On Wed, Feb 20, 2008 at 1:09 PM, Carl-Daniel Hailfinger < [EMAIL PROTECTED]> wrote:
> On 20.02.2008 18:52, Stefan Reinauer wrote: > > Carl-Daniel Hailfinger wrote: > >> On 20.02.2008 17:19, Stefan Reinauer wrote: > >> > >>> * ron minnich <[EMAIL PROTECTED]> [071212 17:19]: > >>> > >>>>> Question to you guys: why is the first wrmsr instruction there? > >>>>> From my > >>>>> understanding, by not properly initialising ECX, EAX and EDX this > >>>>> will > >>>>> overwrite whatever is in the MSR pointed to by ECX?! > >>>>> > >>>>> BTW I tried out your code on our target hardware (Intel Celeron M, > >>>>> 600 MHz) > >>>>> and with that first wrmsr line in place it hangs and without it, > >>>>> it runs > >>>>> just fine. > >>>>> > >>>> Thanks Martin. That looks like quite a nice bug catch you've done :-) > >>>> > >>> Here's a patch that resolves the issue. > >>> > >>> Signed-off-by: Stefan Reinauer <[EMAIL PROTECTED]> > >>> > >>> Index: src/cpu/intel/microcode/microcode.c > >>> =================================================================== > >>> --- src/cpu/intel/microcode/microcode.c (revision 3111) > >>> +++ src/cpu/intel/microcode/microcode.c (working copy) > >>> @@ -33,7 +33,6 @@ > >>> */ > >>> msr_t msr; > >>> __asm__ volatile ( > >>> - "wrmsr\n\t" > >>> > >> > >> ACK. > >> > >> > >>> "xorl %%eax, %%eax\n\t" > >>> "xorl %%edx, %%edx\n\t" > >>> "movl $0x8b, %%ecx\n\t" > >>> @@ -60,7 +59,7 @@ > >>> char *c; > >>> msr_t msr; > >>> > >>> - /* cpuid sets msr 0x8B iff a microcode update has been loaded. */ > >>> + /* cpuid sets msr 0x8B if a microcode update has been loaded. */ > >>> > >> > >> NACK. "IFF" is shorthand for "if and only if", see > >> http://en.wikipedia.org/wiki/If_and_only_if > >> > > > > That's silly. This is not a mathematical expression nor a > > philosophical disquisition but a sentence. I am not even convinced > > that it was meant that way rather than being just a typo. If you have > > reasons to assume it means "If and only if" then let's write it that > way. > > Merriam-Webster agrees with me that "iff" is a word: > http://www.merriam-webster.com/dictionary/iff > So this is a valid sentence and I see no reason to change it. Unless the > bit can be set even of no microcode update has been uploaded, "iff" is > the only correct word. > > Regards, > Carl-Daniel > Meriam-Webster and wikipedia might know, but not everyone does. Why can't we just change it to "if and only if" instead of using an obscure word that looks like a typo? -Corey
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