Re: [PATCH 2 of 2] __raw_memcpy_toio32 for x86_64

From: Bryan O'Sullivan
Date: Wed Jan 11 2006 - 20:26:13 EST


On Thu, 2006-01-12 at 01:56 +0100, Andi Kleen wrote:

> At least some people have complained about the "All Rights reserved"
> in the past. Best you drop it.

OK, thanks.

> Usually one should use .p2align or ENTRY() at function beginning,
> otherwise you might get some penalty on K8.

Will do.

> > +__raw_memcpy_toio32:
> > + movl %edx,%ecx
> > + shrl $1,%ecx
>
> 1? If it's called memcpy it should get a byte argument, no? If not
> name it something else, otherwise everybody will be confused.

It's called toio32 for a reason :-)

Also, the kernel doc clearly states its purpose.

> movsq? I thought you wanted 32bit IO?

The northbridge will split qword writes into pairs of dword writes.

> The movsd also looks weird.

Why?

<b
--
Bryan O'Sullivan <bos@xxxxxxxxxxxxx>

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