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Re: Arduino / compilers on uC

From John Devereux <john@devereux.me.uk>
Newsgroups sci.electronics.design
Subject Re: Arduino / compilers on uC
Date 2017-02-16 16:45 +0000
Message-ID <87wpcqcceg.fsf@devereux.me.uk> (permalink)
References (11 earlier) <o7sidg$291$1@dont-email.me> <8760kae1j8.fsf@devereux.me.uk> <_pipA.466518$sc6.88819@fx25.am4> <871suydwrp.fsf@devereux.me.uk> <zYjpA.47205$Zt.31090@fx43.am4>

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Tom Gardner <spamjunk@blueyonder.co.uk> writes:

> On 16/02/17 14:40, John Devereux wrote:
>> Tom Gardner <spamjunk@blueyonder.co.uk> writes:
>>
>>> On 16/02/17 12:57, John Devereux wrote:
>>>> David Brown <david.brown@hesbynett.no> writes:
>>>>
>>>>> On 10/02/17 01:44, M Philbrook wrote:
>>>>>>
>>>>>>  I am glad you dont do any coding work for me or anyone I deal with..
>>>>>>
>>>>>
>>>>> Why?  Is it just because I explained things in a lot of detail, or do
>>>>> you think any of what I wrote is incorrect?  If so, give me the details
>>>>> and references to the section numbers in a C standard (the N1570 draft
>>>>> of C11 is the modern one) and I will see if we can sort out the
>>>>> differences in understandings.
>>>>
>>>> David, you are an expert.
>>>>
>>>> We've had enough of experts....
>>>
>>> There are two possible translations of that
>>> 1) we don't like people that use facts to point
>>> out where our gut feelings are wrong
>>
>> That is the one I was going for. Along the lines of, we have our own
>> alternative facts.
>>
>> It was of course an excellent post, informative as always from David!
>>
>>> 2) we shouldn't need experts (of this kind) to
>>> implement systems.
>>
>>
>>> The former is disreputable and the realm of
>>> snake-oil salesman.
>>>
>>> The latter is either wishful thinking, or a
>>> statement that this toolset and associated
>>> /necessary/ "language lawyer" mentality is
>>> unacceptable. I tend to the latter.
>>
>> I have been programming in C for a long time in embedded systems, but it
>> is only a small part of my job. I don't consider myself an "expert" and
>> certainly not a language lawyer.
>
> My career trajectory meant I was a heavy user of C
> in the early-late 80s,

That is when I learned all the bad habits I later had to unlearn - using
C on crappy 8 bit processors with only a few registers and not much help
with optimisation from the inefficient buggy compilers.

So the shortage of RAM and index registers meant my code had lots of
global 8bit variables for "efficiency", since the CPUs could not do
indexed or stack based addressing at all well. So code was faster and
shorter with variables in fixed absolute addresses. Stack was limited so
one tended towards long functions instead of breaking things up into
shorter ones. Etc.

The I used the AVR of the thread. This was slightly more modern but
still not perfectly suited for C. For example its 8-bit registers are a
poor match for C's general arithmetic types and the different types of
memory area require some nasty kludges IIRC.

I think the current day cortex M CPUs are probably more like the
minicomputers C was designed for (but much faster). C and c++ are a
perfect match here, with gcc an excellent and free compiler.

>but in the 90s I moved onto
> software for which C was a less good fit.
>
> In the noughties I saw some truly horrific commercial
> code in C/C++, much of it written by youngsters that
> hadn't grown up with it - and who had little conception
> of what was happening "under the hood". Even FSMs and
> caches were things they were only vaguely aware of :(
>
> In such cases, a more modern higher level language
> tended to enable systems with fewer /undiagnosed/
> surprises lurking in the undergrowth. Such surprises,
> if not dealt with by they programmer, were at least
> visible in the source code.
>
>
>> I find that sticking to a few conventions and idioms is enough to avoid
>> issues like the OP had with bool and so forth. In this case, as David
>> says, don't lie to the compiler.  Be hyper-vigilent when writing a cast,
>> it is very likely the wrong way to do things and usually dangerous and
>> not necessary.
>
> Agreed; that's my experience when writing small
> applications in C. But when I can't write all the
> code myself I have to rely on the competence of
> unknown other programmers. And that's a real
> problem given my observations above!
>
> I don't have experience of MISRA-based systems,
> and I don't know how many of the fun and games
> outlined in the FQA are trapped out.
>
>
>> I find C to be fairly pleasant and surprise-free in use.
>
> It gets /much/ nastier on machines with multiple levels
> of memory hierarchy, including caches, local memory
> and remote memory - and, of course, multiprocessors.

I tend to use C on devices using up to ~256k code, so far.

> When considering those factors, the compiler writers
> and compiler users have difficulty agreeing what is
> "meant" by the source code. Doubly so when different
> (generations of) compiler are used.




-- 

John Devereux

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Thread

Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-06 15:43 -0800
  Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-07 10:58 +1100
    Re: Arduino / compilers on uC bitrex <bitrex@de.lete.earthlink.net> - 2017-02-06 19:09 -0500
    Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-06 18:30 -0800
      Re: Arduino / compilers on uC bitrex <bitrex@de.lete.earthlink.net> - 2017-02-06 21:43 -0500
        Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-06 19:02 -0800
          Re: Arduino / compilers on uC bitrex <bitrex@de.lete.earthlink.net> - 2017-02-06 23:26 -0500
            Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-06 21:05 -0800
      Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-07 13:55 +1100
        Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-06 20:00 -0800
          Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-07 19:31 +1100
          Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-07 10:29 +0100
            Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-07 07:39 -0800
              Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-08 12:24 +0100
                Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-09 08:36 -0800
                Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-10 08:15 +1100
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-13 15:37 +0100
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-13 15:35 +0100
          Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-07 08:05 -0800
            Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-08 12:30 +0100
  Re: Arduino / compilers on uC mrdarrett@gmail.com - 2017-02-06 15:59 -0800
  Re: Arduino / compilers on uC Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-06 16:04 -0800
    Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-06 18:41 -0800
      Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-07 14:08 +1100
        Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-06 20:14 -0800
          Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-07 08:00 +0000
            Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-09 05:42 -0800
              Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-09 15:07 +0100
                Re: Arduino / compilers on uC Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-09 09:54 -0800
              Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-09 15:55 +0000
                Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-09 08:46 -0800
                Re: Arduino / compilers on uC Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-09 14:42 -0500
                Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-11 06:54 -0800
                Re: Arduino / compilers on uC pcdhobbs@gmail.com - 2017-02-11 07:31 -0800
                Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-11 07:59 -0800
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-11 17:01 +0000
                Re: Arduino / compilers on uC pcdhobbs@gmail.com - 2017-02-11 12:52 -0800
                Re: Arduino / compilers on uC krw@notreal.com - 2017-02-11 18:46 -0500
                Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-12 10:20 +1100
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-13 16:07 +0100
                Re: Arduino / compilers on uC Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-09 14:16 -0500
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-09 22:39 +0000
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-13 16:06 +0100
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-13 15:29 +0000
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-13 16:49 +0100
                Re: Arduino / compilers on uC Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-13 10:55 -0500
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-13 17:09 +0000
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-14 09:49 +0100
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-13 16:07 +0000
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-14 10:01 +0100
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-14 09:49 +0000
                Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-17 04:21 +1100
                Re: Arduino / compilers on uC pcdhobbs@gmail.com - 2017-02-16 14:47 -0800
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-17 00:17 +0000
          Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-07 19:49 +1100
            Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-09 06:22 -0800
          Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-07 10:42 +0100
            Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-09 06:57 -0800
              Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-09 16:12 +0100
              Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-10 08:24 +1100
  Re: Arduino / compilers on uC bitrex <bitrex@de.lete.earthlink.net> - 2017-02-06 19:08 -0500
    Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-06 18:47 -0800
      Re: Arduino / compilers on uC bitrex <bitrex@de.lete.earthlink.net> - 2017-02-06 21:51 -0500
        Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-06 20:39 -0800
          Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-06 20:55 -0800
            Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-07 20:05 +1100
              Re: Arduino / compilers on uC bitrex <bitrex@de.lete.earthlink.net> - 2017-02-08 12:26 -0500
                Re: Arduino / compilers on uC bitrex <bitrex@de.lete.earthlink.net> - 2017-02-08 12:32 -0500
                Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-09 08:31 +1100
                Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-09 08:21 +1100
                Re: Arduino / compilers on uC Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-08 13:33 -0800
          Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-07 08:15 +0000
            Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-09 05:51 -0800
              Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-09 16:22 +0000
                Re: Arduino / compilers on uC bitrex <bitrex@de.lete.earthlink.net> - 2017-02-09 16:45 -0500
                Re: Arduino / compilers on uC bitrex <bitrex@de.lete.earthlink.net> - 2017-02-09 16:51 -0500
                Re: Arduino / compilers on uC Clifford Heath <no.spam@please.net> - 2017-02-10 09:11 +1100
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-09 22:45 +0000
                Re: Arduino / compilers on uC bitrex <bitrex@de.lete.earthlink.net> - 2017-02-15 10:11 -0500
          Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-07 10:57 +0100
      Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-07 08:07 +0000
        Re: Arduino / compilers on uC rickman <gnuarm@gmail.com> - 2017-02-07 04:01 -0500
          Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-07 09:40 +0000
            Re: Arduino / compilers on uC rickman <gnuarm@gmail.com> - 2017-02-07 05:52 -0500
              Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-07 11:26 +0000
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-07 12:58 +0100
                Re: Arduino / compilers on uC Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-09 14:52 -0500
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-09 22:47 +0000
              Re: Arduino / compilers on uC bitrex <bitrex@de.lete.earthlink.net> - 2017-02-09 14:00 -0500
                Re: Arduino / compilers on uC Tim Wescott <seemywebsite@myfooter.really> - 2017-02-09 13:24 -0600
      Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-07 10:52 +0100
    Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-07 10:50 +0100
  Re: Arduino / compilers on uC rickman <gnuarm@gmail.com> - 2017-02-06 19:49 -0500
  Re: Arduino / compilers on uC "David Eather" <eather@tpg.com.au> - 2017-02-07 12:45 +1000
    Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-06 18:51 -0800
      Re: Arduino / compilers on uC "David Eather" <eather@tpg.com.au> - 2017-02-08 06:35 +1000
        Re: Arduino / compilers on uC "David Eather" <eather@tpg.com.au> - 2017-02-08 06:44 +1000
      Re: Arduino / compilers on uC M Philbrook <jamie_ka1lpa@charter.net> - 2017-02-07 17:11 -0500
        Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-08 12:40 +0100
          Re: Arduino / compilers on uC pcdhobbs@gmail.com - 2017-02-08 07:01 -0800
            Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-08 17:25 +0100
              Re: Arduino / compilers on uC jack4747@gmail.com - 2017-02-09 06:51 -0800
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-09 16:41 +0100
                Re: Arduino / compilers on uC M Philbrook <jamie_ka1lpa@charter.net> - 2017-02-09 19:44 -0500
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-13 16:14 +0100
                Re: Arduino / compilers on uC John Devereux <john@devereux.me.uk> - 2017-02-16 12:57 +0000
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-16 14:11 +0000
                Re: Arduino / compilers on uC John Devereux <john@devereux.me.uk> - 2017-02-16 14:40 +0000
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-16 15:58 +0100
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-16 15:56 +0000
                Re: Arduino / compilers on uC John Devereux <john@devereux.me.uk> - 2017-02-16 16:45 +0000
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-16 17:18 +0000
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-17 14:59 +0100
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-17 14:24 +0000
                Re: Arduino / compilers on uC Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-02-17 21:07 +0200
                Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-17 20:16 +0000
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-17 23:28 +0100
                Re: Arduino / compilers on uC Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-17 10:21 -0500
                Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-17 16:34 +0100
                Re: Arduino / compilers on uC M Philbrook <jamie_ka1lpa@charter.net> - 2017-02-09 19:43 -0500
  Re: Arduino / compilers on uC Tim Wescott <tim@seemywebsite.com> - 2017-02-10 10:41 -0600
    Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-11 07:06 -0800
      Re: Arduino / compilers on uC Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-11 17:09 +0000
    Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-13 16:28 +0100
  Re: Arduino / compilers on uC Tim Wescott <tim@seemywebsite.com> - 2017-02-14 09:59 -0600
    Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-14 13:46 -0800
      Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-15 10:04 +0100
        Re: Arduino / compilers on uC dagmargoodboat@yahoo.com - 2017-02-15 05:57 -0800
          Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-15 16:02 +0100
            Re: Arduino / compilers on uC David Brown <david.brown@hesbynett.no> - 2017-02-15 17:15 +0100
          Re: Arduino / compilers on uC Tim Wescott <tim@seemywebsite.com> - 2017-02-16 14:19 -0600

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