Table of Contents
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143E
C3
143F
143F
143F
FD
1440
8A 08
1442
E8 16E6 R
1445
53
1446
6B C2
1448
E6 13EF R
144B
74 20
1440
2B FO
144F
8A E6
1451
2A E3
1453
1453
E8 142F R
1456
2B F5
1458
2B FD
145A
FE CC
145C
75 F5
145E
145E
56
145F
BO 20
1461
1461
E8 1438 R
1464
2B FD
1466
FE CB
1468
75 F7
146A
E9
1307 R
1460
1460
8A DE
146F
EB ED
1471
1471
1471
SA 08
1473
8B Cl
1475
E8 16A4 R
1478
8B F6
147A
2B 01
147C
81 C2 0101
1480
DO E6
1462
DO E6
1464
80 3E 0449 R 06
1469
73 04
146B
DO E2
1460
01 E7
148F
148F
06
1490
1 F
1491
2A ED
1493
DO E3
1495
DO E3
1497
74 20
1499
8A C3
149B
B4 50
1490
F6 E4
149F
8B F7
14A1
03 FO
14A3
8A E6
14A5
2A E3
14A7
14A7
E8 14CA R
14AA
81 EE 1FBO
14AE
81 EF 1FBO
14B2
FE CC
14B4
75 F1
14B6
14B6
8A C7
14B8
3655
3656
3657
3656
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3676
3679
3660
3661
3682
3683
3684
3685
3686
3687
3688
3669
3690
3691
3692
3693
3694
3695
3696
3697
3696
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3726
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742'
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3756
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3776
3779
3760
C
C
NIl
RET
ENDP
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;
_ _ _ _ _ - - _ . . . . . . . . . . . . -
- _ .. - - - _ .. - - - _ . . . . - _ .. - - - - - _ . . . . -
. . - - - - _ . . - _ .. oo - - - -
SCROLL DOWN
INPUT
TH I S ROUT I NE MO'tES THE CHARACTERS WI TH I N A
DEF I NED BLOCK DOWN ON THE SCREEN,
FILL I NG THE
TOP LINES WITH A DEFINED CHARACTER
(AH)
= CURRENT CRT MODE
(AL)
= NUMBER OF LINES TO SCROLL
(CX)
= UPPER LEFT CORNER OF REGION
(OX)
=
LOWER RIGHT CORNER OF REG I ON
(BH)
=
FILL CHARACTER
;
ml
~ ~~b~NS~~~~~~T
; OUTPUT
;
NONE -- SCREEN I S SCROLLED
§c~~~~-ii~iiN-----P~~C----NE~~-----------------------------
N13:
N14:
N15:
N16:
-
STD
SCROLL DOWN
MOV
BL,AL
LINE COUNT TO BL
CALL
MK ES
PUSH
BX-
MOV
AX, OX
CALL
SCROLL POS I T ION
JZ
N 1 6 -
SUB
SI,AX
MOV
AH,DH
SUB
AH, BL
CALL
SUB
SUB
DEC
JNZ
POP
MOV
CALL
SUB
DEC
JNZ
JMP
Nl0
SI, BP
01, BP
AH
N13
AX
AL,
t
NIl
OI,BP
BL
N15
N5
SAVE ATTR 1 BUTE IN BH
LOWER RIGHT CORN ER
GET REGEN LOCATION
, S I
I S FROM ADDRESS
; GET TOTAL
/I
ROWS
; COUNT TO MOVE 1 N SCROLL
; MOVE ONE ROW
; RECOVER ATTR 1 BUTE IN AH
CLEAR ONE ROW
GO TO NEXT ROW
MOV
JMP
SCROLL_DOWN
BL,DH
N14
ENDP
;
..
---_
..
-_
..........
-_
..........
-_
..............
-_
......
-_
..................
-_
......
--_
...... -- ..
---_
..
SCROLL UP
THIS ROUTINE SCROLLS UP THE INFORMATION ON THE CRT
ENTRY
EXIT
CH,Cl
=
UPPER lEFT CORNER OF REGION TO SCROLL
OH,DL = lOWER RIGHT CORNER OF REGION TO SCROLL
BOTH OF THE ABOVE ARE IN CHARACTER POSITIONS
BH = FILL VALUE FOR BLANKED LINES
Al =
#
LINES TO SCROLL (AL=O MEANS BLANK THE ENT I RE
FIELD)
OS = OAT A SEGMENT
ES = REGEN SEGMENT
;
NOTH I NG,
THE SCREEN I S SCROLLED
:
bR~P~
i CS -U P-----
PR~C
----
NE~~
-------------------------------------
MOV
BL, AL
SAVE LINE COUNT
IN BL
MOV
AX,CX
GET UPPER LEFT POSITION
I NTO
AX
REG
; ----- USE CHARACTER SUBROUT I NE FOR POS I T I ON I NG
;----- ADDRESS RETURNED IS MULTI PLI ED BY 2 FROM CORRECT VALUE
CALL
MOV
;----- DETERMINE SIZE OF WINDOW
SUB
ADD
SAL
SAL
DX,CX
DX,101H
DH, I
DH, I
; ----- DETERM I NE CRT MODE
CMP
JNC
CRT MODE,6
R7 -
;----- MEDIUM RES UP
SAL
SAL
Dl,l
01,1
; ----- DETERM I NE THE SOURCE ADDRESS I N THE BUFFER
SAVE RESULT AS
DESTINATION ADDRESS
ADJUST VALUES
MULT I PLY
II
ROWS BY 4
SINCE B VERT DOTS/CHAR
AND EVEN/ODD ROWS
TEST FOR MED I UM RES
F I NO_SOURCE
*
2
SINCE 2 BYTES/CHAR
C
R7:
FIND SOURCE
GET SEGMENTS BOTH
C
C
C
C
C
C
C
C
C
C
C
C
C
PUSH
POP
SUB
SAL
SAL
JZ
MOV
MOV
MUL
MOV
ADD
MOV
SUB
ES
OS
CH,CH
BL,
I
BL,1
Rl1
AL, BL
AH,80
AH
SI,DI
SI,AX
AH,OH
AH, BL
PO I NT I NG TO REGEN
o
TO HIGH OF COUNT REG
NUMBER OF LINES *4
I F 0, BLANK ENT 1 RE FIELD
NUMBER OF LINES IN AL
80 BYTES/ROW
OFFSET TO SOURCE
SET UP SOURCE
ADD I N OFFSET TO IT
NUMBER OF ROWS IN FIELD
DETERM I NE NUMBER TO MOVE
C
C
C
;----- LOOP THROUGH, MOVING ONE ROW AT A TIME, BOTH EVEN AND ODD FIELDS
C
R8:
C
C
C
C
C
C
C
C
C
R9:
C
C
RIO:
CALL
SUB
SUB
DEC
JNZ
R17
S I ,2000H-60
01,2000H-60
AH
R8
Fill IN THE VACATED LINE(S)
MOV
Al, BH
ROW LOOP
MOVE ONE ROW
MOVE TO NEXT ROW
NUMBER OF ROWS TO MOVE
CONT I NUE TILL ALL MOVED
CLEAR ENTRY
ATTRIBUTE TO FILL WITH
IBM Enhanced Graphics Adapter 131
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