IBM Assembler Interview Question:

How to initialize a register to 0000?

Submitted by: Administrator

XR Rx,Rx

This is the best way and most efficient way of initializing
the register values or Label values to '0'.

Its because the time required to execute a Logical
Instruction is always less than the Arithmetic Instructions.

e.g SR Rx,Rx consumes more execution time than XR Rx,Rx.

So XR Rx,Rx is a better way to do obtain our target.
Submitted by: Administrator