Delay = $CE
Where = $D0

ORG $1001

DW $1001,$100B,0
DB $9E,"4109",0,0,0

SEI
LDA $FF06
AND #$EF
STA $FF06 ;Turn screen off
STA $FF3F ;Switch to RAM

JMP init

main
LDA #$00
STA Delay
LDA #$01
STA Delay+1
JSR play1
LDA #$2F
STA Delay
STA Delay+1
JSR play1
LDA #$00
STA Delay
LDA #$1F
STA Delay+1
JSR play1
JSR done

init
LDA #<sounddata
STA Where
LDA #>sounddata
STA Where+1
LDY #$00
LDA #$FD
STA $FF0E ;Sound #1 low
LDA #$03
STA $FF10 ;Sound #1 high
LDA #$FE
STA $FF0F ;Sound #2 low
LDA $FF12
ORA #$03
STA $FF12 ;Sound #2 high
JMP main

play1
LDA (Where),Y
- DEC Delay
BEQ +
DEC Delay+1
BNE -
NOP
ROL
+ STA $FF11
INC Where
BNE play1
INC Where+1
LDA Where+1
CMP #>endsound ;Check the end of the music
BNE play1
RTS

done
JMP done

sounddata
INCBIN "PCM.bin"
endsound