Re: MCU mimicking a SPI flash slave

Subject	Re: MCU mimicking a SPI flash slave
Newsgroups	comp.arch.embedded
References	(20 earlier) <n282B.1$9u1.0@fx06.am4> <oib6je$vjk$1@dont-email.me> <bea2B.1$TL4.0@fx04.am4> <sjc2B.3$Ik7.2@fx39.am4> <oic0ap$sl1$1@dont-email.me>
From	Tom Gardner <spamjunk@blueyonder.co.uk>
Message-ID	<iEi2B.153$122.141@fx47.am4> (permalink)
Organization	virginmedia.com
Date	2017-06-21 00:58 +0100

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On 20/06/17 21:28, David Brown wrote:
> On 20/06/17 18:46, Tom Gardner wrote:
>> On 20/06/17 15:24, Tom Gardner wrote:
>>> Overall C/C++ has (arguably) become too complex for simple
>>> things, and (unarguably IMNHSHO!) become too poorly
>>> specified for complex things.
>>> Nowadays C (and even more with C++) is part of the problem
>>> rather than part of the solution. The abstractions, which
>>> were a useful valid advance in K&R days, have become *very*
>>> leaky over the years with the advance of technology.
>>
>> Examples I've come across include such gems as...
>>
>> "However, many C compilers use non-standard expression
>> grammar where ?: is designated higher precedence than =,
>> which parses that expression as
>> e = ( ((a < d) ? (a++) : a) = d ), which then fails to
>> compile due to semantic constraints: ?: is never lvalue
>> and = requires a modifiable lvalue on the left. Note
>> that this is different in C++, where the conditional
>> operator has the same precedence as assignment."
>> http://en.cppreference.com/w/c/language/operator_precedence
>>
>> "i = ++i + 1; // undefined behavior[in C] (well-defined in C++11)"
>> http://en.cppreference.com/w/cpp/language/eval_order
>>
>
> Neither C nor C++ is a problem here.  People writing absurd obfuscated nonsense
> in their code may be a problem, but that applies in any language.

Agreed, but the differences between the two languages is a
big hint that there are surprising and unnecessary dragons
lurking to catch people that haven't spent several decades
following the differences and /newly introduced/ pitfalls.

Do you have any comment about the previous point about
/some/ compilers apparently /choosing/ non-standard
expression grammars? That seems remarkable to me.

>> The ability to break a compiler's legitimate optimisations
>> by "casting away constness and volatility" (IIRC that took
>> several years of committee deliberation as to whether
>> it was required or forbidden behaviour!)
>
> "casting away constness and volatility" means writing code that explicitly tells
> the compiler "I know better than you do here, and I know it is safe to break
> rules about the code".  Either that is true, and it lets you write the code you
> want, or it is wrong and you've made a mistake - as you can do in all languages.

That is problematic when a library is compiled and optimised
assuming that the const statements are correct, and later on
someone else in a different company uses that library in a
way which violates those assumptions.

In those circumstances the user probably doesn't know better.

>> And of course, the amusing C++ FQA.
>
> Have you read it?  It is mostly misunderstandings, repetitions, outdated
> information, or completely unrealistic code.  There are a few good points in it,
> but you have to work hard to find them.

Indeed. But not all of the points can be "wished away"; many
a truth is spoken in jest.

>> All of which makes the simplicity of Forth seem appealing :)
>
> C is mostly simple and clear (if well written).  C++ is a much bigger and more
> complex language - it has greater scope for writing good code, but also greater
> scope for making a mess.  Simplicity of a language is not necessarily a good
> thing any more than complexity is - you don't get much simpler than a Turing
> machine, but I would not want to use it for application programming!

I completely agree :)

The major problem with C/C++ is that it can't make up its
mind whether it wants to be simple low-level and near to
the silicon, or an expressive high-level general purpose
applications language. Either would be valid, but in
trying to be both it misses both targets.

Fortunately the marketplace has decided that in most cases
C/C++ isn't "the best" general purpose application language;
Java, Python and similar are the future there.

Thread

MCU mimicking a SPI flash slave John Speth <johnspeth@yahoo.com> - 2017-06-14 10:44 -0700
  Re: MCU mimicking a SPI flash slave Don Y <blockedofcourse@foo.invalid> - 2017-06-14 16:30 -0700
  Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-14 21:54 -0400
    Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-15 08:01 +0100
      Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-15 12:13 -0400
        Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-15 18:01 +0100
          Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-15 16:52 -0400
            Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-15 23:37 +0200
              Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-15 18:15 -0400
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-16 09:25 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-16 13:52 -0400
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-18 22:56 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-19 00:21 -0400
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-19 09:02 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-19 08:36 -0400
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-19 14:47 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-19 09:23 -0400
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-19 15:34 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-20 00:16 -0400
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-20 09:49 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-20 22:44 -0400
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-21 12:10 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-21 12:40 -0400
                Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-21 18:19 +0100
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-21 14:34 -0400
                Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-21 21:41 +0100
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-21 17:14 -0400
                Re: MCU mimicking a SPI flash slave edward.ming.lee@gmail.com - 2017-06-21 13:54 -0700
            Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-15 23:33 +0100
              Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-15 23:12 -0400
                Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-16 07:05 +0100
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-16 02:27 -0400
  Re: MCU mimicking a SPI flash slave Tim Wescott <seemywebsite@myfooter.really> - 2017-06-14 23:17 -0500
  Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-15 08:03 +0100
  Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-15 09:14 +0200
    Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-15 08:25 +0100
      Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-15 10:02 +0200
        Re: MCU mimicking a SPI flash slave Reinhardt Behm <rbehm@hushmail.com> - 2017-06-15 16:25 +0800
          Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-15 10:32 +0200
            Re: MCU mimicking a SPI flash slave Reinhardt Behm <rbehm@hushmail.com> - 2017-06-15 21:48 +0800
          Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-15 10:09 +0100
        Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-15 09:41 +0100
          Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-15 13:04 +0200
            Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-15 12:31 +0100
              Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-15 14:20 +0200
            Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-15 17:46 -0400
              Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-16 13:21 +0200
                Re: MCU mimicking a SPI flash slave stephen@mpeforth.com (Stephen Pelc) - 2017-06-16 13:55 +0000
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-16 16:34 +0200
                Re: MCU mimicking a SPI flash slave stephen@mpeforth.com (Stephen Pelc) - 2017-06-16 15:40 +0000
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-19 00:47 +0200
                Re: MCU mimicking a SPI flash slave stephen@mpeforth.com (Stephen Pelc) - 2017-06-21 15:47 +0000
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-21 19:15 +0200
                Re: MCU mimicking a SPI flash slave stephen@mpeforth.com (Stephen Pelc) - 2017-06-21 15:50 +0000
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-21 19:16 +0200
                Re: MCU mimicking a SPI flash slave stephen@mpeforth.com (Stephen Pelc) - 2017-06-21 18:00 +0000
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-22 11:24 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-22 12:12 -0400
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-16 14:22 -0400
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-19 03:15 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-19 00:54 -0400
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-19 10:30 +0200
                Re: MCU mimicking a SPI flash slave albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-06-19 12:54 +0200
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-19 13:49 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-19 09:28 -0400
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-19 09:19 -0400
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-19 16:23 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-19 23:57 -0400
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-20 12:36 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-20 08:20 -0400
                Re: MCU mimicking a SPI flash slave anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-06-19 14:44 +0000
                Re: MCU mimicking a SPI flash slave albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-06-19 21:39 +0200
                Re: MCU mimicking a SPI flash slave Cecil Bayona <cbayona@cbayona.com> - 2017-06-19 14:59 -0500
                Re: MCU mimicking a SPI flash slave albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-06-20 09:25 +0200
                Re: MCU mimicking a SPI flash slave Cecil Bayona <cbayona@cbayona.com> - 2017-06-20 11:50 -0500
                Re: MCU mimicking a SPI flash slave anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-06-20 12:37 +0000
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-19 22:59 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-20 00:12 -0400
                Re: MCU mimicking a SPI flash slave Dimiter_Popoff <dp@tgi-sci.com> - 2017-06-20 10:25 +0300
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-20 10:44 +0200
                Re: MCU mimicking a SPI flash slave dp <dp@tgi-sci.com> - 2017-06-20 02:36 -0700
                Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-20 11:25 +0100
                Re: MCU mimicking a SPI flash slave Dimiter_Popoff <dp@tgi-sci.com> - 2017-06-20 13:49 +0300
                Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-20 12:54 +0100
                Re: MCU mimicking a SPI flash slave Dimiter_Popoff <dp@tgi-sci.com> - 2017-06-20 16:09 +0300
                Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-20 15:24 +0100
                Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-20 17:46 +0100
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-20 22:28 +0200
                Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-21 00:58 +0100
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-21 13:08 +0200
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-20 16:28 +0200
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-20 12:58 +0200
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-20 12:57 +0200
                Re: MCU mimicking a SPI flash slave Dimiter_Popoff <dp@tgi-sci.com> - 2017-06-20 14:19 +0300
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-20 16:19 +0200
                Re: MCU mimicking a SPI flash slave anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-06-20 12:12 +0000
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-20 16:48 +0200
                Re: MCU mimicking a SPI flash slave Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2017-06-20 21:16 +0100
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-20 23:15 +0200
                Re: MCU mimicking a SPI flash slave Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2017-06-21 07:30 +0100
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-21 12:54 -0400
                Re: MCU mimicking a SPI flash slave David Brown <david.brown@hesbynett.no> - 2017-06-21 19:29 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-21 15:05 -0400
                Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-21 21:34 +0100
                Re: MCU mimicking a SPI flash slave "Elizabeth D. Rather" <erather@forth.com> - 2017-06-21 18:04 -1000
                Re: MCU mimicking a SPI flash slave albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-06-22 10:26 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-22 11:56 -0400
                Re: MCU mimicking a SPI flash slave stephen@mpeforth.com (Stephen Pelc) - 2017-06-22 09:20 +0000
                Re: MCU mimicking a SPI flash slave Wasell <from_usenet@wasell.eu> - 2017-06-22 14:02 +0200
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-22 11:59 -0400
                Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-22 11:58 -0400
                Re: MCU mimicking a SPI flash slave anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-06-22 08:19 +0000
                Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-19 09:53 +0100
        Re: MCU mimicking a SPI flash slave Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-15 10:16 +0100
  Re: MCU mimicking a SPI flash slave John Speth <johnspeth@yahoo.com> - 2017-06-15 13:56 -0700
    Re: MCU mimicking a SPI flash slave Don Y <blockedofcourse@foo.invalid> - 2017-06-15 14:41 -0700
      Re: MCU mimicking a SPI flash slave John Speth <johnspeth@yahoo.com> - 2017-06-15 15:08 -0700
        Re: MCU mimicking a SPI flash slave Don Y <blockedofcourse@foo.invalid> - 2017-06-16 11:34 -0700
    Re: MCU mimicking a SPI flash slave rickman <gnuarm@gmail.com> - 2017-06-15 18:20 -0400
    Re: MCU mimicking a SPI flash slave edward.ming.lee@gmail.com - 2017-06-21 07:58 -0700
  Re: MCU mimicking a SPI flash slave Walter Banks <walter@bytecraft.com> - 2017-06-19 12:23 -0400

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