sysdeps/generic/memset.c

   1 /* Copyright (C) 1991 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <string.h>
  21 #include <memcopy.h>
  22
  23 PTR
  24 DEFUN(memset, (dstpp, c, len), PTR dstpp AND int c AND size_t len)
  25 {
  26   long int dstp = (long int) dstpp;
  27
  28   if (len >= 8)
  29     {
  30       size_t xlen;
  31       op_t cccc;
  32
  33       cccc = (unsigned char) c;
  34       cccc |= cccc << 8;
  35       cccc |= cccc << 16;
  36       if (OPSIZ > 4)
  37         cccc |= cccc << 32;
  38
  39       /* There are at least some bytes to set.
  40          No need to test for LEN == 0 in this alignment loop.  */
  41       while (dstp % OPSIZ != 0)
  42         {
  43           ((byte *) dstp)[0] = c;
  44           dstp += 1;
  45           len -= 1;
  46         }
  47
  48       /* Write 8 `op_t' per iteration until less than 8 `op_t' remain.  */
  49       xlen = len / (OPSIZ * 8);
  50       while (xlen > 0)
  51         {
  52           ((op_t *) dstp)[0] = cccc;
  53           ((op_t *) dstp)[1] = cccc;
  54           ((op_t *) dstp)[2] = cccc;
  55           ((op_t *) dstp)[3] = cccc;
  56           ((op_t *) dstp)[4] = cccc;
  57           ((op_t *) dstp)[5] = cccc;
  58           ((op_t *) dstp)[6] = cccc;
  59           ((op_t *) dstp)[7] = cccc;
  60           dstp += 8 * OPSIZ;
  61           xlen -= 1;
  62         }
  63       len %= OPSIZ * 8;
  64
  65       /* Write 1 `op_t' per iteration until less than OPSIZ bytes remain.  */
  66       xlen = len / OPSIZ;
  67       while (xlen > 0)
  68         {
  69           ((op_t *) dstp)[0] = cccc;
  70           dstp += OPSIZ;
  71           xlen -= 1;
  72         }
  73       len %= OPSIZ;
  74     }
  75
  76   /* Write the last few bytes.  */
  77   while (len > 0)
  78     {
  79       ((byte *) dstp)[0] = c;
  80       dstp += 1;
  81       len -= 1;
  82     }
  83
  84   return dstpp;
  85 }