lkml.org 
[lkml]   [2003]   [Apr]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [RFC][PATCH] Faster generic_fls
FromFalk Hueffner <>
Date30 Apr 2003 15:17:13 +0200
Daniel Phillips <dphillips@sistina.com> writes:

> It's somewhat annoying that __builtin_clz leaves the all-ones case
> dangling instead of returning -1.

I assume you mean all-zero... Well, the semantics of the corresponding
instructions simply differ too much. clz(0) is 31 on some, 32 on some
others, and undefined on some more architectures. So nailing it down
would incur some performance penalty.

--
Falk
-
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: 2005-03-22 13:35    [from the cache]
©2003-2010