It's a bit more complicated than just setting the correct compiler options in libm.mk. Compiling the various math functions for hardfp works ok as you would expect. The issue comes when building the .so library. The linker call is set to merge the software fp version of libgcc.a. I'm having trouble following the library build process to determine where I can change to using .../fpu/libgcc.a.
Any hints would be appreciated.
Bob
Sent from my android device.
-----Original Message----- From: Christian Helmuth <christian.helmuth@...1...> To: genode-main@lists.sourceforge.net Sent: Thu, 01 Oct 2015 5:10 AM Subject: Re: Using ARM/Neon fp hardware with libc
Hello Bob,
On Wed, Sep 30, 2015 at 03:14:26PM -0400, robjsstewart@...9... wrote:
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 target.mk. 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?
With 15.02, you may try to patch repos/libports/lib/mk/arm/libm.mk accordingly. There is not way to just "configure" compilation options for libc that I know of.
Regards