From mboxrd@z Thu Jan 1 00:00:00 1970 From: Graeme Russ Date: Fri, 30 Sep 2011 23:02:02 +1000 Subject: [U-Boot] U-Boot X86 bootstart In-Reply-To: References: Message-ID: <4E85BDCA.8020101@gmail.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Ondrej Kupka On 30/09/11 21:06, 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? Nice catch :) At least one of them is wrong - I'll sort out a patch (unless you want to submit a patch yourself that is) > > Thanks a lot, > Ondrej Kupka Thank you Regards, Graeme