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INPUT
SOURCE
(BIOS FOR THE
IBM PERSONAL COMPUTER XT)
I I 108/82
5-155
TEST FOR BW CARD
GET
#
COLUMNS TO CLEAR
MOVE ONE ROW
S I
I S FROM ADDRESS
GET TOTAL
#
ROWS
COUNT TO MOVE
I N SCROLL
CLEAR ONE ROW
GO TO NEXT ROW
STORE THE FILL CHARACTER
DIRECT I ON FOR SCROLL DOWN
LINE COUNT TO BL
TEST FOR GRAPH I CS
GET # OF COLS TO MOVE
RECOVER ATTR IBUTE
IN AH
CaNT I NUE DOWN
SAVE ATTRIBUTE
IN BH
LOWER RIGHT CORNER
GET REGEN LOCA T I ON
FOR BOTH PO INTER S
o SCROLL MEANS BLANK FIELD
RETURN WITH FLAGS SET
SAVE START ADDRESS
MOVE THAT LINE ON SCREEN
; RECOVER ADDRESSES
AX
AL,
BX
AX,DX
SCROLL pas I T I ON
NI6
-
S I
,AX
AH,DH
AH,BL
01
S I
BL,AL
AH,4
NI2
AH,1
NI2
GRAPH I CS_DOWN
NIO
SI,BP
DI,BP
AH
NI3
Nil
DI,BP
BL
NI5
N5
NEAR
CL,DL
01
STOSW
NEAR
CL,DL
S I
01
MOVSW
POP
01
RET
ENDP
POP
MOV
CALL
SUB
DEC
JNZ
JMP
CALL
SUB
SUB
DEC
JNZ
PUSH
MOV
CALL
JZ
SUB
MOV
SUB
PROC
MOV
PUSH
REP
PROC
MOV
PUSH
PUSH
REP
POP
POP
RET
ENDP
PC-XT System BIOS (11/08/82)
; ----- CLEAR_ROW
( AH )
=
CURRENT CRT MODE
( AL)
=
NUMBER OF LINES TO SCROLL
(CX)
=
UPPER LEFT CORNER OF REG I ON
(OX)
=
LOWER RIGHT CORNER OF REG I ON
(BH)
=
FILL CHARACTER
(OS)
=
DATA SEGMENT
(ES)
=
REGEN SEGMENT
OUTPUT
NONE - -
SCREEN I S SCROLLED
e
_
SCROLL DOWN
PROC
NEAR
-
STD
MOV
CMP
JC
CMP
JE
JMP
MOV
BL ,DH
JMP
N14
SCROLL_DOWN
ENDP
SCROLL DOWN
TH I S ROUT I NE MOVES THE CHARACTER S WITH I N A
DEF I NED BLOCK DOWN ON THE SCREEN, FILL I NG THE
TOP LINES WITH A DEF I NED CHARACTER
POP
OS
CMP
BL,O
RET
SCROLL_pas I T I ON ENDP
N15:
N16:
N12:
N13:
N14:
Nl0
NIO
3816
3811
3818
3819
3880
3881
3882
3883
3884
3885
3886
3864
3865
3866
3861
3868
3869
3810
3811
3812
3813
3814
3815
3881
3888
3889
3890
3891
3892
3893
3894
3895
3896
3891
3898
3899
3900
3901
3902
3903
3904
3905
3906
3901
3908
3909
3910
3911
3912
3913
3914
3915
3916
3911
3918
3919
3920
3921
3922
3923
3924
3925
3926
3921
3928
3929
3930
3931
3932
3933
3934
3935
3936
3931
3938
3939
3940
LINE
F338
F338 FD
F339 8AD8
F33B 80FC04
F33E 1208
F340 80FC01
F343 1403
F345 E9A60 1
F348
F348 53
F349 8BC2
F34B E894FF
F34E 1420
F350 2BFO
F352 8AE6
F354 2AE3
F356
F356 E8CFFF
F359 2BF5
F35B 2BFD
F35D FECC
F35F 15F5
F361
F361
58
F362 B020
F364
F364 E8CAFF
F361 2BFD
F369 FECB
F36B 15F1
F36D E95AFF
F310
F310 8ADE
F312 EBED
LaC OBJECT
F33 :
F33:
8ACA
F333 51
F334 F3
F335 AB
F336 5F
F331 C3
F323
IF
F324 80FBOO
F321 C3
F328
F328 8ACA
F32A 56
F32B 51
F32C F3
F32D A5
F32E 5F
F32F 5E
F330 C3
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