Apple II manual INY NO, INC Index X-COORD

Models: II

1 257
Download 257 pages 49.17 Kb
Page 21
Image 21

F820: C8

119

 

INY

 

; NO, INC INDEX (X-COORD)

F821: 20 0E F8

120

 

JSR

PLOT1

;PLOT NEXT SQUARE

F824: 90 F6

121

 

BCC

HLINE1

;ALWAYS TAKEN

F826: 69 01

122

VLINEZ

ADC

#$01

;NEXT Y-COORD

F828: 48

123

VLINE

PHA

 

; SAVE ON STACK

F829: 20 00 F8

124

 

JSR

PLOT

; PLOT SQUARE

F82C: 68

125

 

PLA

 

 

 

F82D: C5 2D

126

 

CMP

V2

;DONE?

F82F: 90 F5

127

 

BCC

VLINEZ

; NO, LOOP

F831: 60

128

RTS1

RTS

 

 

 

F832: A0 2F

129

CLRSCR

LDY

#$2F

;MAX Y, FULL SCRN CLR

F834: D0 02

130

 

BNE

CLRSC2

;ALWAYS TAKEN

F836: A0 27

131

CLRTOP

LDY

#$27

;MAX Y, TOP SCREEN CLR

F838: 84 2D

132

CLRSC2

STY

V2

;STORE AS BOTTOM COORD

 

133

 

 

 

; FOR VLINE CALLS

F83A: A0 27

134

 

LDY

#$27

;RIGHTMOST X-COORD (COLUMN)

F83C: A9 00

135

CLRSC3

LDA

#$00

;TOP COORD FOR VLINE CALLS

F83E: 85 30

136

 

STA

COLOR

;CLEAR COLOR (BLACK)

F840: 20 28 F8

137

 

JSR

VLINE

;DRAW VLINE

F843: 88

138

 

DEY

 

;NEXT LEFTMOST X-COORD

F844: 10 F6

139

 

BPL

CLRSC3

;LOOP UNTIL DONE

F846: 60

140

 

RTS

 

 

 

F847: 48

141

GBASCALC PHA

 

;FOR INPUT 000DEFGH

F848: 4A

142

 

LSR

 

 

 

F849: 29 03

143

 

AND

#$03

 

 

F84B: 09 04

144

 

ORA

#$04

;

GENERATE GBASH=000001FG

F84D: 85 27

145

 

STA

GBASH

 

 

F84F: 68

146

 

PLA

 

;

AND GBASL=HDEDE000

F850: 29 18

147

 

AND

#$18

 

 

F852: 90 02

148

 

BCC

GBCALC

 

 

F854: 69 7F

149

 

ADC

#$7F

 

 

F856: 85 26

150

GBCALC

STA

GBASL

 

 

F858: 0A

151

 

ASL

 

 

 

F859: 0A

152

 

ASL

 

 

 

F85A: 05 26

153

 

ORA

GBASL

 

 

F85C: 85 26

154

 

STA

GBASL

 

 

F85E: 60

155

 

RTS

 

 

 

F85F: A5 30

156

NXTCOL

LDA

COLOR

;INCREMENT COLOR BY 3

F861: 18

157

 

CLC

 

 

 

F862: 69 03

158

 

ADC

#$03

 

 

F864: 29 0F

159

SETCOL

AND

#$0F

;SETS COLOR=17*A MOD 16

F866: 85 30

160

 

STA

COLOR

 

 

F868: 0A

161

 

ASL

 

;BOTH HALF BYTES OF COLOR EQUAL

F869: 0A

162

 

ASL

 

 

 

F86A: 0A

163

 

ASL

 

 

 

F86B: 0A

164

 

ASL

 

 

 

F86C: 05 30

165

 

ORA

COLOR

 

 

F86E: 85 30

166

 

STA

COLOR

 

 

F870: 60

167

 

RTS

 

 

 

F871: 4A

168

SCRN

LSR

 

;READ SCREEN Y-COORD/2

F872: 08

169

 

PHP

 

;SAVE LSB (CARRY)

F873: 20 47 F8

170

 

JSR

GBASCALC

;CALC BASE ADDRESS

F876: B1 26

171

 

LDA

(GBASL),Y

;GET BYTE

F878: 28

172

 

PLP

 

;RESTORE LSB FROM CARRY

F879: 90 04

173

SCRN2

BCC

RTMSKZ

;IF EVEN, USE LO H

F87B: 4A

174

 

LSR

 

 

 

F87C: 4A

175

 

LSR

 

 

 

F87D: 4A

176

 

LSR

 

;SHIFT HIGH HALF BYTE DOWN

F87E: 4A

177

 

LSR

 

 

 

F87F: 29 0F

178

RTMSKZ

AND

#$0F

;MASK 4-BITS

F881: 60

179

 

RTS

 

 

 

F882: A6 3A

180

INSDS1

LDX

PCL

;PRINT PCL,H

 

 

 

 

 

 

 

Page 21
Image 21
Apple II manual INY NO, INC Index X-COORD