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SDL_memops.h
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/
SDL_memops.h
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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
*/
#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 */