From: "Kevin D. Kissell" <kevink@paralogos.com>
To: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: linux-mips@linux-mips.org
Subject: Re: [Q] enabling FPU for vpe1
Date: Wed, 04 Aug 2010 08:26:52 -0700 [thread overview]
Message-ID: <4C5986BC.9000307@paralogos.com> (raw)
In-Reply-To: <AANLkTinVxFnNzQaHUCqxTQk708MEuUAiEuRGGPN8WcuS@mail.gmail.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
>>>
>>>
>>>
>>
>>
next prev parent reply other threads:[~2010-08-04 15:27 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-04 7:02 [Q] enabling FPU for vpe1 Deng-Cheng Zhu
2010-08-04 8:09 ` Kevin D. Kissell
2010-08-04 10:14 ` Deng-Cheng Zhu
2010-08-04 15:26 ` Kevin D. Kissell [this message]
2010-08-05 1:58 ` Deng-Cheng Zhu
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