tonecloud.2a03

	.data
tick:	.byt 0  ; tick counter
rnum:	.byt 0  ; row number
sidx:	.byt 0  ; scales index

	.text
_init:
	; reset playroutine variables
	lda	#0
	sta	tick
	sta	rnum

	rts

_play: .(
	; check if tick counter has overflowed
	lda	tick
	inc	tick
	cmp	#12
	beq	run_row
	; return if it hasn't
	rts

_text:
run_row:
	; if it has, reset to 0 and increment row counter
	lda	#0
	sta	tick
	lda	rnum
	inc	rnum

	tax
	and	#$7
	lda	_text,x
	lsr
	lsr
	lsr
	and	#$3
	tax
	inc
	lda	pulse,x
	sta	$4000
	and	#$3
	tax
	lda	pulse,x
	sta	$4004
	lda	#%10111111
	sta	$4008

	lda	rnum
	lsr
	lsr
	lsr
	lsr
	and	#$7
	tax
	lda	song,x
	asl
	asl
	asl
	sta	sidx

	lda	rnum
	and	#$15
	tax
	lda	p1_pat,x
	and	#$7
	clc
	adc	sidx
	tax
	lda	p1_scales,x
	tax
	lda	freq_lo,x
	sta	$4002
	lda	freq_hi,x
	sta	$4003

p2_pat:
	lda	rnum
	and	#$15
	tax
	lda	p2_pat,x
	and	#$7
	clc
	adc	sidx
	tax
	lda	p2_scales,x
	tax
	lda	freq_lo,x
	sta	$4006
	lda	freq_hi,x
	sta	$4007

p1_pat:
	lda	rnum
	and	#$7
	tax
	lda	tri_pat,x
	and	#$7
	clc
	adc	sidx
	tax
	lda	tri_scales,x
	tax
	lda	freq_lo,x
	sta	$400a
	lda	freq_hi,x
	sta	$400b
	rts
.)

	; auto-generated frequency tables
freq_hi:
	.byt $03,$03,$03,$03,$03,$02,$02,$02,$02,$02,$02,$02,$01,$01,$01,$01,
	.byt $01,$01,$01,$01,$01,$01,$01,$01,$00,$00,$00,$00,$00,$00,$00,$00,
	.byt $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,
	.byt $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,
freq_lo:
	.byt $d4,$9c,$69,$37,$09,$dd,$b4,$8d,$69,$46,$25,$06,$e9,$cd,$b4,$9b,
	.byt $84,$6e,$59,$46,$34,$22,$12,$02,$f4,$e6,$d9,$cd,$c1,$b6,$ac,$a2,
	.byt $99,$90,$88,$80,$79,$72,$6c,$66,$60,$5a,$55,$50,$4c,$47,$43,$3f,
	.byt $3c,$38,$35,$32,$2f,$2c,$2a,$27,$25,$23,$21,$1f,$1d,$1b,$1a,$18,
p1_scales:
	.byt 12,15,19,22,24,27,31,34
	.byt 15,19,22,15,19,22,15,19
	.byt 15,19,22,15,19,22,15,19
	.byt 15,19,22,15,19,22,15,19
p2_scales:
	.byt 31,34,12,15,19,22,24,27
	.byt 12,15,19,22,15,19,22,15
	.byt 12,15,19,22,15,19,22,15
	.byt 31,34,12,15,19,22,24,27
tri_scales:
	.byt  0,24, 0,12, 0,12,19,22
	.byt 27, 3,10, 3,15,15,27,27
	.byt 20, 8,12, 8,20, 8, 8, 8
	.byt  6, 6, 6, 6,18,18,18,18
tri_pat:
	.byt  7, 0, 1, 2, 3, 4, 5, 6
song:
	.byt  0, 1, 0, 1, 2, 1, 2, 3
pulse:
	.byt %00110111
	.byt %11110110
	.byt %10110111
	.byt %01110100

_end: