lkml.org 
[lkml]   [2012]   [Aug]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH] MPILIB: Provide count_leading/trailing_zeros() based on arch functions
From
From: Jan Engelhardt <jengelh@inai.de>
Date: Fri, 10 Aug 2012 14:51:49 +0200 (CEST)

>
> On Saturday 2012-07-21 02:46, David Miller wrote:
>>> Arnd Bergmann <arnd@arndb.de> wrote:
>>>
>>>> I don't generally like to put stuff into asm-generic when it's unlikely
>>>> to be overridden by architectures. It would really belong into
>>>> include/linux, but then again we have all the other bitops in asm-generic
>>>> as well, so whatever...
>>>
>>> Some arches (such as Sparc, I think) have count-leading-zero instructions.
>>
>>Yes, newer sparc64 chips have leading-zero-detect, and I was pretty
>>sure that powerpc had something similar. It's called count-leading-
>>zeros or something like that.
>
> And gcc has a __builtin_clz.

Which I can't use. I have to patch the code at run time based upon
whether the cpu has the 'lzd' instruction or not.


\
 
 \ /
  Last update: 2012-08-10 23:41    [W:2.028 / U:0.508 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site