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SubjectRe: Use of C99 int types
Stephen Rothwell wrote:

>On Sun, 03 Apr 2005 13:55:39 +0200 Dag Arne Osvik <> 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
#define fast_u32 u32

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