From: Gabriel Gambetta To: SDL Mailing List <sdl@libsdl.org> Date: Fri, 17 Nov 2006 00:39:29 -0200 Subject: [SDL] Alpha blending bug - fixed? It turns out mm5 never got the correct value. This failed : [...] "movd %1, %%mm5\n\t" : : "m" (amask), "m" (sf->Ashift) ); mm5 got 0xFF000018 instead of 0x00000018. However I did this : Uint32 ashift = sf->Ashift; [...] "movd %1, %%mm5\n\t" : : "m" (amask), "m" (ashift) ); and everything worked fine. The only thing I could find out was that ashift is 32-bit aligned but sf->Ashift isn't: printf("ashift %8X [%d]\n", &ashift, (int)(&ashift) % 4); printf("sf->Ashift %8X [%d]\n", &sf->Ashift, (int)(&sf->Ashift) % 4); ashift at BFF0E0C4 [0] sf->Ashift at 08AFB9CD [1] Could this be the problem? If it is, the fix is extremely trivial. Should I submit a patch? --Gabriel

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

#include <stdio.h>
#include <stdlib.h>

#include "SDL.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);
	SDL_Quit();
	return(0);
}