https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.3.0/com.ibm.zos.v2r3.ieab100/reus.htm
BTW Your 'refreshable' ...
PTR DC A(0)
label L R15,PTR
LTR R15,R15
BNZ CALLIT
... ... Code that always leaves the same value in R15
ST R15,PTR
CALLIT BALR R14,R15
... would not assemble with a CC=00 if coded as an *RSECT* methinks.
Chris Poncelet (retired etc.)
On 08/02/2021 22:47, Seymour J Metz wrote:
> That "therefore" is incorrect. Nor would refreshing my example cause an
> incorrect branch. If you'll give me the URL I'll submit a RCF.
>
> There's now way that z/OS will refresh anything smaller than a page, much
> less smaller than a word.
>
>
> --
> Shmuel (Seymour J.) Metz
> http://mason.gmu.edu/~smetz3
>
> ________________________________________
> From: IBM Mainframe Discussion List [[email protected]] on behalf of
> Michael Stein [[email protected]]
> Sent: Monday, February 8, 2021 5:33 PM
> To: [email protected]
> Subject: Re: LINK vs LOAD/CALL
>
>>> This is refreshable, and even runs on S/360
>> PTR DC A(0)
>> label L R15,PTR
>> LTR R15,R15
>> BNZ CALLIT
>> ... ... Code that always leaves the same value in R15
>> ST R15,PTR
>> CALLIT BALR R14,R15
> According to the manual no.
>
> refreshable:
> all or part of the module can be replaced at any time without notice
> by the operating system. *therefore* must not modify itself in
> any way.
>
> So if part of your address got refreshed (to 0) you would then branch
> to some wrong address...
>
> Most likely the way it is/would be implemented it wouldn't just refresh
> a part of a fullword on a fullword boundary. But that's not the what
> the manual says it might do.
>
> The first I saw of REFR was OS/MVT 360. Aactual refreshing was only
> mentioned as action by the machine check handler for storage errors in
> parts of the nucleus.
>
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