[coreboot] rfc - gcc builtins and memset memcpy memmove memcmp

Marc Jones marcj303 at gmail.com
Sun Sep 12 22:16:49 CEST 2010

On Sat, Sep 11, 2010 at 1:59 PM, Peter Stuge <peter at stuge.se> wrote:
> Marc Jones wrote:
>> doesn't really explain why gcc doesn't do a rep stos or rep mov
>> (which should hit the cache)/ That should be an easy optimization
>> for gcc.
> Except I don't think it's an optimization performance-wise. But if
> you enable -Os then I would expect it to use rep stosb.

It is an optimzation over a byte copy, which is what the code does. We
don't have optimized mem functions.

>> It also doesn't address why coreboot has a functions when we could
>> use gcc intrinsic that should be optimized for the architecture
>> they are built for.
> Good point! I guess we rolled our own to be less dependent on gcc. I
> think it would be OK to use gcc's implementations though.

Good point, but most compilers have intrinsics for these functions, Do
we need a compiler intrinsics layer?



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