I watched a super interesting Black Hat video on youtube that talked about discovering secret instructions on CPUs by iterating over each bit of opcodes until y

I watched a super interesting Black Hat video on youtube that talked about discovering secret instructions on CPUs by iterating over each bit of opcodes until you get an illegal instruction, and thereby discovering if an opcode is valid or not. He set up a room full of PCs running his code and had hardware to auto-reset them when they crashed. https://youtu.be/KrksBdWcZgQ https://youtu.be/KrksBdWcZgQ