Empty program: Difference between revisions
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Puppydrum64 (talk | contribs) |
Puppydrum64 (talk | contribs) |
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Without an infinite loop the program counter will execute undefined behavior, depending on how "empty" bytes are padded. If we're generous and assume that empty bytes are padded with <code>NOP</code>, eventually the program counter will attempt to execute the interrupt vectors as executable code. If we assume that an "empty program" needs to not crash (even though you really can't tell the difference with nothing on screen), we need a way to "trap" the program counter. |
Without an infinite loop the program counter will execute undefined behavior, depending on how "empty" bytes are padded. If we're generous and assume that empty bytes are padded with <code>NOP</code>, eventually the program counter will attempt to execute the interrupt vectors as executable code. If we assume that an "empty program" needs to not crash (even though you really can't tell the difference with nothing on screen), we need a way to "trap" the program counter. |
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<lang 6502asm>.org $8000 ;usually $8000 but it depends on the mapper. |
<lang 6502asm>.org $8000 ;usually $8000 but it depends on the mapper. |
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RESET: ;execution starts here |
RESET: ;execution starts here |
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JMP RESET |
JMP RESET |
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