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,
Perhaps the ultimate death code is on the
TI 990 series,
instruction "store immediate 0" has the
opcode 0. The
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).