Yeah, but that still doesn’t mean there aren’t theoretical bugs. Testing every input would effectively mean testing every stimulus, which is combinatorially impossible. You might still have subtle timing bugs, bugs with very uncommon instruction sequences etc.
But my point was exactly that the (extremely vastly) smaller subset of tests that you performed is more than enough to proclaim a CPU to be “working”.
But my point was exactly that the (extremely vastly) smaller subset of tests that you performed is more than enough to proclaim a CPU to be “working”.