Re: [PATCH] [2.5] asm-generic/atomic.h and changes to arm, parisc,

[Roman Zippel]

Hi,

On 9 Aug 2002, Luca Barbieri wrote:

> > The compiler can cache the value in a register
> It shouldn't since it is volatile and the machine has instructions with
> memory operands.

volatile is no guarantee for that:

volatile int x;

void f(int y)
{
        x += y;
}

becomes:

	move.l x,%d0
	add.l 8(%a6),%d0
	move.l %d0,x

I agree that volatile should avoid caching, but it does not guarantee an
atomic modify.

bye, Roman