On Thu, 6 Dec 2012 10:44:43 -0500, John Gilmore wrote:
>
>Let me therefore take full responsibility for that paraphrase myself.
> AMODE(64) seems to me to be the only appreopiate way to mark an
>object that is to be resident above the bar, and in particular, one
>that while refreshable contains metadata, relocatable doubleword
>pointers to locations within itself.
> 
Is there no RMODE(64)?  This is complicated because programs may
dynamically switch addressing modes in execution, and AMODE(64)
with RMODE(31) seems a useful combination for programs which
access above-the-bar data but need 4-byte VCONs to invoke existing
services.

Should there be an exception for paired +/- RLDs?  Those should be
algebraically valid for any module less than 2 GiB in size.

Otherwise I believe such enforcement should be done by the Binder
or even by the assembler, not deferred until ABEND at execution.

>IBM has an understandably long history of omitting to enforce some
>eminently reasonable constraint until that point in time at which it
>judges it appropriate to do so; and marking an object, even a
>read-only one, that is destined to reside above the bar as AMODE(31)
>is, I think, an act of hubris.
> 
And then prolonging the omission for the sake of "compatibility" with
historic customer foolishness.  For example, is REFRPROT yet not the
default?

How do you determine "destined to reside"?

-- gil

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