arch/v850/lib/memset.c

   1 /*
   2  * arch/v850/lib/memset.c -- Memory initialization
   3  *
   4  *  Copyright (C) 2001,02,04  NEC Corporation
   5  *  Copyright (C) 2001,02,04  Miles Bader <miles@gnu.org>
   6  *
   7  * This file is subject to the terms and conditions of the GNU General
   8  * Public License.  See the file COPYING in the main directory of this
   9  * archive for more details.
  10  *
  11  * Written by Miles Bader <miles@gnu.org>
  12  */
  13
  14 #include <linux/types.h>
  15
  16 void *memset (void *dst, int val, __kernel_size_t count)
  17 {
  18         if (count) {
  19                 register unsigned loop;
  20                 register void *ptr asm ("ep") = dst;
  21
  22                 /* replicate VAL into a long.  */
  23                 val &= 0xff;
  24                 val |= val << 8;
  25                 val |= val << 16;
  26
  27                 /* copy initial unaligned bytes.  */
  28                 if ((long)ptr & 1) {
  29                         *(char *)ptr = val;
  30                         ptr = (void *)((char *)ptr + 1);
  31                         count--;
  32                 }
  33                 if (count > 2 && ((long)ptr & 2)) {
  34                         *(short *)ptr = val;
  35                         ptr = (void *)((short *)ptr + 1);
  36                         count -= 2;
  37                 }
  38
  39                 /* 32-byte copying loop.  */
  40                 for (loop = count / 32; loop; loop--) {
  41                         asm ("sst.w %0, 0[ep]; sst.w %0, 4[ep];"
  42                              "sst.w %0, 8[ep]; sst.w %0, 12[ep];"
  43                              "sst.w %0, 16[ep]; sst.w %0, 20[ep];"
  44                              "sst.w %0, 24[ep]; sst.w %0, 28[ep]"
  45                              :: "r" (val) : "memory");
  46                         ptr += 32;
  47                 }
  48                 count %= 32;
  49
  50                 /* long copying loop.  */
  51                 for (loop = count / 4; loop; loop--) {
  52                         *(long *)ptr = val;
  53                         ptr = (void *)((long *)ptr + 1);
  54                 }
  55                 count %= 4;
  56
  57                 /* finish up with any trailing bytes.  */
  58                 if (count & 2) {
  59                         *(short *)ptr = val;
  60                         ptr = (void *)((short *)ptr + 1);
  61                 }
  62                 if (count & 1) {
  63                         *(char *)ptr = val;
  64                 }
  65         }
  66
  67         return dst;
  68 }