[En-Nut-Discussion] Using the FPU on Cortex-M4

Philipp Burch phip at hb9etc.ch
Fri Oct 24 11:37:20 CEST 2014

Hi Uwe!

On 24.10.2014 11:03, Uwe Bonnes wrote:
>>>>>> "Philipp" == Philipp Burch <phip at hb9etc.ch> writes:
>     Philipp> Hi everyone, as noted earlier, I'm currently porting Nut/OS to
>     Philipp> the TIVA TM4C architecture (see branches/devnut_tiva). It works
>     Philipp> well so far, as I can take a lot of code from the LM3S
>     Philipp> branch. Right now, the operating system itself, the GPIO API
>     Philipp> and the UART devices are working.
> ...
>     Philipp> Can anyone tell me what to do with this?
> Getting the use the FPU is hard. There are issues with fp register save on
> context switch. Did you compiled th library also with -mfloat-abi=hard?

Yes, that option is included. Context switching might become the next
issue, but I haven't checked that yet. All I did was to enable the lazy
register saving, so at least it should work when using floats in
interrupts (and somewhere else).


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