[Info-vax] VAX VMS going forward

[John Reagan]

On Tuesday, July 28, 2020 at 8:51:46 AM UTC-4, Simon Clubley wrote:
> On 2020-07-28, Arne Vajhøj <arne at vajhoej.dk> wrote:
> > On 7/28/2020 8:31 AM, Simon Clubley wrote:
> >> 
> >> Only on VMS. This is (mostly) not a significant problem on other
> >> operating systems because the vast majority of the work is done for
> >> you by the compiler and linker in those environments after you tell
> >> the compiler whether you want your code to run with 32-bit or 64-bit
> >> addresses and other features.
> >
> > ????
> >
> > On what other platform is it common to pass 64 bit addresses
> > as 32 bit bit values with implicit values for the remaining bits?
> >
> 
> As you should well know, you simply don't have to worry about this
> in those environments. My answer above should have been enough for
> you to understand the point I was making.
> 
> You tell the compiler whether you want a 32-bit or 64-bit executable
> and it, the linker, and OS support libraries takes care of most of
> the work for you (if not all the work).
> 
> I wish it was that simple on VMS.
> 
> Simon.
> 
> -- 
> Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
> Walking destinations on a map are further away than they appear.

We must be working with different compilers.  There is no qualifier or setting to tell the compilers to generate 32-bit code or 64-bit code.  The code is the same.  You can ask the linker to place it different with LINK/SEG=CODE=P2 or =P0.  You can even copy code from P0 into P2 on Alpha, Itanium, and x86.  You might have to readjust some relocations but the instructions are perfectly fine in either area (the exception is the Itanium C++ compiler).