FC/nes music sample program Happy Birthday Song

; Start address: $ bff0
; End address: $ FFFF
; File length: $4010


Counter = $00
Music_offset1 = $01
Music_offset2 = $02

. Org $ bff0
. DB "Nes", $ 1A, $01, $01, $00, $00
. Dw $00, $00, $00, $00
. Start $ c000
. Org $ c000
Reset:
SEI; Disable interruption
ClD
Ldx # $ ff; initialize the top pointer of the stack to $ FF
TXS

Bytes
STX counter
STX music_offset1
STX music_offset2

_ VB1:
LDA $2002
BPL _ VB1
_ VB2:
LDA $2002
BPL _ VB2

LDA #$00
Sta $2001

 
LDA # $ 0f; sound switching: 0000 1111, square wave #1 #2, triangle wave, noise
Sta $4015

LDA # $ 8f
Sta $4000; Apu square wave #1 control port

LDA #$00
Sta $4001; Apu square wave #1 control port
 
LDA # $80; Enable NMI interruption
Sta $2000

Main:
JMP main


NMI:
INC counter; increase in counters
Ldx music_offset1
LDA music1, X; obtain the Sound Length
CMP counter; Determine whether to play the video
Beq next2; playback
CMP # $ FF
Beq next1; Whether to end
JMP over; exit
Next1:
Ldx # $00; back to start
STX music_offset1
JMP over
Next2:
LDA #$00
Sta counter
LDA music_offset2
Tay
LDA music2, Y; eight low wavelength bits
CMP # $ ff; is it over?
Beq next3
Sta $4002

Iny
LDA music2, Y; high wavelength + sound length counter
CMP # $ ff; is it over?
Beq next3
Sta $4003

Iny; next note
Sty music_offset2
Bytes
STX music_offset1
JMP over
Next3:
Ldy # $00; back to start
Sty music_offset2
Over:
RRTI

Music1:
; Audio length 8*4 + 1 = 33
. DB $10, $10, $20, $20, $20, $20, $20, $10
. DB $10, $20, $20, $20, $20, $20, $20, $10
. DB $10, $20, $20, $20, $20, $20, $20, $20
. DB $20, $10, $10, $20, $20, $20, $20, $20
. DB $20, $ FF
Music2:
; Two groups, $ FF is the end of 8*8 + 2 = 66
. DB $ 1C, $09, $ 1C, $09, $ FD, $08, $ 1C, $09
. DB $ D4, $08, $ E1, $08, $00, $00, $ 1C, $09
. DB $ 1C, $ D9, $ FD, $08, $ 1C, $09, $ BD, $08
. DB $ D4, $08, $ D4, $08, $00, $00, $ 1C, $09
. DB $ 1C, $09, $ 8D, $08, $ A8, $08, $ D4, $08
. DB $ E1, $08, $ FD, $08, $ FD, $08, $ FD, $08
. DB $00, $00, $ 9f, $08, $ 9f, $08, $ A8, $08
. DB $ D4, $08, $ BD, $08, $ D4, $08, $ D4, $ D4
. DB $08, $00, $ ff, $ FF

IRQ:
RRTI


. Org $ fffa
. Dw NMI, reset, IRQ

Girl don't cry (QQ: 191035066) @ 2012-08-13 16:45:32 @ http://www.cnblogs.com/nbsofer