IBM 5150 Hardware Reference Manual page 257

lOC OBJ LINE SOLIRCE
F722
F722 50
F723 50
F724 8403
F726 COlO
F728 58
F7Z9 3C08
f'728 7459
F72D 3COD
F72F 745£
F731 3eOA
F733 745E
F735 lC07
F737 7461
F739 6A3E6200
F73D B40A
F73F 890100
F742 COlO
F7" FEe2
F746 3Al64AOO
F74A 753(,
F74C B200
F74E 80F£18
F751 7520
F753
F753 B402
F755 8700
F757 COlO
F759 A04900
F75C 3C04
F75E 12.06
F760 3e07
F762 B700
F764 7506
F766
F766 6408
F768 COlO
f76A SAFe
F76C
F76C 880106
F76F 690000
F772 B618
F774 8A164ADO
F778 FECA
F77A
F77A COlO
F77C
F77C 58
4662
THE 0 COLOR IS USED.
4663 ~
ENTRY -­
4664 (AH)
=
CURRENT CRT MODE
4665
(AL)
=
CHARACTER
TO
BE WRInEN
4666 NOTE THAT BACK SPACE, CAR RET, BEll AND LINE FEED ARE HANDLED
4667
AS COI1MANOS RATHER THAN AS DISPUYABLE GRAPHICS
4668 (BLI
=
FOReGROUND COLOR FOR CHAR
WRITE
IF CURRENTLY IN A GRAPHICS
f10DE
4669
EXIT -­
4670 All REGISTERS SAVED
~671
46n: ASSUME CS:CQDE.DS:DATA
4673 WRITE_TTY PROC NEAR
4674 PUSH
AX • SAVE REGISTERS
4675
PUSH
Ax
; SAVE CHAR TO WRITE
4676 MOV
AH.3
4677
INT 10H ; READ THE CURRENT CURSOR POSITION
4678
POP
AX ; RECOVER CHAR
4679
4680
;------ DX
NOW
HAS THE CURRENT CURSOR pOSITION
4681
4682
CM'
AL,e ; IS IT A BACKSPACE
4683
JE U8
j
BACK_SPACE
4684
CM"
Al.ODH
j
IS IT
CARRIAGE RE11.mN
4685 JE U9 ; CAR_RET
4686 CMP ALtOAH ; IS
IT
A LINE
FEED
4687
JE
UIO
; LINEJEED
468a
Ct1P AL,07H ; IS IT A BELL
4689
JE Ull
; BELL
4690
4691
;------ WRITE THE CHAR TO THE SCREEN
4692
4693
MOV BH.ACTIVE_PAGE; GH THE CURRENT ACTIVE PAGE
4694 MOV AH.I0 ; I..'RIT£ CHAR ONLY
4695 t1Qy CX.l ; ONLY ONE CHAR
4696 tNT 10H
i
WR ITE
THE CHAR
4697
4698 ;------ POSITION THE CURSOR FOR NEXT CHAR
4699
4700 IHC OL
4701
eMP
OL,BYTE PTR CRT_COLS ; TEST FOR COLUMN OVERflOW
4702 JNl U7 ; SET_CURSOR
4703
MOV
DL,D ; COLUMN FOR CURSOR
4704
CM'
DH,24
4705
JHZ U6
4706
4707 ; ------ SCROLL REQUIRED
4708
VI:
4709
4710 HOV AH.2
4711 MOV BH,O
4712
INT
10"
; SET TH E CURSOR
4713
4714 1------ DfTERMINE VALUE TO FILL WITH DURING S'ROLL
4715
4716
l10V Al.eRT_MOOE
GET THE CURRENT HOOE
4717
CM' Al.4
4718
JC
ua
READ-CURSOR
4719
CM"
Al.7
4720
MOV
8H,0 ; FILL a.llTH BACKGROUND
4721 JNE U3 ; SCROLL-UP
4722
4723
U2: ; READ-CURSOR
4724
HOV AH,e
4725
INT IOH
; READ CHAR/AHR AT CURRENT CURSOR
4726
MOV
BH.AH STORE IN BH
472.7
4128
U3: I SCROLL-UP
4729 I10V AX.601H SCROLL ONE LINE
4730
HOV
CX,O ; UPPER LEFT CORNER
4731
MOV
OH,24 ; LOWER RIGHT ROW
4732 MOV OL,BYTE PTR CRT_COLS ; LOlolfR RIGHT COLutIN
4733
DEC OL
4734
lJ4,
, VIDEO-CALL-RETURN
4735
INT 10H
; SCROLL UP THE SCREEN
4736
us:
; TTY-R!;TURN
4737
POP AX
; JilESTORE THE CHARACTER
A-64