[FreeVMS] gcc and VMS calling standard

[Graham Toal]

On Tue, May 6, 2008 at 5:00 AM, Roar Thronæs <roart at nvg.ntnu.no> wrote:
> On Mon, May 05, 2008 at 09:02:37AM -0700, Gregory John Casamento wrote:
> > Is there a plan to make FreeVMS binary compatible with VAX VMS on the VAX architecture?
>
> Sorry, VAX is not a target architecture.

However if the system calls keep to the VMS interface, and calling
conventions are roughly similar, it ought to be possible to write
something similar to VEST which would translate old binaries to run on
the x86 architecture.  Static binary translation isn't that hard; it
won't have to be super optimised to exceed the speed of a real Vax.
Not so sure about matching the speed of Alpha binaries though.  My
experience has been that a translated binary uses about 3 instructions
per original instruction (as opposed to regular emulation which has
about a 10:1 overhead for a tightly-written emulator)

The loader could look at object types and translate on the fly, or
even kick off an emulator transparently.

Graham