mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-06-08 15:29:41 +00:00
168 lines
2.1 KiB
ArmAsm
168 lines
2.1 KiB
ArmAsm
play_frame:
|
|
|
|
|
|
;============================
|
|
; see if still counting down
|
|
|
|
lda SONG_COUNTDOWN
|
|
bpl done_update_song
|
|
|
|
set_notes_loop:
|
|
|
|
|
|
;==================
|
|
; load next byte
|
|
|
|
ldy SONG_OFFSET
|
|
track_smc:
|
|
lda track4,Y
|
|
|
|
;==================
|
|
; see if hit end
|
|
|
|
cmp #$ff
|
|
bne not_end
|
|
|
|
;====================================
|
|
; if at end, loop back to beginning
|
|
|
|
inc WHICH_TRACK
|
|
ldy WHICH_TRACK
|
|
cpy #5
|
|
bne no_wrap
|
|
ldy #1
|
|
sty WHICH_TRACK
|
|
no_wrap:
|
|
lda tracks_l,Y
|
|
sta track_smc+1
|
|
; lda tracks_h,Y
|
|
; sta track_smc+2
|
|
|
|
lda bamps_l,Y
|
|
sta bamp_smc+1
|
|
; lda bamps_h,Y
|
|
; sta bamp_smc+2
|
|
|
|
lda #0
|
|
sta SONG_OFFSET
|
|
|
|
beq set_notes_loop ; bra
|
|
|
|
not_end:
|
|
|
|
|
|
; NNNNNEEC -- c=channel, e=end, n=note
|
|
|
|
pha ; save note
|
|
|
|
and #1
|
|
; tax
|
|
; ldy #$0E
|
|
; sty AY_REGS+8,X ; $08 set volume A,B
|
|
|
|
asl
|
|
tax ; put channel offset in X
|
|
|
|
|
|
pla ; restore note
|
|
pha
|
|
|
|
and #$6
|
|
lsr
|
|
tay
|
|
lda lengths,Y
|
|
sta SONG_COUNTDOWN ;
|
|
|
|
pla
|
|
lsr
|
|
lsr
|
|
lsr ; get note in A
|
|
|
|
tay ; lookup in table
|
|
|
|
lda frequencies_high,Y
|
|
sta AY_REGS+1,X
|
|
; sta $500,X
|
|
|
|
lda frequencies_low,Y
|
|
sta AY_REGS,X ; set proper register value
|
|
|
|
; visualization
|
|
;blah_urgh:
|
|
; sta $400,Y
|
|
; inc blah_urgh+1
|
|
|
|
|
|
;============================
|
|
; point to next
|
|
|
|
; assume less than 256 bytes
|
|
inc SONG_OFFSET
|
|
|
|
|
|
done_update_song:
|
|
|
|
|
|
;=================================
|
|
; coundown song
|
|
|
|
dec SONG_COUNTDOWN
|
|
bmi set_notes_loop
|
|
|
|
|
|
|
|
|
|
;===============================
|
|
;===============================
|
|
; things that happen every frame
|
|
;===============================
|
|
;===============================
|
|
|
|
|
|
;=================================
|
|
; rotate through channel A volume
|
|
|
|
lda FRAME ; repeating 8-long pattern
|
|
and #$7
|
|
tay
|
|
lda channel_a_volume,Y
|
|
sta AY_REGS+8 ; A volume
|
|
|
|
|
|
;=================================
|
|
; handle channel B volume
|
|
chanb:
|
|
; lda FRAME
|
|
; and #$7
|
|
tya
|
|
bne bamps_skip
|
|
|
|
lda BAMP_COUNTDOWN
|
|
bne bamps_good
|
|
|
|
bamp_smc:
|
|
lda bamps4
|
|
pha
|
|
and #$f
|
|
sta AY_REGS+9 ; B volume
|
|
pla
|
|
|
|
lsr
|
|
lsr
|
|
lsr
|
|
lsr
|
|
; clc
|
|
; adc #1
|
|
sta BAMP_COUNTDOWN
|
|
|
|
inc bamp_smc+1
|
|
|
|
bamps_good:
|
|
dec BAMP_COUNTDOWN
|
|
bamps_skip:
|
|
|
|
;=================================
|
|
; inc frame counter
|
|
|
|
inc FRAME
|