[Info-vax] Technical issues with VMS BASIC port to x86-64 ?

[Arne Vajhøj]

On 2/20/2024 2:36 PM, mjos_examine wrote:
> On 2024-02-20 2:24 p.m., Craig A. Berry wrote:
>> On 2/20/24 12:27 PM, Simon Clubley wrote:
>>> I am curious, at a purely technical level, about the issues that VSI
> 
>> I'm pretty sure this has already been explained multiple times.  What I
>> think I remember is that exception handling and dynamic maps pose some
>> challenges, and there may be RTL dependencies that are somewhat
>> different from the other compilers.  But I don't think COBOL was easy
>> either -- it just has a lot more users and was thus a higher priority.
> 
> There has been some information posted over the past 11 months.
> 
> On 2023-03-01 2:13 p.m., John Reagan wrote in Message ID 
> <2f1b5bc7-ee3c-4e9b-8be6-601bef09e868n at googlegroups.com>:
>>> Don't blow the BASIC issue out of proportion.  It is just that the 
>>> BASIC frontend
>>> generates GEM symbol table that look "different" than everybody else.  I
>>> just haven't had the time (or desire) to change how G2L has to 
>>> operate.  I'd
>>> rather change the BASIC frontend.  I have other things to do first.  
>>> It is not
>>> a multiple person-year task.  We have all the real HARD pieces of 
>>> BASIC already
>>> working.
> 
> On 2023-09-07 9:56 p.m., John Reagan wrote in Message Id 
> <311392ca-9f5d-41e0-b15c-b383d5a682b5n at googlegroups.com>:
>>> We have resolved one of the difficult issues with BASIC MAP statements
>>> and can actually pass a significant number of tests.  However, we 
>>> still have
>>> a few more things to track down before I would say it is useful.

There are other similar.

Apr 8, 2022, 9:16:12 AM

<quote>
- BASIC is still waiting on an enhancement to our G2L converter. BASIC's 
MAP statement uses
COMMON blocks in a "unique" way that the converter was not prepared for. 
And the way OpenVMS
implements common blocks is different than the presentation you see on 
UNIX/Linux systems.
(I can really bore you on overlaid PSECTs on OpenVMS vs .comm directives 
in UNIX)
</quote>

Jan 25, 2023, 5:16:05 PM

<quote>
As I've said before, the issue is COMMON blocks. When I first did the 
design of
how to convert GEM CIL and GEM symbol table to LLVM, I didn't appreciate the
difference in how COMMON blocks are described to LLVM and the UNIX 
environment
in general. It isn't just BASIC, you can see broken COMMON blocks in the 
Fortran
cross-compiler if you look hard enough. The problem is that the BASIC 
MAP statement
doesn't work right and almost every BASIC program uses MAPs for 
something. I have
a BASIC cross-compiler. If you don't use a MAP, it probably works 
(although the test
system doesn't very far without MAP).
</quote>

Arne