[U-Boot] U-Boot X86 bootstart
Marek Vasut
marek.vasut at gmail.com
Fri Sep 30 13:09:03 CEST 2011
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
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