LOC OB.JECT
LINE
SOURCE
(B
I
OS
FOR
THE
I
BM
PER SONAL COMPUTER
XT)
1 1
/08/82
;
-----
TURN
DR
I
VE
0 MOTOR
ON
SETUP
PRINTER
AND
RS232
BASE
ADDRESSES
IF
DEVICE
ATTACHED
.----------------------------------------------------------------
F9:
·
------------------------------------------------------------------------
; A CHECKSUM
IS
DONE FOR
THE
4 ROS MODULES
CONTAINING
BASIC
CODE
SET
BEG I NN I
NG
ADDRESS
SET
BX=OOOO
GET
1ST
WORD
FROM MODULE
PO I
NT
TO
NEXT
2K
ADDRESS
RECAL
I
BRATE
DISKETTE
GO
TO ERR SUBROUT I NE I F ERR
SELECT
TRACK
34
SEEK TO TRACK
34
OK,
TURN MOTOR
OFF
DSK
ERR:
GET-
ADDR OF
MSG
GO
PR I
NT
ERROR
MSG
GET
ADDR OF FDC CARD
TURN MOTOR
ON,
EN
DMA
/ I
NT
WR
I
TE
FDC CONTROL REG
DRO
OFF:
TURN
DR
I VE 0 MOTOR
OFF
FDC
CTL
ADDRESS
MOTOR
WAIT:
WA
I T FOR 1 SECOND
MOTOR_WA I T 1:
SELECT
DR
I VE 0
SELECT
TRACK 1
AT
F6000
YET?
GO
CHECK ANOTHER
ADD.
I F NOT
GO
CHECK
BAS
I C
ROM
BUS
SETTL
I
NG
= TO
ID
WORD?
PROCEED TO
NEXT
ROM
I F NOT
GO
CHECK OUT MODULE
CHECK FOR END OF
ROM
SPACE
AL,OCH
DX,03F2H
DX,AL
DX,OC800H
DX,0080H
DX,OF600H
ROM
SCAN 1
BASE_ROM=CHK
DS,DX
BX,BX
AX,
[BX]
BX
BX
AX,OAA55H
NEXT
ROM
ROM
CHECK
ARE=WE_DONE
MOV
DX,03F2H
MOV
AL,ICH
OUT
DX,AL
SUB
CX,CX
LOOP
Fl1
LOOP
F12
XOR
DX,DX
MOV
CH,I
MOV
SEEK_STATUS
,DL
CALL
SEEK
.JC
F13
MOV
CH,34
CALL
SEEK
.JNC
F14
MOV
S I
,OFFSET
F3
CALL
E_MSG
MOV
MOV
OUT
POP
OS
MOV
AL,
BYTE
PTR EQU I P
_FLAG
DISKETTE
PRESENT?
AND
AL,O
lH
NO
-
BYPASS
DISKETTE
TEST
.JZ
F15
FlO:
01
SK_
TEST:
IN
AL,
INTAO
1
AND
AL,OBFH
ENABLE
0 I
SKETTE
INTERRUPTS
OUT
INTA01,AL
MOV
AH,O
RESET
NEC FDC
MOV
DL,AH
SET
FOR
DR
I VE 0
INT
13H
VERIFY
STATUS
AFTER
RESET
TEST
AH,OFFH
STATUS
OK?
.JNZ
F13
NO
- FDC F A I
LED
;
-----
TURN
DR
I VE 0 MOTOR
OFF
F15:
MOV
I
NTR_FLAG,
OOH
SET
STRAY
I
NTERRUPT
FLAG
=
00
MOV
SI,OFFSET
KB_BUFFER
SETUP
KEYBOARD PARAMETERS
MOV
BUFFER
HEAD,
S I
MOV
BUFFER
=T
A I L , S I
MOV
BUFFER_START,
S I
ADD
S
1,32
;
DEF
AUL
T
BUFFER
OF
32
BYTES
MOV
BUFFER
END,
S I
MOV
oI
,OFFSET
PR
INT_
TIM_OUT
;
SET
DEF
AUL
T PR
INTER
TIMEOUT
PUSH
OS
POP
ES
MOV
AX,1414H
;
DEFAUL
T=20
STOSW
STOSW
MOV
AX,O
10 1H
;
RS232
DEFAUL
T=O
I
STOSW
STOSW
IN
AL,INTAOI
AND
AL,OFCH
;
ENABLE
T I
MER
AND
KB
INTS
OUT
INTA01,AL
E4:
SUB
BX,BX
SETUP
STARTING
ROS
ADDR
MOV
DS,DX
CHECK ROS
CALL
ROS_CHECKSUM
.JE
E5
CONTINUE
IF
OK
CALL
ROM_ERR
POST
ERROR
E5:
ADD
DX,0200H
PO I
NT
TO
NEXT
8K
MODULE
DEC
AH
ANY
MORE
TO DO?
.JNZ
E4
YES
-
CONTINUE
.---------------------------------------------------------------
; CHECK FOR
OPTI
ONAL
ROM
FROM
C8000->F4000
IN
2K
BLOCKS
(A
VALID
MODULE HAS
'55AA'
IN
THE
FIRST
2
LOCATIONS,
LENGTH
I
NO
I CATOR
(LENGTH
/512)
I N
THE
3D
LOCAT
I
ON
AND
TEST/INIT.
CODE
STARTING
IN
THE
4TH
LOCATION.)
DISKETTE
ATTACHMENT
TEST
DESCR I
PT
I
ON
CHECK
IF
IPL
DISKETTE
DRIVE
IS
ATTACHED
TO
SYSTEM.
IF
ATTACHED,
VER I
FY
STATUS
OF NEC FDC
AFTER
A
RESET.
ISSUE
A
RECAL
AND SEEK
CMD
TO FDC AND CHECK
STATUS.
COMPLETE
SYSTEM
INITIALIZATION
THEN
PASS
CONTROL TO
THE
BOOT
LOADER PROGRAM.
F13:
F14:
Fl1
:
F12:
·
---------------------------------------------------------------
ROM
SCAN:
-
MOV
ROM
SCAN
1:
-
MOV
SUB
MOV
PUSH
POP
CMP
.JNZ
CALL
.JMP
NEXT
ROM:
- ADD
ARE
WE
DONE:
- -
CMP
.JL
.JMP
·
------------------------------------------------------------------------
BASE
ROM
CHK:
-
MOV
AH,
4
NO.
OF
ROS
MODULES TO CHECK
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
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
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
E591
E591
BOOC
E593
BAF203
E596
EE
E56A
BAF203
E56D
BO
1C
E56F
EE
E570
2BC9
E572
E572
E2FE
E574
E574
E2FE
E576
3302
E578
B501
E5
7A
88163EOO
E57E
E8FC08
E581
7207
E583
B522
E585
E8F508
E588
7307
E58A
E58A
BE52EC90
E58E
E81814
E551
E551
IF
E552
AO
1
000
E555
2401
E557
743E
E559
E559
E421
E55B
24BF
E55D
E621
E55F
B400
E561
8AD4
E563
CD13
E565
F6C4FF
E568
7520
E597
E597
C6066BOOOO
E59C
BE
1
EOO
E59F
89361
AOO
E5A3
89361
COO
E5A
7
89368000
E5AB
83C620
E5AE
89368200
E5B2
BF7800
E5B5
IE
E5B6
07
E5B7
B81414
E5BA
AB
E5BB
AB
E5BC
B80
10 1
E5BF
AB
E5CO AB
E5Cl
E421
E5C3
24FC
E5C5
E621
E541
E8AE13
E544
7403
E546
E88201
E549
E549
81
C20002
E54D
FECC
E54F
75EC
E53B
E53B
B404
E53D
E53D
2BDB
E53F
8EDA
E518
E518
BAOOC8
E51B
E51B
8EDA
E51D
2BDB
E51F
8B07
E521
53
E522
5B
E523
3D55AA
E526
7506
E528
E82814
E52B
EB0590
E52E
E52E
81
C28000
E532
E532
81
FAOOF6
E536
7CE3
E538
EBO
190
5-124
PC-XT System BIOS
(11/08/82)
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