[Info-vax] C and assembly language, was: Re: WHY IS VSI REQUIRING A HYPERVISOR FOR X86 OPENVMS?

[Simon Clubley]

On 2020-12-22, John Reagan <xyzzy1959 at gmail.com> wrote:
> On Tuesday, December 22, 2020 at 11:30:10 AM UTC-5, Simon Clubley wrote:
>> On 2020-12-21, Wilm Boerhout <wboerhou... at this-gmail.com> wrote: 
>> > John Reagan schreef op 21-12-2020 om 02:55: 
>> >>
>> >> "Much"? I think Clair did a line count/module posting in the last year or so. The Macro-32 contribution was getting pretty low (less than 20%?) However, just the difficult and nasty parts that nobody wants to attempt to rewrite. I'd pay real money to watch somebody try to rewrite the shadow driver out of Macro-32 (pretty much every routine can jump into any other routine in an alternative universe threading scheme). And I've recently had to look at chunks of DECnet IV and even I couldn't make heads-or-tails out of some of the algorithms. 
>> >> 
>> > 
>> > Apropos DECnet IV: a bunch of us in the HECnet alternate universe have 
>> > been running pydecnet (that is, DECnet IV written in python from the 
>> > original DECnet specifications) for a while now, thanks to Paul Koning's 
>> > implementation effort ***bows to Paul*** 
>> >
>> $ set response/mode=good_natured 
>> 
>> DECnet Phase IV in Python ??? That's just unnatural. ;-) 
>> 
>> On a more serious note, I wonder why John was looking at the DECnet 
>> Phase IV code. I wonder if something in there found a problem in the 
>> new compilers ?
>> Simon. 
>> 
>> -- 
>> Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP 
>> Walking destinations on a map are further away than they appear.
> No conspiracies here.  We were looking at the code that did MAC address lookups for MOP loads.  It has some Alpha vs Itanium conditionals.  I was asked by another engineer to explain why the two platforms were different what x86 needs.  The original VAX version pushed routine addresses on the stack and did some "JSB @(SP)+"  along with some hard resets of the SP (think of it as a cheap form of setjmp/longjmp).    You can't do a store into SP on Itanium so the code had to do something else. 
>
> If you want a list of known bugs with the current x86 cross-compilers?  I have that list too.  There are several.  I'm currently working on a linker issue that cropped up with our bootstrapping native compilers to x86.  Our linker doesn't handle code in SHT_GROUP but EH data not in the group.  It ended up trying to apply relocations to non-existent code.  A sanity check was raised.  What else do you want to know?  For C, I have one bug dealing with a #pragma linkage, one with changing "align(page)", and request for a new builtin to read/write the Time Stamp Counter.  There are a few open for Macro-32 and two for BLISS (all worked around with simple edits).
>

No conspiracy theory here. :-)

As I am sure _everyone_ around here knows, production code that was
working just fine in an old environment can sometimes break big time
in a new environment. Sometimes it turns out the code was only accidently
working :-) and sometimes it turns out the code found a problem in
the new environment. I was just curious if it was something like that.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.