How to handle float-point operations

[priyaranjan]

Hi Arun,


>On Thu, Jun 25, 2015 at 2:33 PM, Arun KS <getarunks at gmail.com> wrote:
>Hello Mudongliang,
>
>
> >On Tue, Jun 23, 2015 at 9:01 AM, 慕冬亮 <mudongliangabcd at gmail.com> wrote:
> >>
> >> I know there are rarely float-point operations! What's the exception?
> > In the linux kernel, how does it handle the float-point operations in
> the >userland?
>
> >>Most of the userspace programs do not use FP instructions. So by
> >>default floating point engine is turned off during a context switch.
> >>When a process executes floating point instruction, an undefined
> >>exception is generated. Exception handler enables the floating point
> >>engine and jump back to the same instruction which caused the
> >>exception so that it will get re executed with FP engine on.
>
> Is this somehow related to the platform in which linux runs? If the FP
> operations are valid, then will that still generate the exception or it
> does a context switch, turns on FP engine and re-executed?
>
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