4cade/src/ui.sound.a

44 lines
816 B
Plaintext

;license:MIT
;(c) 2018-9 by 4am
;
; sound effects
;
; Public functions
; - SoftBell
;
;------------------------------------------------------------------------------
; SoftBell
;
; in: none
; out: all registers and flags preserved
;------------------------------------------------------------------------------
SoftBell
php
pha
txa
pha
ldx #32
- lda #2
jsr @wait
bit $C030
lda #33
jsr @wait
bit $C030
dex
bne -
pla
tax
pla
plp
rts
@wait ; identical to $FCA8 ROM routine, but ROM is switched out when we need it
sec
-- pha
- sbc #1
bne -
pla
sbc #1
bne --
rts