RE: [avr-libc-dev] Inline assembler and compiler optimization

[Weddington, Eric]

> -----Original Message-----
> From: 
> address@hidden 
> [mailto:address@hidden
> org] On Behalf Of Joerg Wunsch
> Sent: Tuesday, March 17, 2009 10:02 AM
> To: address@hidden
> Subject: Re: [avr-libc-dev] Inline assembler and compiler optimization
> 
> As Weddington, Eric wrote:
> 
> > > Anyway, it might make sense to provide an additional macro like
> > > __memory_barrier() that expands to __asm__
> > > __volatile__(""::"memory").
> 
> > If we do that, we might as well make it a public symbol, yes?:
> > #define memory_barrier()  __asm__ __volatile__(""::"memory")
> 
> If we document it, it /is/ public. ;-)
> 
> The point is that user programs might already use the identifier
> memory_barrier so we'd better avoid redefining it (at least, as long
> as it goes into one of the existing header files).

Hmm. I really hate having to explain the two leading underscores all over again.

First, we should do some research to see if there is already a gcc builtin, 
available to the AVR, that does the same thing.