memset.c

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/*
 * 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);