Question about printcpuinfo in sys/amd64/amd64/indentcpu.c

John Baldwin jhb at freebsd.org
Mon Aug 23 12:40:28 UTC 2010


On Friday, August 20, 2010 10:14:46 am Garrett Cooper wrote:
> Hi,
>     Currently the code in identcpu.c does a check for a specific cpu
> value extension. This is set to 0x80000004 (even though the
> corresponding code below iterates through 0x80000002:0x80000005):

It does not invoke 0x80000005 (<, not <=, is used as the loop terminator).

>         /* Check for extended CPUID information and a processor name. */
>         if (cpu_exthigh >= 0x80000004) {
>                 brand = cpu_brand;
>                 for (i = 0x80000002; i < 0x80000005; i++) {
>                         do_cpuid(i, regs);
>                         memcpy(brand, regs, sizeof(regs));
>                         brand += sizeof(regs);
>                 }
>         }

-- 
John Baldwin


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