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 -- http://www.hailfinger.org/ -- coreboot mailing list [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
