demo: shave a few more bytes

This commit is contained in:
Vince Weaver 2022-11-12 21:22:20 -05:00
parent 7c9f3ebf6c
commit 3afabf3af4
3 changed files with 25 additions and 29 deletions

View File

@ -40,7 +40,7 @@ ESCAPE: escape.o
ld65 -o ESCAPE escape.o -C $(LINKER_SCRIPTS)/apple2_c00.inc ld65 -o ESCAPE escape.o -C $(LINKER_SCRIPTS)/apple2_c00.inc
escape.o: escape.s \ escape.o: escape.s \
logo_intro.s \ logo_intro.s zp.inc \
ay3_write_regs.s escape.s interrupt_handler.s \ ay3_write_regs.s escape.s interrupt_handler.s \
play_frame.s \ play_frame.s \
mA2E_4.s mockingboard_constants.s mockingboard_init.s tracker_init.s mA2E_4.s mockingboard_constants.s mockingboard_init.s tracker_init.s

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@ -13,9 +13,9 @@ set_notes_loop:
;================== ;==================
; load next byte ; load next byte
ldy SONG_OFFSET ; Y = offset into song ; ldy SONG_OFFSET ; Y = offset into song
track_smc: track_smc:
lda track4,Y ; get next byte into A lda track4;,Y ; get next byte into A
;================== ;==================
; see if hit end ; see if hit end
@ -45,10 +45,10 @@ no_wrap:
; lda bamps_h,Y ; enforce in same page ; lda bamps_h,Y ; enforce in same page
; sta bamp_smc+2 ; sta bamp_smc+2
lda #0 ; reset song offset ; lda #0 ; reset song offset
sta SONG_OFFSET ; sta SONG_OFFSET
beq set_notes_loop ; bra ; try again in new track jmp set_notes_loop ; bra ; try again in new track
not_end: not_end:
@ -78,24 +78,18 @@ not_end:
tay ; lookup in table tay ; lookup in table
lda frequencies_high,Y lda frequencies_high,Y ; get high frequency
sta AY_REGS+1,X sta AY_REGS+1,X ; put in AY register
; sta $500,X
lda frequencies_low,Y lda frequencies_low,Y ; get low frequency
sta AY_REGS,X ; set proper register value sta AY_REGS,X ; also put in AY register
; visualization
;blah_urgh:
; sta $400,Y
; inc blah_urgh+1
;============================ ;============================
; point to next ; point to next
; assume less than 256 bytes ; assume less than 256 bytes
inc SONG_OFFSET inc track_smc+1 ; SONG_OFFSET
done_update_song: done_update_song:
@ -104,7 +98,9 @@ done_update_song:
;================================= ;=================================
; coundown song ; coundown song
dec SONG_COUNTDOWN dec SONG_COUNTDOWN ; if length was 0, means there
; was another note starting at same
; time, so go back and play that too
bmi set_notes_loop bmi set_notes_loop
@ -135,28 +131,28 @@ chanb:
tya tya
bne bamps_skip bne bamps_skip
lda BAMP_COUNTDOWN lda BAMP_COUNTDOWN ; b-amp conutdown
bne bamps_good bne bamps_good
bamp_smc: bamp_smc:
lda bamps4 lda bamps4 ; get new value
pha pha
and #$f and #$f ; bottom 4 its is ampllitude
sta AY_REGS+9 ; B volume sta AY_REGS+9 ; B volume
pla pla
lsr ; top 4 bits are length
lsr lsr
lsr lsr
lsr lsr
lsr
; clc
; adc #1
sta BAMP_COUNTDOWN sta BAMP_COUNTDOWN
inc bamp_smc+1 inc bamp_smc+1 ; increment to next location
; assumes on same page
; and less than 256
bamps_good: bamps_good:
dec BAMP_COUNTDOWN dec BAMP_COUNTDOWN ; countdown
bamps_skip: bamps_skip:
;================================= ;=================================

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@ -13,7 +13,7 @@ AY_REGS = $70
SONG_L = $80 SONG_L = $80
SONG_H = $81 SONG_H = $81
SONG_OFFSET = $82 ;SONG_OFFSET = $82
SONG_COUNTDOWN = $83 SONG_COUNTDOWN = $83
OCTAVE = $84 OCTAVE = $84
REGISTER = $85 REGISTER = $85