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; void __fastcall__ psg_outb( unsigned char b );
; void __fastcall__ psg_delayms( unsigned char c);
; void __fastcall__ bios_playsound( void *b, unsigned char c);
; void psg_silence( void );
.export _psg_outb, _psg_silence, _psg_delay
.export _bios_playsound
.import popa
.include "creativision.inc"
_psg_outb:
;* Let BIOS output the value
jmp $FE77
_psg_silence:
jmp $FE54
_psg_delay:
tay
l1: lda #200
l2: sbc #1
bne l2
lda #200
l3: sbc #1
bne l3
dey
bne l1
rts
;* Creativision Sound Player
;*
;* Based on BIOS sound player.
;* Pass a pointer to a set of note triples, terminated with a tempo byte
;* and the len (max 255)
_bios_playsound:
pha ; Save Length Byte
sei
lda #$D5 ; BIOS volume table low
sta $4
lda #$FC ; BIOS volume table high
sta $5
jsr popa ; Get Sound table pointer low
sta $0
jsr popa ; Get Sound table pointer high
sta $1
pla
tay ; Put length in Y
dey
php
jmp $FBED ; Let BIOS do it's thing
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