Xlnt idea! And hopefully execution when target is page aligned would behave as MVCL* does and not pollute caches.
-----Original Message----- From: IBM Mainframe Assembler List [mailto:[email protected]] On Behalf Of Tom Harper Sent: Thursday, April 14, 2022 1:06 PM To: [email protected] Subject: Next instruction needed Caution! This message was sent from outside your organization. IMHO, the next instruction to add to z/Architecture would be an instruction to clear storage to zeros. Right now a number of methods are in widespread use, none of which are clean and simple. I mean, it’s been almost sixty years. MVCL takes three registers to set up beforehand; XC sets the condition code and is not variable length, and the overlapping MVC is a kluge and not variable length either. An EX instruction is also a kluge. All you need is the address and length to accomplish this, preferably in two versions, one with an immediate operand for the length and another which uses, for example, a register, perhaps register zero. A long displacement would be a plus. To avoid issues with interruptibility, the length would need to be limited to 256 bytes. I don’t think the length restriction would be an issue in most cases. Such an instruction might look like this: CLEAR FieldA Or LLGF R0,Varlen CLEARR Similar instructions for compare logical and move would be nice as well. Tom Harper Phoenix Software International Sent from my iPhone -------------------------------------------------------------------------------- This e-mail message, including any attachments, appended messages and the information contained therein, is for the sole use of the intended recipient(s). If you are not an intended recipient or have otherwise received this email message in error, any use, dissemination, distribution, review, storage or copying of this e-mail message and the information contained therein is strictly prohibited. If you are not an intended recipient, please contact the sender by reply e-mail and destroy all copies of this email message and do not otherwise utilize or retain this email message or any or all of the information contained therein. Although this email message and any attachments or appended messages are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by the sender for any loss or damage arising in any way from its opening or use.
