diff src/video/SDL_memops.h @ 0:74212992fb08

Initial revision
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:45:43 +0000
parents
children cf2af46e9e2a
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/video/SDL_memops.h	Thu Apr 26 16:45:43 2001 +0000
@@ -0,0 +1,127 @@
+/*
+    SDL - Simple DirectMedia Layer
+    Copyright (C) 1997, 1998, 1999, 2000, 2001  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@devolution.com
+*/
+
+#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_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_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 */