Great links, thanks! The first one has an awesome typo (I hope, else they're being a bit evil) with a double negative in the text explaining the instruction:

Great links, thanks! The first one has an awesome typo (I hope, else they're being a bit evil) with a double negative in the text explaining the instruction: Inactive elements will not not cause a read from Device memory or signal a fault, and are set to zero in the destination vector. Note the double "not" in the first half. Ouch.