[Mplayer-cvslog] CVS: main/postproc swscale.c,1.21,1.22 swscale.h,1.1,1.2

[Michael Niedermayer]

Hi

On Sunday 28 October 2001 20:08, Nick Kurshev wrote:
> Hello, Michael!
...
> [snip]
>
> I've study your stuff. Let me some minor warnings:
> 1. Why you don't use SFENCE?
oops
> 2. Why you ignore 3DNOW optimization?
do i?!
>
> I want suggest you to make some changes:
>
> 1.
> #include "../mmx_defs.h"
ok

>
> 2.
> It would be more readable to have:
> -			MOVNTQ(%%mm0, (%4, %%eax, 4))\
> -			MOVNTQ(%%mm2, 8(%4, %%eax, 4))\
> -			MOVNTQ(%%mm1, 16(%4, %%eax, 4))\
> -			MOVNTQ(%%mm3, 24(%4, %%eax, 4))\
> +			MOVNTQ" %%mm0, (%4, %%eax, 4)\n\t"\
> +			MOVNTQ" %%mm2, 8(%4, %%eax, 4)\n\t"\
> +			MOVNTQ" %%mm1, 16(%4, %%eax, 4)\n\t"\
> +			MOVNTQ" %%mm3, 24(%4, %%eax, 4)\n\t"\
> (Althrough it's looks like cosmetic)
i dont see why this would be better

> 3.
> -#ifdef HAVE_MMX2
> -#define FUNNY_Y_CODE \
> -			"prefetchnta 1024(%%esi)	\n\t"\
> -			"prefetchnta 1056(%%esi)	\n\t"\
> -			"prefetchnta 1088(%%esi)	\n\t"\
> -			"call funnyYCode		\n\t"\
> -			"movq temp0, %%mm2		\n\t"\
> -			"xorl %%ecx, %%ecx		\n\t"
> -#else
>  #define FUNNY_Y_CODE \
> +			PREFETCH" 1024(%%esi)	\n\t"\
> +			PREFETCH" 1056(%%esi)	\n\t"\
> +			PREFETCH" 1088(%%esi)	\n\t"\
>  			"call funnyYCode		\n\t"\
>  			"movq temp0, %%mm2		\n\t"\
>  			"xorl %%ecx, %%ecx		\n\t"
> -#endif
ok

>
> 4.
> -#ifdef HAVE_3DNOW
> -	asm volatile("femms");
> -#elif defined (HAVE_MMX)
> -	asm volatile("emms");
> -#endif
> +	__asm __volatile(SFENCE:::"memory");
> +	__asm __volatile(EMMS:::"memory");
ok

>
> 5. before every C loop:
> +		__asm __volatile(SFENCE:::"memory");
>  #else
>  //FIXME unroll C loop and dont recalculate UV
>  		if(dstbpp==32 || dstbpp==24)
not ok, because it might slow things down, and i never touch data after 
movntq so i doubt it would have any effect

Michael