Re: Use of C99 int types

[Dag Arne Osvik]

Stephen Rothwell wrote:

> On Sun, 03 Apr 2005 13:55:39 +0200 Dag Arne Osvik <da@xxxxxxxx> wrote:
>  
>
> > I've been working on a new DES implementation for Linux, and ran into
> > the problem of how to get access to C99 types like uint_fast32_t for
> > internal (not interface) use.  In my tests, key setup on Athlon 64 slows
> > down by 40% when using u32 instead of uint_fast32_t.
> >    
>
> If you look in stdint.h you may find that uint_fast32_t is actually
> 64 bits on Athlon 64 ... so does it help if you use u64?
>
>  

Yes, but wouldn't it be much better to avoid code like the following, 
which may also be wrong (in terms of speed)?

#ifdef CONFIG_64BIT  // or maybe CONFIG_X86_64?
 #define fast_u32 u64
#else
 #define fast_u32 u32
#endif

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