[Info-vax] How much of VMS is still in MACRO-32?

[Arne Vajhøj]

On 5/29/2021 1:57 PM, John Dallman wrote:
> Out of curiosity, I took a look at the documentation for the MACRO-32
> compilers for Alpah and Itanium, and started reading the VAX MACRO
> instruction set manual.

Very nice CISC ISA.

> I now understand the 32/64-bit issues with VMS a bit better, but I'm
> curious as to how much of the OS is still written in MACRO-32.

30 years ago the word was that it was 1/3 <acro-32 and 1/3 Bliss
and 1/3 everything else.

Since then I suspect very little Macro-32 and Bliss has been
added but that some C has been added.

> Obviously, this begs the problem of defining the OS, as separate from its
> utility programs. Let's say "The stuff that's running once the OS has
> booted and is ready to run applications, plus the programs that needed to
> run to get it there."

Why separate?

It is common in *nix world to distinguish between kernel and
userland.

But not sure that it makes much sense on VMS:
* both were developed by DEC
* both were developed in the same languages
* they have always been consider a single entity

The only difference I can see is that at least some of
the kernel code may be non-trivial to write in HLL,
while all userland code could be rewritten in C++ or Rust
(assuming Rust become supported on VMS).

And VSI would probably even like to do it if some
millions of dollars dumped down from the sky to do it.
With a limited budget (and limited developer resources)
they need to prioritize and rewriting DCL and DCL
commands in C++/Rust just doesn't provide short and
mid term benefits that can justify spending the money.

Arne