* [Q] enabling FPU for vpe1
@ 2010-08-04 7:02 Deng-Cheng Zhu
2010-08-04 8:09 ` Kevin D. Kissell
0 siblings, 1 reply; 5+ messages in thread
From: Deng-Cheng Zhu @ 2010-08-04 7:02 UTC (permalink / raw)
To: linux-mips
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
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Q] enabling FPU for vpe1
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
0 siblings, 1 reply; 5+ messages in thread
From: Kevin D. Kissell @ 2010-08-04 8:09 UTC (permalink / raw)
To: Deng-Cheng Zhu; +Cc: linux-mips
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
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Q] enabling FPU for vpe1
2010-08-04 8:09 ` Kevin D. Kissell
@ 2010-08-04 10:14 ` Deng-Cheng Zhu
2010-08-04 15:26 ` Kevin D. Kissell
0 siblings, 1 reply; 5+ messages in thread
From: Deng-Cheng Zhu @ 2010-08-04 10:14 UTC (permalink / raw)
To: Kevin D. Kissell; +Cc: linux-mips
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
>>
>>
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Q] enabling FPU for vpe1
2010-08-04 10:14 ` Deng-Cheng Zhu
@ 2010-08-04 15:26 ` Kevin D. Kissell
2010-08-05 1:58 ` Deng-Cheng Zhu
0 siblings, 1 reply; 5+ messages in thread
From: Kevin D. Kissell @ 2010-08-04 15:26 UTC (permalink / raw)
To: Deng-Cheng Zhu; +Cc: linux-mips
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
>>>
>>>
>>>
>>
>>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Q] enabling FPU for vpe1
2010-08-04 15:26 ` Kevin D. Kissell
@ 2010-08-05 1:58 ` Deng-Cheng Zhu
0 siblings, 0 replies; 5+ messages in thread
From: Deng-Cheng Zhu @ 2010-08-05 1:58 UTC (permalink / raw)
To: Kevin D. Kissell; +Cc: linux-mips
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
>>>>
>>>>
>>>>
>>>
>>>
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2010-08-05 2:00 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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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
2010-08-05 1:58 ` Deng-Cheng Zhu
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