[Info-vax] VMS Software needs to port VAX DIBOL to OpenVMS X86 platform

[Tim Sneddon]

Arne Vajh??j <arne at vajhoej.dk> wrote:
> On 1/5/2021 1:51 AM, Tim Sneddon wrote:
>> Rich Alderson <news at alderson.users.panix.com> wrote:
>>> As I remember the book on the VAX (VMS) port, the goal was very much to
>>> "emulate" (implement) IBM PL/I, so I doubt that there would be that much
>>> effort for any implementation with the same goal...
>> 
>> I don't think so.  DEC PL/I was a port of the PL/I compiler developed by
>> Robert Freibourghouse.  The DEC team even ported it off of a Multics
>> system.  The real target was ANSI Subset G (general purpose) PL/I as
>> I understand it.
>> 
>> The book I am guessing everyone is talking about is Engeneering a Compiler:
>> VAX-11 Code Generation.  It really covers the development of a VAX backend
>> and very little about the PL/I language itself.  The Epilogue also discusses
>> the fact the backend was reused for VAX C as well as Pearl and likely
>> another language.  It was also used for SCAN (although I think that came
>> after the book).
> 
> I am not sure that being used by VAX C is a good thing.
> 

:-)

> As I remember it then VAX C was the only DEC compiler where it was
> common to turn off optimization to get code working.
>

I certainly experienced that when using builtins that accessed registers.
However, beyond that I never had any huge problems.

Regards, Tim.