View difference between Paste ID: <a href="/7rFNR8n9">7rFNR8n9</a> and <a href="/YTBZzx1X">YTBZzx1X</a>

; MADS options
1		; MADS options
2		; generate headers
3
4		opt h+
5
6		; zero page variables
7
8		screen_pointer = $80
9		current_color = $82
10		lines_counter = $83
11		lines_counter_add = $84
12		bar_counter = $85
13
14		; OS equates
15
16		RTCLOK = $0012
17		SDLSTL = $0230
18		GPRIOR = $026f
19		COLOR4 = $02c8
20		COLBK = $d01a
21		WSYNC = $d40a
22		VCOUNT = $d40b
23
24		org $2000
25
26		; init with black color
27
28		lda #0
29		sta COLOR4
30
31		; store screen pointer on zero page
32
33		jsr set_screen_pointer
34
35		; set display list
36
37		lda <display_list
38		sta SDLSTL
39		lda >display_list
40		sta SDLSTL+1
41
42		; activate GTIA mode
43
44		lda #$40
45		sta GPRIOR
46
47		; initialize color to 0 (black)
48
49		lda #0
50		sta current_color
51
52		; draw 6 horizontal bars
53
54		lda #6
55		sta bar_counter
56
57		; colors 0 → 14
58
59		@ ldx #14
60		@ jsr draw_line
61		jsr increase_color_brightness
62		jsr increase_screen_pointer
63		dex
64		bpl @-
65
66		; colors 14 → 0
67
68		ldx #14
69		@ jsr draw_line
70		jsr decrease_color_brightness
71		jsr increase_screen_pointer
72		dex
73		bpl @-
74
75		dec bar_counter
76		bne @-2
77
78		; reset screen pointer
79
80		jsr set_screen_pointer
81
82		; center add bar
83
84		adw screen_pointer #11
85
86		; start loop which will create center bar
87
88		lda #192
89		sta lines_counter
90
91		; move to center of line
92
93		@ adw screen_pointer #40
94
95		; and copy 15 bytes
96
97		ldy #0
98		ldx #0
99		@ lda colors_pixels,x
100		sta (screen_pointer),y
101		iny
102		inx
103		cpx #18
104		bne @-
105
106		dec lines_counter
107		bne @-1
108
109		; add one more bar in the middle
110
111		lda <screen+((192/2)-20)*40
112		sta screen_pointer
113		lda >screen+((192/2)-20)*40
114		sta screen_pointer + 1
115
116		; colors 0 → 14
117
118		ldx #14
119		@ jsr draw_line
120		jsr increase_color_brightness
121		jsr increase_screen_pointer
122		dex
123		bpl @-
124
125		; colors 14 → 0
126
127		ldx #14
128		@ jsr draw_line
129		jsr decrease_color_brightness
130		jsr increase_screen_pointer
131		dex
132		bpl @-
133
134		; dirty method for coloring the screen
135		; without display list interrupts
136
137		loop
138
139		; wait for start of new frame
140
141		lda RTCLOK+2
142		cmp RTCLOK+2
143		beq *-2
144
145		; border should be black
146		; set black color
147
148		lda #0
149		sta COLOR4
150
151		; so wait for 8 lines
152
153		lda #8
154		sta lines_counter
155
156		; set color index
157
158		ldx #7
159
160		; draw 2 full bars
161		; first
162
163		ldy #15
164		jsr draw_bar
165
166		; move color index
167
168		dex
169
170		; second full bar
171
172		ldy #15
173		jsr draw_bar
174
175		; move color index
176
177		dex
178
179		; draw half bar
180
181		ldy #8
182		jsr draw_bar
183
184		; move color index
185
186		dex
187
188		; draw full bar (in the middle)
189
190		ldy #14
191		jsr draw_bar
192
193		; move color index
194
195		dex
196
197		; draw half bar
198
199		ldy #7
200		jsr draw_bar
201
202		; move color index
203
204		dex
205
206		; draw full bar
207
208		ldy #15
209		jsr draw_bar
210
211		; move color index
212
213		dex
214
215		; draw full bar
216
217		ldy #15
218		jsr draw_bar
219
220		; move color index
221
222		dex
223
224		; draw full bar
225
226		ldy #17
227		jsr draw_bar
228
229		jmp loop
230
231		; procedures ------------------------
232
233		; set screen pointer
234
235		set_screen_pointer
236		lda <screen
237		sta screen_pointer
238		lda >screen
239		sta screen_pointer + 1
240		rts
241
242		; drawing line - simply put 40 bytes
243
244		draw_line
245		ldy #39
246		lda current_color
247		@ sta (screen_pointer),y
248		dey
249		bpl @-
250		rts
251
252		; increase color + 1
253
254		increase_color_brightness
255		lda current_color
256		clc
257		adc #17
258		sta current_color
259		rts
260
261		; decrease color - 1
262
263		decrease_color_brightness
264		lda current_color
265		sec
266		sbc #17
267		sta current_color
268		rts
269
270		; move screen pointer by 40 bytes
271
272		increase_screen_pointer
273		lda screen_pointer
274		clc
275		adc #40
276		sta screen_pointer
277		bcc @+
278		inc screen_pointer+1
279		@ rts
280
281		draw_bar ; x = color_table index, y = lines
282
283		sty lines_counter_add
284		lda VCOUNT
285		cmp lines_counter
286		bne *-5
287
288		lda colors_horizontal,x
289		sta WSYNC
290		sta COLBK
291
292		lda lines_counter
293		add lines_counter_add
294		sta lines_counter
295		rts
296
297		; display list
298
299		org $3000
300
301		display_list
302		.byte $70 ; 8 empty lines
303		.byte $4f ; LMS + ANTIC $f
304		.word $4010
305		:100 .byte $f ; 101 lines
306		.byte $4f ; LMS + ANTIC $f
307		.word $5000
308		:77 .byte $f ; 80 lines
309		.byte $41 ; JVB
310		.word display_list
311
312		; horizontal stripes
313
314		colors_pixels
315		.byte 0, $01, $23, $45, $67, $89, $ab, $cd, $ef, $fe, $dc, $ba, $98, $76, $54, $32, $10, 0
316
317		; center bar - table of colors
318
319		colors_horizontal
320		.byte $0, $70, $80, $90, $a0, $c0, $10, $30
321
322		; video RAM
323
324		org $4010
325
326		screen .byte 0