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ds: so close on credits

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This commit is contained in:
Vince Weaver 2019-11-08 20:58:53 -05:00
parent 8323b8ff8b
commit 176af12a61
2 changed files with 47 additions and 30 deletions
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22
demosplash/credits.s
View File

@ -626,23 +626,27 @@ credits_text_end:
fake_music_play:
; 1239 - 6 = 1233
; 1239 - 6 (ret) = 1233
; Try X=60 Y=4 cycles=1225R8
; jsr clear_ay_both
jsr clear_ay_both ; 6+1048
; 1233-1054=179
; Try X=2 Y=11 cycles=177R2
nop
nop
nop
nop
ldy #4 ; 2
uloop1: ldx #60 ; 2
ldy #11 ; 2
uloop1: ldx #2 ; 2
uloop2: dex ; 2
bne uloop2 ; 2nt/3
dey ; 2
bne uloop1 ; 2nt/3
rts
fake_music_play_end:
.assert >fake_music_play = >fake_music_play_end, error, "fake_musis_play crosses page"

55
demosplash/pt3_lib_mockingboard.s
View File

@ -85,41 +85,54 @@ reset_ay_both:
write_ay_both:
; address
stx MOCK_6522_ORA1 ; put address on PA1 ; 3
stx MOCK_6522_ORA2 ; put address on PA2 ; 3
stx MOCK_6522_ORA1 ; put address on PA1 ; 4
stx MOCK_6522_ORA2 ; put address on PA2 ; 4
lda #MOCK_AY_LATCH_ADDR ; latch_address on PB1 ; 2
sta MOCK_6522_ORB1 ; latch_address on PB1 ; 3
sta MOCK_6522_ORB2 ; latch_address on PB2 ; 3
sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
ldy #MOCK_AY_INACTIVE ; go inactive ; 2
sty MOCK_6522_ORB1 ; 3
sty MOCK_6522_ORB2 ; 3
sty MOCK_6522_ORB1 ; 4
sty MOCK_6522_ORB2 ; 4
;===========
; 28
; value
lda MB_VALUE ; 3
sta MOCK_6522_ORA1 ; put value on PA1 ; 3
sta MOCK_6522_ORA2 ; put value on PA2 ; 3
sta MOCK_6522_ORA1 ; put value on PA1 ; 4
sta MOCK_6522_ORA2 ; put value on PA2 ; 4
lda #MOCK_AY_WRITE ; ; 2
sta MOCK_6522_ORB1 ; write on PB1 ; 3
sta MOCK_6522_ORB2 ; write on PB2 ; 3
sty MOCK_6522_ORB1 ; 3
sty MOCK_6522_ORB2 ; 3
sta MOCK_6522_ORB1 ; write on PB1 ; 4
sta MOCK_6522_ORB2 ; write on PB2 ; 4
sty MOCK_6522_ORB1 ; 4
sty MOCK_6522_ORB2 ; 4
;===========
; 29
rts ; 6
;===========
; 51
; 63
write_ay_both_end:
.assert >write_ay_both = >write_ay_both_end, error, "write_ay_both crosses page"
;=======================================
; clear ay -- clear all 14 AY registers
; should silence the card
;=======================================
; 7+(74*14)+5=1048
clear_ay_both:
ldx #14
lda #0
sta MB_VALUE
ldx #14 ; 2
lda #0 ; 2
sta MB_VALUE ; 3
clear_ay_left_loop:
jsr write_ay_both
dex
bpl clear_ay_left_loop
rts
jsr write_ay_both ; 6+63
dex ; 2
bpl clear_ay_left_loop ; 3
; -1
rts ; 6
clear_ay_end:
.assert >clear_ay_both = >clear_ay_end, error, "clea_ay_both crosses page"
;=======================================
; Detect a Mockingboard card