Startup files for STM32F4xx

[Johannes Pfau via Digitalmars-d-learn]

Am Sat, 25 Apr 2015 18:31:45 +0000
schrieb "Jens Bauer" <doctor at who.no>:

> On Saturday, 25 April 2015 at 17:58:59 UTC, Timo Sintonen wrote:
> > On Saturday, 25 April 2015 at 17:04:18 UTC, Jens Bauer wrote:
> >
> >> I think volatileLoad and volatileStore are intended for this 
> >> (please correct me if my understanding is wrong).
> >>
> > Yes. Actually I am not sure whether they already exist in gdc 
> > or not.
> >
> > Try to write for example
> > regs.cmdr |= 0x20
> > with these functions and guess how many users will move to 
> > another language.
> 
> Ah, I get the point now. :)
> 
> I don't want to start another volatile discussion, but to me it 
> seems an attribute would not be a bad idea.
> -And for completeness... read-only, write-only, read/write and 
> perhaps even 'prohibited access'. I recall that something was 
> marked prohibited in some way in a library once; I forgot how 
> they did it, though.

volatileLoad is not in gdc yet. I've written the code some months ago
but I need to update it and then it needs to be reviewed.

Always using volatileLoad/Store is annoying. The solution is to write a
wrapper:


Volatile!T: http://dpaste.dzfl.pl/dd7fa4c3d42b

Volatile!size_t value;
value += 1;
assert(value == 1);



Register wrapper: http://dpaste.dzfl.pl/3e6314714541
Register definition:

enum Level : ubyte
{
    low = 0,
    high = 1
}

enum fields = [
    Field("PIN0", 0, 0, true, "Level", Access.readWrite),
    Field("PIN1", 1, 1, true, "Level", Access.readWrite),
    Field("TEST", 2, 4, false, "ubyte", Access.readWrite)];

mixin(generateRegisterType!ubyte("PORT", fields));
pragma(address, 0x25) extern __gshared PORTRegister PORTB;

Usage:
    auto b = PORTB.load();
    PORTB.toggle!"PIN0";
    PORTB.PIN0 = Level.low;
    writeln(PORTB.PIN0);
    PORTB.TEST = 0b000;


The remaining problem is performance. (With optimization the generated
code is as good as equivalent C code. However, we need to avoid size
overhead: e.g. struct initializers and the opX functions shouldn't
generate functions in the executable, though tha can be fixed with the
linker)