building RTEMS 4.11 leon3 with floating point support?

Cudmore, Alan P. (GSFC-5820) alan.p.cudmore at
Wed Sep 2 14:33:52 UTC 2015

I have not analyzed it to determine what floating point code is being

As soon as we try to FTP to the board, it generates an FP trap on GRMON.
When I enabled the floating point context support on the FTP task, it does
not crash. 

But I agree, it is worth trying to figure out where the FP code is being
generated in the FTP task.


On 9/2/15, 10:14 AM, "Joel Sherrill" <joel.sherrill at> wrote:

>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
>> works.
>> I did get a floating point exception in the FTP task and had to change
>> 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
>just to move data or calculate array indices?
>On some CPUs, when hard FP is turned on, GCC assumes the FPU can be used
>for some non-intuitive things and it is safer to implicitly make all tasks
>FP rather than letting people trip over implicit uses of the FPU.
>> Thanks,
>> Alan
>> On 8/31/15, 2:40 AM, "Sebastian Huber"
>> <sebastian.huber at> wrote:
>>> Hello Alan,
>>> I am not sure how Gaisler manages this in their RCC, but I think for
>>> standard RTEMS we need additional BSPs (e.g. via leon3_fp.cfg and
>>> ngmp_fp.cfg configuration files).
>>> On 17/08/15 17:29, Cudmore, Alan P. (GSFC-5820) wrote:
>>>> Hi,
>>>> We are currently trying to use the leon3 BSP for RTEMS 4.11.
>>>> We have used the 4.10 RCC/Gaisler tools with the Driver Manager in the
>>>> past, but we would like to be on 4.11 for the SMP support.
>>>> When I build the 4.11 leon3 BSP, I seem to only have soft-float
>>>> support. When I try to build with the ‹enable-multilib configure
>>>> switch, the build fails. Before I start trying to determine the cause
>>>> of the compile failure, I wanted to make sure I am enabling floating
>>>> point support for the LEON3 correctly.
>>>> Thanks,
>>>> Alan
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>>> --
>>> Sebastian Huber, embedded brains GmbH
>>> Address : Dornierstr. 4, D-82178 Puchheim, Germany
>>> Phone   : +49 89 189 47 41-16
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>Joel Sherrill, Ph.D.             Director of Research & Development
>joel.sherrill at        On-Line Applications Research
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