2015-02-18 11:05:18 +00:00
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; Create an iNES header
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.ines {"prog": 1, "char": 0, "mapper": 0, "mirror": 1}
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; Here is the start of our code
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.org $C000
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start:
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2015-02-18 03:05:37 +00:00
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LDA #$01 ; square 1
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STA $4015
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2015-03-01 01:43:43 +00:00
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LDA #$F8 ; period low
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2015-02-18 03:05:37 +00:00
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STA $4002
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LDA #$02 ; period high
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STA $4003
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LDA #$BF ; volume
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STA $4000
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forever:
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JMP forever
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2015-02-18 11:05:18 +00:00
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nmi:
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RTI
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.org $FFFA ; Here are the three interrupt vectors
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.dw nmi ; VBlank non-maskable interrupt
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.dw start ; When the processor is reset or powers on
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.dw $0 ; External interrupt IRQ
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