[Info-vax] VAX VMS going forward

[Arne Vajhøj]

On 7/30/2020 7:57 AM, hb wrote:
> On 7/30/20 2:36 AM, John Reagan wrote:
>> The linker simply won't put static data in a memory region that
>> needs a 64-bit pointer to access it.  Of course, you are welcome to
>> create-and-map-section-64 into 64-bit space and access it as you
>> see fit.
> 
> I think John wanted to say that the linker can't move static data
> from 32 to 64 bit address space - as it can with code, as long as the
> PSECT is PIC. However, static data can have the ALLOC_64BIT
> attribute. The linker puts static data according to the absence or
> presence of that attribute into 32 or 64 bit address space. I only
> saw this attribute set by FORTRAN - I don't know but doubt that other
> compilers support it. And no, the linker does not accept an option to
> set that PSECT attribute.

Maybe I am being picky, but I don't really like the terminology:

32 bit address space ~= P0
64 bit address space ~= P2

It is:

       accessible via      accessible via
       32 bit pointers     64 bit pointers
P0        yes                  yes
P2        no                   yes

so to me the 32 bit address space is a subset of the 64 bit
address space - not two distinct address spaces.

Arne