On 2/10/26 08:03, Jonathan Scott wrote:
would normally use XC to clear a storage field to binary zero. I think current IBM Z
hardware typically recognizes XC of a field with itself as a special case meaning
"set storage to zero", so it does not need to fetch the operand at all, and it
certainly doesn't need to fetch it twice.
...
Be careful using such a length as a count in a ccw or
decremented by 1 in EX -> MVC.
<https://en.wikipedia.org/wiki/Law_of_triviality>
(My speech output pronounces "XC" as "ninety"!)
--
gil
