Date: Tue, 19 Aug 2003 17:57:00 +0200 From: Stephane Marchesin Subject: Re: [SDL] [patch] MMX alpha blit patches with MMX detection I think everything is correct now. I've done as much testing as I could, but some real-world testing wouldn't hurt, I think. The patch is here : http://icps.u-strasbg.fr/~marchesin/sdl_mmxblit.patch If you do byte-by-byte comparison of the output between C and MMX functions, you'll notice that the results for 555 and 565 RGB alpha blits aren't exactly the same. This is because MMX functions for 555 and 565 RGB have an higher accuracy. If you want the exact same behaviour that's possible by masking the three lower alpha bits in the MMX functions. Just ask ! I removed one MMX function because after I fixed it to match its C equivalent, it revealed to be slower than the C version on a PIII (although a bit faster on an Athlon XP). I've also added MMX and PIII replacements for SDL_memcpy. Those provide some speed up in testvidinfo -benchmark (at least for me, under linux & X11).

/* Test program to compare the compile-time version of SDL with the linked
   version of SDL
*/

#include <stdio.h>

#include "SDL.h"
#include "SDL_byteorder.h"

int main(int argc, char *argv[])
{
	SDL_version compiled;

	/* Initialize SDL */
	if ( SDL_Init(0) < 0 ) {
		fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
		exit(1);
	}
#ifdef DEBUG
	fprintf(stderr, "SDL initialized\n");
#endif
#if SDL_VERSION_ATLEAST(1, 2, 0)
	printf("Compiled with SDL 1.2 or newer\n");
#else
	printf("Compiled with SDL older than 1.2\n");
#endif
	SDL_VERSION(&compiled);
	printf("Compiled version: %d.%d.%d\n",
			compiled.major, compiled.minor, compiled.patch);
	printf("Linked version: %d.%d.%d\n",
			SDL_Linked_Version()->major,
			SDL_Linked_Version()->minor,
			SDL_Linked_Version()->patch);
	printf("This is a %s endian machine.\n",
		(SDL_BYTEORDER == SDL_LIL_ENDIAN) ? "little" : "big");
	SDL_Quit();
	return(0);
}