Re: Compiler implementation of speciallized needs annexes.

[dewar@gnat.com]

In article <7belqo$rl7@dfw-ixnews12.ix.netcom.com>,
  Richard D Riehle <laoXhai@ix.netcom.com> wrote:
>  Perhaps, in the spirit of the FSF, other compiler
>  publishers could simply incorporate the GNAT annexes
>  into their product and avoid the duplication associated
>  with more implementations.

To the extent that this is just a matter of acquiring
copies of GNAT run time routines, this is fine, and indeed
for a while at least Aonix was using some of the GNAT
routines in their distribution. Providing the copyright
is properly respected, and the license conditions followed
this usage is welcome.

However, it is unfortunately naive to suppose that this
gets you very far. We have often heard of sales people for
another Ada vendor claiming that it is no problem to have
the System Information Annex, since you can just use the
GNAT routines, but this is quite bogus. The GNAT
implentation depends on some critical intrinsic routines
in the compiler, and also on the full support of 18 digit
decimal fixed-point. These are not run-time library issues.

For the real-time annex, of course the GNAT run-time
routines can be used, but this would require major compiler
changes, to the point where it could hardly make sense.

As for the distribution annex, sure you can use the GNAT
PCS, but there is huge front end work to be done.

In short, Richard's suggestion does not lead to much
simplification in the hard task of implementing all the
Annexes in their entirety in the context of a compiler
other than GNAT.

Robert Dewar
Ada Core Technologies

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