FOO EX R0,BAR BAR JCTG Rx,FOO
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Assembler List <[email protected]> on behalf of Robin Vowels <[email protected]> Sent: Monday, August 10, 2020 10:19 PM To: [email protected] Subject: Re: Clearing a register From: "Steve Smith" <[email protected]> Sent: Tuesday, August 11, 2020 11:07 AM > For the whole register, LGHI, LLILL (or HL, LH, or HH) are best. LLILF, > LLIHF take up more space. XGR, SGR, SLGR set the CC. > For only the low half, XR, SR, SLR have the shortness advantage, and LHI > the non-CC advantage. > Chances are that the CC setting is irrelevant in timing on modern CPUs. > The worst way to zero a register is more interesting. JCTG Rx,* is my > favorite. If Rx is already 0, guess how long that will take. I think that EX JCTG Rx,* takes longer. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
