Re: [PATCH 5/6] include: Add __rdtsc and __rdtscp intrinsics.

[Jacek Caban]

Hi Rémi,

On 10.03.2021 12:22, Rémi Bernon wrote:
> Signed-off-by: Rémi Bernon
>
> include/msvcrt/intrin.h | 30 ++++++++++++++++++++++++++++++
>   1 file changed, 30 insertions(+)
>
> diff --git a/include/msvcrt/intrin.h b/include/msvcrt/intrin.h
> index 781c6fac823..061866fe63b 100644
> --- a/include/msvcrt/intrin.h
> +++ b/include/msvcrt/intrin.h
> @@ -20,6 +20,36 @@ static inline void __cpuid(int info[4], int ax)
>   {
>       return __cpuidex(info, ax, 0);
>   }
> -
>
> +#ifdef __i386
> +static inline unsigned __int64 __rdtsc(void)
> +{
> - unsigned __int64 a;
> - __asm__ ("rdtsc" : "=A" (a));
> - return a;
>
> +}
> -
>
> +static inline unsigned __int64 __rdtscp(unsigned int *aux)
> +{
> - unsigned __int64 a;
> - __asm__ ("rdtscp" : "=A" (a), "=c" (*aux));
> - return a;
>
> +}
> +#elif defined __amd64
> +static inline unsigned __int64 __rdtsc(void)
> +{
> - unsigned __int64 a, d;
> - __asm__ ("rdtsc" : "=a" (a), "=d" (d));
> - return (d << 32) | a;
>
> +}
> -
>
> +static inline unsigned __int64 __rdtscp(unsigned int *aux)
> +{
> - unsigned __int64 a, d;
> - __asm__ ("rdtscp" : "=a" (a), "=d" (d), "=c" (*aux));
> - return (d << 32) | a;
>
> +}
> +#endif
>   #endif

I think you meant __i386__ and __x86_64__ for guards. If guards were 
right, you'd get a redefinition because __rdtsc is a compiler builtin. 
It seems to me that all we need for __rdtsc is to provide MSVC-style 
declaration in winnt.h, like it's done in WinSDK.

Thanks,

Jacek