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INPUT
INPUT
SOURCE
(B I OS FOR THE I BM PERSONAL COMPUTER XT)
1 1
108/82
5-167
I NTERRUPTS BACK ON
SAVE SEGMENT REGISTER
GET THE CURRENT SETT I NGS
RECOVER SEGMENT
RETURN TO CALLER
I NTERRUPTS BACK ON
SA VE SEGMENT
GET VALUE
RECOVER SEGMENT
RETURN TO CALLER
;
CARRY
INDICATOR=1
FAR
AH,86H
2
ENDP
OF859H
PROC
FAR
ENDP
CS:CODE,DS:DATA
OF84DH
PROC
FAR
DS
DDS
AX,EQUIP FLAG
DS
-
DS
DDS
AX ,MEMORY SIZE
DS
-
PC-XT System BIOS (11/08/82)
ORG
CASSETTE 10
STC
MOV
RET
CASSETTE_IO
ASSUME
ORG
EQUIPMENT
STI
PUSH
CALL
MOV
POP
IRET
EQUIPMENT
;---
INT 11
-----------------------------------------------------
; EQU I PMENT DETERM I NA T I ON
:
;
TH I S ROUT I NE ATTEMPTS TO DETERM I NE WHAT OPT 10NAL
DEVICES ARE ATTACHED TO THE SYSTEM.
NO REG I STERS
THE EQU I P FLAG VAR I ABLE I S SET DUR I NG THE POWER ON
D I AGNOST I CS US I NG THE FOLLOW I NG HARDWARE ASSUMPT IONS:
PORT 60
= LOW ORDER BYTE OF EQUPMENT
PORT 3FA = INTERRUPT ID REGISTER OF 8250
BITS 7-3 ARE ALWAYS 0
PORT 378 = OUTPUT PORT OF PR INTER - -
8255 PORT THAT
CAN BE READ AS WELL AS WR I TTEN
OUTPUT
(AX)
IS SET, BIT SIGNIFICANT, TO INDICATE ATTACHED I/O
BIT
15,14 = NUMBER OF PRINTERS ATTACHED
BIT
I 3 NOT USED
BIT 12 = GAME
1/0
ATTACHED
BIT 11,10,9 = NUMBER OF RS232 CARDS ATTACHED
BIT 8 UNUSED
BIT 7,6 = NUMBER OF DISKETTE DR I VES
00=1, 01=2,
10=3,
11=4 ONLY IF BIT 0 = 1
BIT 5,4 = I N I TI AL V I DEO MODE
00 - UNUSED
01
-
40X25 BW US I NG COLOR CARD
10 -
80X25 BW US I NG COLOR CARD
I I
-
80X25 BW US I NG BW CARD
BIT 3,2 = PLANAR RAM SIZE
(00=16K,OI=32K,10=48K,I1=64K)
B IT I NOT USED
BIT 0 = IPL FROM DISKETTE -- THIS BIT INDICATES THAT
THERE ARE DISKETTE DR I VES ON THE SYSTEM
NO OTHER REG I SlERS AFFECTED
OUTPUT
(AX)
= NUMBER OF CONTI GUOUS
1K BLOCKS OF MEMORY
NO REG I STERS
THE MEMORY SIZE VAR I ABLE I S SET DUR I NG POWER ON D I AGNOST I CS
ACCORD I NG-TO THE FOLLOW I NG HARDWARE ASSUMPT IONS:
PORT 60 BITS 3,2 = 00 -
16K BASE RAM
01
-
32K BASE RAM
10 -
48K BASE RAM
1 1 -
64K BASE RAM
PORT 62 BITS 3-0
INDICATE AMOUNT OF
1/0
RAM IN 32K
INCREMENTS
E.G.,
0000 -
NO RAM IN
1/0
CHANNEL
0010 -
64K RAM IN
1/0
CHANNEL, ETC.
; - --
I NT 15 - - ------ ---- ------------- --- ----------------- -------- ---- ----
DUMMY CASSETTE
10 ROUT I NE-RETURNS ' I NVALI D CMD'
I F THE ROUT I NE I S :
I S EVER CALLED BY ACC I DENT
(AH=86H, CARRY FLAG= 1 )
; ---
I NT 12 ------------------------------------------------------------
; MEMORY SIZE DET
;
TH I S ROUT I NE DETERM I NES THE AMOUNT OF MEMORY
I N THE SYSTEM
;
AS REPRESENTED BY THE SW I TCHES ON THE PLANAR.
NOTE THAT THE
;
SYSTEM MAY NOT BE ABLE TO USE
1/0
MEMORY UNLESS THERE
IS A FULL
;
COMPLEMENT OF 64K BYTES ON THE PLANAR.
ASSUME
CS:CODE,DS:DATA
ORG
OF841H
MEMORY SIZE DET PROC
-
STI-
PUSH
CALL
MOV
POP
IRET
MEMORY_S I ZE_DET
ENDP
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
LINE
F859
F859
F859 F9
F85A B486
F85C CA0200
LOC OBJECT
F84D
F84D
F84D FB
F84E IE
F84F E80702
F852 AI 1000
F855
IF
F856 CF
F841
F841
F841
FB
F842
IE
F843 E81302
F846 A I 1300
F849
IF
F84A CF
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