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view test/torturethread.c @ 3899:081aecdb0911 SDL-1.2
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
author | Ryan C. Gordon <icculus@icculus.org> |
---|---|
date | Tue, 21 Nov 2006 23:17:00 +0000 |
parents | 290b5baf2fca |
children | 782fd950bd46 c121d94672cb |
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/* Simple test of the SDL threading code */ #include <stdio.h> #include <stdlib.h> #include <signal.h> #include <string.h> #include "SDL.h" #include "SDL_thread.h" #define NUMTHREADS 10 static char volatile time_for_threads_to_die[NUMTHREADS]; /* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */ static void quit(int rc) { SDL_Quit(); exit(rc); } int SDLCALL SubThreadFunc(void *data) { while(! *(int volatile *)data) { ; /*SDL_Delay(10);*/ /* do nothing */ } return 0; } int SDLCALL ThreadFunc(void *data) { SDL_Thread *sub_threads[NUMTHREADS]; int flags[NUMTHREADS]; int i; int tid = (int)(uintptr_t)data; fprintf(stderr, "Creating Thread %d\n", tid); for(i = 0; i < NUMTHREADS; i++) { flags[i] = 0; sub_threads[i] = SDL_CreateThread(SubThreadFunc, &flags[i]); } printf("Thread '%d' waiting for signal\n", tid); while(time_for_threads_to_die[tid] != 1) { ; /* do nothing */ } printf("Thread '%d' sending signals to subthreads\n", tid); for(i = 0; i < NUMTHREADS; i++) { flags[i] = 1; SDL_WaitThread(sub_threads[i], NULL); } printf("Thread '%d' exiting!\n", tid); return 0; } int main(int argc, char *argv[]) { SDL_Thread *threads[NUMTHREADS]; int i; /* Load the SDL library */ if ( SDL_Init(0) < 0 ) { fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError()); return(1); } signal(SIGSEGV, SIG_DFL); for(i = 0; i < NUMTHREADS; i++) { time_for_threads_to_die[i] = 0; threads[i] = SDL_CreateThread(ThreadFunc, (void *)(uintptr_t)i); if ( threads[i] == NULL ) { fprintf(stderr, "Couldn't create thread: %s\n", SDL_GetError()); quit(1); } } for(i = 0; i < NUMTHREADS; i++) { time_for_threads_to_die[i] = 1; } for(i = 0; i < NUMTHREADS; i++) { SDL_WaitThread(threads[i], NULL); } SDL_Quit(); return(0); }