Re: [PIC] Learning C

Use the latest GCC available, which it seems to be 13.1.0.

Download 'mingw-get' from 
<https://sourceforge.net/projects/mingw/files/Installer/>. It is the 
installer that fetches the latest version.

As an IDE I suggest Code::Blocks. It is very basic and the latest 
version is almost five years old, but it is simple and compact.


Cheers,

Isaac



Em 11/11/2024 10:20, David C Brown escreveu:
> And, of course a recommendation for a compiler
> __________________________________________
> David C Brown
> 43 Bings Road
> Whaley Bridge
> High Peak                           Phone: 01663 733236
> Derbyshire                eMail: [email protected]
> SK23 7ND          web: www.bings-knowle.co.uk/dcb
> <http://www.jb.man.ac.uk/~dcb>
>
>
>
> *Sent from my etch-a-sketch*
>
>
> On Mon, 11 Nov 2024 at 00:26, Isaac Marino Bavaresco <
> [email protected]> wrote:
>
>> I rarely use other people's code, unless it is deemed to be of very high
>> quality. I prefer to study the code and write my own version based on
>> it. It is slow but has proven to save a lot of problems in the long run.
>>
>> I write the absolute majority of my code in C (C99 if possible) and try
>> to keep with GCC. If a platform doesn't have a GCC port it is very
>> likely that I won't adopt it. That's not the case for PICs, which I use
>> for so many years that it predates the GCC wide availability.
>>
>> My LCD routines were written in C in the early 1990s for 8051 MCUs and I
>> still use them for ARM and MIPS (PIC32). If they were written in
>> assembly language I would have needed to recreate them at least five
>> times (AVR, PIC, PIC18F, PIC32, ARM).
>>
>> I rewrote a large part of FATFS, because the code was so complicated and
>> obscure that I could not understand it. I think that I found a few
>> mistakes in the implementation during the process.
>>
>> I also wrote my own RTOS because I was not satisfied with the code of
>> FreeRTOS.
>>
>>
>> Cheers,
>>
>> Isaac
>>
>>
>> Em 10/11/2024 21:36, smplx escreveu:
>>> Hi Isaac,
>>> The point isn't really what I could or should do, it's more to do with
>>> what someone else has written and the rest of us have to use. How
>>> often have you come across some code that was abandoned by the
>>> original author many years ago and has been hacked by uncareing
>>> individuals to fix an immediate problem. How often have you come
>>> across comments that no longer reflect what the code actually does.
>>>
>>> And to make the NaN situation even more interesting a floating point
>>> library might implement NaNs correctly (or not) where the "noddy" MCU
>>> compiler doesn't. This is another reason why it's best to learn C in a
>>> proven high quality dev environment like a PC. Look at the early PIC C
>>> compilers - I dare you not to laugh.
>>>
>>> Another way to express a NaN's character is to say "it is unordered".
>>>
>>> Friendly Regards
>>> Sergio Masci
>>>
>>> On Sun, 10 Nov 2024, Isaac Marino Bavaresco wrote:
>>>
>>>> But you could use also the function 'isnan', which is easier to
>>>> understand for someone reading your code.
>>>>
>>>> There are also other functions like 'isinf', etc.
>>>>
>>>>
>>>> Interestingly, a NaN is not greater, nor smaller nor equal to
>>>> anything, not even itself. It is only different than everything.
>>>>
>>>>
>>>> Cheers,
>>>>
>>>> Isaac
>>>>
>>>>
>>>> Em 10/11/2024 20:09, smplx escreveu:
>>>>> Hi Colin,
>>>>>
>>>>> You might be intested to know that to check for floating point
>>>>> errors / exceptions in C you would use:
>>>>>
>>>>> if (x == x)...
>>>>> or
>>>>> if (x != x)...
>>>>>
>>>>> where x is a float
>>>>>
>>>>> e.g.
>>>>>      float    x
>>>>>
>>>>>      x = 1.0 / 0.0;
>>>>>
>>>>>      if (x != x)
>>>>>      {    // x is a NaN which is an error
>>>>>      }
>>>>>
>>>>> Here clearly "x 'is the same as' x" but the test is "x 'is a NaN'".
>>>>>
>>>>> Friendly Regards
>>>>> Sergio
>>>>>
>>>>> On Sun, 10 Nov 2024, CDB wrote:
>>>>>
>>>>>> I have always separated the difference of =  and == in C by
>>>>>> referring to the latter as 'is the same as'
>>>>>>
>>>>>> if (X is the same as Y) then ......  if (X == Y) then
>>>>>> x = y       x now contains the value of Y.
>>>>>>
>>>>>> Colin
>>>>>>
>>>>>>
>>>>>> --
>>>>>>
>>>>>> [email protected]  11 November 2024
>>>>>>
>>>>>> Hosted by: www.superdomains.com.au
>>>>>>
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>>>>>> individual or Personnel Department, and public if addressed to a
>>>>>> blog,  forum or news article.
>>>>>>
>>>>>>
>>>>>>
>>>>>> __________________________________
>>>>>> Sent from eM Client | www.emclient.com <https://www.emclient.com/get>
>>>>>>
>>>>>>
>>>>>> On 11/11/2024 08:24:15, "smplx" <[email protected]> wrote:
>>>>>>
>>>>>>>
>>>>>>> On Sun, 10 Nov 2024, Neil wrote:
>>>>>>>
>>>>>>>> Agree with a couple things from other comments such as C being
>>>>>>>> high-level assembler and using a PC at first (you can just use
>>>>>>>> gcc already on Linux).
>>>>>>>>
>>>>>>>> Already knowing a structured language is very helpful.
>>>>>>>> But IMO you'll have to wrap your head around pointers, which can
>>>>>>>> get confusing. I find this C visualizer very helpful for figuring
>>>>>>>> out some algorithm... https://pythontutor.com/c.html
>>>>>>>>
>>>>>>>> One more note: = != ==
>>>>>>>> Or in other words, the equal sign ( = ) and the double equal size
>>>>>>>> ( == ) are very different things in C. The first assigns a value
>>>>>>>> and the other compares values. But people new to C will
>>>>>>>> invariably use a single equal for a comparison and the code is
>>>>>>>> true every time, as C will compile it as valid code, do the
>>>>>>>> assignment, then the comparison. You have been warned ;P
>>>>>>> Sorry to wade in here but:
>>>>>>>
>>>>>>> if (y = x)...
>>>>>>>
>>>>>>> assigns x to y then compares the result to 0. 0 is nomally taken to
>>>>>>> mean false and "not 0" as true. So it is almost alway true except
>>>>>>> in the case where x is 0.
>>>>>>>
>>>>>>> I'm not sure what happens if x and y are floats and x is a NaN or
>>>>>>> if x and y are structures.
>>>>>>>
>>>>>>> if you're looking for a real headache try debugging a program that
>>>>>>> contains:
>>>>>>>
>>>>>>> if (! x == y)...
>>>>>>>
>>>>>>> Trying to learn C on bare metal is like trying to learn to fly by
>>>>>>> crashing a lot. It's a lot quicker and easier if you learn on a
>>>>>>> simulator.
>>>>>>>
>>>>>>> Friendly Regards
>>>>>>> Sergio Masci
>>>>>>>
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