If you want to load two doublewords, block concurrency guarantees each
(aligned) doubleword is consistent, but if task 2 is in process of updating
both doublewords, using (for example) LMG may result in you loading one
doubleword from before task 2's change and one after.
-----Original Message-----
From: IBM Mainframe Assembler List <ASSEMBLER-LIST@LISTSERV.UGA.EDU> On Behalf
Of Keven
Sent: Monday, January 14, 2019 16:54
To: ASSEMBLER-LIST@LISTSERV.UGA.EDU
Subject: Re: Multi CPU interlock question
Shouldn’t that be:Protection for readers is only necessary when the
storage in question doesn’t cross a doubleword boundary?
Keven
On Mon, Jan 14, 2019 at 4:17 PM -0600, "Ngan, Robert" <rn...@dxc.com> wrote:
Protection for readers is only necessary when the storage in question is larger
than a doubleword.
For quadwords, you can use either LPQ or PLO function 3 (CLX).
Robert Ngan
HCL Technologies
-----Original Message-----
From: IBM Mainframe Assembler List On Behalf Of Joe Owens
Sent: Thursday, January 10, 2019 04:28
To: ASSEMBLER-LIST@LISTSERV.UGA.EDU
Subject: Re: Multi CPU interlock question
Yes, your illustration is exactly what I was concerned about. My instinct was
CS was just about updaters of storage, and not readers, so there must be some
other type of protection for readers.
Thanks, Joe
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