compile kernel with hard float support
Andrew Turner
andrew at fubar.geek.nz
Thu Oct 1 09:25:24 UTC 2015
On Thu, 1 Oct 2015 11:45:03 +0300
Stefan Parvu <sparvu at kronometrix.org> wrote:
>
> I understood, by default, the image
> FreeBSD-armv6-11.0-RPI2-286947.img.gz has soft float support. All
> float-point operations are done in software not using the ARM hardware
> VFP. Correct ?
No, armv6 is built with softfp. This means the compiler is free to use
the VFP, but when passing floating-point data between functions it
needs to copy this to the general-purpose registers.
Even without this the helper functions detect the presence of the VFP
unit and make use of this when available.
>
> If I want to build FreeBSD 11 with hard float support can I do this
> already ? Do we support hard float ? And how should I compile things ?
>
> # setenv ARCH armv6hf (is this correct ?)
> # make buildkernel KERNCONF=RPI2
The kernel doesn't use any floating-point hardware, other than to
enable and disable it in the VFP driver. As such it doesn't matter if
you've built the kernel for hard-float or not, it will make no
difference to the code generated.
Andrew
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