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Russell Bull
08/21/05 06:47
Read: 1046 times

#99773 - Outlaw coding!
Responding to: Erik Malund's previous message

"5) anything timing dependent that is not interrupt based is outlawed. "

In the interests of having provable software, one should minimise interrupts where possible, even eliminate them as they provide asynchronous interruption to the program flow. To fully prove the code, one would need to test having an interrupt occur in each line of code to ensure the response is correct. This is, of course, time consuming. As you will agree, a system with no interrupt source is a lot easier to test than a system with 10 interrupt sources.

In my extensive experience and reading, suggesting that timing must be reliant on interrupts has no base. However, using timer hardware should be encouraged and why discourage a software delay where appropriate?

I was asked earlier this year by a young engineer given the task of doing a code review of code I wrote why I used in some instances NOP(); for some delays and a for loop in another. I explained that one loop of the for loops took quite a few cycles, so when I only wanted to use a couple of cycles for a delay, I used NOP(), for longer delays I used the for loop.

Misra makes no mention of this 'rule'! What standard are you working from that makes this assertion?

DoWhile Jones wrote a compeling article about the (ab)use of interrupts some time ago in circuit Cellar. Therac25 would have benefitted by avoiding interrupts!

List of 57 messages in thread
defensive coding how and why      Erik Malund      08/12/05 15:33      
   What do you mean?      Craig Steiner      08/12/05 17:32      
      Elegant      Steve M. Taylor      08/13/05 00:20      
         Paradox?      Rob Klein      08/13/05 05:10      
      clarification      Erik Malund      08/15/05 06:35      
         Remember      Neil Kurzman      08/15/05 11:43      
            Absolutely, and even then should be avoi      Erik Malund      08/15/05 12:19      
            Absolutely, and even then should be avoi      Erik Malund      08/15/05 12:19      
            extrodiaray?      Jan Waclawek      08/15/05 13:12      
                extrodiaray?      Craig Steiner      08/15/05 13:17      
                  Goooooogle      Jan Waclawek      08/15/05 15:08      
                     No, he does not      Erik Malund      08/15/05 15:30      
                        proofreading      Jan Waclawek      08/16/05 03:27      
                     Another challeneg      Craig Steiner      08/15/05 15:49      
                        another challenge      Jan Waclawek      08/16/05 03:45      
               OK, I can not Spell      Neil Kurzman      08/15/05 19:18      
                  this is my point      Jan Waclawek      08/16/05 03:30      
                     I sure you could, But      Neil Kurzman      08/16/05 09:35      
                        Really?      Craig Steiner      08/16/05 10:20      
                           professors and classes      Jan Waclawek      08/16/05 10:50      
                           Really !      Neil Kurzman      08/17/05 14:05      
                              Hmmm      Craig Steiner      08/17/05 14:09      
            defensive commenting      Jan Waclawek      08/16/05 03:59      
         Don't know      Craig Steiner      08/15/05 12:47      
            Ok, let me get away from that word      Erik Malund      08/15/05 13:49      
               Gotcha      Craig Steiner      08/15/05 14:44      
                  and I came to truly despise that word wh      Erik Malund      08/15/05 15:07      
                     Just like driving      Kalpak Dabir      08/17/05 20:48      
            Elegant equals...      Dan Henry      08/15/05 17:21      
               that it      Erik Malund      08/16/05 06:11      
               Oh, how true...!      Andy Neil      08/23/05 05:29      
                  It's never the author's problem      Dan Henry      08/23/05 08:51      
                     I knew a person who told me about a real      Erik Malund      08/23/05 09:38      
                        A blissful existence      Dan Henry      08/23/05 18:37      
                  Your bugs versus my bugs (or vice versa)      Dan Henry      08/23/05 18:34      
                     common wisdom has it that the average pr      Erik Malund      08/24/05 07:34      
   One exception      Ian Bell      08/13/05 08:32      
      exceptions      Erik Malund      08/15/05 06:45      
         vice versa      Jan Waclawek      08/15/05 06:53      
            what is obvious      Erik Malund      08/15/05 07:58      
               your mileage may vary      Jan Waclawek      08/15/05 08:15      
                  that is the very same      Erik Malund      08/15/05 09:05      
                     competent      Jan Waclawek      08/15/05 13:40      
                        please define "working"      Erik Malund      08/15/05 14:02      
                           competent programming => working program      Jan Waclawek      08/15/05 15:48      
   i'm new      Emem Essien      08/18/05 05:10      
      if you move your eyeballs a bit to the l      Erik Malund      08/18/05 06:22      
         Coding Bible      Russell Bull      08/20/05 08:16      
            Precedence vs. explicitness      Dan Henry      08/20/05 09:27      
   Outlaw coding!      Russell Bull      08/21/05 06:47      
      a program it is, by definition, asynchro      Erik Malund      08/22/05 07:42      
         Methinks the point was missed      Russell Bull      08/22/05 18:20      
            "Easy?"      Andy Neil      08/23/05 03:13      
            but we agree      Erik Malund      08/23/05 07:34      
      VIPER?      Andy Neil      08/22/05 10:53      
      What does "timing" mean?        Dan Henry      08/22/05 20:03      
         excuse the foreigner, if he was not clea      Erik Malund      08/23/05 07:36      

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