6 ms·
There are lots of amazing stories about the AGC: - It has a mysterious intruction named EDRUPT ("Ed's interrupt") that took several years to be reverse enginee
by l_perrin 12y ago
There are lots of amazing stories about the AGC:
- It has a mysterious intruction named EDRUPT ("Ed's interrupt") that took several years to be reverse engineered afterwards.
- The 32k ROM was stored on rope memory: bundles of wires with a ferrite core assembled by hand in factories.
- TheLoneWolfling 12y agoEDRUPT 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.