vbl equ 216

; org $0000

pmain equ *

bank0 lda #0
 sta $d301

cm_0 lda #0
iad0_m adc #0
 sta cm_0+1
 lda p_0c+1
iad0_s adc #0
 sta p_0c+1
 bcc p_0c
 inc p_0c+2
 lda p_0c+2
ien0_s cmp #0
 bcc p_0c

rep0_m lda #0
 sta p_0c+1
rep0_s lda #0
 sta p_0c+2
 jmp bank1

p_0c ldx $4000
ivol10 lda $d800,x
ch_0 sta $d600

bank1 lda #0
 sta $d301

cm_1 lda #0
iad1_m adc #0
 sta cm_1+1
 lda p_1c+1
iad1_s adc #0
 sta p_1c+1
 bcc p_1c
 inc p_1c+2
 lda p_1c+2
ien1_s cmp #0
 bcc p_1c

rep1_m lda #0
 sta p_1c+1
rep1_s lda #0
 sta p_1c+2
 jmp bank2

p_1c ldx $4000
ivol11 lda $d800,x
ch_1 sta $d601

bank2 lda #0
 sta $d301

cm_2 lda #0
iad2_m adc #0
 sta cm_2+1
 lda p_2c+1
iad2_s adc #0
 sta p_2c+1
 bcc p_2c
 inc p_2c+2
 lda p_2c+2
ien2_s cmp #0
 bcc p_2c

rep2_m lda #0
 sta p_2c+1
rep2_s lda #0
 sta p_2c+2
 jmp bank3

p_2c ldx $4000
ivol12 lda $d800,x
ch_2 sta $d602

bank3 lda #0
 sta $d301

cm_3 lda #0
iad3_m adc #0
 sta cm_3+1
 lda p_3c+1
iad3_s adc #0
 sta p_3c+1
 bcc p_3c
 inc p_3c+2
 lda p_3c+2
ien3_s cmp #0
 bcc p_3c

rep3_m lda #0
 sta p_3c+1
rep3_s lda #0
 sta p_3c+2
 jmp p_e

p_3c ldx $4000
ivol13 lda $d800,x
ch_3 sta $d603

p_e dey
 beq pat
 jmp $0000

pat dec cnts
 beq pre
 ldy #vbl
 jmp $0000

pre lda #0
 sta patend
 lda #$fe
 sta $d301

 jmp i_0