[Info-vax] LLVM, volatile and async VMS I/O and system calls

[Simon Clubley]

On 2021-09-25, chris <chris-nospam at tridac.net> wrote:
>
> We are probably in agreement, just different interpretations of
> the same thing ?. One thing I always do when confronted with a new
> compiler or tool chain is to look at the assembler source output
> to make sure it's doing what I expect it to. Don't bother once
> i'm happy with the compiler, but it does help to get to know what
> the compiler is doing under various conditions. It's also useful
> if you are trying to optimise performance. For example, trying to
> decide which loop construct to use for / next, or do / while. Quite
> important in the old 8 bit days, but moderm micros are so good
> now, it's less of an issue. Quite often a single line of asm
> per C statement, but you can fine tune the programming style to'
> get the best results form the compiler....
>

:-)

Looking at the generated code has proved interesting at times. :-)

The following Ada Issue is a direct result of me looking at someone's
problem on comp.lang.ada a number of years ago which was caused by
the code the Ada compiler had generated:

http://www.ada-auth.org/cgi-bin/cvsweb.cgi/ai12s/ai12-0128-1.txt?rev=1.15&raw=N

The following AI is also directly related to this:

http://www.ada-auth.org/cgi-bin/cvsweb.cgi/ai12s/ai12-0127-1.txt?rev=1.27&raw=N

[I am _not_ a member of the ARG or anything like that. I am just a
normal programmer who includes Ada in the list of languages I know.]

Simon.

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