From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marek Vasut <marek.vasut@gmail.com>
Date: Fri, 30 Sep 2011 13:09:03 +0200
Subject: [U-Boot] U-Boot X86 bootstart
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References: <CANq5_NmMp7HJJEo03_V4DrGmoW7pKtBr05yd6cWnryjaY+BUMw@mail.gmail.com>
Message-ID: <201109301309.04152.marek.vasut@gmail.com>
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On Friday, September 30, 2011 01:06:04 PM Ondra Kupka wrote:
> Hello,
> 
> I've been digging a bit in X86 bootstart asm code and found possibly wrong
> code, as far as I understand:
> 
> In u-boot/arch/x86/cpu/start.S, there is piece of code to disable caches:
> 
>     /* Turn of cache (this might require a 486-class CPU) */
>     movl    %cr0, %eax
>     orl     $(X86_CR0_NW | X86_CR0_CD), %eax
>     movl    %eax, %cr0
>     wbinvd
> 
> , which perfectly makes sense to me. What doesn't really make sense then
> is:
> 
>     /* Turn of cache (this might require a 486-class CPU) */
>     movl    %cr0, %eax
>     orl     $(X86_CR0_NW & X86_CR0_CD), %eax    - AND HERE???
>     movl    %eax, %cr0
>     wbinvd
> 
> in start16.S of the same directory.
> 
> Is is wrong or not?
> 
> Thanks a lot,
> Ondrej Kupka

Ccing Graeme, cheers