That is correct. All GP registers are actually 64 bits wide and 32-bit instructions use the lower half only.
To use all 64 bits use the "Grande" version of the 32-bit instructions (most are suffixed with "G"). There are also instructions that affect only the upper 32-bit halves of the GP registers. As usual, check a recent PoOPS the first time you use them to make sure you aren't running into any special-case issues. Peter -----Original Message----- From: IBM Mainframe Assembler List <[email protected]> On Behalf Of Dave Clark Sent: Wednesday, January 19, 2022 1:45 PM To: [email protected] Subject: 64-bit registers (was: Unsigned Binary Formats) "IBM Mainframe Assembler List" <[email protected]> wrote on 01/19/2022 01:00:07 PM: > I'd suggest you clear the high-order word of R2 then use CVDG. > > Would that work for you? OK, that brings up a question that I have not had to address before this. Up till now I've used odd-even register pairs for 64-bit operations. But I'm given to understand that all general registers are actually 64-bit now instead of the traditional 32-bit. Is that correct? So, 32-bit instructions just use the low order 32 bits of the general purpose register and 64-bit instructions automatically use the full register -- with no register "pairs" involved. Is that correct? Sincerely, Dave Clark -- This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system.
