Re: [lwip-users] use of static variables in tcp_in.c

[address@hidden]

> > I think it would be a good thing moving from global variables to
> > parameters,
> > but I remember adam writing about intentionally using global variables
> > as a design goal in embedded systems (using a smaller stack, favouring
> > statically configured memory) which is an opinion I don't share, but we
> > would
> > have to discuss that!
>
> I think Adam made a good design choice. The stack is designed to be 
> single-threaded so what's the point doing otherwise. I would add, 
> though, that it's not just a question of stack space (although that's 
> a good enough reason on its own), but also code space and performance 
> - marshalling all the various arguments into the right position for 
> function calls would take extra code and time. It would also add to 
> register pressure.
>
> Incidentally there are other ways to deal with different priority of 
> operations depending on the thread priority of the threads using the 
> stack.

What you say is true, of course when using the stack single-threaded. 
But when it comes to multithreading, there are some restrictions with 
this design choice. In the spirit of 'lw', however, I think we'll stay 
with the current implementation...

Simon