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LOC OBJECT
LI NE
SOURCE
(B I OS FOR THE I BM PERSONAL COMPUTER
xn
1 1 /08/82
.
--------------------------------------------------------
07:
I S PRESENT
GET FIRST 2 LOCATIONS
SET PGM LOOP CNT
WR I TE T I MER 0 CNT REG
<><><>CRT ERR CHKPT.
06<><><>
TOP OF V IDEO ROM AREA YET?
GO SCAN FOR ANOTHER MODULE
PO I NT TO NEXT 2K BLOCK
GO BEEP SPEAKER
GO CHECK HOR I ZONT AL LINE
01 SPLA Y CURSOR:
GET V IDEO SENSE SWS
(AH)
SET MODE AND 0 I SPLA Y CUR SOR
CALL V IDEO I /0 PROCEDURE
SEE IF ADV ANCED V IDEO CARD
READ IMR
IMR
=
O?
GO TO ERR ROUT I NE
I F NOT 0
o
I SABLE DEV I CE
INTERRUPTS
WR I TE TO IMR
READ IMR
ALL I MR BIT ON?
NO -
GO TO ERR ROUT I NE
LET BUS SETTLE
PRESENT?
NO? GO LOOK FOR OTHER MODULES
GO SCAN MODULE
NXT LINE:
GET-NEXT BIT TO CHECK
; MIGHT OCCUR
; 01 SPLAY
101
ERROR
; HALT THE SYSTEM
CHECK THAT NO INTERRUPT S OCCUR.
AX
AH,O
10H
CX,CX
04
DATA_AREA[OFFSET INTR FLAG] ,OIH
-
0 lOT I MER 0
I NTERRUPT OCCUR?
YES -
CHECK T I MER OP FOR SLOW T I ME
WAIT FOR
INTR FOR SPECIFIED TIME
TIMER 0
INTR DIDN'T OCCUR - ERR
DATA AREA [OFFSET I NTR FLAG], 0 1H ; 0 lOTI MER 0
I NTERRUPT OCCUR?
06
-
-
;
YES -
TIMER CNTING TOO FAST, ERR
010
; WAIT FOR
INTR FOR SPECIFIED TIME
AL,OFEH
INTA01,AL
AL,OOOIOOOOB
TIM CTL,AL
CX,T6H
AL,CL
TIMERO,AL
DX,OCOOOH
S I, OFFSET EO
E_MSG
DATA_AREA[OFFSET INTR FLAG] ,AL
; CLEAR
INTERRUPT FLAG
-
ENABLE EXTERNAL INTERRUPTS
WA I T
I
SEC FOR ANY
I NTRS THAT
DA T A AREA [ OFF SET MFR ERR FLAG], 02H
-
-
;- <><><><><><><><><><><><><><><><>
;
<><><>T I MER CHECKPO I NT
(2) <><><>
; MASK ALL INTRS EXCEPT LVL 0
;
WR I TE THE 8259 I MR
;
SEL TIM 0, LSB, MODE 0, BINARY
;
WR I TE T I MER CONTROL MODE REG
;
SET PGM LOOP CNT
;
SET T I MER 0 CNT REG
;
WR ITE Tl MER 0 CNT REG
05
DATA AREA[OFFSET
INTR FLAG] ,OOH , DID ANY INTERRUPTS OCCUR?
07
-
-
NO -
GO TO NEXT TEST
DATA AREA[OFFSET MFR ERR FLAG] ,05H
-
-
;- <><><><><><><><><><><><>
;
<><><>CHECKPO I NT 5<><><>
;
SET
I MR TO ZERO
CL,I2
AL,OFFH
TIMERO,AL
OAT A AREA [OFFSET I NTR FLAG], 0
; RESET I NTR RECE I VED FLAG
AL,OFEH
-
; REENABLE T I MER 0
I NTERRUTS
INTAO I ,AL
DX,OC800H
EI8A
DS,DX
BX,BX
AX, [BX]
BX
BX
AX,OAA55H
EI8B
ROM CHECK
SHORT E 18C
DX,0080H
OS
OS
OS: MFG ERR FLAG, 06H
DX,102H
-
ERR BEEP
SHORT E18
CL,3
AH,CL
EI2
09
08
06
AL,O
INTAOI,AL
AL, INTAO 1
AL,AL
06
AL,OFFH
INTA01,AL
AL, INTAO 1
AL,I
06
ADD
CMP
JL
MOV
OUT
IN
OR
JNZ
MOV
OUT
IN
ADD
JNZ
MOV
OUT
MOV
OUT
MOV
MOV
OUT
TEST
TEST
JNZ
LOOP
MOV
JNZ
LOOP
JMP
MOV
STI
SUB
MOV
MOV
CALL
CLI
HLT
LOOP
MOV
MOV
OUT
MOV
MOV
OUT
ASSUME
OS: ABSO
POP
OS
MOV
SHR
JNZ
LOOP
CMP
JZ
POP
MOV
INT
MOV
MOV
SUB
MOV
PUSH
POP
CMP
JNZ
CALL
JMP
POP
PUSH
MOV
MOV
CALL
JMP
I NTERRUPTS ARE MASKED OFF.
8259
I NTERRUPT CONTROLLER TEST
DESCR I PT I ON
READ/WRITE THE INTERRUPT MASK REGISTER
(IMR)
WITH ALL ONES AND ZEROES. ENABLE SYSTEM
INTERRUPTS.
MASK DEV I CE I NTERRUPTS OFF. CHECK
FOR HOT INTERRUPTS
(UNEXPECTED).
;
8253 Tl MER CHECKOUT
; DESCR I PTi ON
:
VERIFY THAT THE SYSTEM TIMER
(0)
DOESN'T COUNT
:
TOO FAST OR TOO SLOW.
;----- TEST THE IMR REGISTER
; - - - - -
CHECK FOR HOT INTERRUPT S
C21A:
010:
05:
C21 :
E18:
EI8B:
EI8C:
E17:
E16:
EI8A:
149
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
80
I
802
803
804
805
806
807
808
809
810
81
I
812
813
814
815
04:
816
817
818
819
820
821
06:
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
08:
844
845
846
847
848
849
09:
850
851
852
853
854
855
856
857
858
859
860
E35D
E35D C606150402
E32A C606150405
E376 7504
E378 E2F7
E37A EBD8
E37C
E37C BlOC
E37E BOFF
E380 E640
E382 C6066B0400
E387 BOFE
E389 E621
E38B
E38B F6066B040 I
E390 75C2
E392 E2F7
E362 BOFE
E364 E621
E366 BO I 0
E368 E643
E36A B91600
E36D 8AC 1
E36F E640
E371
E371 F6066B040 I
E329 1F
E32F BOOO
E331 E621
E333 E421
E335 OACO
E337 751B
E339 BOFF
E33B E621
E33D E421
E33F 040 I
E341
7511
E343 A26B04
E346 FB
E347 2BC9
E349
E349 E2FE
E34B
E34B E2FE
E34D 803E6B0400
E352 7409
E354
E354 BEFFF890
E358 E84E 16
E35B FA
E35C F4
E2FO
E2FO
IF
E2Fl
IE
E2F2 C606150006
E2F7 BA020 I
E2FA E8DB 16
E2FD EB06
E2FF
E2FF BI03
E30 I D2EC
E303 7507
E305
E305 58
E306 B400
E308 CD 10
E30A
E30A BAOOCO
E30D
E30D 8EDA
E30F 2BDB
E311
8B07
E313 53
E314 5B
E315 3D55AA
E318 7505
E31 A E83616
E31D EB04
E31F
E31F 81C28000
E323
E323 81 FAOOC8
E327 7CE4
5-120
PC-XT System BIOS (11/08/82)
- Quick Links:
- Section 1. System Board
- 64/256K System Board
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