building RTEMS 4.11 leon3 with floating point support?

Gedare Bloom gedare at rtems.org
Wed Sep 2 14:53:08 UTC 2015


On Wed, Sep 2, 2015 at 10:29 AM, Daniel Gutson
<daniel.gutson at tallertechnologies.com> wrote:
>
> El 2/9/2015 11:14, "Joel Sherrill" <joel.sherrill at oarcorp.com> escribió:
>>
>>
>>
>> On 8/31/2015 5:47 AM, Cudmore, Alan P. (GSFC-5820) wrote:
>>>
>>> Having a floating point configuration of the BSP makes sense. I was able
>>> to rebuild the BSP with the hardware floating point compiler option and
>>> it
>>> works.
>>>
>>> I did get a floating point exception in the FTP task and had to change
>>> the
>>> FTP task create to enable floating point. Is it worth submitting a patch
>>> to change that?
>>
>>
>> What did it use the FPU for? Is this a case where GCC emits FPU
>> instructions
>> just to move data or calculate array indices?
>
> Offtopic: this seems very suboptimal. Have you got an actual example of
> that? I'd like to take a look.
>
Daniel, I don't have a specific example, but the history is that GCC
could (used to?) emit instructions that make use of FP registers of
the CPU in case GCC thinks that an FPU co-processor is used.

Gedare



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