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Re: [Q] enabling FPU for vpe1

To: "Kevin D. Kissell" <kevink@paralogos.com>
Subject: Re: [Q] enabling FPU for vpe1
From: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Date: Thu, 5 Aug 2010 09:58:15 +0800
Cc: linux-mips@linux-mips.org
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You are correct. I did miss something earlier. The NCP1 needs to be
set. Thanks, Kevin.


Deng-Cheng



2010/8/4 Kevin D. Kissell <kevink@paralogos.com>:
> You can only set the TC's CU bits if the VPE to which the TC is bound has
> access to the coprocessor.  See sections 8.2 andf 6.7 of the currently
> online spec, and read the MIPS MT Principles of Operation document, if you
> can find it.
>
> On 08/04/10 03:14, Deng-Cheng Zhu wrote:
>>
>> Thanks for looking into this.
>>
>> I did do that. But the CU1 bit of TC#1 (in VPE#1) can not be set by
>> TC#0 or itself. Looks like VPE#1 is not seeing the FPU at all...
>>
>>
>> Deng-Cheng
>>
>>
>> 2010/8/4 Kevin D. Kissell<kevink@paralogos.com>:
>>
>>>
>>> Check the MIPS MT spec.  If I recall correctly, it's possible to enable
>>> access to the FPU by either VPE by setting the right bits while the
>>> processor is in the MT configuration mode.
>>>
>>> Deng-Cheng Zhu wrote:
>>>
>>>>
>>>> Hi,
>>>>
>>>>
>>>> I'm working on a 34Kf CPU. I understand that only one TC can use the
>>>> FPU at any given time.
>>>>
>>>> My question is: If a TC is attached to the 2nd VPE (i.e. VPE1), can I
>>>> enable FPU for it?
>>>>
>>>> I experimented on this, but failed to do it. Am I missing something?
>>>>
>>>>
>>>> Thanks
>>>>
>>>> Deng-Cheng
>>>>
>>>>
>>>>
>>>
>>>
>
>

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