Apple-2-SW/dos33fsprogs
1
0
Fork 0
mirror of https://github.com/deater/dos33fsprogs.git synced 2024-06-07 08:30:20 +00:00
Code Issues Projects Releases Wiki Activity

demo: shave off some more bytes

Browse Source
This commit is contained in:
Vince Weaver 2022-11-12 19:24:51 -05:00
parent 647adeb54f
commit 7c9f3ebf6c
1 changed files with 19 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
demos/demosplash2022/play_frame.s
View File

@ -13,40 +13,42 @@ set_notes_loop:
;==================
; load next byte
ldy SONG_OFFSET
ldy SONG_OFFSET ; Y = offset into song
track_smc:
lda track4,Y
lda track4,Y ; get next byte into A
;==================
; see if hit end
cmp #$ff
cmp #$ff ; FF means we hit end
bne not_end
;====================================
; if at end, loop back to beginning
inc WHICH_TRACK
ldy WHICH_TRACK
cpy #5
ldy WHICH_TRACK ; get current track in Y
iny ; increment track
cpy #5 ; see if off end
bne no_wrap
ldy #1
sty WHICH_TRACK
ldy #1 ; loop to track 1
no_wrap:
lda tracks_l,Y
sty WHICH_TRACK
lda tracks_l,Y ; self-modify track
sta track_smc+1
; lda tracks_h,Y
; lda tracks_h,Y ; enforce in same page
; sta track_smc+2
lda bamps_l,Y
lda bamps_l,Y ; self modify B-amplitude
sta bamp_smc+1
; lda bamps_h,Y
; lda bamps_h,Y ; enforce in same page
; sta bamp_smc+2
lda #0
lda #0 ; reset song offset
sta SONG_OFFSET
beq set_notes_loop ; bra
beq set_notes_loop ; bra ; try again in new track
not_end:
@ -56,21 +58,17 @@ not_end:
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
tax ; put channel offset*2 in X
pla ; restore note
pha
and #$6
and #$6 ; get note length
lsr
tay
lda lengths,Y
lda lengths,Y ; lookup in table
sta SONG_COUNTDOWN ;
pla