IBM XT 5160

LOC OB..JECT
LINE SOURCE (BIOS FOR THE IBM PERSONAL COMPUTER XT) I I 108/82
;----- OX NOW HAS THE CURRENT CURSOR POSITION
; ----- DETERM I NE VALUE TO FILL WITH OUR I NG SCROLL
SAVE REGISTERS
SA VE CHAR TO WR I TE
WR I TE CHAR ONL Y
ONL Y ONE CHAR
WR I TE THE CHAR
ALREADY AT END OF LINE
SET CURSOR
NO =- ..JUST MOVE I T BACK
SET_CURSOR
BOTTOM OF SCREEN
YES, SCROLL THE SCREEN
NO, ..JUST SET THE CURSOR
TEST FOR COLUMN OVERFLOW
SET CURSOR
COLUMN FOR CURSOR
I SIT A BACKSPACE
BACK SPACE
I SIT CARR I AGE RETURN
CAR RET
I S IT A LINE FEED
LINE FEED
I S IT A BELL
8ELL
GET THE CURRENT ACT I VE PAGE
READ THE CURRENT CURSOR POS I T I ON
RECOVER CHAR
MOVE TO FIRST COLUMN
SET_CURSOR
; SET THE CURSOR
AH,2
10H
AH, 10
CX,I
10H
DL,O
U7
DL
U7
DH,24
U6
UI
CS: CODE ,DS: DATA
PROC NEAR
AX
AX
AH,3
BH, ACT I VE PAGE
10H -
AX
DL,O
U7
AL,8
U8
AL,ODH
U9
AL,OAH
UIO
AL,07H
Ull
DL
DL,BYTE PTR CRT COLS
U7 -
DL,O
DH,24
U6
(AH) = CURRENT CRT MODE
(AL) = CHARACTER TO BE WR I TTEN
NOTE THAT BACK SPACE, CAR RET, BELL AND LI NE FEED ARE HANDLED
AS COMMANDS RATHER THAN AS DISPLAYABLE GRAPHICS
( BL ) = FOREGROUND COLOR FOR CHAR WR I TE IF CURRENTL YIN A
GRAPH I CS MODE
ALL REGISTERS SAVED
CMP
..JE
CMP
..JE
CMP
..JE
CMP
..JE
CMP
..JNE
..JMP
CMP
..JE
DEC
..JMP
MOV
INT
MOV
MOV
INT
INC
CMP
..JNZ
MOV
CMP
..JNZ
MOV
..JMP
SCROLL REQU I RED
WR I TE TTY
TH I S I NTERF ACE PROV I DES A TELETYPE LIKE I NTERF ACE TO THE V IDEO
CARD. THE I NPUT CHARACTER IS WR I TTEN TO THE CURRENT CURSOR
POS I T
ION, AND THE CURSOR I S MOVED TO THE NEXT POS I T I ON. I F THE
CURSOR LEAVES THE LAST COLUMN OF THE FIELD, THE COLUMN I S SET
TO ZERO, AND THE ROW V ALUE I S INCREMENTED. I F THE ROW VALUE
LEAVES THE FIELD, THE CURSOR I S PLACED ON THE LAST ROW, FIRST
COLUMN, AND THE ENT I RE SCREEN I S SCROLLED UP ONE LINE. WHEN
THE SCREEN I S SCROLLED UP, THE A TTR IBUTE FOR FILL I NG THE NEWLY
BLANKED LINE I S READ FROM THE CURSOR POS I T I ON ON THE PREY I OUS
LINE BEFORE THE SCROLL, I N CHARACTER MODE. I N GRAPH I CS MODE,
THE 0 COLOR I S USED.
ENTRY
EXIT
; - - - - - WR I TE THE CHAR TO THE SCREEN
;----- POSITION THE CURSOR FOR NEXT CHAR
;
----- LINE FEED FOUND
; - - - - - CARR I AGE
RETURN FOUND
;
----- BACK SPACE FOUND
ASSUME
WR I TE TTY
- PUSH
PUSH
MOV
MOV
INT
POP
MOV
AL,CRT_MODE
GET THE CURRENT MODE
CMP
AL,4
..JC
U2
READ-CURSOR
CMP AL,7
MOV
BH,O
FILL WITH BACKGROUND
..JNE
U3
SCROLL-UP
U2:
READ-CURSOR
MOV
AH,8
INT
10H
READ CHAR 1A TTR AT CURRENT CUR SOR
MOV
BH,AH
STORE IN BH
U3:
SCROLL-UP
MOV
AX,60lH
SCROLL ONE LINE
SUB
CX,CX
UPPER LEFT CORNER
MOV
DH,24
LOWER RIGHT ROW
MOV
DL,BYTE PTR CRT_COLS
LOWER RIGHT COLUMN
DEC
DL
U4:
V I DEO-CALL -RETURN
INT
10H
SCROLL UP THE SCREEN
U5:
TTY-RETURN
POP
AX
RESTORE THE CHARACTER
..JMP
V IDEO_RETURN
RETURN TO CALLER
U6:
SET-CURSOR- INC
INC
DH
NEXT ROW
U7:
SET-CURSOR
MOV
AH,2
..JMP
U4
ESTABLI SH THE NEW CURSOR
UIO:
4795
4796
4797
4798
4799
4800
480 I
4802
4803
4804
4805
4806
4807
4808
4809
4810
481 I
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
UI:
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891 U8:
4892
4893
4894
4895
4896
4897
4898
4899 U9:
4900
490 I
4902
4903
4904
4905
4906
4907
4908
F779
F779
80FAOO
F77C 74F7
F77E FECA
F780 EBF3
F782
F782
B200
F784 EBEF
F786
F786
80FE 18
F789 75E8
F78B EBBC
F749
F749
B402
F74B COlO
F73A FEC2
F73C 3A 164AOO
F740 7533
F742 B200
F74480FEI8
F747 752A
F733 B40A
F735 B90 I 00
F738 COlO
F74D A04900
F750 3C04
F752 7206
F754 3C07
F756 B700
F758 7506
F75A
F75A
B408
F75C COlO
F75E 8AFC
F760
F760
880 I 06
F763 2BC9
F7658618
F767 8AI64AOO
F76B FECA
F76D
F76D
COlO
F76F
F76F 58
F770 E952FA
F773
F773 FEC6
F775
F775
B402
F777 EBF4
F723 3C08
F725 7452
F727 3COD
F729 7457
F72B 3COA
F72D 7457
F72F 3C07
F731 745A
F718
F7 I 8 50
F7 I 9 50
F7 I A B403
F7 I C 8A3E6200
F720 COlO
F722 58
5-164
PC-XT System BIOS (11/08/82)