view include/SDL_cpuinfo.h @ 1544:ab1e4c41ab71

Fixed bug #33 Mike Frysinger wrote: > with libsdl-1.2.9, some games (like bomberclone) started > segfaulting in Gentoo [...snip...] > the last change in the last hunk: [...snip...] > if i change the statement to read: > (table[which].blit_features & GetBlitFeatures()) == GetBlitFeatures() > bomberclone no longer segfaults on my box Alex Volkov wrote: > The test "(table[which].blit_features & GetBlitFeatures()) == > table[which].blit_features)" is correct, and the previous > "(table[which].cpu_mmx == SDL_HasMMX())" was actually broken. I think there is potentially a slightly different cause of the above problem. During the introduction of the Altivec code, the blit_table struct field 'alpha' got changed from a straightforward enum to a bitmask, which makes perfect sense by itself. However, now the table driven blitter selection code in SDL_CalculateBlitN() can choose the wrong blitters when searching for a NO_ALPHA blitter because of the following code: int a_need = 0; ... (a_need & table[which].alpha) == a_need && When searching through the normal_blit_2[] table, a SET_ALPHA blitter (like Blit_RGB565_ARGB8888) can now be selected instead of a NO_ALPHA one, causing alpha channel bits to appear in a non-alpha destination surface. I suppose this could theoretically be an indirect cause of the segfault mentioned above. I *think* this can be fixed by changing to int a_need = NO_ALPHA;
author Sam Lantinga <slouken@libsdl.org>
date Wed, 15 Mar 2006 15:47:49 +0000
parents ef9a9064bff2
children 782fd950bd46 c121d94672cb a1b03ba2fcd0
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* CPU feature detection for SDL                                       */

#ifndef _SDL_cpuinfo_h
#define _SDL_cpuinfo_h

#include "SDL_stdinc.h"

#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif

/* This function returns true if the CPU has the RDTSC instruction
 */
extern DECLSPEC SDL_bool SDLCALL SDL_HasRDTSC(void);

/* This function returns true if the CPU has MMX features
 */
extern DECLSPEC SDL_bool SDLCALL SDL_HasMMX(void);

/* This function returns true if the CPU has MMX Ext. features
 */
extern DECLSPEC SDL_bool SDLCALL SDL_HasMMXExt(void);

/* This function returns true if the CPU has 3DNow features
 */
extern DECLSPEC SDL_bool SDLCALL SDL_Has3DNow(void);

/* This function returns true if the CPU has 3DNow! Ext. features
 */
extern DECLSPEC SDL_bool SDLCALL SDL_Has3DNowExt(void);

/* This function returns true if the CPU has SSE features
 */
extern DECLSPEC SDL_bool SDLCALL SDL_HasSSE(void);

/* This function returns true if the CPU has SSE2 features
 */
extern DECLSPEC SDL_bool SDLCALL SDL_HasSSE2(void);

/* This function returns true if the CPU has AltiVec features
 */
extern DECLSPEC SDL_bool SDLCALL SDL_HasAltiVec(void);

/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include "close_code.h"

#endif /* _SDL_cpuinfo_h */