IBM 5150 Hardware Reference Manual page 258

LOC OBJ
LINE SOURCE
F77D E947FA
4738 JHP
VIDEO_RETURN RETURN TO CAllER
4719
nea
4740 U6:
l
SET-CURSOR-INC
F7BD FEC6
4741
INC
DH
; NEXT ROW
F782 4742
U7:
SET-CURSOR
F762 B40Z 4743
HOV
AH .2
F784 EBF4 4744
JHP
U4 J ESTABLISH THE NEW CURSOR
~
4745
4746 ;------ BACK SPACE FOUND
4747
F786
4748 US:
F786 eOFAao 4749
CHP OL.O ; ALREADY AT END OF LINE
F789 74F7
4750
JE U7 SET_CURSOR
F7BB FECA
4751
DEC
Dl NO -­ JUST MOVE IT BACK
F7BD f6F! 4752
JMP U7
SET_CURSOR
4753
475'1 ­
j-----~
CARRIAGE RETURN FOUND
4755
F78F 4756 U9:
F7Sf 82:00
4757
HDV CL,O ; HOVE TO FIRST COlUtfN
f7'91 EBEF 4758
J"P
U7
; SET_CURSOR
4759
4760 ;------ LINE FEED FOUND
4761
F793
4762 UlO:
F793 BOFEle
4763 CMP OH.24 ; BOTTOM OF SCREEN
F796 75E8
4764 JNE
U.
; YES, SCROLL THE SCREEN
F798 ESB9 4765
JHP Ul ; NO. JUST SET THE CURSOR
4766
4767
j~-----
BElL FOUND
4768
F79A 4769 Ull:
F79A 8302
4770 HOV BL,Z ; SET UP COUNT FOR BEEP
F79C ESC7EE
4771
CALL BEEP ; SOUND THE POD BElL
F79f fBDB 477Z
jMP U5 ; TTY_RETURN
4773 ENDP
~
4774
j
~------------------------------------------
4775 LIGHT PEN
4776 THIS ROUTINE TESTS THE LI~HT PEN SWITCH AND THE LIGHT
4777 PEN TRIGGER. IF BOTH ARE SET, THE LOCATION OF THE LIGHT
4778 PEN IS DETERMINED. OTHERWISE, A RETURN WITH NO INFORMATION
4779 IS MADE.
4780 ON EXIT:
4781 IAH) :: 0 IF NO LIGHT PEN INFORMATION IS AVAILABLE
4782: Bx.ex,Ox ARE DESTROYED
4783 'AH) :: 1 IF LIGHT PEN IS AVAILABLE
4784
{OH,OU :: ROW,COLUMN OF CURREtrr LIGHT PEN POSITION
4785 (CHI
=
RASTER POSITIml
4786 (BX)
=
BEST GUESS AT PIXEL HORIZONTAL POSITION
4787 ; -------------------------------------------­
4788 ASSUME CS:COOE.DS:OATA
4789
j------
SUBTRACT_TABLE
F7U
4790 Vl
LABEL BYTE
F7Al 0]03050503030304 4791
3.3,5.5.3.3.3.4 ;
F7A9 4792
PRoe NEAR
4793
4794 ;------ WAIT FOR LIGHT PEN TO BE DEPRESSED
4795
F7A9 6400 4796
HDV AH,O SET
NO
LIGHT PEN RETURN CODE
F7AB 88166300 4797
MDV DX,ADDR_6845 ; GET BASE ADDRESS OF 6845
F7AF 83C206
4798
ADD
OX.6
; POINT TO STATUS REGISTER
F7BZ EC 4799 Hi AL.OX ; GET STATUS REGISTER
FiB3 A804 4800
TEST
AL,4 ; TEST LIGHT
PEN SWITCH
F7B5 7578 4801
JNZ V. i NOT SET. RETt.mN
4802
4803
j - - - - - ­
NOW TEST FOR LIGHT PEN TRIGGER
4804
F7S? A802: 4805
TEST AL.2 ; TEST LIGHT PEN TRIGGER
F7B9 747E
4806
JZ
V7
j
RETURN WITHOUT RESETTING TRIGGER
4807
4808 j------ TRIGGER HAS BEEN SET. READ THE VALUE IN
4809
FlBB 8410
4810 MDV AH.l6 ; LIGHT PEN REGISTERS ON 6845
4811
4812 ;-----­ WPUT REGS POINTED TO BY AH, AND COHVERT TO
~OW
COLUMN IH OX
4813
F7BO 88166300 4814
HOV
j
JlODRESS REGISTER FOR 6845
A-65