libfbx-memmove.c

libfxb是linux下只写操作framebuffer的一个轻量级的库。

/*
 * libfbx-memmove.c -- Intel Compatible ASM Optimizations
 * (C)opyright 2000-2001 U4X Labs
 *
 * Updated by: Michael Bourgeous <[e-mail]>
 *             Paul Mundt        <[e-mail]>
 *	       Sat Oct 14 15:13:22 MDT 2000
 *
 *  $Id: libfbx-memmove.c,v 1.4 2001/01/01 08:46:17 lethal Exp $
 *
 *      Architecture Optimized Routines for i386, i486,
 *  i586, MMX, 3DNow, and compatible processors.
 * 
 *  See ChangeLog for modifications, CREDITS for credits.
 *
 *  All source herein is copyright U4X Labs and its original author.
 *  Any code modifications or additions are (C)opyright the original
 *  author and U4X Labs respectively.
 *
 *  libfbx 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.
 *
 *  libfbx 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 libfbx; if not, write to the Free Software 
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 *  USA
 */
#include <stdio.h>
#include <linux/types.h>
#include <string.h>

#if defined(__i386__)

static inline void *fb_arch_memmove(void *d, const void *s, size_t count)
{
	int d0, d1, d2, d3;
	
	if (d < s) {
		__asm__ __volatile__ (
			"cld\n\t"
			"shrl $1,%%ecx\n\t"
			"jnc 1f\n\t"
			"movsb\n"
			"1:\tshrl $1,%%ecx\n\t"
			"jnc 2f\n\t"
			"movsw\n"
			"2:\trep\n\t"
			"movsl"
			: "=&c" (d0), "=&D" (d1), "=&S" (d2)
			:"0"(count),"1"((long)d),"2"((long)s)
			:"memory"
		);
	} else {
		__asm__ __volatile__ (
			"std\n\t"
			"shrl $1,%%ecx\n\t"
			"jnc 1f\n\t"
			"movb 3(%%esi),%%al\n\t"
			"movb %%al,3(%%edi)\n\t"
			"decl %%esi\n\t"
			"decl %%edi\n"
			"1:\tshrl $1,%%ecx\n\t"
			"jnc 2f\n\t"
			"movw 2(%%esi),%%ax\n\t"
			"movw %%ax,2(%%edi)\n\t"
			"decl %%esi\n\t"
			"decl %%edi\n\t"
			"decl %%esi\n\t"
			"decl %%edi\n"
			"2:\trep\n\t"
			"movsl\n\t"
			"cld"
			: "=&c" (d0), "=&D" (d1), "=&S" (d2), "=&a" (d3)
			:"0"(count),"1"(count-4+(long)d),"2"(count-4+(long)s)
			:"memory"
		);
	}

	return d;
}
#else
static inline void *fb_arch_memmove(void *d, const void *s, size_t count)
{
	return memmove(d, s, count);
}
#endif /* __i386__ */

inline void *fb_memmove(void *d, const void *s, size_t count)
{
	return fb_arch_memmove(d, s, count);
}