On Sun, Nov 26, 2006 at 02:20:10PM -0800, Linus Torvalds wrote:
> So arguably, the result is _more_ like a normal C operation this way.
> Type-wise, the "ALIGN()" macro acts like any other C operation (ie if you
> feed it an "unsigned char", the end result is an "int" due to the normal C
> type
On Sun, 26 Nov 2006, Roland Dreier wrote:
>
> > +#define ALIGN(x,a)__ALIGN_MASK(x,(typeof(x))(a)-1)
> > +#define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask))
>
> Fine by me, but it loses the extra (typeof(x)) cast that Al wanted to
> make sure that the result of ALIGN() is
On Sun, 26 November 2006 12:26:08 -0800, Roland Dreier wrote:
>
> > +#define ALIGN(x,a)__ALIGN_MASK(x,(typeof(x))(a)-1)
> > +#define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask))
>
> Fine by me, but it loses the extra (typeof(x)) cast that Al wanted to
> make sure that the re
> +#define ALIGN(x,a) __ALIGN_MASK(x,(typeof(x))(a)-1)
> +#define __ALIGN_MASK(x,mask)(((x)+(mask))&~(mask))
Fine by me, but it loses the extra (typeof(x)) cast that Al wanted to
make sure that the result of ALIGN() is not wider than x.
- R.
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On Sun, 26 Nov 2006, Andrew Morton wrote:
>
> I'd be inclined to merge it for 2.6.19. Is everyone OK with it?
I'd _much_ rather make it more readable while at it. Something like this
instead, which has just _one_ "typeof" cast, and at least to me makes it a
lot more obvious what is going on
> I'd be inclined to merge it for 2.6.19. Is everyone OK with it?
I'm OK with that -- your previous email made me thing you didn't want
to, but I think the risks are rather low, and there's a least a chance
that we'll fix some obscure regression.
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On Sun, 26 Nov 2006 11:10:23 -0800
Roland Dreier <[EMAIL PROTECTED]> wrote:
> Commit 4c8bd7ee ("Do not truncate to 'int' in ALIGN() macro.") was
> merged to fix the case of code like the following:
>
> unsigned long addr;
> unsigned int alignment;
> addr = ALIGN(addr, alignment)
> Changes this late in the piece rather hurt.
Fair enough. This was a really close call to me but let's leave it
for 2.6.19. I'll ask Linus to merge the patch below to fix amso1100.
I'm a little worried that other such uses might be lurking in the
tree but I guess no one has complained...
> Y
Commit 4c8bd7ee ("Do not truncate to 'int' in ALIGN() macro.") was
merged to fix the case of code like the following:
unsigned long addr;
unsigned int alignment;
addr = ALIGN(addr, alignment);
The original ALIGN macro calculated a mask as ~(alignment - 1), and
when alignme
On Sat, Nov 25, 2006 at 05:17:08PM -0800, Roland Dreier wrote:
> >(typeof(x))((x + a - 1) & ~(a - 1ULL))
>
> Yes I was being stupid thinking I needed a temporary variable to use
> typeof. But what does the cast to typeof(x) accomplish if we write
> things the way you suggested above? It see
> (typeof(x))((x + a - 1) & ~(a - 1ULL))
Yes I was being stupid thinking I needed a temporary variable to use
typeof. But what does the cast to typeof(x) accomplish if we write
things the way you suggested above? It seems that the right things is
really just
(((x) + (a) - 1) & ~((
On Sat, Nov 25, 2006 at 03:05:00PM -0800, David Miller wrote:
> From: Roland Dreier <[EMAIL PROTECTED]>
> Date: Sat, 25 Nov 2006 14:56:22 -0800
>
> > > Perhaps a better way to fix this is to use
> > > typeof() like other similar macros do.
> >
> > I tried doing
> >
> > #define ALIGN(x,a)
On Sat, 25 Nov 2006 15:09:38 -0800
Roland Dreier <[EMAIL PROTECTED]> wrote:
> > But yes, given the array sizing case in the neighbour code,
> > perhaps we can use your original patch for now. Feel free
> > to push that to Linus.
>
> akpm is CC'ed on this thread. Andrew, are you going to pick
> You would need to also cast the constants with typeof() to.
Why? I'm not much of a C language lawyer, but I would have thought
that in something like
(x) + _a - 1
the "1" will be promoted to the type of the rest of the expression
without any explicit cast. I tested the unsigned long
From: Roland Dreier <[EMAIL PROTECTED]>
Date: Sat, 25 Nov 2006 14:56:22 -0800
> > Perhaps a better way to fix this is to use
> > typeof() like other similar macros do.
>
> I tried doing
>
> #define ALIGN(x,a)\
> ({ \
>
> Perhaps a better way to fix this is to use
> typeof() like other similar macros do.
I tried doing
#define ALIGN(x,a) \
({ \
typeof(x) _a = (a); \
((x) + _a - 1) & ~(_a - 1);
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