Apple II User Manual
57 A2L EQU $3E
58 A2H EQU $3F
59 A3L EQU $40
59 A3L EQU $40
60 A3H EQU $41
61 A4L EQU $42
61 A4L EQU $42
62 A4H EQU $43
63 A5L EQU $44
63 A5L EQU $44
64 A5H EQU $45
65 ACC EQU $45
65 ACC EQU $45
66 XREG EQU $46
67 YREG EQU $47
67 YREG EQU $47
68 STATUS EQU $48
69 SPNT EQU $49
69 SPNT EQU $49
70 RNDL EQU $4E
71 RNDH EQU $4F
71 RNDH EQU $4F
72 ACL EQU $50
73 ACH EQU $51
73 ACH EQU $51
74 XTNDL EQU $52
75 XTNDH EQU $53
75 XTNDH EQU $53
76 AUXL EQU $54
77 AUXH EQU $55
77 AUXH EQU $55
78 PICK EQU $95
79 IN EQU $0200
79 IN EQU $0200
80 USRADR EQU $03F8
81 NMI EQU $03FB
81 NMI EQU $03FB
82 IRQLOC EQU $03FE
83 IOADR EQU $C000
83 IOADR EQU $C000
84 KBD EQU $C000
85 KBDSTRB EQU $C010
85 KBDSTRB EQU $C010
86 TAPEOUT EQU $C020
87 SPKR EQU $C030
87 SPKR EQU $C030
88 TXTCLR EQU $C050
89 TXTSET EQU $C051
89 TXTSET EQU $C051
90 MIXCLR EQU $C052
91 MIXSET EQU $C053
91 MIXSET EQU $C053
92 LOWSCR EQU $C054
93 HISCR EQU $C055
93 HISCR EQU $C055
94 LORES EQU $C056
95 HIRES EQU $C057
95 HIRES EQU $C057
96 TAPEIN EQU $C060
97 PADDL0 EQU $C064
97 PADDL0 EQU $C064
98 PTRIG EQU $C070
99 BASIC EQU $E000
99 BASIC EQU $E000
100 BASIC2 EQU $E003
101 ORG $F800 ;ROM START ADDRESS
101 ORG $F800 ;ROM START ADDRESS
F800: 4A 102 PLOT LSR ;Y-COORD/2
F801: 08 103 PHP ;SAVE LSB IN CARRY
F801: 08 103 PHP ;SAVE LSB IN CARRY
F802: 20 47 F8 104 JSR GBASCALC ;CALC BASE ADR IN GBASL,H
F805: 28 105 PLP ;RESTORE LSB FROM CARRY
F805: 28 105 PLP ;RESTORE LSB FROM CARRY
F806: A9 0F 106 LDA #$0F ;MASK $0F IF EVEN
F808: 90 02 107 BCC RTMASK
F808: 90 02 107 BCC RTMASK
F80A: 69 E0 108 ADC #$E0 ;MASK $F0 IF ODD
F80C: 85 2E 109 RTMASK STA MASK
F80C: 85 2E 109 RTMASK STA MASK
F80E: B1 26 110 PLOT1 LDA (GBASL),Y ;DATA
F810: 45 30 111 EOR COLOR ; EOR COLOR
F810: 45 30 111 EOR COLOR ; EOR COLOR
F812: 25 2E 112 AND MASK ; AND MASK
F814: 51 26 113 EOR (GBASL),Y ; EOR DATA
F814: 51 26 113 EOR (GBASL),Y ; EOR DATA
F816: 91 26 114 STA (GBASL),Y ; TO DATA
F818: 60 115 RTS
F818: 60 115 RTS
F819: 20 00 F8 116 HLINE JSR PLOT ;PLOT SQUARE
F81C: C4 2C 117 HLINE1 CPY H2 ;DONE?
F81C: C4 2C 117 HLINE1 CPY H2 ;DONE?
F81E: B0 11 118 BCS RTS1 ; YES, RETURN