view src/video/SDL_memops.h @ 1122:e253d5448fce

From Patrice Mandin: "Just a request about test subdirectory: the autotools files (config.guess, config.sub, etc...) are a bit outdated, and I have to update them for my cross-compilation party. So it would be nice to have these updated. ... Just removing these files works, because then configure will use those of SDL's topdir. Could someone else check this, just to be sure? i.e. remove config.guess, config.sub, install-sh and mkinstalldirs from test subdir." I tested on Linux and MacOSX...seems to be safe, so I'm nuking the files. --ryan.
author Ryan C. Gordon <icculus@icculus.org>
date Sat, 20 Aug 2005 21:39:06 +0000
parents b8d311d90021
children c9b51268668f
line wrap: on
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    slouken@libsdl.org
*/

#ifdef SAVE_RCSID
static char rcsid =
 "@(#) $Id$";
#endif

#ifndef _SDL_memops_h
#define _SDL_memops_h

/* System dependent optimized memory manipulation routines:
*/
#include <string.h>

#if defined(__GNUC__) && defined(i386)
/* Thanks to Brennan "Bas" Underwood, for the inspiration. :)
 */
#define SDL_memcpy(dst, src, len)					  \
do {									  \
	int u0, u1, u2;						  \
	__asm__ __volatile__ (						  \
		"cld\n\t"						  \
		"rep ; movsl\n\t"					  \
		"testb $2,%b4\n\t"					  \
		"je 1f\n\t"						  \
		"movsw\n"						  \
		"1:\ttestb $1,%b4\n\t"					  \
		"je 2f\n\t"						  \
		"movsb\n"						  \
		"2:"							  \
		: "=&c" (u0), "=&D" (u1), "=&S" (u2)			  \
		: "0" ((unsigned)(len)/4), "q" (len), "1" (dst),"2" (src) \
		: "memory" );						  \
} while(0)

#define SDL_memcpy4(dst, src, len)				\
do {								\
	int ecx, edi, esi;					\
	__asm__ __volatile__ (					\
		"cld\n\t"					\
		"rep ; movsl"					\
		: "=&c" (ecx), "=&D" (edi), "=&S" (esi)		\
		: "0" ((unsigned)(len)), "1" (dst), "2" (src)	\
		: "memory" );					\
} while(0)

#define SDL_revcpy(dst, src, len)			\
do {							\
	int u0, u1, u2;					\
	char *dstp = (char *)(dst);			\
	char *srcp = (char *)(src);			\
	int n = (len);					\
	if ( n >= 4 ) {					\
	__asm__ __volatile__ (				\
		"std\n\t"				\
		"rep ; movsl\n\t"			\
		: "=&c" (u0), "=&D" (u1), "=&S" (u2)	\
		: "0" (n >> 2),				\
		  "1" (dstp+(n-4)), "2" (srcp+(n-4))	\
		: "memory" );				\
	}						\
	switch (n & 3) {				\
		case 3: dstp[2] = srcp[2];		\
		case 2: dstp[1] = srcp[1];		\
		case 1: dstp[0] = srcp[0];		\
			break;				\
		default:				\
			break;				\
	}						\
} while(0)

#define SDL_memmove(dst, src, len)			\
do {							\
	if ( (dst) < (src) ) {				\
		SDL_memcpy((dst), (src), (len));	\
	} else {					\
		SDL_revcpy((dst), (src), (len));	\
	}						\
} while(0)

#define SDL_memset4(dst, val, len)				\
do {								\
	int u0, u1, u2;					\
	__asm__ __volatile__ (					\
		"cld\n\t"					\
		"rep ; stosl\n\t"				\
		: "=&D" (u0), "=&a" (u1), "=&c" (u2)		\
		: "0" (dst), "1" (val), "2" ((Uint32)(len))	\
		: "memory" );					\
} while(0)

#endif /* GNU C and x86 */

/* If there are no optimized versions, define the normal versions */
#ifndef SDL_memcpy
#define SDL_memcpy(dst, src, len)	memcpy(dst, src, len)
#endif

#ifndef SDL_memcpy4
#define SDL_memcpy4(dst, src, len)	memcpy(dst, src, (len) << 2)
#endif

#ifndef SDL_revcpy
#define SDL_revcpy(dst, src, len)	memmove(dst, src, len)
#endif

#ifndef SDL_memset4
#define SDL_memset4(dst, val, len)		\
do {						\
	unsigned _count = (len);		\
	unsigned _n = (_count + 3) / 4;		\
	Uint32 *_p = (Uint32 *)(dst);		\
	Uint32 _val = (val);			\
        switch (_count % 4) {			\
        case 0: do {    *_p++ = _val;		\
        case 3:         *_p++ = _val;		\
        case 2:         *_p++ = _val;		\
        case 1:         *_p++ = _val;		\
		} while ( --_n );		\
	}					\
} while(0)
#endif

#endif /* _SDL_memops_h */