On Tue, Nov 29, 2011 at 12:40, Barry Smith <[email protected]> wrote:

The very first google hit for "pause instruction spin loop"

This is documentation for the first chip to use it. They are asserting that it does not cause illegal-opcode exceptions for prior chips, so it is valid to use unconditionally, even in software that needs to run on older chips. I think this is clear from context (certainly if you had been reading the documented instead of skipping to the end), but it could have been more explicit.