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=0.2 required=5.0 tests=BAYES_00,INVALID_MSGID, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: fac41,2c6139ce13be9980 X-Google-Attributes: gidfac41,public X-Google-Thread: 1108a1,2c6139ce13be9980 X-Google-Attributes: gid1108a1,public X-Google-Thread: f43e6,2c6139ce13be9980 X-Google-Attributes: gidf43e6,public X-Google-Thread: 103376,3d3f20d31be1c33a X-Google-Attributes: gid103376,public From: donh@syd.csa.com.au (Don Harrison) Subject: Re: Safety-critical development in Ada and Eiffel Date: 1997/07/21 Message-ID: #1/1 X-Deja-AN: 257900966 Sender: news@syd.csa.com.au X-Nntp-Posting-Host: dev50 References: Organization: CSC Australia, Sydney Reply-To: donh@syd.csa.com.au Newsgroups: comp.object,comp.software-eng,comp.lang.ada,comp.lang.eiffel Date: 1997-07-21T00:00:00+00:00 List-Id: Robert Dewar wrote: :The evaluation of any boolean expressoin has side effects at the level :we are talking about, at the very least it takes time and can affect :timing relationships, which of course in this kind of code can be :critical. Given that assertions are executed sequentially, there wouldn't appear to be any easy solution to this problem. The only options seem to be: a) Not using them at all, or b) Leaving them turned on in the production system. Obviously, this would mean efficiency problems. :The idea that REMOVING the evaluation of boolean expressions completely :is semantically neutral is also completely bogus. Such removal can affect :Icache locality of the code that is left, again affecting timing, and can :also result in code being at different locations, resulting in differences :of behavior with unbounded consequences. This issue would be avoided by b) above but the loss of efficiency would usually be unacceptable for hard realtime. Don. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Don Harrison donh@syd.csa.com.au