1. 根目录:
2. arch
3. m68k
4. lib
5. memset.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

#include <linux/module.h>
#include <linux/string.h>

void *memset(void *s, int c, size_t count)
{
	void *xs = s;
	size_t temp;

	if (!count)
		return xs;
	c &= 0xff;
	c |= c << 8;
	c |= c << 16;
	if ((long)s & 1) {
		char *cs = s;
		*cs++ = c;
		s = cs;
		count--;
	}
	if (count > 2 && (long)s & 2) {
		short *ss = s;
		*ss++ = c;
		s = ss;
		count -= 2;
	}
	temp = count >> 2;
	if (temp) {
		long *ls = s;
#if defined(CONFIG_M68000) || defined(CONFIG_COLDFIRE)
		for (; temp; temp--)
			*ls++ = c;
#else
		size_t temp1;
		asm volatile (
			"	movel %1,%2\n"
			"	andw  #7,%2\n"
			"	lsrl  #3,%1\n"
			"	negw  %2\n"
			"	jmp   %%pc@(2f,%2:w:2)\n"
			"1:	movel %3,%0@+\n"
			"	movel %3,%0@+\n"
			"	movel %3,%0@+\n"
			"	movel %3,%0@+\n"
			"	movel %3,%0@+\n"
			"	movel %3,%0@+\n"
			"	movel %3,%0@+\n"
			"	movel %3,%0@+\n"
			"2:	dbra  %1,1b\n"
			"	clrw  %1\n"
			"	subql #1,%1\n"
			"	jpl   1b"
			: "=a" (ls), "=d" (temp), "=&d" (temp1)
			: "d" (c), "0" (ls), "1" (temp));
#endif
		s = ls;
	}
	if (count & 2) {
		short *ss = s;
		*ss++ = c;
		s = ss;
	}
	if (count & 1) {
		char *cs = s;
		*cs = c;
	}
	return xs;
}
EXPORT_SYMBOL(memset);