lkml.org 
[lkml]   [2007]   [Oct]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/1] unify DMA_..BIT_MASK definitions: v3.1
On Fri, 05 Oct 2007 14:28:45 -0700
Jeremy Fitzhardinge <jeremy@goop.org> wrote:

> Andreas Schwab wrote:
> > #define DMA_BIT_MASK(n) ((u64)-1 >> (64 - (n)))
> >
>
> Yeah, that's cleaner.
>

Well yes, but DMA_BIT_MASK(0) invokes undefined behaviour, generates a
compiler warning and evaluates to 0xffffffffffffffff (with my setup).
That won't be a problem in practice, but it is strictly wrong and doesn't set
a good exmaple for the children ;)

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-10-06 00:27    [from the cache]
©2003-2011 Jasper Spaans