On Fri, Jul 18, 2014 at 10:05:29PM +0400, Sergei Shtylyov wrote:
> >>>+#define GICBIS(reg, mask, bits) \
> >>>+ do { u32 data; \
> >>>+ GICREAD((reg), data); \
>
> >> Why () only around 'reg', not around 'data'?
>
> >Brackets aren't necessary around "data" because it is declared at the start of
> >the "do" code block, so it can't expand to anything else within that scope.
>
> Oh, I was not attentive enough, sorry about that... :-<
> However, it makes sense to at least put that declaration at a separate line.
And it's not safe against multiple evaluation of macro arguments. Imagine
what's going to happen if GICBIS is called as something like
GICBIS(++a, ++b, c);
That'll expand to:
do { u32 data;
GICREAD((++a), data);
data &= ~(++b);
data |= ((bits) & (++b));
GICWRITE((++a), data);
} while (0)
Paranoia?
Ralf
