Re: kernel compile: -mno-fpu
On Sun, Jun 15, 2003 at 12:01:00AM -0400, Brian C Miles wrote:
>
> While building 2.4.21 on my SS20 SMP box, I noticed "-mno-fpu" being used
> as a CFLAG. Does anyone know why? This isn't an indication that fp
> emulation is being compiled into the kernel (i.e. though it may very well
> be), but a directive to tell GCC to try and use software implementations
> of fp math. Does anyone know why this is enabled by default? Does this
> have any negative performance impact on machines that have hardware FPU?
> Is it safe to compile the kernel without this flag?
>
> There are several dead-end threads about this topic on various newsgroup
> archives. If any one could shed some light on this, it would be much
> appreciated.
There is no floating point used in the kernel. So it has no real affect.
I don't know for sure, but -mno-fpu may also allow the compiler to make
some assumptions about the code it is compiling, for better scheduling
and performance.
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