From: "Rob van der Heij" <[email protected]> Sent: Monday, 23 August 2010 5:43 PM
Sure, it does take some effort to change things when you find that your initial choice of registers was unlucky. One I found in my inherited code is using a LM to load length and address, and then use 3 XR instructions to swap the registers so you can do a MVCL. A straight path is so much easier to follow.
Agreed, that LM/3XR sequence sounds silly. Two loads (L) are a lot shorter than 4 instructions, and far clearer. Alternatively, one could use LM to load one of the operands into the correct register, followed by a LR to get the second operand into its correct register.
