Fun Question. Looking forward to answers. I use XR a lot. Not worried about efficiency or speed. It just looks cool and if someone sees it and does not know what it does they could guess it is clearing the register, like X'ing it out.
================================ Duffy Nightingale Sound Software Printing, Inc. www.soundsoftware.us Phone: 360.385.3456 Fax: 973.201.8921 The information in this e-mail, and any attachment therein, is confidential and for use by the addressee only. If you are not the intended recipient, please return the e-mail to the sender and delete it from your computer. Although Sound Software Printing, Inc. attempts to sweep e-mail and attachments for viruses, it does not guarantee that either are virus-free and accepts no liability for any damage sustained as a result of viruses. -----Original Message----- From: IBM Mainframe Assembler List <[email protected]> On Behalf Of Schmitt, Michael Sent: Monday, August 10, 2020 12:13 PM To: [email protected] Subject: Clearing a register There are many ways to set a register to binary zero. My question is, which is the most efficient? 1. XR Rn,Rn 2. SR Rn,RN 3. SRA Rn,Rn 4. LHI Rn,0 5. Other instruction 6. Depends on hardware 7. Depends on other factors. (What?) 8. They are have equal performance 9. Method X has worse performance but other advantages. (What?) ____________________________________ Michael Schmitt | DXC.technology (469) 808-4403 | [email protected] DXC Technology Company - Headquarters: 1775 Tysons Boulevard, Tysons, Virginia 22102, USA. DXC Technology Company -- This message is transmitted to you by or on behalf of DXC Technology Company or one of its affiliates. It is intended exclusively for the addressee. The substance of this message, along with any attachments, may contain proprietary, confidential or privileged information or information that is otherwise legally exempt from disclosure. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient of this message, you are not authorized to read, print, retain, copy or disseminate any part of this message. If you have received this message in error, please destroy and delete all copies and notify the sender by return e-mail. Regardless of content, this e-mail shall not operate to bind DXC Technology Company or any of its affiliates to any order or other contract unless pursuant to explicit written agreement or government initiative expressly permitting the use of e-mail for such purpose. --.
