Atari 400 Technical Reference Manual page 373

ERR LINE AD DR
Bl B2 B3 B4 DISPLAY HANDLER -- 10-30-78 -- DISPLC PAGE 112
5001
5002 FAE4 AO 00 OFFCRS: LDY 10
5003 FAE6 A5 50 LOA OLOCHR
5004 FAE8 91 5E STA (OLOAOR), Y
5005 FAEA 60 RTS
5006
5007
5008
5009
BITMAP ROUTINES:
5010
5011 BITCON: PUT MASK IN BITMSK AND INDEX IN X
5012 BITPUT: PUT CARRY INTO BITMAP
5013 BITROL: ROL CARRY INTO BOTTOM OF BITMAP (SCROLL)
5014 BITSET: SET PROPER BIT
5015 BITCLR: CLEAR PROPER BIT
5016 BITGET: RETURN CARRY SET IF BIT IS THERE
5017 LOGGET: DO BITGET FOR LOGMAP INSTEAD OF TABMAP
5018
5019 FAEB 48 BITCON: PHA
5020 FAEC
29 07 AND #7
5021 FAEE
AA TAX
i
GET MASK
5022 FAEF
BD B9 FE LOA MASKTB, X
5023 FAF2 85 6E STA BITMSK
5024 FAF4 68 PLA
iPROCESS INDEX
5025 FAF5 4A LSR A
5026 FAF6 4A
LSR A
5027 FAF7 4A LSR A
5028 FAF8 AA TAX
5029 FAF9 60
RTS
5030
5031
5032 FAFA 2E B4 02 BITROL: ROL
LOGMAP+2
5033 FAFD
2E B3 02 ROL LOGMAP+1
5034 FBOO 2E B2 02
ROL LOGMAP
5035 FB03 60 RTS
5036
5037
5038 FB04 90 OC BITPUT: BCC
BITCLR
i
AND RETURN
5039
i
OTHERWISE FALL THROUGH TO BITSET AND RETURN
5040 FB06
20 EB FA BITSET: JSR BITCON
5041 FB09 BD A3 02 LDA TABMAP,X
5042 FBOC 05 6E ORA BITMSK
5043 FBOE 9D A3 02
STA
TABMAP,X
5044 FB11 60
RTS
5045
5046 FB12 20 EB FA BITCLR: JSR
BITCON
5047 FB15 A5 6E
LDA BITMSK
5048 FB17 49 FF
EOR I$FF
5049 FB19
30 A3 02 AND TABMAP, X
5050 FB1C 90 A3 02 STA TABMAP, X
5051 FB1F 60
RTS
5052
5053 FB20 A5 54 LOGGET: LDA ROWCRS
5054 FB22 18 L01GET: CLC