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memset.c

/*
 * arch/v850/lib/memset.c -- Memory initialization
 *
 *  Copyright (C) 2001,02,04  NEC Corporation
 *  Copyright (C) 2001,02,04  Miles Bader <miles@gnu.org>
 *
 * 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.
 *
 * Written by Miles Bader <miles@gnu.org>
 */

#include <linux/types.h>

void *memset (void *dst, int val, __kernel_size_t count)
{
      if (count) {
            register unsigned loop;
            register void *ptr asm ("ep") = dst;

            /* replicate VAL into a long.  */
            val &= 0xff;
            val |= val << 8;
            val |= val << 16;

            /* copy initial unaligned bytes.  */
            if ((long)ptr & 1) {
                  *(char *)ptr = val;
                  ptr = (void *)((char *)ptr + 1);
                  count--;
            }
            if (count > 2 && ((long)ptr & 2)) {
                  *(short *)ptr = val;
                  ptr = (void *)((short *)ptr + 1);
                  count -= 2;
            }

            /* 32-byte copying loop.  */
            for (loop = count / 32; loop; loop--) {
                  asm ("sst.w %0, 0[ep]; sst.w %0, 4[ep];"
                       "sst.w %0, 8[ep]; sst.w %0, 12[ep];"
                       "sst.w %0, 16[ep]; sst.w %0, 20[ep];"
                       "sst.w %0, 24[ep]; sst.w %0, 28[ep]"
                       :: "r" (val) : "memory");
                  ptr += 32;
            }
            count %= 32;

            /* long copying loop.  */
            for (loop = count / 4; loop; loop--) {
                  *(long *)ptr = val;
                  ptr = (void *)((long *)ptr + 1);
            }
            count %= 4;

            /* finish up with any trailing bytes.  */
            if (count & 2) {
                  *(short *)ptr = val;
                  ptr = (void *)((short *)ptr + 1);
            }
            if (count & 1) {
                  *(char *)ptr = val;
            }
      }

      return dst;
}

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