Atari 400 Technical Reference Manual page 368

ERR LINE ADDR B1 B2 B3 B4
DISPLAY HANDLER -- 10-30-78 -- DISPLC
PAGE 107
4731
. PAGE
4732
4733
4734
ROUTINES
4735
4736
4737
i
DOUBLE BYTE DECREMENT OF INDIRECT POINTER
4738
; INCLUDING DB SUBTRACT AND DB DOUBLE DECREMENT
4739
4740 F913 A9 02
DBDDEC: LDA #2
4741
F915 DO OA
BNE DB SUB ; (UNCONDITIONAL)
4742
4743
i
STORE DATA INDIRECT AND DECREMENT POINTER
4744
i
(PLACED HERE TO SAVE JMP DBDEC AFTER STORE)
4745 F917 A4 4C
STORE: LOY DSTAT iRETURN ON ERROR
4746
F919 30 2B
BMI STROK
4747 F91B
AO 00 LDY #0
4748 F91D 91 64
STORE1: STA
(ADRESS),Y
4749
JMP DB DEC DECREMENT AND RETURN
4750
4751 F91F A9 01
DBDEC: LDA #1
4752 F921 8D 9E 02
DBSUB: STA SUBTMP
4753 F924 A5 4C
LDA DSTAT iRETURN ON ERROR
4754 F926
30 1E
BMI STROK
4755 F928 A5 64
LDA ADRESS
4756
F92A 38 SEC
4757 F92B
ED 9E 02 SBC SUBTMP
4758 F92E 85 64 STA
ADRESS
4759 F930 BO 02
BCS DBSUB1
4760 F932 C6 65
DEC ADRESS+1
4761 F934 A5 OF
DBSUB1: LDA APPMHI+l
iMAKE SURE NOTHING EVER OVERWRITES APPMHI
4762 F936 C5 65
CMP ADRESS+1
4763 F938 90 oe
Bee STROK
i
OK
4764 F93A
DO 06 BNE STRERR
i
ERROR
4765 F93C A5 OE
LOA APPMHI
4766
F93E C5 64 CMP
ADRESS
4767 F940 90 04
BCC STROK
4768
F942 A9 93 STRERR: LDA
#SCRMEM iSHOW MEM TOO SMALL FOR SCREEN ERROR
4769 F944
85 4C STA
DSTAT
4770 F946 60
STROK: RTS
4771
4772
4773
4774
i
CONVERT ROW/COLUMN CURSOR INTO REAL ADDRESS <FROM SAVMSC ON UP>
4775
4776 F947
A5 54 CONVRT: LDA
ROWCRS iSAVE CURSOR
4777 F949
48 PHA
4778 F94A A5 55
LDA COLCRS
4779 F94C
48 PHA
4780 F94D
A5 56 LDA COLCRS+1
4781 F94F
48
PHA
4782 F950
20 F3 FC JSR PUTMSC
4783 F953 A5 54
LDA ROWCRS
iPUT 10*ROWCRS INTO MLTTMP
4784 F955 85 66
STA MLTTMP