2014-04-26 10:52:28 -04:00
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death code
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2014-04-26 11:54:15 -04:00
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n. A routine whose job is to set everything in the computer registers,
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memory, flags, everything to zero, including that portion of memory where it
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is running; its last act is to stomp on its own store zero instruction.
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Death code isn't very useful, but writing it is an interesting hacking
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challenge on architectures where the instruction set makes it possible, such
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as the PDP-8 (it has also been done on the DG Nova). Perhaps the ultimate
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death code is on the TI 990 series, where all registers are actually in RAM,
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and the instruction store immediate 0 has the opcode 0. The PC will
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immediately wrap around core as many times as it can until a user hits HALT.
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Any empty memory location is death code. Worse, the manufacturer recommended
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use of this instruction in startup code (which would be in ROM and therefore
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survive).
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