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