IBM XT 5160 Technical Reference page 269

LOC OBJECT LINE SOURCE (B I OS FOR THE I BM PERSONAL COMPUTER XT) 1 1 /08/82
.-------------------------------_._------------------------------
; EXPANS I ON I/O BOX TEST
CHECK TO SEE IF EXPANSION BOX PRESENT - IF INSTALLED,
, TEST DATA AND ADDRESS BUSES TO I/O BOX
; ERROR='180I'
; ----- CHECK DATA BUS
; ----- CHECK ADDRESS BUS
; ----- DETERM I NE I F BOX I S PRESENT
EXP_IO:
READ ADDR. HIGH
FORM NEW DATA PATTERN
LOOP TILL BIT WALKS ACROSS AL
GO ON TO NEXT TEST
RETR I VE VALUE FROM REG
= TO SAVED VALUE
WR I TE ADDRESS FOOOO+BX
DO 8 TIMES
SAVE DATA BUS VALUE
SEND VALUE TO REG
GO ERROR IF M I SCOMPARE
DX=216H (ADDR. LOW REG)
MAKE DX=214H (DATA BUS REG)
LOOP TILL '1' WALKS ACROSS BX
DX BACK TO 2 I 5H
COMPARE TO LOW ADDRESS
LOAD HI ADDR. REG ADDRESS
GO ACROSS 16 BITS
RECOVER DATA
MAKE AL DIFFERENT
RECOVER DATA
REPLY?
NO RESPONSE, GO TO NEXT TEST
MAKE DATA=AAAA
(CARD WAS ENABLED EARL I ER)
CONTROL PORT ADDRESS
SET DATA PATTERN
S I ,OFFSET F3C
E_MSG
CX,0008
AL,O I
DX
AH,AL
DX,AL
AL,O IH
AL,DX
AL,AH
SHORT EXP ERR
AL,I -
EXP4
SHORT E 19
CS:[BXJ,AL
AL,DX
AL,BH
EXP ERR
DX -
AL,DX
AL,BL
EXP ERR
DX -
BX, I
EXP3
BX,OOOIH
DX,0215H
CX,0016
DX, 021 OH
AX,5555H
DX,AL
AL,O IH
AL,DX
AL,AH
E19
AX
DX,AL
AL,OIH
AL,DX
AL,AH
E19
MOV
NOP
IN
CMP
JNE
INC
IN
CMP
JNE
DEC
SHL
LOOP
MOV
MOV
MOV
MOV
MOV
OUT
MOV
IN
CMP
JNE
NOT
OUT
MOV
IN
CMP
JNE
MOV
MOV
DEC
MOV
OUT
MOV
IN
CMP
JNE
SHL
LOOP
JMP
EXP ERR:
- MOV
CALL
EXP4:
EXP3:
EXP2:
940
941
942
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946
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950
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989
990
991
992
993
994
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997
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999
1000
100 I
E44D B90800
E450 BOO 1
E452 4A
E453
E453 8AEO
E455 EE
E456 BOO 1
E458 EC
E459 3AC4
E45B 7506
E45D DOEO
E45F E2F2
E461 EB07
E463
E463 BEOFF990
E467 E83F15
E430
E430 BBO 100
E433 BA 1502
E436 B91000
E439
E439 2E8807
E43C 90
E43D EC
E43E 3AC7
E440 7521
E442 42
E443 EC
E444 3AC3
E446 751B
E448 4A
E449 DIE3
E44B E2EC
E418
E418 BA1002
E41B B85555
E41E EE
E41F BOOI
E421 EC
E422 3AC4
E424 7544
E426 F7DO
E428 EE
E429 BOO I
E42B EC
E42C 3AC4
E42E 753A
5-122
PC-XT System BIOS (11/08/82)