Program termination: Difference between revisions
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There is no firmware or BASIC to return to, so the easiest way to do this is to "trap" the program counter with a branch back to itself. This isn't a complete termination since NMI code will still run, unless you disable the screen. In order to display a static "THE END" screen that doesn't take user input, which is what many games did once the game was beaten, you can do this: |
There is no firmware or BASIC to return to, so the easiest way to do this is to "trap" the program counter with a branch back to itself. This isn't a complete termination since NMI code will still run, unless you disable the screen. In order to display a static "THE END" screen that doesn't take user input, which is what many games did once the game was beaten, you can do this: |
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<lang 6502asm> |
<lang 6502asm>sei ;disable IRQs |
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sei ;disable IRQs |
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halt: |
halt: |
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jmp halt ;trap the program counter</lang> |
jmp halt ;trap the program counter</lang> |
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