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Date: Thu, 16 Dec 2004 09:33:06 -0800
From: Jun Sun <jsun@junsun.net>
To: zhan rongkai <zhanrk@gmail.com>
Cc: linux-mips@linux-mips.org
Subject: Re: About task->used_math and TIF_USEDFPU
Message-ID: <20041216173306.GA3230@gw.junsun.net>
References: <73e6204504121600066a2ce0b1@mail.gmail.com>
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On Thu, Dec 16, 2004 at 04:06:12PM +0800, zhan rongkai wrote:
> hi all,
> 
> I am a little confused about the task_struct member 'used_math', and
> thread_info flag TIF_USEDFPU.
> 
> What are their meaning, and what is the difference between them?
> 

used_math is used to indicate whether a process has ever used FPU since
it is created (which typically is true due to the glibc using FPU at the
beginning of each program).

TIF_USEDFPU indicates whether a _running_ process has used FPU since
it is context-switched on.

Jun