Re: questions about rd{msr|tsc|pmc} instruction with x86-64

Jike Song
2008-10-16T16:31:30Z

On Thu, Oct 16, 2008 at 2:39 PM, H. Peter Anvin <hpa@zytor.com> wrote:
> Jike Song wrote:
>> {snip}
>
> "A" means rdx:rax on x86-64, not edx:eax. For a 64-bit number, it means,
> literally, "one of rdx or rax"! As you correctly point out, this is not how
> rdmsr works.
>
> -hpa
>

Thanks, Peter! So I misunderstood the gcc constraint 'A' for x86-64,
but seems the comment "while x86_64 returns at rax" still wrong,
should this be fixed?

--
Thanks,
Jike