IBM 5170 Technical Reference page 192

OBCB 2B DB
SUB
BX, BX TO THE FIRST LOCATION
OBCo 89 07 MOV [ BX],AX
OBCF EB 00
JMP
SHORT $+2 ALLOW BUS TO SETTLE
OBol 8B 07
MOV AX, [BX]
READ THE FIRST LOCATION
OB03 3D AA55 CMP AX,OAA55H
I S THE MONO VIDEO CARD THERE?
OB06 1 F POP OS
RESTORE THE DATA SEGMENT
OB07 75 56
JNZ
E17 3
GO I F NOT
OB09 81 OE 0010 R 0030
OR
EQUIP FLAG,30H TURN ON MONO BITS IN EQU I P FLAG
OBoF Al 0010 R
MOV
AX, EQU I P_FLAG ENABLE VIDEO
OBE2 2A E4 SUB AH,AH
OBE4 CO 10
INT
INT VIDEO
OBE6 EB 35 90 JMP
E17::::1
CONT I NUE
; -------- MONO ..AI LED TRY COLOR
OBE9 TRY COLOR:
OBE9 BO 01
- MOV
AL,01H SET MODE COLOR 40X25
OBEB 2A E4 SUB AH,AH
OBED CD 10
INT
INT VIDEO
OBEF BA 0308
MOV DX,3D8H
o I SABLE COLOR
OBF2 BO 00
MOV AL,O
OBF4 EE OUT DX,AL OUTPUT THE DISABLE
OBF5 BB B800 MOV BX,OB800H
CHECK FOR COLOR VIDEO RAM
OBF8 8E DB
MOV OS, BX
OBFA B8 AA55
MOV
AX,OAA55H WR I TE AN AA55
OBFD 2B DB SUB BX, BX
TO THE FIRST LOCATION
OBFF
OCOl
89
EB
07
00
MOV
JMP
[ BX],AX
SHORT $+2
ALLOW BUS TO SETTLE
OC03
OC05
8B
3D
07
AA55
MOV
CMP
AX, [BX]
AX,OAA55H
READ HIE FIRST LOCATION
I S THE COLOR VIOEO CARD THERE?
OC08 1 F
POP OS
RESTORE THE DATA SEGMENT
OC09 75 24
JNZ
E17 3
GO IF NOT
OCOB 81 26 0010 R FFCF AND EQUIP FLAG,OFFCFH TURN OFF VIDEO BITS
OCll 81 OE 0010 R 0010
DR
EQU I P-FLAG, 10H SET COLOR 40X24
OC17 BO 01
MOV
AL,O,.i=i
OC19 2A Ell SUB AH,AH
OCl B CD 10
INT
INT_VIDEO
OC1D
OC1D 58 POP
AX SET NEW V IDEO TYPE ON STACK
OC1E Al 0010 R
MOV
AX, EQU I P _FLAG
OC2l 24 30 AND AL,30H
OC23 3C 30 CMP AL,30H
IS IT THE B!W?
OC25 2A CO
SUB
AL,AL
OC27 74 02 JZ E17 2 GO I F YES
OC29 FE CO
INC
AL -
INIT FOR 40X25
OC2B 50
E17 2: PUSH AX
OC2C E9 OB63 R E17::::4: JMP E18
;------- BOTH VIDEO CARDS FAILED SET DUMMY RETURN IF RETRACE FALIURE
OC2F
OC2 F 1 E PUSH
OS
OC30 2B CO
SUB
AX, AX ; SET OS SEGMENT TO 0
OC32 8E 08 MOV DS,AX
OC34 BF 0040 R MOV
DI,OFFSET VIDEO_INT , SET INT 10H TO DUMMY
OC37 C7 05 0000 E
MOV
WORD PTR [DI],OFFSET DUMMY_RETURN ; RETURN IF NO VIDEO CARD
OC3B 1 F POP OS
OC3C E9 OB68 R
JMP
E18_1 ; BYPASS REST OF VIDEO TEST
OC3F
POSTl ENDP
OC3 F
CODE ENDS
END
5-50 Test 1