUNTS-HOUR
EQU
65543
;
COUNTS=DAY
EQU
1573040
=
1800BOH
·
------------------------------------------------------
PR I
NT
_ T I
M_
OUT DB 4 DUP ( ? )
·
----------------------------------------
BIOS
BREAK DB ;
BIT
7=1
IF
BREAK KEY HAS
BEEN
HIT
RESET_FLAG
OW
;
WORD=
1234H
I F KEYBOARD
RESET
UNDERWAY
·
----------------------------------------
io
ROM
INIT
OW
; PNTR TO
OPTIONAL
I/O
ROM
INIT
ROUTINE
10-ROM-SEG
OW
; PO I
NTER
TO
10
ROM
SEGMENT
INTR_FLAG
DB ;
FLAG
TO
INDICATE
AN
INTERRUPT
HAPPEND
POST
DATA
AREA
CURSOR
MODE
ACT I
VE-PAGE
ADDR
6845
CRT MODE
SET
CRT=PALETTE
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
20
I
202
203
204
205
206
207
208
006C
7777
006E
7777
0070
??"
007177
0072
??71
0074
7777
0076
????
0078
(4
77
)'
007C
(4
77
)'
0049
77
004A
7777
004C
????
004E
7777
0050
(8"
7777
)'"
0060
7777
0062
77
0063
??71
0065
77
0066
??
0067
7777
0069
????
006B
??
5-114
PC-XT System BIOS
(11/08/82)
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