Questions about FPU and NEON on Cortex-A9 with armv7 instructions!

[David Yang]

Hi,Martin

    I see.

    But I will  try to use FPU in kernel for testing. I hope kernel won't crash.


Thank you！


On Wed, Jul 28, 2010 at 4:57 PM, Martin Guy <martinwguy at gmail.com> wrote:
> On 7/28/10, David Yang <david.yangshuai at gmail.com> wrote:
>>        Because I need use the NEON on Cortex-A9, so I want to add the
>>  parameter : -mfpu=neon -mfloat-abi=softfp to the KBUILD_CFLAGS and
>>  KBUILD_AFLAGS in the Makefile of the top dir like below:
>
> Hi David
>   Linux never uses the FPU internally, in fact it doesn't use
> floating point at all. Linux's task with the FPU is only to initialize
> it so that user-space applications can use it, and to save/restore FP
> register contents when two processes are both using it.
>   In the kernel itself only integer math is used.
>
> Cheers
>
>    M
>