death code
A routine whose job is to set everything in the computer - registers, memory,
flags - to zero, including that portion of memory where it is running; its last
act is to stomp on its own "store zero" instruction. Death code isn't very
useful, but writing it is an interesting hacking challenge on architectures
where the instruction set makes it possible, such as the PDP-8 or the Data
General Nova.
Perhaps the ultimate death code is on the TI 990 series, where all registers are
actually in RAM, and the instruction "store immediate 0" has the opcode 0. The
program counter will immediately wrap around core as many times as it can until
a user hits HALT. Any empty memory location is death code. Worse, the
manufacturer recommended use of this instruction in startup code (which would be
in ROM and therefore survive).
[Jargon File]
Nearby terms:
dead tree « dead tree edition « deamon « death
code » Death Star » deb » Debbugs
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