Re: [PATCH 4/4] msvcrt: Add an SSE2 memset_aligned_32 implementation.

[Piotr Caban]

Hi Rémi,

I think you're undervaluing the SSE2 codepath. While erms was introduced 
on Intel CPU's quite long ago it's a fairly new thing on AMD CPU's (as 
far as I understand the first AMD CPU to set the cpuid flag was released 
in mid 2019).

On 9/13/21 2:23 PM, Rémi Bernon wrote:
> +#ifdef __i386__
> - if (n < 2048 && sse2_supported)

if ((n < 2048 && sse2_supported) || !erms_supported)
> +#else
> - if (n < 2048)

if (n < 2048 || !erms_supported)
> +#endif
> - {
> -
>    __asm__ __volatile__ (
> -
>        "movd %1, %%xmm0\n\t"
> -
>        "pshufd $0, %%xmm0, %%xmm0\n\t"
> -
>        "test $0x20, %2\n\t"
> -
>        "je 1f\n\t"
> -
>        "sub $0x20, %2\n\t"
> -
>        "movdqa %%xmm0, 0x00(%0,%2)\n\t"
> -
>        "movdqa %%xmm0, 0x10(%0,%2)\n\t"
> -
>        "je 2f\n\t"
> -
>        "1:\n\t"
> -
>        "sub $0x40, %2\n\t"
> -
>        "movdqa %%xmm0, 0x00(%0,%2)\n\t"
> -
>        "movdqa %%xmm0, 0x10(%0,%2)\n\t"
> -
>        "movdqa %%xmm0, 0x20(%0,%2)\n\t"
> -
>        "movdqa %%xmm0, 0x30(%0,%2)\n\t"
> -
>        "ja 1b\n\t"
> -
>        "2:\n\t"
> -
>        :
> -
>        : "r"(d), "r"((uint32_t)v), "c"(n)
> -
>        : "memory"
> -
>    );

Shouldn't xmm0 be added to clobbered registers list?

Thanks,
Piotr