[En-Nut-Discussion] Nut/OS Initialization

[Alain M.]

In *my* ideal world, only memory, clock should be done in a hidden 
manner. This comes from many years debugging invisible things. Even 
system timer is questionable because it is often board dependent...

To accomodate with this last summary from Harald, maybe we can have one 
(preferably only one) function, probably named NutInit() that can be 
called before main for compatibility reasons, but that I can choose 
(how: hack crt.S or have a Nut option?) not to call before main.

IMHO, this accomedates both compibility with older systems and can make 
debugging easier.

:)
Alain

Harald Kipp escreveu:
> Alain M. wrote:
>> The reason is not only phylosophical, it makes simple debugging become 
>> possible nightmares. As you apen a nut system in Eclipse it goes 
>> straight to main() and you cannot debug anything before that. I had to 
>> do it with Nut, and it took me 2 days to find a simple error in one 
>> initialization ... :(
> 
> Another good argument to let us distinguish between system and 
> application initialization.
> 
> If you are an application programmer, you rely on a bug free OS and 
> start debugging at main(). If main calls your application specific 
> HardwareInit(), you need to debug this as well.
> 
> If you need to debug the OS, you have to find a way to start debugging 
> at the reset entry.
> 
> And luckily this will perfectly fit with my initial intention. :-) 
> Here's my view so far:
> 
> 1. Basic hardware initialization is typically done for a specific CPU, 
> sometimes for a specific board. We should move this out of NutInit to 
> new modules. Example: System timer initialization.
> 
> 2. Default initialization is done for a specific board, pre-initializing 
> the available hardware to some meaningful defaults. When building the 
> Nut/OS libraries, the developer must have the choice to disable this 
> fully or partly. Example: NutRegister the UART device, set the baud rate 
> and redirect stdout to it.
> 
> 3. Application initialization is done by the application programmer and 
> takes place after main is called.
> 
> I'm happy with this and you all like it too, right? ;-)
> 
> Harald
> 
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