EDRUPT does the following: * Inhibits interrupts until the next RESUME instruction (as if a hardware interrupt had been encountered). * Loads the Z register i

EDRUPT does the following: * Inhibits interrupts until the next RESUME instruction (as if a hardware interrupt had been encountered). * Loads the Z register into the ZRUPT register. (Incidentally, so far I've seen only a single instance of this instruction, in Luminary 131, and the return address is never used.) * Takes the next instruction from address 0 (which presumably has been pre-loaded with "TC something"). The instruction also shoves a couple of register values onto the data bus, but does not save them into memory. My assumption is that some kind of external instrumentation was able to capture these values, but that they were irrelevant to normal execution. Source: http://www.ibiblio.org/apollo/assembly_language_manual.html http://www.ibiblio.org/apollo/assembly_language_manual.html Supposedly it was mainly used for self-testing.