Re: [patch 1/2] x86: head_64.S cleanup - use straight move to CR4register

From: Cyrill Gorcunov
Date: Tue May 13 2008 - 13:07:44 EST


[H. Peter Anvin - Tue, May 13, 2008 at 10:03:42AM -0700]
> Cyrill Gorcunov wrote:
>> There is no need for testing the values because we already know
>> what they should be. Just set them in straight way.
>
> He isn't testing them, he's setting individual bits.

not exactly - bts: bit test and set

>
> Either of these is pretty silly; the right way to do this is:
>
> movl $(X86_CR4_PAE|X86_CR4_PGE), %eax
> movq %rax, %cr4
>
> A movl in 64-bit mode zero extends.
>
> -hpa
>
ok, thanks Peter, i'll update in minute ;)

- Cyrill -
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