From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=0.1 required=5.0 tests=BAYES_05,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,f777c296cbb8a95a,start
X-Google-Attributes: gid103376,public
From: John Connett <jrc@art.co.uk>
Subject: Ada, Alpha & IEEE Computational Models?
Date: 1999/01/22
Message-ID: <36A88A73.BF261F63@art.co.uk>#1/1
X-Deja-AN: 435638496
Content-Transfer-Encoding: 7bit
X-NNTP-Posting-Host: threebti.demon.co.uk:158.152.73.32
Content-Type: text/plain; charset=us-ascii
X-Complaints-To: abuse@demon.net
X-Trace: news.demon.co.uk 917015133 nnrp-11:14363 NO-IDENT
 threebti.demon.co.uk:158.152.73.32
Organization: Advanced Rendering Technology
MIME-Version: 1.0
Newsgroups: comp.lang.ada
Date: 1999-01-22T00:00:00+00:00
List-Id: <comp.lang.ada>

The Alpha architecture provides a choice of three IEEE computational
models:

    *   IEEE compliant arithmetic;
    *   IEEE compilant arithmetic without inexact exception;
    *   High performance IEEE-format arithmetic.

The model used is controlled by instruction qualifiers.  The choice of
model can have an impact on the speed of the code.

For the language systems with which I am familiar, gcc/egcs on Alpha
Linux, the choice of computational model is made on a per compilation
unit basis through the use of compile time switches.

The use of pragmas would seem to offer a mechanism for finer control of
the computational model within compilation units.  Do any existing Ada
language systems which target the Alpha architecture offer this level of
control?

Any pointer to further information on this topic would be gratefully
received.

Regards
--
John Connett (jrc@art.co.uk)