Using ARM/Neon fp hardware with libc

robjsstewart at ...196... robjsstewart at ...196...
Tue Oct 6 13:23:27 CEST 2015

Thanks, Stefan, I'll take a look at the context switching implementation for the Cortex A9.


Sent from my android device.

-----Original Message-----
From: Stefan Kalkowski <stefan.kalkowski at ...1...>
To: genode-main at
Sent: Tue, 06 Oct 2015 2:35 AM
Subject: Re: Using ARM/Neon fp hardware with libc

Hi Bob,

On 09/30/2015 09:14 PM, robjsstewart at ...9... wrote:
> Hi all,
> I'm exploring compiling a couple of targets in my Genode, base-hw system to use the hardware fp in the Neon coprocessor on an ARM Cortex A8 SOC, to get some performance improvement. I can add the CC_OPT line containing -mfloat-abi=hard and -mfu=neon-vfpv4 to appropreate That should result in the Neon fp unit being called to perform the calculations. If I want use libc math functions I assume I must recompile libc with the same compile options added. Are there build variables that allow me to do that to the libc library? 

I just wanted to add that currently FPU context switching is implemented
in base-hw for Cortex A9 only. It might be no big deal to enable it for
Cortex A8 by looking at the other implementation. As long as more than
one of your components uses the FPU this has to be done first.


> I'm currently building on Genode 15.02.
> Thanks for any info.
> Bob Stewart
> Sent from my android device.
> ------------------------------------------------------------------------------
> _______________________________________________
> genode-main mailing list
> genode-main at

Stefan Kalkowski
Genode Labs ยท

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